[syserror] Split usermem package

Split usermem package to help remove syserror dependency in go_marshal.
New hostarch package contains code not dependent on syserror.

PiperOrigin-RevId: 365651233

45 files changed, 179 insertions, 148 deletions

diff --git a/pkg/sentry/fs/BUILD b/pkg/sentry/fs/BUILD
index 420fbae34..0dc100f9b 100644
--- a/pkg/sentry/fs/BUILD
+++ b/pkg/sentry/fs/BUILD
@@ -48,6 +48,7 @@ go_library(
         "//pkg/abi/linux",
         "//pkg/amutex",
         "//pkg/context",
+        "//pkg/hostarch",
         "//pkg/log",
         "//pkg/p9",
         "//pkg/refs",
diff --git a/pkg/sentry/fs/anon/BUILD b/pkg/sentry/fs/anon/BUILD
index aedcecfa1..1ce56d79f 100644
--- a/pkg/sentry/fs/anon/BUILD
+++ b/pkg/sentry/fs/anon/BUILD
@@ -12,9 +12,9 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/hostarch",
         "//pkg/sentry/device",
         "//pkg/sentry/fs",
         "//pkg/sentry/fs/fsutil",
-        "//pkg/usermem",
     ],
 )
diff --git a/pkg/sentry/fs/anon/anon.go b/pkg/sentry/fs/anon/anon.go
index 5c421f5fb..8bda22a8e 100644
--- a/pkg/sentry/fs/anon/anon.go
+++ b/pkg/sentry/fs/anon/anon.go
@@ -19,9 +19,9 @@ package anon
 import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // NewInode constructs an anonymous Inode that is not associated
@@ -37,6 +37,6 @@ func NewInode(ctx context.Context) *fs.Inode {
 		Type:      fs.Anonymous,
 		DeviceID:  PseudoDevice.DeviceID(),
 		InodeID:   PseudoDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 	})
 }
diff --git a/pkg/sentry/fs/copy_up.go b/pkg/sentry/fs/copy_up.go
index 58deb25fc..5aa668873 100644
--- a/pkg/sentry/fs/copy_up.go
+++ b/pkg/sentry/fs/copy_up.go
@@ -20,6 +20,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sync"
@@ -339,7 +340,7 @@ func cleanupUpper(ctx context.Context, parent *Inode, name string, copyUpErr err
 // size is the same used by io.Copy.
 var copyUpBuffers = sync.Pool{
 	New: func() interface{} {
-		b := make([]byte, 8*usermem.PageSize)
+		b := make([]byte, 8*hostarch.PageSize)
 		return &b
 	},
 }
diff --git a/pkg/sentry/fs/dev/BUILD b/pkg/sentry/fs/dev/BUILD
index 9379a4d7b..23a3a9a2d 100644
--- a/pkg/sentry/fs/dev/BUILD
+++ b/pkg/sentry/fs/dev/BUILD
@@ -18,6 +18,7 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/hostarch",
         "//pkg/rand",
         "//pkg/safemem",
         "//pkg/sentry/arch",
diff --git a/pkg/sentry/fs/dev/dev.go b/pkg/sentry/fs/dev/dev.go
index acbd401a0..e84ba7a5d 100644
--- a/pkg/sentry/fs/dev/dev.go
+++ b/pkg/sentry/fs/dev/dev.go
@@ -19,6 +19,7 @@ import (
 	"math"
 
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/ramfs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/tmpfs"
@@ -49,7 +50,7 @@ func newCharacterDevice(ctx context.Context, iops fs.InodeOperations, msrc *fs.M
 	return fs.NewInode(ctx, iops, msrc, fs.StableAttr{
 		DeviceID:        devDevice.DeviceID(),
 		InodeID:         devDevice.NextIno(),
-		BlockSize:       usermem.PageSize,
+		BlockSize:       hostarch.PageSize,
 		Type:            fs.CharacterDevice,
 		DeviceFileMajor: major,
 		DeviceFileMinor: minor,
@@ -60,7 +61,7 @@ func newMemDevice(ctx context.Context, iops fs.InodeOperations, msrc *fs.MountSo
 	return fs.NewInode(ctx, iops, msrc, fs.StableAttr{
 		DeviceID:        devDevice.DeviceID(),
 		InodeID:         devDevice.NextIno(),
-		BlockSize:       usermem.PageSize,
+		BlockSize:       hostarch.PageSize,
 		Type:            fs.CharacterDevice,
 		DeviceFileMajor: memDevMajor,
 		DeviceFileMinor: minor,
@@ -72,7 +73,7 @@ func newDirectory(ctx context.Context, contents map[string]*fs.Inode, msrc *fs.M
 	return fs.NewInode(ctx, iops, msrc, fs.StableAttr{
 		DeviceID:  devDevice.DeviceID(),
 		InodeID:   devDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.Directory,
 	})
 }
@@ -82,7 +83,7 @@ func newSymlink(ctx context.Context, target string, msrc *fs.MountSource) *fs.In
 	return fs.NewInode(ctx, iops, msrc, fs.StableAttr{
 		DeviceID:  devDevice.DeviceID(),
 		InodeID:   devDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.Symlink,
 	})
 }
@@ -137,7 +138,7 @@ func New(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
 	return fs.NewInode(ctx, iops, msrc, fs.StableAttr{
 		DeviceID:  devDevice.DeviceID(),
 		InodeID:   devDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.Directory,
 	})
 }
diff --git a/pkg/sentry/fs/dev/net_tun.go b/pkg/sentry/fs/dev/net_tun.go
index 11a2984d8..77e8d222a 100644
--- a/pkg/sentry/fs/dev/net_tun.go
+++ b/pkg/sentry/fs/dev/net_tun.go
@@ -17,6 +17,7 @@ package dev
 import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
@@ -110,7 +111,7 @@ func (n *netTunFileOperations) Ioctl(ctx context.Context, file *fs.File, io user
 		}
 
 		// Validate flags.
-		flags, err := netstack.LinuxToTUNFlags(usermem.ByteOrder.Uint16(req.Data[:]))
+		flags, err := netstack.LinuxToTUNFlags(hostarch.ByteOrder.Uint16(req.Data[:]))
 		if err != nil {
 			return 0, err
 		}
@@ -119,7 +120,7 @@ func (n *netTunFileOperations) Ioctl(ctx context.Context, file *fs.File, io user
 	case linux.TUNGETIFF:
 		var req linux.IFReq
 		copy(req.IFName[:], n.device.Name())
-		usermem.ByteOrder.PutUint16(req.Data[:], netstack.TUNFlagsToLinux(n.device.Flags()))
+		hostarch.ByteOrder.PutUint16(req.Data[:], netstack.TUNFlagsToLinux(n.device.Flags()))
 		_, err := req.CopyOut(t, data)
 		return 0, err
 
diff --git a/pkg/sentry/fs/fdpipe/BUILD b/pkg/sentry/fs/fdpipe/BUILD
index c83baf464..2120f2bad 100644
--- a/pkg/sentry/fs/fdpipe/BUILD
+++ b/pkg/sentry/fs/fdpipe/BUILD
@@ -40,6 +40,7 @@ go_test(
         "//pkg/context",
         "//pkg/fd",
         "//pkg/fdnotifier",
+        "//pkg/hostarch",
         "//pkg/sentry/contexttest",
         "//pkg/sentry/fs",
         "//pkg/syserror",
diff --git a/pkg/sentry/fs/fdpipe/pipe_test.go b/pkg/sentry/fs/fdpipe/pipe_test.go
index faeb3908c..ab0e9dac7 100644
--- a/pkg/sentry/fs/fdpipe/pipe_test.go
+++ b/pkg/sentry/fs/fdpipe/pipe_test.go
@@ -27,6 +27,8 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/usermem"
+
+	"gvisor.dev/gvisor/pkg/hostarch"
 )
 
 func singlePipeFD() (int, error) {
@@ -52,7 +54,7 @@ func mockPipeDirent(t *testing.T) *fs.Dirent {
 	}
 	inode := fs.NewInode(ctx, node, fs.NewMockMountSource(nil), fs.StableAttr{
 		Type:      fs.Pipe,
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 	})
 	return fs.NewDirent(ctx, inode, "")
 }
diff --git a/pkg/sentry/fs/fsutil/BUILD b/pkg/sentry/fs/fsutil/BUILD
index d388f0e92..6469cc3a9 100644
--- a/pkg/sentry/fs/fsutil/BUILD
+++ b/pkg/sentry/fs/fsutil/BUILD
@@ -76,6 +76,7 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/hostarch",
         "//pkg/log",
         "//pkg/safemem",
         "//pkg/sentry/arch",
@@ -105,6 +106,7 @@ go_test(
     library = ":fsutil",
     deps = [
         "//pkg/context",
+        "//pkg/hostarch",
         "//pkg/safemem",
         "//pkg/sentry/contexttest",
         "//pkg/sentry/fs",
diff --git a/pkg/sentry/fs/fsutil/dirty_set.go b/pkg/sentry/fs/fsutil/dirty_set.go
index 2c9446c1d..38383e730 100644
--- a/pkg/sentry/fs/fsutil/dirty_set.go
+++ b/pkg/sentry/fs/fsutil/dirty_set.go
@@ -18,9 +18,9 @@ import (
 	"math"
 
