From d00a3810c16207d2541b7796a73cca5a24ea3742 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 27 May 2015 15:39:40 +0100 Subject: [PATCH] arm64: context-switch user tls register tpidr_el0 for compat tasks MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Tested-by: André Hentschel Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/processor.h | 19 +++++++++++- arch/arm64/kernel/process.c | 47 +++++++++++++----------------- 2 files changed, 38 insertions(+), 28 deletions(-) diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index d2c37a1df0eb..e4c893e54f01 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -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) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index c506bee6b613..369f485f4b71 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -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" -- 2.45.2