Messages in this thread Patch in this message | | | From | Andy Lutomirski <> | Subject | [PATCH 06/16] x86: code shrink in paranoid_exit | Date | Thu, 26 Feb 2015 14:40:29 -0800 |
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From: Denys Vlasenko <dvlasenk@redhat.com>
RESTORE_EXTRA_REGS + RESTORE_C_REGS looks small, but it's a lot of instructions (fourteen). Let's reuse them.
[I changed the labels. In vda's version of this patch, paranoid_exit_restore was paranoid_restore1 and paranoid_exit_no_swapgs was paranoid_restore. This still isn't great, but I think it's a lot better. --Andy]
Link: http://lkml.kernel.org/r/1421272101-16847-2-git-send-email-dvlasenk@redhat.com Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> CC: Linus Torvalds <torvalds@linux-foundation.org> CC: Oleg Nesterov <oleg@redhat.com> CC: Borislav Petkov <bp@alien8.de> CC: "H. Peter Anvin" <hpa@zytor.com> CC: Andy Lutomirski <luto@amacapital.net> CC: Frederic Weisbecker <fweisbec@gmail.com> CC: X86 ML <x86@kernel.org> CC: Alexei Starovoitov <ast@plumgrid.com> CC: Will Drewry <wad@chromium.org> CC: Kees Cook <keescook@chromium.org> CC: linux-kernel@vger.kernel.org Signed-off-by: Andy Lutomirski <luto@amacapital.net> --- arch/x86/kernel/entry_64.S | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index b4469ed2b30f..e5cad016cb60 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1282,15 +1282,13 @@ ENTRY(paranoid_exit) DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF_DEBUG testl %ebx,%ebx /* swapgs needed? */ - jnz paranoid_restore + jnz paranoid_exit_no_swapgs TRACE_IRQS_IRETQ 0 SWAPGS_UNSAFE_STACK - RESTORE_EXTRA_REGS - RESTORE_C_REGS - REMOVE_PT_GPREGS_FROM_STACK 8 - INTERRUPT_RETURN -paranoid_restore: + jmp paranoid_exit_restore +paranoid_exit_no_swapgs: TRACE_IRQS_IRETQ_DEBUG 0 +paranoid_exit_restore: RESTORE_EXTRA_REGS RESTORE_C_REGS REMOVE_PT_GPREGS_FROM_STACK 8 -- 2.1.0
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