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // DirtySet maps offsets into a memmap.Mappable to DirtyInfo. It is used to
@@ -215,7 +215,7 @@ func syncDirtyRange(ctx context.Context, mr memmap.MappableRange, cache *FileRan
 		if max < wbr.Start {
 			break
 		}
-		ims, err := mem.MapInternal(cseg.FileRangeOf(wbr), usermem.Read)
+		ims, err := mem.MapInternal(cseg.FileRangeOf(wbr), hostarch.Read)
 		if err != nil {
 			return err
 		}
diff --git a/pkg/sentry/fs/fsutil/dirty_set_test.go b/pkg/sentry/fs/fsutil/dirty_set_test.go
index e3579c23c..48448c97c 100644
--- a/pkg/sentry/fs/fsutil/dirty_set_test.go
+++ b/pkg/sentry/fs/fsutil/dirty_set_test.go
@@ -18,18 +18,18 @@ import (
 	"reflect"
 	"testing"
 
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 func TestDirtySet(t *testing.T) {
 	var set DirtySet
-	set.MarkDirty(memmap.MappableRange{0, 2 * usermem.PageSize})
-	set.KeepDirty(memmap.MappableRange{usermem.PageSize, 2 * usermem.PageSize})
-	set.MarkClean(memmap.MappableRange{0, 2 * usermem.PageSize})
+	set.MarkDirty(memmap.MappableRange{0, 2 * hostarch.PageSize})
+	set.KeepDirty(memmap.MappableRange{hostarch.PageSize, 2 * hostarch.PageSize})
+	set.MarkClean(memmap.MappableRange{0, 2 * hostarch.PageSize})
 	want := &DirtySegmentDataSlices{
-		Start:  []uint64{usermem.PageSize},
-		End:    []uint64{2 * usermem.PageSize},
+		Start:  []uint64{hostarch.PageSize},
+		End:    []uint64{2 * hostarch.PageSize},
 		Values: []DirtyInfo{{Keep: true}},
 	}
 	if got := set.ExportSortedSlices(); !reflect.DeepEqual(got, want) {
diff --git a/pkg/sentry/fs/fsutil/file_range_set.go b/pkg/sentry/fs/fsutil/file_range_set.go
index 1dc409d38..fdaceb1db 100644
--- a/pkg/sentry/fs/fsutil/file_range_set.go
+++ b/pkg/sentry/fs/fsutil/file_range_set.go
@@ -20,11 +20,11 @@ import (
 	"math"
 
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/pgalloc"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // FileRangeSet maps offsets into a memmap.Mappable to offsets into a
@@ -130,7 +130,7 @@ func (frs *FileRangeSet) Fill(ctx context.Context, required, optional memmap.Map
 						// MemoryFile.AllocateAndFill truncates down to a page
 						// boundary, but FileRangeSet.Fill is supposed to
 						// zero-fill to the end of the page in this case.
-						donepgaddr, ok := usermem.Addr(done).RoundUp()
+						donepgaddr, ok := hostarch.Addr(done).RoundUp()
 						if donepg := uint64(donepgaddr); ok && donepg != done {
 							dsts.DropFirst64(donepg - done)
 							done = donepg
@@ -184,7 +184,7 @@ func (frs *FileRangeSet) DropAll(mf *pgalloc.MemoryFile) {
 // bytes after the new EOF on the same page are zeroed, and pages after the new
 // EOF are freed.
 func (frs *FileRangeSet) Truncate(end uint64, mf *pgalloc.MemoryFile) {
-	pgendaddr, ok := usermem.Addr(end).RoundUp()
+	pgendaddr, ok := hostarch.Addr(end).RoundUp()
 	if ok {
 		pgend := uint64(pgendaddr)
 
@@ -208,7 +208,7 @@ func (frs *FileRangeSet) Truncate(end uint64, mf *pgalloc.MemoryFile) {
 	if seg.Ok() {
 		fr := seg.FileRange()
 		fr.Start += end - seg.Start()
-		ims, err := mf.MapInternal(fr, usermem.Write)
+		ims, err := mf.MapInternal(fr, hostarch.Write)
 		if err != nil {
 			// There's no good recourse from here. This means
 			// that we can't keep cached memory consistent with
diff --git a/pkg/sentry/fs/fsutil/host_file_mapper.go b/pkg/sentry/fs/fsutil/host_file_mapper.go
index 54f7b7cdc..23528bf25 100644
--- a/pkg/sentry/fs/fsutil/host_file_mapper.go
+++ b/pkg/sentry/fs/fsutil/host_file_mapper.go
@@ -18,11 +18,11 @@ import (
 	"fmt"
 
 	"golang.org/x/sys/unix"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sync"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // HostFileMapper caches mappings of an arbitrary host file descriptor. It is
@@ -50,13 +50,13 @@ type HostFileMapper struct {
 }
 
 const (
-	chunkShift = usermem.HugePageShift
+	chunkShift = hostarch.HugePageShift
 	chunkSize  = 1 << chunkShift
 	chunkMask  = chunkSize - 1
 )
 
 func pagesInChunk(mr memmap.MappableRange, chunkStart uint64) int32 {
-	return int32(mr.Intersect(memmap.MappableRange{chunkStart, chunkStart + chunkSize}).Length() / usermem.PageSize)
+	return int32(mr.Intersect(memmap.MappableRange{chunkStart, chunkStart + chunkSize}).Length() / hostarch.PageSize)
 }
 
 type mapping struct {
diff --git a/pkg/sentry/fs/fsutil/host_mappable.go b/pkg/sentry/fs/fsutil/host_mappable.go
index c15d8a946..e1e38b498 100644
--- a/pkg/sentry/fs/fsutil/host_mappable.go
+++ b/pkg/sentry/fs/fsutil/host_mappable.go
@@ -18,6 +18,7 @@ import (
 	"math"
 
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
@@ -59,7 +60,7 @@ func NewHostMappable(backingFile CachedFileObject) *HostMappable {
 }
 
 // AddMapping implements memmap.Mappable.AddMapping.
-func (h *HostMappable) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) error {
+func (h *HostMappable) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) error {
 	// Hot path. Avoid defers.
 	h.mu.Lock()
 	mapped := h.mappings.AddMapping(ms, ar, offset, writable)
@@ -71,7 +72,7 @@ func (h *HostMappable) AddMapping(ctx context.Context, ms memmap.MappingSpace, a
 }
 
 // RemoveMapping implements memmap.Mappable.RemoveMapping.
-func (h *HostMappable) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) {
+func (h *HostMappable) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) {
 	// Hot path. Avoid defers.
 	h.mu.Lock()
 	unmapped := h.mappings.RemoveMapping(ms, ar, offset, writable)
@@ -82,18 +83,18 @@ func (h *HostMappable) RemoveMapping(ctx context.Context, ms memmap.MappingSpace
 }
 
 // CopyMapping implements memmap.Mappable.CopyMapping.
-func (h *HostMappable) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR usermem.AddrRange, offset uint64, writable bool) error {
+func (h *HostMappable) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR hostarch.AddrRange, offset uint64, writable bool) error {
 	return h.AddMapping(ctx, ms, dstAR, offset, writable)
 }
 
 // Translate implements memmap.Mappable.Translate.
-func (h *HostMappable) Translate(ctx context.Context, required, optional memmap.MappableRange, at usermem.AccessType) ([]memmap.Translation, error) {
+func (h *HostMappable) Translate(ctx context.Context, required, optional memmap.MappableRange, at hostarch.AccessType) ([]memmap.Translation, error) {
 	return []memmap.Translation{
 		{
 			Source: optional,
 			File:   h,
 			Offset: optional.Start,
-			Perms:  usermem.AnyAccess,
+			Perms:  hostarch.AnyAccess,
 		},
 	}, nil
 }
@@ -124,7 +125,7 @@ func (h *HostMappable) NotifyChangeFD() error {
 }
 
 // MapInternal implements memmap.File.MapInternal.
-func (h *HostMappable) MapInternal(fr memmap.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) {
+func (h *HostMappable) MapInternal(fr memmap.FileRange, at hostarch.AccessType) (safemem.BlockSeq, error) {
 	return h.hostFileMapper.MapInternal(fr, h.backingFile.FD(), at.Write)
 }
 
diff --git a/pkg/sentry/fs/fsutil/inode_cached.go b/pkg/sentry/fs/fsutil/inode_cached.go
index 0ed7aafa5..7856b354b 100644
--- a/pkg/sentry/fs/fsutil/inode_cached.go
+++ b/pkg/sentry/fs/fsutil/inode_cached.go
@@ -19,6 +19,7 @@ import (
 	"io"
 
