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| 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/kernel/process_64.c | |
| parent | x86/asm/entry/64: Remove stub_iopl (diff) | |
| download | linux-dev-263042e4630a85e856b4a8cd72f28dab33ef4741.tar.xz linux-dev-263042e4630a85e856b4a8cd72f28dab33ef4741.zip | |
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/kernel/process_64.c')
| -rw-r--r-- | arch/x86/kernel/process_64.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 1e393d27d701..e8c124a1f885 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -602,6 +602,5 @@ long sys_arch_prctl(int code, unsigned long addr) unsigned long KSTK_ESP(struct task_struct *task) { - return (test_tsk_thread_flag(task, TIF_IA32)) ? - (task_pt_regs(task)->sp) : ((task)->thread.usersp); + return task_pt_regs(task)->sp; } |