Update package locations.

Because the abi will depend on the core types for marshalling (usermem,
context, safemem, safecopy), these need to be flattened from the sentry
directory. These packages contain no sentry-specific details.

PiperOrigin-RevId: 291811289

1 files changed, 74 insertions, 0 deletions

diff --git a/pkg/safecopy/memclr_arm64.s b/pkg/safecopy/memclr_arm64.s
new file mode 100644
index 000000000..7361b9067
--- /dev/null
+++ b/pkg/safecopy/memclr_arm64.s
@@ -0,0 +1,74 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "textflag.h"
+
+// handleMemclrFault returns (the value stored in R0, the value stored in R1).
+// Control is transferred to it when memclr below receives SIGSEGV or SIGBUS,
+// with the faulting address stored in R0 and the signal number stored in R1.
+//
+// It must have the same frame configuration as memclr so that it can undo any
+// potential call frame set up by the assembler.
+TEXT handleMemclrFault(SB), NOSPLIT, $0-28
+	MOVD R0, addr+16(FP)
+	MOVW R1, sig+24(FP)
+	RET
+
+// See the corresponding doc in safecopy_unsafe.go
+//
+// The code is derived from runtime.memclrNoHeapPointers.
+//
+// func memclr(ptr unsafe.Pointer, n uintptr) (fault unsafe.Pointer, sig int32)
+TEXT ·memclr(SB), NOSPLIT, $0-28
+	// Store 0 as the returned signal number. If we run to completion,
+	// this is the value the caller will see; if a signal is received,
+	// handleMemclrFault will store a different value in this address.
+	MOVW $0, sig+24(FP)
+	MOVD ptr+0(FP), R0
+	MOVD n+8(FP), R1
+
+	// If size is less than 16 bytes, use tail_zero to zero what remains
+	CMP $16, R1
+	BLT tail_zero
+	// Get buffer offset into 16 byte aligned address for better performance
+	ANDS $15, R0, ZR
+	BNE unaligned_to_16
+aligned_to_16:
+	LSR $4, R1, R2
+zero_by_16:
+	STP.P (ZR, ZR), 16(R0) // Store pair with post index.
+	SUBS $1, R2, R2
+	BNE zero_by_16
+	ANDS $15, R1, R1
+	BEQ end
+
+	// Zero buffer with size=R1 < 16
+tail_zero:
+	TBZ $3, R1, tail_zero_4
+	MOVD.P ZR, 8(R0)
+tail_zero_4:
+	TBZ $2, R1, tail_zero_2
+	MOVW.P ZR, 4(R0)
+tail_zero_2:
+	TBZ $1, R1, tail_zero_1
+	MOVH.P ZR, 2(R0)
+tail_zero_1:
+	TBZ $0, R1, end
+	MOVB ZR, (R0)
+end:
+	RET
+
+unaligned_to_16:
+	MOVD R0, R2
+head_loop:
+	MOVBU.P ZR, 1(R0)
+	ANDS $15, R0, ZR
+	BNE head_loop
+	// Adjust length for what remains
+	SUB R2, R0, R3
+	SUB R3, R1
+	// If size is less than 16 bytes, use tail_zero to zero what remains
+	CMP $16, R1
+	BLT tail_zero
+	B aligned_to_16