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
@@ -622,7 +623,7 @@ func (rw *inodeReadWriter) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error) {
 		switch {
 		case seg.Ok():
 			// Get internal mappings from the cache.
-			ims, err := mem.MapInternal(seg.FileRangeOf(seg.Range().Intersect(mr)), usermem.Read)
+			ims, err := mem.MapInternal(seg.FileRangeOf(seg.Range().Intersect(mr)), hostarch.Read)
 			if err != nil {
 				unlock()
 				return done, err
@@ -647,7 +648,7 @@ func (rw *inodeReadWriter) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error) {
 				// Read into the cache, then re-enter the loop to read from the
 				// cache.
 				reqMR := memmap.MappableRange{
-					Start: uint64(usermem.Addr(gapMR.Start).RoundDown()),
+					Start: uint64(hostarch.Addr(gapMR.Start).RoundDown()),
 					End:   fs.OffsetPageEnd(int64(gapMR.End)),
 				}
 				optMR := gap.Range()
@@ -729,7 +730,7 @@ func (rw *inodeReadWriter) WriteFromBlocks(srcs safemem.BlockSeq) (uint64, error
 		case seg.Ok() && seg.Start() < mr.End:
 			// Get internal mappings from the cache.
 			segMR := seg.Range().Intersect(mr)
-			ims, err := mf.MapInternal(seg.FileRangeOf(segMR), usermem.Write)
+			ims, err := mf.MapInternal(seg.FileRangeOf(segMR), hostarch.Write)
 			if err != nil {
 				rw.maybeGrowFile()
 				rw.c.dataMu.Unlock()
@@ -786,7 +787,7 @@ func (c *CachingInodeOperations) useHostPageCache() bool {
 }
 
 // AddMapping implements memmap.Mappable.AddMapping.
-func (c *CachingInodeOperations) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) error {
+func (c *CachingInodeOperations) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) error {
 	// Hot path. Avoid defers.
 	c.mapsMu.Lock()
 	mapped := c.mappings.AddMapping(ms, ar, offset, writable)
@@ -808,7 +809,7 @@ func (c *CachingInodeOperations) AddMapping(ctx context.Context, ms memmap.Mappi
 }
 
 // RemoveMapping implements memmap.Mappable.RemoveMapping.
-func (c *CachingInodeOperations) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) {
+func (c *CachingInodeOperations) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) {
 	// Hot path. Avoid defers.
 	c.mapsMu.Lock()
 	unmapped := c.mappings.RemoveMapping(ms, ar, offset, writable)
@@ -836,12 +837,12 @@ func (c *CachingInodeOperations) RemoveMapping(ctx context.Context, ms memmap.Ma
 }
 
 // CopyMapping implements memmap.Mappable.CopyMapping.
-func (c *CachingInodeOperations) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR usermem.AddrRange, offset uint64, writable bool) error {
+func (c *CachingInodeOperations) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR hostarch.AddrRange, offset uint64, writable bool) error {
 	return c.AddMapping(ctx, ms, dstAR, offset, writable)
 }
 
 // Translate implements memmap.Mappable.Translate.
-func (c *CachingInodeOperations) Translate(ctx context.Context, required, optional memmap.MappableRange, at usermem.AccessType) ([]memmap.Translation, error) {
+func (c *CachingInodeOperations) Translate(ctx context.Context, required, optional memmap.MappableRange, at hostarch.AccessType) ([]memmap.Translation, error) {
 	// Hot path. Avoid defer.
 	if c.useHostPageCache() {
 		mr := optional
@@ -853,7 +854,7 @@ func (c *CachingInodeOperations) Translate(ctx context.Context, required, option
 				Source: mr,
 				File:   c,
 				Offset: mr.Start,
-				Perms:  usermem.AnyAccess,
+				Perms:  hostarch.AnyAccess,
 			},
 		}, nil
 	}
@@ -885,7 +886,7 @@ func (c *CachingInodeOperations) Translate(ctx context.Context, required, option
 		segMR := seg.Range().Intersect(optional)
 		// TODO(jamieliu): Make Translations writable even if writability is
 		// not required if already kept-dirty by another writable translation.
-		perms := usermem.AccessType{
+		perms := hostarch.AccessType{
 			Read:    true,
 			Execute: true,
 		}
@@ -1050,7 +1051,7 @@ func (c *CachingInodeOperations) DecRef(fr memmap.FileRange) {
 // MapInternal implements memmap.File.MapInternal. This is used when we
 // directly map an underlying host fd and CachingInodeOperations is used as the
 // memmap.File during translation.
-func (c *CachingInodeOperations) MapInternal(fr memmap.FileRange, at usermem.AccessType) (safemem.BlockSeq, error) {
+func (c *CachingInodeOperations) MapInternal(fr memmap.FileRange, at hostarch.AccessType) (safemem.BlockSeq, error) {
 	return c.hostFileMapper.MapInternal(fr, c.backingFile.FD(), at.Write)
 }
 
diff --git a/pkg/sentry/fs/fsutil/inode_cached_test.go b/pkg/sentry/fs/fsutil/inode_cached_test.go
index 1547584c5..e107c3096 100644
--- a/pkg/sentry/fs/fsutil/inode_cached_test.go
+++ b/pkg/sentry/fs/fsutil/inode_cached_test.go
@@ -20,6 +20,7 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/contexttest"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
@@ -249,7 +250,7 @@ func (f *sliceBackingFile) Allocate(ctx context.Context, offset int64, length in
 type noopMappingSpace struct{}
 
 // Invalidate implements memmap.MappingSpace.Invalidate.
-func (noopMappingSpace) Invalidate(ar usermem.AddrRange, opts memmap.InvalidateOpts) {
+func (noopMappingSpace) Invalidate(ar hostarch.AddrRange, opts memmap.InvalidateOpts) {
 }
 
 func anonInode(ctx context.Context) *fs.Inode {
@@ -259,14 +260,14 @@ func anonInode(ctx context.Context) *fs.Inode {
 		}, 0),
 	}, fs.NewPseudoMountSource(ctx), fs.StableAttr{
 		Type:      fs.Anonymous,
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 	})
 }
 
 func pagesOf(bs ...byte) []byte {
-	buf := make([]byte, 0, len(bs)*usermem.PageSize)
+	buf := make([]byte, 0, len(bs)*hostarch.PageSize)
 	for _, b := range bs {
-		buf = append(buf, bytes.Repeat([]byte{b}, usermem.PageSize)...)
+		buf = append(buf, bytes.Repeat([]byte{b}, hostarch.PageSize)...)
 	}
 	return buf
 }
@@ -292,28 +293,28 @@ func TestRead(t *testing.T) {
 	// expects to only cache mapped pages), then call Translate to force it to
 	// be cached.
 	var ms noopMappingSpace
-	ar := usermem.AddrRange{usermem.PageSize, 2 * usermem.PageSize}
-	if err := iops.AddMapping(ctx, ms, ar, usermem.PageSize, true); err != nil {
+	ar := hostarch.AddrRange{hostarch.PageSize, 2 * hostarch.PageSize}
+	if err := iops.AddMapping(ctx, ms, ar, hostarch.PageSize, true); err != nil {
 		t.Fatalf("AddMapping got %v, want nil", err)
 	}
-	mr := memmap.MappableRange{usermem.PageSize, 2 * usermem.PageSize}
-	if _, err := iops.Translate(ctx, mr, mr, usermem.Read); err != nil {
+	mr := memmap.MappableRange{hostarch.PageSize, 2 * hostarch.PageSize}
+	if _, err := iops.Translate(ctx, mr, mr, hostarch.Read); err != nil {
 		t.Fatalf("Translate got %v, want nil", err)
 	}
-	if cached := iops.cache.Span(); cached != usermem.PageSize {
-		t.Errorf("SpanRange got %d, want %d", cached, usermem.PageSize)
+	if cached := iops.cache.Span(); cached != hostarch.PageSize {
+		t.Errorf("SpanRange got %d, want %d", cached, hostarch.PageSize)
 	}
 
 	// Try to read 4 pages. The first and third pages should be read directly
 	// from the "file", the second page should be read from the cache, and only
 	// 3 pages (the size of the file) should be readable.
-	rbuf := make([]byte, 4*usermem.PageSize)
+	rbuf := make([]byte, 4*hostarch.PageSize)
 	dst := usermem.BytesIOSequence(rbuf)
 	n, err := iops.Read(ctx, file, dst, 0)
-	if n != 3*usermem.PageSize || (err != nil && err != io.EOF) {
-		t.Fatalf("Read got (%d, %v), want (%d, nil or EOF)", n, err, 3*usermem.PageSize)
+	if n != 3*hostarch.PageSize || (err != nil && err != io.EOF) {
+		t.Fatalf("Read got (%d, %v), want (%d, nil or EOF)", n, err, 3*hostarch.PageSize)
 	}
-	rbuf = rbuf[:3*usermem.PageSize]
+	rbuf = rbuf[:3*hostarch.PageSize]
 
