arm64: context-switch user tls register tpidr_el0 for compat tasks
Since commit a4780adeefd0 ("ARM: 7735/2: Preserve the user r/w register
TPIDRURW on context switch and fork"), arch/arm/ has context switched
the user-writable TLS register, so do the same for compat tasks running
under the arm64 kernel.
Reported-by: André Hentschel <nerv@dawncrow.de>
Tested-by: André Hentschel <nerv@dawncrow.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index d2c37a1..e4c893e 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -78,13 +78,30 @@
struct thread_struct {
struct cpu_context cpu_context; /* cpu context */
- unsigned long tp_value;
+ unsigned long tp_value; /* TLS register */
+#ifdef CONFIG_COMPAT
+ unsigned long tp2_value;
+#endif
struct fpsimd_state fpsimd_state;
unsigned long fault_address; /* fault info */
unsigned long fault_code; /* ESR_EL1 value */
struct debug_info debug; /* debugging */
};
+#ifdef CONFIG_COMPAT
+#define task_user_tls(t) \
+({ \
+ unsigned long *__tls; \
+ if (is_compat_thread(task_thread_info(t))) \
+ __tls = &(t)->thread.tp2_value; \
+ else \
+ __tls = &(t)->thread.tp_value; \
+ __tls; \
+ })
+#else
+#define task_user_tls(t) (&(t)->thread.tp_value)
+#endif
+
#define INIT_THREAD { }
static inline void start_thread_common(struct pt_regs *regs, unsigned long pc)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index c506bee..369f485 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -244,35 +244,35 @@
unsigned long stk_sz, struct task_struct *p)
{
struct pt_regs *childregs = task_pt_regs(p);
- unsigned long tls = p->thread.tp_value;
memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
if (likely(!(p->flags & PF_KTHREAD))) {
*childregs = *current_pt_regs();
childregs->regs[0] = 0;
- if (is_compat_thread(task_thread_info(p))) {
- if (stack_start)
+
+ /*
+ * Read the current TLS pointer from tpidr_el0 as it may be
+ * out-of-sync with the saved value.
+ */
+ asm("mrs %0, tpidr_el0" : "=r" (*task_user_tls(p)));
+
+ if (stack_start) {
+ if (is_compat_thread(task_thread_info(p)))
childregs->compat_sp = stack_start;
- } else {
- /*
- * Read the current TLS pointer from tpidr_el0 as it may be
- * out-of-sync with the saved value.
- */
- asm("mrs %0, tpidr_el0" : "=r" (tls));
- if (stack_start) {
- /* 16-byte aligned stack mandatory on AArch64 */
- if (stack_start & 15)
- return -EINVAL;
+ /* 16-byte aligned stack mandatory on AArch64 */
+ else if (stack_start & 15)
+ return -EINVAL;
+ else
childregs->sp = stack_start;
- }
}
+
/*
* If a TLS pointer was passed to clone (4th argument), use it
* for the new thread.
*/
if (clone_flags & CLONE_SETTLS)
- tls = childregs->regs[3];
+ p->thread.tp_value = childregs->regs[3];
} else {
memset(childregs, 0, sizeof(struct pt_regs));
childregs->pstate = PSR_MODE_EL1h;
@@ -281,7 +281,6 @@
}
p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
p->thread.cpu_context.sp = (unsigned long)childregs;
- p->thread.tp_value = tls;
ptrace_hw_copy_thread(p);
@@ -292,18 +291,12 @@
{
unsigned long tpidr, tpidrro;
- if (!is_compat_task()) {
- asm("mrs %0, tpidr_el0" : "=r" (tpidr));
- current->thread.tp_value = tpidr;
- }
+ asm("mrs %0, tpidr_el0" : "=r" (tpidr));
+ *task_user_tls(current) = tpidr;
- if (is_compat_thread(task_thread_info(next))) {
- tpidr = 0;
- tpidrro = next->thread.tp_value;
- } else {
- tpidr = next->thread.tp_value;
- tpidrro = 0;
- }
+ tpidr = *task_user_tls(next);
+ tpidrro = is_compat_thread(task_thread_info(next)) ?
+ next->thread.tp_value : 0;
asm(
" msr tpidr_el0, %0\n"
