From c04958e2fa456587277baef361868bddc0df9e49 Mon Sep 17 00:00:00 2001
From: Haibo Xu <haibo.xu@arm.com>
Date: Mon, 13 Jan 2020 07:44:58 +0000
Subject: Enable thread local storage support on arm64.

Linux use the task.thread.uw.tp_value field to store the
TLS pointer on arm64 platform, and we use a similar way
in gvisor to store it in the arch/State struct.

Signed-off-by: Haibo Xu <haibo.xu@arm.com>
Change-Id: Ie76b5c6d109bc27ccfd594008a96753806db7764
---
 pkg/sentry/arch/arch_aarch64.go |  5 +++++
 pkg/sentry/arch/arch_arm64.go   | 13 +++++++------
 2 files changed, 12 insertions(+), 6 deletions(-)

(limited to 'pkg/sentry/arch')

diff --git a/pkg/sentry/arch/arch_aarch64.go b/pkg/sentry/arch/arch_aarch64.go
index 5053393c1..b998f84fc 100644
--- a/pkg/sentry/arch/arch_aarch64.go
+++ b/pkg/sentry/arch/arch_aarch64.go
@@ -95,6 +95,9 @@ type State struct {
 	// Our floating point state.
 	aarch64FPState `state:"wait"`
 
+	// TLS pointer
+	TPValue uint64
+
 	// FeatureSet is a pointer to the currently active feature set.
 	FeatureSet *cpuid.FeatureSet
 }
@@ -145,6 +148,7 @@ func (s *State) Fork() State {
 	return State{
 		Regs:           s.Regs,
 		aarch64FPState: s.aarch64FPState.fork(),
+		TPValue:        s.TPValue,
 		FeatureSet:     s.FeatureSet,
 	}
 }
@@ -255,6 +259,7 @@ func (s *State) PtraceSetFPRegs(src io.Reader) (int, error) {
 const (
 	_NT_PRSTATUS = 1
 	_NT_PRFPREG  = 2
+	_NT_ARM_TLS  = 0x401
 )
 
 // PtraceGetRegSet implements Context.PtraceGetRegSet.
diff --git a/pkg/sentry/arch/arch_arm64.go b/pkg/sentry/arch/arch_arm64.go
index 885115ae2..db99c5acb 100644
--- a/pkg/sentry/arch/arch_arm64.go
+++ b/pkg/sentry/arch/arch_arm64.go
@@ -140,16 +140,17 @@ func (c *context64) SetStack(value uintptr) {
 
 // TLS returns the current TLS pointer.
 func (c *context64) TLS() uintptr {
-	// TODO(gvisor.dev/issue/1238): TLS is not supported.
-	// MRS_TPIDR_EL0
-	return 0
+	return uintptr(c.TPValue)
 }
 
 // SetTLS sets the current TLS pointer. Returns false if value is invalid.
 func (c *context64) SetTLS(value uintptr) bool {
-	// TODO(gvisor.dev/issue/1238): TLS is not supported.
-	// MSR_TPIDR_EL0
-	return false
+	if value >= uintptr(maxAddr64) {
+		return false
+	}
+
+	c.TPValue = uint64(value)
+	return true
 }
 
 // SetOldRSeqInterruptedIP implements Context.SetOldRSeqInterruptedIP.
-- 
cgit v1.2.3