 	// Did we get the bytes we expect?
 	if !bytes.Equal(rbuf, buf) {
@@ -323,7 +324,7 @@ func TestRead(t *testing.T) {
 	// Delete the memory mapping before iops.Release(). The cached page will
 	// either be evicted by ctx's pgalloc.MemoryFile, or dropped by
 	// iops.Release().
-	iops.RemoveMapping(ctx, ms, ar, usermem.PageSize, true)
+	iops.RemoveMapping(ctx, ms, ar, hostarch.PageSize, true)
 }
 
 func TestWrite(t *testing.T) {
@@ -348,25 +349,25 @@ func TestWrite(t *testing.T) {
 	// CachingInodeOperations expects to only cache mapped pages), then call
 	// Translate to force them to be cached.
 	var ms noopMappingSpace
-	ar := usermem.AddrRange{usermem.PageSize, 3 * usermem.PageSize}
-	if err := iops.AddMapping(ctx, ms, ar, usermem.PageSize, true); err != nil {
+	ar := hostarch.AddrRange{hostarch.PageSize, 3 * hostarch.PageSize}
+	if err := iops.AddMapping(ctx, ms, ar, hostarch.PageSize, true); err != nil {
 		t.Fatalf("AddMapping got %v, want nil", err)
 	}
-	defer iops.RemoveMapping(ctx, ms, ar, usermem.PageSize, true)
-	mr := memmap.MappableRange{usermem.PageSize, 3 * usermem.PageSize}
-	if _, err := iops.Translate(ctx, mr, mr, usermem.Read); err != nil {
+	defer iops.RemoveMapping(ctx, ms, ar, hostarch.PageSize, true)
+	mr := memmap.MappableRange{hostarch.PageSize, 3 * hostarch.PageSize}
+	if _, err := iops.Translate(ctx, mr, mr, hostarch.Read); err != nil {
 		t.Fatalf("Translate got %v, want nil", err)
 	}
-	if cached := iops.cache.Span(); cached != 2*usermem.PageSize {
-		t.Errorf("SpanRange got %d, want %d", cached, 2*usermem.PageSize)
+	if cached := iops.cache.Span(); cached != 2*hostarch.PageSize {
+		t.Errorf("SpanRange got %d, want %d", cached, 2*hostarch.PageSize)
 	}
 
 	// Write to the first 2 pages.
 	wbuf := pagesOf('e', 'f')
 	src := usermem.BytesIOSequence(wbuf)
 	n, err := iops.Write(ctx, src, 0)
-	if n != 2*usermem.PageSize || err != nil {
-		t.Fatalf("Write got (%d, %v), want (%d, nil)", n, err, 2*usermem.PageSize)
+	if n != 2*hostarch.PageSize || err != nil {
+		t.Fatalf("Write got (%d, %v), want (%d, nil)", n, err, 2*hostarch.PageSize)
 	}
 
 	// The first page should have been written directly, since it was not cached.
@@ -382,7 +383,7 @@ func TestWrite(t *testing.T) {
 	}
 
 	// Now the second page should have been written as well.
-	copy(want[usermem.PageSize:], pagesOf('f'))
+	copy(want[hostarch.PageSize:], pagesOf('f'))
 	if !bytes.Equal(buf, want) {
 		t.Errorf("File contents are %v, want %v", buf, want)
 	}
diff --git a/pkg/sentry/fs/gofer/BUILD b/pkg/sentry/fs/gofer/BUILD
index b210e0e7e..c4a069832 100644
--- a/pkg/sentry/fs/gofer/BUILD
+++ b/pkg/sentry/fs/gofer/BUILD
@@ -27,6 +27,7 @@ go_library(
         "//pkg/abi/linux",
         "//pkg/context",
         "//pkg/fd",
+        "//pkg/hostarch",
         "//pkg/log",
         "//pkg/p9",
         "//pkg/refs",
diff --git a/pkg/sentry/fs/gofer/attr.go b/pkg/sentry/fs/gofer/attr.go
index cffc756cc..d6bff3f40 100644
--- a/pkg/sentry/fs/gofer/attr.go
+++ b/pkg/sentry/fs/gofer/attr.go
@@ -17,11 +17,11 @@ package gofer
 import (
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/p9"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // getattr returns the 9p attributes of the p9.File. On success, Mode, Size, and RDev
@@ -98,7 +98,7 @@ func bsize(pattr p9.Attr) int64 {
 	// Some files, particularly those that are not on a local file system,
 	// may have no clue of their block size. Better not to report something
 	// misleading or buggy and have a safe default.
-	return usermem.PageSize
+	return hostarch.PageSize
 }
 
 // ntype returns an fs.InodeType from 9p attributes.
diff --git a/pkg/sentry/fs/inotify.go b/pkg/sentry/fs/inotify.go
index fb81d903d..1b83643db 100644
--- a/pkg/sentry/fs/inotify.go
+++ b/pkg/sentry/fs/inotify.go
@@ -20,6 +20,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sentry/uniqueid"
@@ -216,7 +217,7 @@ func (i *Inotify) Ioctl(ctx context.Context, _ *File, io usermem.IO, args arch.S
 			n += uint32(e.sizeOf())
 		}
 		var buf [4]byte
-		usermem.ByteOrder.PutUint32(buf[:], n)
+		hostarch.ByteOrder.PutUint32(buf[:], n)
 		_, err := io.CopyOut(ctx, args[2].Pointer(), buf[:], usermem.IOOpts{})
 		return 0, err
 
diff --git a/pkg/sentry/fs/inotify_event.go b/pkg/sentry/fs/inotify_event.go
index 686e1b1cd..399aff1ed 100644
--- a/pkg/sentry/fs/inotify_event.go
+++ b/pkg/sentry/fs/inotify_event.go
@@ -19,6 +19,7 @@ import (
 	"fmt"
 
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/usermem"
 )
 
@@ -100,10 +101,10 @@ func (e *Event) sizeOf() int {
 // construct the output. We use a buffer allocated ahead of time for
 // performance. buf must be at least inotifyEventBaseSize bytes.
 func (e *Event) CopyTo(ctx context.Context, buf []byte, dst usermem.IOSequence) (int64, error) {
-	usermem.ByteOrder.PutUint32(buf[0:], uint32(e.wd))
-	usermem.ByteOrder.PutUint32(buf[4:], e.mask)
-	usermem.ByteOrder.PutUint32(buf[8:], e.cookie)
-	usermem.ByteOrder.PutUint32(buf[12:], e.len)
+	hostarch.ByteOrder.PutUint32(buf[0:], uint32(e.wd))
+	hostarch.ByteOrder.PutUint32(buf[4:], e.mask)
+	hostarch.ByteOrder.PutUint32(buf[8:], e.cookie)
+	hostarch.ByteOrder.PutUint32(buf[12:], e.len)
 
 	writeLen := 0
 
diff --git a/pkg/sentry/fs/offset.go b/pkg/sentry/fs/offset.go
index 53b5df175..3a8c97d8f 100644
--- a/pkg/sentry/fs/offset.go
+++ b/pkg/sentry/fs/offset.go
@@ -17,14 +17,14 @@ package fs
 import (
 	"math"
 
-	"gvisor.dev/gvisor/pkg/usermem"
+	"gvisor.dev/gvisor/pkg/hostarch"
 )
 
 // OffsetPageEnd returns the file offset rounded up to the nearest
 // page boundary. OffsetPageEnd panics if rounding up causes overflow,
 // which shouldn't be possible given that offset is an int64.
 func OffsetPageEnd(offset int64) uint64 {
-	end, ok := usermem.Addr(offset).RoundUp()
+	end, ok := hostarch.Addr(offset).RoundUp()
 	if !ok {
 		panic("impossible overflow")
 	}
diff --git a/pkg/sentry/fs/overlay.go b/pkg/sentry/fs/overlay.go
index 01a1235b8..f96f5a3e5 100644
--- a/pkg/sentry/fs/overlay.go
+++ b/pkg/sentry/fs/overlay.go
@@ -19,11 +19,11 @@ import (
 	"strings"
 
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
 	"gvisor.dev/gvisor/pkg/sync"
 	"gvisor.dev/gvisor/pkg/syserror"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // The virtual filesystem implements an overlay configuration. For a high-level
@@ -274,7 +274,7 @@ func (o *overlayEntry) markDirectoryDirty() {
 }
 
 // AddMapping implements memmap.Mappable.AddMapping.
-func (o *overlayEntry) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) error {
+func (o *overlayEntry) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) error {
 	o.mapsMu.Lock()
 	defer o.mapsMu.Unlock()
 	if err := o.inodeLocked().Mappable().AddMapping(ctx, ms, ar, offset, writable); err != nil {
@@ -285,7 +285,7 @@ func (o *overlayEntry) AddMapping(ctx context.Context, ms memmap.MappingSpace, a
 }
 
