Messages in this thread Patch in this message | | | From | Denys Vlasenko <> | Subject | [PATCH 3/3] x86: do not save callee-preserved registers around lockdep_sys_exit_thunk | Date | Wed, 25 Mar 2015 21:14:28 +0100 |
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Internally, lockdep_sys_exit_thunk saves callee-clobbered registers, and calls a C function, lockdep_sys_exit. Thus, callee-preserved registers won't be mangled, there is no need to save them.
Patch was run-tested.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> CC: Linus Torvalds <torvalds@linux-foundation.org> CC: Steven Rostedt <rostedt@goodmis.org> CC: Ingo Molnar <mingo@kernel.org> CC: Borislav Petkov <bp@alien8.de> CC: "H. Peter Anvin" <hpa@zytor.com> CC: Andy Lutomirski <luto@amacapital.net> CC: Oleg Nesterov <oleg@redhat.com> CC: Frederic Weisbecker <fweisbec@gmail.com> CC: Alexei Starovoitov <ast@plumgrid.com> CC: Will Drewry <wad@chromium.org> CC: Kees Cook <keescook@chromium.org> CC: x86@kernel.org CC: linux-kernel@vger.kernel.org --- arch/x86/include/asm/irqflags.h | 2 -- 1 file changed, 2 deletions(-)
diff --git a/arch/x86/include/asm/irqflags.h b/arch/x86/include/asm/irqflags.h index 19355f3..9a63eae 100644 --- a/arch/x86/include/asm/irqflags.h +++ b/arch/x86/include/asm/irqflags.h @@ -179,9 +179,7 @@ static inline int arch_irqs_disabled(void) # define LOCKDEP_SYS_EXIT_IRQ \ TRACE_IRQS_ON; \ sti; \ - SAVE_EXTRA_REGS; \ call lockdep_sys_exit_thunk; \ - RESTORE_EXTRA_REGS; \ cli; \ TRACE_IRQS_OFF; # else -- 1.8.1.4
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