From 9b064fc3f95a8e44e929fdf4d6037334ea03d15b Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 14 Dec 2012 13:49:35 -0500 Subject: new helper: compat_user_stack_pointer() Compat counterpart of current_user_stack_pointer(); for most of the biarch architectures those two are identical, but e.g. arm64 and arm use different registers for stack pointer... Note that amd64 variants of current_user_stack_pointer/compat_user_stack_pointer do *not* rely on pt_regs having been through FIXUP_TOP_OF_STACK. Signed-off-by: Al Viro --- arch/arm64/include/asm/compat.h | 5 +++-- arch/x86/include/asm/ptrace.h | 7 +++++++ include/linux/compat.h | 3 +++ 3 files changed, 13 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/compat.h b/arch/arm64/include/asm/compat.h index 37e610dc084e..d9ec40217a27 100644 --- a/arch/arm64/include/asm/compat.h +++ b/arch/arm64/include/asm/compat.h @@ -209,10 +209,11 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr) return (u32)(unsigned long)uptr; } +#define compat_user_stack_pointer() (current_pt_regs()->compat_sp) + static inline void __user *arch_compat_alloc_user_space(long len) { - struct pt_regs *regs = task_pt_regs(current); - return (void __user *)regs->compat_sp - len; + return (void __user *)compat_user_stack_pointer() - len; } struct compat_ipc64_perm { diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 19f16ebaf4fa..7e560b6daf5d 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -203,6 +203,13 @@ static inline bool user_64bit_mode(struct pt_regs *regs) return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs; #endif } + +#define current_user_stack_pointer() this_cpu_read(old_rsp) +/* ia32 vs. x32 difference */ +#define compat_user_stack_pointer() \ + (test_thread_flag(TIF_IA32) \ + ? current_pt_regs()->sp \ + : this_cpu_read(old_rsp)) #endif #ifdef CONFIG_X86_32 diff --git a/include/linux/compat.h b/include/linux/compat.h index a7877fa809fd..62bb76f91baf 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -65,6 +65,9 @@ #endif /* CONFIG_HAVE_SYSCALL_WRAPPERS */ +#ifndef compat_user_stack_pointer +#define compat_user_stack_pointer() current_user_stack_pointer() +#endif #define compat_jiffies_to_clock_t(x) \ (((unsigned long)(x) * COMPAT_USER_HZ) / HZ) -- cgit v1.2.3