 // RemoveMapping implements memmap.Mappable.RemoveMapping.
-func (o *overlayEntry) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) {
+func (o *overlayEntry) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) {
 	o.mapsMu.Lock()
 	defer o.mapsMu.Unlock()
 	o.inodeLocked().Mappable().RemoveMapping(ctx, ms, ar, offset, writable)
@@ -293,7 +293,7 @@ func (o *overlayEntry) RemoveMapping(ctx context.Context, ms memmap.MappingSpace
 }
 
 // CopyMapping implements memmap.Mappable.CopyMapping.
-func (o *overlayEntry) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR usermem.AddrRange, offset uint64, writable bool) error {
+func (o *overlayEntry) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR hostarch.AddrRange, offset uint64, writable bool) error {
 	o.mapsMu.Lock()
 	defer o.mapsMu.Unlock()
 	if err := o.inodeLocked().Mappable().CopyMapping(ctx, ms, srcAR, dstAR, offset, writable); err != nil {
@@ -304,7 +304,7 @@ func (o *overlayEntry) CopyMapping(ctx context.Context, ms memmap.MappingSpace,
 }
 
 // Translate implements memmap.Mappable.Translate.
-func (o *overlayEntry) Translate(ctx context.Context, required, optional memmap.MappableRange, at usermem.AccessType) ([]memmap.Translation, error) {
+func (o *overlayEntry) Translate(ctx context.Context, required, optional memmap.MappableRange, at hostarch.AccessType) ([]memmap.Translation, error) {
 	o.dataMu.RLock()
 	defer o.dataMu.RUnlock()
 	return o.inodeLocked().Mappable().Translate(ctx, required, optional, at)
diff --git a/pkg/sentry/fs/proc/BUILD b/pkg/sentry/fs/proc/BUILD
index b8b2281a8..7af7e0b45 100644
--- a/pkg/sentry/fs/proc/BUILD
+++ b/pkg/sentry/fs/proc/BUILD
@@ -30,6 +30,7 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/hostarch",
         "//pkg/log",
         "//pkg/sentry/fs",
         "//pkg/sentry/fs/fsutil",
diff --git a/pkg/sentry/fs/proc/exec_args.go b/pkg/sentry/fs/proc/exec_args.go
index e6171dd1d..24426b225 100644
--- a/pkg/sentry/fs/proc/exec_args.go
+++ b/pkg/sentry/fs/proc/exec_args.go
@@ -21,6 +21,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
@@ -113,7 +114,7 @@ func (f *execArgFile) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequen
 	defer m.DecUsers(ctx)
 
 	// Figure out the bounds of the exec arg we are trying to read.
-	var execArgStart, execArgEnd usermem.Addr
+	var execArgStart, execArgEnd hostarch.Addr
 	switch f.arg {
 	case cmdlineExecArg:
 		execArgStart, execArgEnd = m.ArgvStart(), m.ArgvEnd()
@@ -172,8 +173,8 @@ func (f *execArgFile) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequen
 			// https://elixir.bootlin.com/linux/v4.20/source/fs/proc/base.c#L208
 			// we'll return one page total between argv and envp because of the
 			// above page restrictions.
-			if lengthEnvv > usermem.PageSize-len(buf) {
-				lengthEnvv = usermem.PageSize - len(buf)
+			if lengthEnvv > hostarch.PageSize-len(buf) {
+				lengthEnvv = hostarch.PageSize - len(buf)
 			}
 			// Make a new buffer to fit the whole thing
 			tmp := make([]byte, length+lengthEnvv)
diff --git a/pkg/sentry/fs/proc/inode.go b/pkg/sentry/fs/proc/inode.go
index d2859a4c2..78132f7a5 100644
--- a/pkg/sentry/fs/proc/inode.go
+++ b/pkg/sentry/fs/proc/inode.go
@@ -17,13 +17,13 @@ package proc
 import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/fs/proc/device"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/mm"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // LINT.IfChange
@@ -125,7 +125,7 @@ func newProcInode(ctx context.Context, iops fs.InodeOperations, msrc *fs.MountSo
 	sattr := fs.StableAttr{
 		DeviceID:  device.ProcDevice.DeviceID(),
 		InodeID:   device.ProcDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      typ,
 	}
 	if t != nil {
diff --git a/pkg/sentry/fs/proc/meminfo.go b/pkg/sentry/fs/proc/meminfo.go
index 91617267d..7d975d333 100644
--- a/pkg/sentry/fs/proc/meminfo.go
+++ b/pkg/sentry/fs/proc/meminfo.go
@@ -19,10 +19,10 @@ import (
 	"fmt"
 
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs/proc/seqfile"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // LINT.IfChange
@@ -53,7 +53,7 @@ func (d *meminfoData) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle)
 	anon := snapshot.Anonymous + snapshot.Tmpfs
 	file := snapshot.PageCache + snapshot.Mapped
 	// We don't actually have active/inactive LRUs, so just make up numbers.
-	activeFile := (file / 2) &^ (usermem.PageSize - 1)
+	activeFile := (file / 2) &^ (hostarch.PageSize - 1)
 	inactiveFile := file - activeFile
 
 	var buf bytes.Buffer
diff --git a/pkg/sentry/fs/proc/net.go b/pkg/sentry/fs/proc/net.go
index 203cfa061..91c35eea9 100644
--- a/pkg/sentry/fs/proc/net.go
+++ b/pkg/sentry/fs/proc/net.go
@@ -23,6 +23,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/proc/seqfile"
@@ -35,7 +36,6 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // LINT.IfChange
@@ -367,10 +367,10 @@ func (n *netRoute) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]
 		)
 		if len(rt.GatewayAddr) == header.IPv4AddressSize {
 			flags |= linux.RTF_GATEWAY
-			gw = usermem.ByteOrder.Uint32(rt.GatewayAddr)
+			gw = hostarch.ByteOrder.Uint32(rt.GatewayAddr)
 		}
 		if len(rt.DstAddr) == header.IPv4AddressSize {
-			prefix = usermem.ByteOrder.Uint32(rt.DstAddr)
+			prefix = hostarch.ByteOrder.Uint32(rt.DstAddr)
 		}
 		l := fmt.Sprintf(
 			"%s\t%08X\t%08X\t%04X\t%d\t%d\t%d\t%08X\t%d\t%d\t%d",
@@ -520,7 +520,7 @@ func networkToHost16(n uint16) uint16 {
 	// binary.BigEndian.Uint16() require a read of binary.BigEndian and an
 	// interface method call, defeating inlining.
 	buf := [2]byte{byte(n >> 8 & 0xff), byte(n & 0xff)}
-	return usermem.ByteOrder.Uint16(buf[:])
+	return hostarch.ByteOrder.Uint16(buf[:])
 }
 
 func writeInetAddr(w io.Writer, family int, i linux.SockAddr) {
@@ -542,14 +542,14 @@ func writeInetAddr(w io.Writer, family int, i linux.SockAddr) {
 		// __be32 which is a typedef for an unsigned int, and is printed with
 		// %X. This means that for a little-endian machine, Linux prints the
 		// least-significant byte of the address first. To emulate this, we first
-		// invert the byte order for the address using usermem.ByteOrder.Uint32,
+		// invert the byte order for the address using hostarch.ByteOrder.Uint32,
 		// which makes it have the equivalent encoding to a __be32 on a little
 		// endian machine. Note that this operation is a no-op on a big endian
 		// machine. Then similar to Linux, we format it with %X, which will print
 		// the most-significant byte of the __be32 address first, which is now
 		// actually the least-significant byte of the original address in
 		// linux.SockAddrInet.Addr on little endian machines, due to the conversion.
-		addr := usermem.ByteOrder.Uint32(a.Addr[:])
+		addr := hostarch.ByteOrder.Uint32(a.Addr[:])
 
 		fmt.Fprintf(w, "%08X:%04X ", addr, port)
 	case linux.AF_INET6:
@@ -559,10 +559,10 @@ func writeInetAddr(w io.Writer, family int, i linux.SockAddr) {
 		}
 
