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| author | Denys Vlasenko <dvlasenk@redhat.com> | 2015-03-19 18:17:45 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-03-24 19:42:37 +0100 |
| commit | b3fe8ba320ace38cee6859b4c015d81627254ddb (patch) | |
| tree | 5d831988166280490c4593f4505dacfca46e54c4 /arch/x86/kernel/entry_64.S | |
| parent | x86/asm/entry/64: Fold syscall32_cpu_init() into its sole user (diff) | |
| download | linux-b3fe8ba320ace38cee6859b4c015d81627254ddb.tar.xz linux-b3fe8ba320ace38cee6859b4c015d81627254ddb.zip | |
x86/asm/entry/64: Change the THREAD_INFO() definition to not depend on KERNEL_STACK_OFFSET
This changes the THREAD_INFO() definition and all its callsites
so that they do not count stack position from
(top of stack - KERNEL_STACK_OFFSET), but from top of stack.
Semi-mysterious expressions THREAD_INFO(%rsp,RIP) - "why RIP??"
are now replaced by more logical THREAD_INFO(%rsp,SIZEOF_PTREGS)
- "calculate thread_info's address using information that
rsp is SIZEOF_PTREGS bytes below top of stack".
While at it, replace "(off)-THREAD_SIZE(reg)" with equivalent
"((off)-THREAD_SIZE)(reg)". The form without parentheses
falsely looks like we invoke THREAD_SIZE() macro.
Improve comment atop THREAD_INFO macro definition.
This patch does not change generated code (verified by objdump).
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
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/1426785469-15125-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/entry_64.S')
| -rw-r--r-- | arch/x86/kernel/entry_64.S | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 9184392a47b3..8076df982a18 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -258,7 +258,7 @@ GLOBAL(system_call_after_swapgs) SAVE_C_REGS_EXCEPT_RAX_RCX_R11 movq $-ENOSYS,RAX(%rsp) CFI_REL_OFFSET rip,RIP - testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP) + testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,SIZEOF_PTREGS) jnz tracesys system_call_fastpath: #if __SYSCALL_MASK == ~0 @@ -276,7 +276,7 @@ system_call_fastpath: * Has incompletely filled pt_regs, iret frame is also incomplete. */ ret_from_sys_call: - testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP) + testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,SIZEOF_PTREGS) jnz int_ret_from_sys_call_fixup /* Go the the slow path */ LOCKDEP_SYS_EXIT |