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| author | Al Viro <viro@zeniv.linux.org.uk> | 2012-12-14 13:49:35 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2012-12-19 18:07:40 -0500 |
| commit | 9b064fc3f95a8e44e929fdf4d6037334ea03d15b (patch) | |
| tree | dd1a2a6075667841f88b1ea8b62f4df2e18c3c68 /arch | |
| parent | 5c49574ffd7ac07eae8c3b065d19e6ebc7e4760f (diff) | |
| download | lwn-9b064fc3f95a8e44e929fdf4d6037334ea03d15b.tar.gz lwn-9b064fc3f95a8e44e929fdf4d6037334ea03d15b.zip | |
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 <viro@zeniv.linux.org.uk>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/compat.h | 5 | ||||
| -rw-r--r-- | arch/x86/include/asm/ptrace.h | 7 |
2 files changed, 10 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 |