 		port := networkToHost16(a.Port)
-		addr0 := usermem.ByteOrder.Uint32(a.Addr[0:4])
-		addr1 := usermem.ByteOrder.Uint32(a.Addr[4:8])
-		addr2 := usermem.ByteOrder.Uint32(a.Addr[8:12])
-		addr3 := usermem.ByteOrder.Uint32(a.Addr[12:16])
+		addr0 := hostarch.ByteOrder.Uint32(a.Addr[0:4])
+		addr1 := hostarch.ByteOrder.Uint32(a.Addr[4:8])
+		addr2 := hostarch.ByteOrder.Uint32(a.Addr[8:12])
+		addr3 := hostarch.ByteOrder.Uint32(a.Addr[12:16])
 		fmt.Fprintf(w, "%08X%08X%08X%08X:%04X ", addr0, addr1, addr2, addr3, port)
 	}
 }
diff --git a/pkg/sentry/fs/proc/seqfile/BUILD b/pkg/sentry/fs/proc/seqfile/BUILD
index 21338d912..713b81e08 100644
--- a/pkg/sentry/fs/proc/seqfile/BUILD
+++ b/pkg/sentry/fs/proc/seqfile/BUILD
@@ -9,6 +9,7 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/hostarch",
         "//pkg/sentry/fs",
         "//pkg/sentry/fs/fsutil",
         "//pkg/sentry/fs/proc/device",
diff --git a/pkg/sentry/fs/proc/seqfile/seqfile.go b/pkg/sentry/fs/proc/seqfile/seqfile.go
index 6121f0e95..b01688b1d 100644
--- a/pkg/sentry/fs/proc/seqfile/seqfile.go
+++ b/pkg/sentry/fs/proc/seqfile/seqfile.go
@@ -20,6 +20,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/fs/proc/device"
@@ -131,7 +132,7 @@ func NewSeqFileInode(ctx context.Context, source SeqSource, msrc *fs.MountSource
 	sattr := fs.StableAttr{
 		DeviceID:  device.ProcDevice.DeviceID(),
 		InodeID:   device.ProcDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.SpecialFile,
 	}
 	return fs.NewInode(ctx, iops, msrc, sattr)
diff --git a/pkg/sentry/fs/proc/sys_net.go b/pkg/sentry/fs/proc/sys_net.go
index bbe282c03..1d09afdd7 100644
--- a/pkg/sentry/fs/proc/sys_net.go
+++ b/pkg/sentry/fs/proc/sys_net.go
@@ -21,6 +21,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/fs/proc/device"
@@ -76,7 +77,7 @@ func newTCPMemInode(ctx context.Context, msrc *fs.MountSource, s inet.Stack, dir
 	sattr := fs.StableAttr{
 		DeviceID:  device.ProcDevice.DeviceID(),
 		InodeID:   device.ProcDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.SpecialFile,
 	}
 	return fs.NewInode(ctx, tm, msrc, sattr)
@@ -136,7 +137,7 @@ func (f *tcpMemFile) Write(ctx context.Context, _ *fs.File, src usermem.IOSequen
 	f.tcpMemInode.mu.Lock()
 	defer f.tcpMemInode.mu.Unlock()
 
-	src = src.TakeFirst(usermem.PageSize - 1)
+	src = src.TakeFirst(hostarch.PageSize - 1)
 	size, err := readSize(f.tcpMemInode.dir, f.tcpMemInode.s)
 	if err != nil {
 		return 0, err
@@ -192,7 +193,7 @@ func newTCPSackInode(ctx context.Context, msrc *fs.MountSource, s inet.Stack) *f
 	sattr := fs.StableAttr{
 		DeviceID:  device.ProcDevice.DeviceID(),
 		InodeID:   device.ProcDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.SpecialFile,
 	}
 	return fs.NewInode(ctx, ts, msrc, sattr)
@@ -264,7 +265,7 @@ func (f *tcpSackFile) Write(ctx context.Context, _ *fs.File, src usermem.IOSeque
 
 	// Only consider size of one memory page for input for performance reasons.
 	// We are only reading if it's zero or not anyway.
-	src = src.TakeFirst(usermem.PageSize - 1)
+	src = src.TakeFirst(hostarch.PageSize - 1)
 
 	var v int32
 	n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts)
@@ -294,7 +295,7 @@ func newTCPRecoveryInode(ctx context.Context, msrc *fs.MountSource, s inet.Stack
 	sattr := fs.StableAttr{
 		DeviceID:  device.ProcDevice.DeviceID(),
 		InodeID:   device.ProcDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.SpecialFile,
 	}
 	return fs.NewInode(ctx, ts, msrc, sattr)
@@ -354,7 +355,7 @@ func (f *tcpRecoveryFile) Write(ctx context.Context, _ *fs.File, src usermem.IOS
 	if src.NumBytes() == 0 {
 		return 0, nil
 	}
-	src = src.TakeFirst(usermem.PageSize - 1)
+	src = src.TakeFirst(hostarch.PageSize - 1)
 
 	var v int32
 	n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts)
@@ -413,7 +414,7 @@ func newIPForwardingInode(ctx context.Context, msrc *fs.MountSource, s inet.Stac
 	sattr := fs.StableAttr{
 		DeviceID:  device.ProcDevice.DeviceID(),
 		InodeID:   device.ProcDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.SpecialFile,
 	}
 	return fs.NewInode(ctx, ipf, msrc, sattr)
@@ -486,7 +487,7 @@ func (f *ipForwardingFile) Write(ctx context.Context, _ *fs.File, src usermem.IO
 
 	// Only consider size of one memory page for input for performance reasons.
 	// We are only reading if it's zero or not anyway.
-	src = src.TakeFirst(usermem.PageSize - 1)
+	src = src.TakeFirst(hostarch.PageSize - 1)
 
 	var v int32
 	n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts)
@@ -524,7 +525,7 @@ func newPortRangeInode(ctx context.Context, msrc *fs.MountSource, s inet.Stack)
 	sattr := fs.StableAttr{
 		DeviceID:  device.ProcDevice.DeviceID(),
 		InodeID:   device.ProcDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.SpecialFile,
 	}
 	return fs.NewInode(ctx, ipf, msrc, sattr)
@@ -589,7 +590,7 @@ func (pf *portRangeFile) Write(ctx context.Context, _ *fs.File, src usermem.IOSe
 
 	// Only consider size of one memory page for input for performance
 	// reasons.
-	src = src.TakeFirst(usermem.PageSize - 1)
+	src = src.TakeFirst(hostarch.PageSize - 1)
 
 	ports := make([]int32, 2)
 	n, err := usermem.CopyInt32StringsInVec(ctx, src.IO, src.Addrs, ports, src.Opts)
diff --git a/pkg/sentry/fs/proc/task.go b/pkg/sentry/fs/proc/task.go
index f43d6c221..ae5ed25f9 100644
--- a/pkg/sentry/fs/proc/task.go
+++ b/pkg/sentry/fs/proc/task.go
@@ -23,6 +23,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/fs/proc/device"
@@ -469,7 +470,7 @@ func (m *memDataFile) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequen
 	defer mm.DecUsers(ctx)
 	// Buffer the read data because of MM locks
 	buf := make([]byte, dst.NumBytes())
-	n, readErr := mm.CopyIn(ctx, usermem.Addr(offset), buf, usermem.IOOpts{IgnorePermissions: true})
+	n, readErr := mm.CopyIn(ctx, hostarch.Addr(offset), buf, usermem.IOOpts{IgnorePermissions: true})
 	if n > 0 {
 		if _, err := dst.CopyOut(ctx, buf[:n]); err != nil {
 			return 0, syserror.EFAULT
@@ -632,7 +633,7 @@ func (s *taskStatData) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle)
 			rss = mm.ResidentSetSize()
 		}
 	})
-	fmt.Fprintf(&buf, "%d %d ", vss, rss/usermem.PageSize)
+	fmt.Fprintf(&buf, "%d %d ", vss, rss/hostarch.PageSize)
 
 	// rsslim.
 	fmt.Fprintf(&buf, "%d ", s.t.ThreadGroup().Limits().Get(limits.Rss).Cur)
@@ -684,7 +685,7 @@ func (s *statmData) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([
 	})
 
 	var buf bytes.Buffer
-	fmt.Fprintf(&buf, "%d %d 0 0 0 0 0\n", vss/usermem.PageSize, rss/usermem.PageSize)
+	fmt.Fprintf(&buf, "%d %d 0 0 0 0 0\n", vss/hostarch.PageSize, rss/hostarch.PageSize)
 
 	return []seqfile.SeqData{{Buf: buf.Bytes(), Handle: (*statmData)(nil)}}, 0
 }
@@ -939,8 +940,8 @@ func (f *auxvecFile) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequenc
 
 	buf := make([]byte, size)
 	for i, e := range auxv {
-		usermem.ByteOrder.PutUint64(buf[16*i:], e.Key)
-		usermem.ByteOrder.PutUint64(buf[16*i+8:], uint64(e.Value))
+		hostarch.ByteOrder.PutUint64(buf[16*i:], e.Key)
+		hostarch.ByteOrder.PutUint64(buf[16*i+8:], uint64(e.Value))
 	}
 
 	n, err := dst.CopyOut(ctx, buf[offset:])
@@ -1020,7 +1021,7 @@ func (f *oomScoreAdjFile) Write(ctx context.Context, _ *fs.File, src usermem.IOS
 	}
 
