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arm64: context-switch user tls register tpidr_el0 for compat tasks

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Since commit a4780adeef ("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>
This commit is contained in:
Will Deacon 2015-05-27 15:39:40 +01:00 committed by Catalin Marinas
parent 05981277a4
commit d00a3810c1
2 changed files with 38 additions and 28 deletions
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19
arch/arm64/include/asm/processor.h
View File

@ -78,13 +78,30 @@ struct cpu_context {
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)

47
arch/arm64/kernel/process.c
View File

@ -244,35 +244,35 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
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 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
}
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 @@ static void tls_thread_switch(struct task_struct *next)
{
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"