diff options
| author | Denys Vlasenko <dvlasenk@redhat.com> | 2015-03-09 19:39:23 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-03-10 13:56:10 +0100 |
| commit | 263042e4630a85e856b4a8cd72f28dab33ef4741 (patch) | |
| tree | 268f16dc93d2f111ffd484300042df3bb089e050 /arch/x86/include/asm/compat.h | |
| parent | 616ab249f1e42f6135642183529f910fcedc2642 (diff) | |
x86/asm/entry/64: Save user RSP in pt_regs->sp on SYSCALL64 fastpath
Prepare for the removal of 'usersp', by simplifying PER_CPU(old_rsp) usage:
- use it only as temp storage
- store the userspace stack pointer immediately in pt_regs->sp
on syscall entry, instead of using it later, on syscall exit.
- change C code to use pt_regs->sp only, instead of PER_CPU(old_rsp)
and task->thread.usersp.
FIXUP/RESTORE_TOP_OF_STACK are simplified as well.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1425926364-9526-4-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/compat.h')
| -rw-r--r-- | arch/x86/include/asm/compat.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h index 59c6c401f79f..acdee09228b3 100644 --- a/arch/x86/include/asm/compat.h +++ b/arch/x86/include/asm/compat.h @@ -301,7 +301,7 @@ static inline void __user *arch_compat_alloc_user_space(long len) sp = task_pt_regs(current)->sp; } else { /* -128 for the x32 ABI redzone */ - sp = this_cpu_read(old_rsp) - 128; + sp = task_pt_regs(current)->sp - 128; } return (void __user *)round_down(sp - len, 16); |