 	// Limit input size so as not to impact performance if input size is large.
-	src = src.TakeFirst(usermem.PageSize - 1)
+	src = src.TakeFirst(hostarch.PageSize - 1)
 
 	var v int32
 	n, err := usermem.CopyInt32StringInVec(ctx, src.IO, src.Addrs, &v, src.Opts)
diff --git a/pkg/sentry/fs/proc/uid_gid_map.go b/pkg/sentry/fs/proc/uid_gid_map.go
index 2bc9485d8..30d5ad4cf 100644
--- a/pkg/sentry/fs/proc/uid_gid_map.go
+++ b/pkg/sentry/fs/proc/uid_gid_map.go
@@ -21,6 +21,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
@@ -132,7 +133,7 @@ func (imfo *idMapFileOperations) Write(ctx context.Context, file *fs.File, src u
 	// the system page size, and the write must be performed at the start of
 	// the file ..." - user_namespaces(7)
 	srclen := src.NumBytes()
-	if srclen >= usermem.PageSize || offset != 0 {
+	if srclen >= hostarch.PageSize || offset != 0 {
 		return 0, syserror.EINVAL
 	}
 	b := make([]byte, srclen)
diff --git a/pkg/sentry/fs/ramfs/BUILD b/pkg/sentry/fs/ramfs/BUILD
index a51d00d86..4a3d9636b 100644
--- a/pkg/sentry/fs/ramfs/BUILD
+++ b/pkg/sentry/fs/ramfs/BUILD
@@ -14,13 +14,13 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/hostarch",
         "//pkg/sentry/fs",
         "//pkg/sentry/fs/anon",
         "//pkg/sentry/fs/fsutil",
         "//pkg/sentry/socket/unix/transport",
         "//pkg/sync",
         "//pkg/syserror",
-        "//pkg/usermem",
         "//pkg/waiter",
         "@org_golang_x_sys//unix:go_default_library",
     ],
diff --git a/pkg/sentry/fs/ramfs/tree.go b/pkg/sentry/fs/ramfs/tree.go
index dfc9d3453..0ace636c9 100644
--- a/pkg/sentry/fs/ramfs/tree.go
+++ b/pkg/sentry/fs/ramfs/tree.go
@@ -20,9 +20,9 @@ import (
 	"strings"
 
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/anon"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // MakeDirectoryTree constructs a ramfs tree of all directories containing
@@ -71,7 +71,7 @@ func emptyDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
 	return fs.NewInode(ctx, dir, msrc, fs.StableAttr{
 		DeviceID:  anon.PseudoDevice.DeviceID(),
 		InodeID:   anon.PseudoDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.Directory,
 	})
 }
diff --git a/pkg/sentry/fs/sys/BUILD b/pkg/sentry/fs/sys/BUILD
index f2e8b9932..fdbc5f912 100644
--- a/pkg/sentry/fs/sys/BUILD
+++ b/pkg/sentry/fs/sys/BUILD
@@ -14,11 +14,11 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/hostarch",
         "//pkg/sentry/device",
         "//pkg/sentry/fs",
         "//pkg/sentry/fs/fsutil",
         "//pkg/sentry/fs/ramfs",
         "//pkg/sentry/kernel",
-        "//pkg/usermem",
     ],
 )
diff --git a/pkg/sentry/fs/sys/sys.go b/pkg/sentry/fs/sys/sys.go
index 0891645e4..101779a7a 100644
--- a/pkg/sentry/fs/sys/sys.go
+++ b/pkg/sentry/fs/sys/sys.go
@@ -17,16 +17,16 @@ package sys
 
 import (
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/ramfs"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 func newFile(ctx context.Context, node fs.InodeOperations, msrc *fs.MountSource) *fs.Inode {
 	sattr := fs.StableAttr{
 		DeviceID:  sysfsDevice.DeviceID(),
 		InodeID:   sysfsDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.SpecialFile,
 	}
 	return fs.NewInode(ctx, node, msrc, sattr)
@@ -37,7 +37,7 @@ func newDir(ctx context.Context, msrc *fs.MountSource, contents map[string]*fs.I
 	return fs.NewInode(ctx, d, msrc, fs.StableAttr{
 		DeviceID:  sysfsDevice.DeviceID(),
 		InodeID:   sysfsDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.SpecialDirectory,
 	})
 }
diff --git a/pkg/sentry/fs/timerfd/BUILD b/pkg/sentry/fs/timerfd/BUILD
index d16cdb4df..c7977a217 100644
--- a/pkg/sentry/fs/timerfd/BUILD
+++ b/pkg/sentry/fs/timerfd/BUILD
@@ -8,6 +8,7 @@ go_library(
     visibility = ["//pkg/sentry:internal"],
     deps = [
         "//pkg/context",
+        "//pkg/hostarch",
         "//pkg/sentry/fs",
         "//pkg/sentry/fs/anon",
         "//pkg/sentry/fs/fsutil",
diff --git a/pkg/sentry/fs/timerfd/timerfd.go b/pkg/sentry/fs/timerfd/timerfd.go
index 46511a6ac..c8ebe256c 100644
--- a/pkg/sentry/fs/timerfd/timerfd.go
+++ b/pkg/sentry/fs/timerfd/timerfd.go
@@ -20,6 +20,7 @@ import (
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/anon"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
@@ -124,7 +125,7 @@ func (t *TimerOperations) Read(ctx context.Context, file *fs.File, dst usermem.I
 	}
 	if val := atomic.SwapUint64(&t.val, 0); val != 0 {
 		var buf [sizeofUint64]byte
-		usermem.ByteOrder.PutUint64(buf[:], val)
+		hostarch.ByteOrder.PutUint64(buf[:], val)
 		if _, err := dst.CopyOut(ctx, buf[:]); err != nil {
 			// Linux does not undo consuming the number of expirations even if
 			// writing to userspace fails.
diff --git a/pkg/sentry/fs/tmpfs/BUILD b/pkg/sentry/fs/tmpfs/BUILD
index b521a86a2..90398376a 100644
--- a/pkg/sentry/fs/tmpfs/BUILD
+++ b/pkg/sentry/fs/tmpfs/BUILD
@@ -15,6 +15,7 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/hostarch",
         "//pkg/safemem",
         "//pkg/sentry/device",
         "//pkg/sentry/fs",
@@ -42,6 +43,7 @@ go_test(
     library = ":tmpfs",
     deps = [
         "//pkg/context",
+        "//pkg/hostarch",
         "//pkg/sentry/fs",
         "//pkg/sentry/kernel/contexttest",
         "//pkg/sentry/usage",
diff --git a/pkg/sentry/fs/tmpfs/file_test.go b/pkg/sentry/fs/tmpfs/file_test.go
index d4d613ea9..1718f9372 100644
--- a/pkg/sentry/fs/tmpfs/file_test.go
+++ b/pkg/sentry/fs/tmpfs/file_test.go
@@ -19,6 +19,7 @@ import (
 	"testing"
 
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/contexttest"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
@@ -31,7 +32,7 @@ func newFileInode(ctx context.Context) *fs.Inode {
 	return fs.NewInode(ctx, iops, m, fs.StableAttr{
 		DeviceID:  tmpfsDevice.DeviceID(),
 		InodeID:   tmpfsDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.RegularFile,
 	})
 }
diff --git a/pkg/sentry/fs/tmpfs/inode_file.go b/pkg/sentry/fs/tmpfs/inode_file.go
index ad4aea282..f4de8c968 100644
--- a/pkg/sentry/fs/tmpfs/inode_file.go
+++ b/pkg/sentry/fs/tmpfs/inode_file.go
@@ -21,6 +21,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
@@ -125,7 +126,7 @@ func NewMemfdInode(ctx context.Context, allowSeals bool) *fs.Inode {
 		Type:      fs.RegularFile,
 		DeviceID:  tmpfsDevice.DeviceID(),
 		InodeID:   tmpfsDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 	})
 }
 
@@ -392,7 +393,7 @@ func (rw *fileReadWriter) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error) {
 		switch {
 		case seg.Ok():
 			// Get internal mappings.
-			ims, err := mf.MapInternal(seg.FileRangeOf(seg.Range().Intersect(mr)), usermem.Read)
+			ims, err := mf.MapInternal(seg.FileRangeOf(seg.Range().Intersect(mr)), hostarch.Read)
 			if err != nil {
 				return done, err
 			}
@@ -463,7 +464,7 @@ func (rw *fileReadWriter) WriteFromBlocks(srcs safemem.BlockSeq) (uint64, error)
 		//
 		// See Linux, mm/filemap.c:generic_perform_write() and
 		// mm/shmem.c:shmem_write_begin().
-		if pgstart := int64(usermem.Addr(rw.f.attr.Size).RoundDown()); end > pgstart {
+		if pgstart := int64(hostarch.Addr(rw.f.attr.Size).RoundDown()); end > pgstart {
 			end = pgstart
 		}
 		if end <= rw.offset {
@@ -483,8 +484,8 @@ func (rw *fileReadWriter) WriteFromBlocks(srcs safemem.BlockSeq) (uint64, error)
 	mf := rw.f.kernel.MemoryFile()
 	// Page-aligned mr for when we need to allocate memory. RoundUp can't
 	// overflow since end is an int64.
-	pgstartaddr := usermem.Addr(rw.offset).RoundDown()
-	pgendaddr, _ := usermem.Addr(end).RoundUp()
+	pgstartaddr := hostarch.Addr(rw.offset).RoundDown()
+	pgendaddr, _ := hostarch.Addr(end).RoundUp()
 	pgMR := memmap.MappableRange{uint64(pgstartaddr), uint64(pgendaddr)}
 
 	var done uint64
@@ -494,7 +495,7 @@ func (rw *fileReadWriter) WriteFromBlocks(srcs safemem.BlockSeq) (uint64, error)
 		switch {
 		case seg.Ok():
 			// Get internal mappings.
-			ims, err := mf.MapInternal(seg.FileRangeOf(seg.Range().Intersect(mr)), usermem.Write)
+			ims, err := mf.MapInternal(seg.FileRangeOf(seg.Range().Intersect(mr)), hostarch.Write)
 			if err != nil {
 				return done, err
 			}
@@ -527,7 +528,7 @@ func (rw *fileReadWriter) WriteFromBlocks(srcs safemem.BlockSeq) (uint64, error)
 }
 
 // AddMapping implements memmap.Mappable.AddMapping.
-func (f *fileInodeOperations) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) error {
+func (f *fileInodeOperations) AddMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) error {
 	f.mapsMu.Lock()
 	defer f.mapsMu.Unlock()
 
@@ -544,7 +545,7 @@ func (f *fileInodeOperations) AddMapping(ctx context.Context, ms memmap.MappingS
 		pagesBefore := f.writableMappingPages
 
 		// ar is guaranteed to be page aligned per memmap.Mappable.
-		f.writableMappingPages += uint64(ar.Length() / usermem.PageSize)
+		f.writableMappingPages += uint64(ar.Length() / hostarch.PageSize)
 
 		if f.writableMappingPages < pagesBefore {
 			panic(fmt.Sprintf("Overflow while mapping potentially writable pages pointing to a tmpfs file. Before %v, after %v", pagesBefore, f.writableMappingPages))
@@ -555,7 +556,7 @@ func (f *fileInodeOperations) AddMapping(ctx context.Context, ms memmap.MappingS
 }
 
 // RemoveMapping implements memmap.Mappable.RemoveMapping.
-func (f *fileInodeOperations) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar usermem.AddrRange, offset uint64, writable bool) {
+func (f *fileInodeOperations) RemoveMapping(ctx context.Context, ms memmap.MappingSpace, ar hostarch.AddrRange, offset uint64, writable bool) {
 	f.mapsMu.Lock()
 	defer f.mapsMu.Unlock()
 
@@ -565,7 +566,7 @@ func (f *fileInodeOperations) RemoveMapping(ctx context.Context, ms memmap.Mappi
 		pagesBefore := f.writableMappingPages
 
 		// ar is guaranteed to be page aligned per memmap.Mappable.
-		f.writableMappingPages -= uint64(ar.Length() / usermem.PageSize)
+		f.writableMappingPages -= uint64(ar.Length() / hostarch.PageSize)
 
 		if f.writableMappingPages > pagesBefore {
 			panic(fmt.Sprintf("Underflow while unmapping potentially writable pages pointing to a tmpfs file. Before %v, after %v", pagesBefore, f.writableMappingPages))
@@ -574,12 +575,12 @@ func (f *fileInodeOperations) RemoveMapping(ctx context.Context, ms memmap.Mappi
 }
 
 // CopyMapping implements memmap.Mappable.CopyMapping.
-func (f *fileInodeOperations) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR usermem.AddrRange, offset uint64, writable bool) error {
+func (f *fileInodeOperations) CopyMapping(ctx context.Context, ms memmap.MappingSpace, srcAR, dstAR hostarch.AddrRange, offset uint64, writable bool) error {
 	return f.AddMapping(ctx, ms, dstAR, offset, writable)
 }
 
 // Translate implements memmap.Mappable.Translate.
-func (f *fileInodeOperations) Translate(ctx context.Context, required, optional memmap.MappableRange, at usermem.AccessType) ([]memmap.Translation, error) {
+func (f *fileInodeOperations) Translate(ctx context.Context, required, optional memmap.MappableRange, at hostarch.AccessType) ([]memmap.Translation, error) {
 	f.dataMu.Lock()
 	defer f.dataMu.Unlock()
 
@@ -612,7 +613,7 @@ func (f *fileInodeOperations) Translate(ctx context.Context, required, optional
 			Source: segMR,
 			File:   mf,
 			Offset: seg.FileRangeOf(segMR).Start,
-			Perms:  usermem.AnyAccess,
+			Perms:  hostarch.AnyAccess,
 		})
 		translatedEnd = segMR.End
 	}
diff --git a/pkg/sentry/fs/tmpfs/tmpfs.go b/pkg/sentry/fs/tmpfs/tmpfs.go
index cf4ed5de0..577052888 100644
--- a/pkg/sentry/fs/tmpfs/tmpfs.go
+++ b/pkg/sentry/fs/tmpfs/tmpfs.go
@@ -20,6 +20,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/fs/ramfs"
@@ -28,7 +29,6 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/socket/unix/transport"
 	"gvisor.dev/gvisor/pkg/sentry/usage"
 	"gvisor.dev/gvisor/pkg/syserror"
-	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 var fsInfo = fs.Info{
@@ -41,8 +41,8 @@ var fsInfo = fs.Info{
 	// chosen to ensure that BlockSize * Blocks does not overflow int64 (which
 	// applications may also handle incorrectly).
 	// TODO(b/29637826): allow configuring a tmpfs size and enforce it.
-	TotalBlocks: math.MaxInt64 / usermem.PageSize,
-	FreeBlocks:  math.MaxInt64 / usermem.PageSize,
+	TotalBlocks: math.MaxInt64 / hostarch.PageSize,
+	FreeBlocks:  math.MaxInt64 / hostarch.PageSize,
 }
 
 // rename implements fs.InodeOperations.Rename for tmpfs nodes.
@@ -99,7 +99,7 @@ func NewDir(ctx context.Context, contents map[string]*fs.Inode, owner fs.FileOwn
 	return fs.NewInode(ctx, d, msrc, fs.StableAttr{
 		DeviceID:  tmpfsDevice.DeviceID(),
 		InodeID:   tmpfsDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.Directory,
 	})
 }
@@ -232,7 +232,7 @@ func (d *Dir) newCreateOps() *ramfs.CreateOps {
 			return fs.NewInode(ctx, iops, dir.MountSource, fs.StableAttr{
 				DeviceID:  tmpfsDevice.DeviceID(),
 				InodeID:   tmpfsDevice.NextIno(),
-				BlockSize: usermem.PageSize,
+				BlockSize: hostarch.PageSize,
 				Type:      fs.RegularFile,
 			}), nil
 		},
@@ -281,7 +281,7 @@ func NewSymlink(ctx context.Context, target string, owner fs.FileOwner, msrc *fs
 	return fs.NewInode(ctx, s, msrc, fs.StableAttr{
 		DeviceID:  tmpfsDevice.DeviceID(),
 		InodeID:   tmpfsDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.Symlink,
 	})
 }
@@ -311,7 +311,7 @@ func NewSocket(ctx context.Context, socket transport.BoundEndpoint, owner fs.Fil
 	return fs.NewInode(ctx, s, msrc, fs.StableAttr{
 		DeviceID:  tmpfsDevice.DeviceID(),
 		InodeID:   tmpfsDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.Socket,
 	})
 }
@@ -348,7 +348,7 @@ func NewFifo(ctx context.Context, owner fs.FileOwner, perms fs.FilePermissions,
 	return fs.NewInode(ctx, fifoIops, msrc, fs.StableAttr{
 		DeviceID:  tmpfsDevice.DeviceID(),
 		InodeID:   tmpfsDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.Pipe,
 	})
 }
diff --git a/pkg/sentry/fs/tty/BUILD b/pkg/sentry/fs/tty/BUILD
index e6d0eb359..86ada820e 100644
--- a/pkg/sentry/fs/tty/BUILD
+++ b/pkg/sentry/fs/tty/BUILD
@@ -17,6 +17,7 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/hostarch",
         "//pkg/marshal/primitive",
         "//pkg/refs",
         "//pkg/safemem",
diff --git a/pkg/sentry/fs/tty/dir.go b/pkg/sentry/fs/tty/dir.go
index c2da80bc2..13c9dbe7d 100644
--- a/pkg/sentry/fs/tty/dir.go
+++ b/pkg/sentry/fs/tty/dir.go
@@ -22,6 +22,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
@@ -122,7 +123,7 @@ func newDir(ctx context.Context, m *fs.MountSource) *fs.Inode {
 		// TODO(b/75267214): Since ptsDevice must be shared between
 		// different mounts, we must not assign fixed numbers.
 		InodeID:   ptsDevice.NextIno(),
-		BlockSize: usermem.PageSize,
+		BlockSize: hostarch.PageSize,
 		Type:      fs.Directory,
 	})
 }