Messages in this thread | | | Date | Wed, 11 Feb 2015 22:13:57 +0100 | From | Denys Vlasenko <> | Subject | Re: [PATCH 02/11] x86: code shrink in paranoid_exit |
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On 02/11/2015 09:36 PM, Andy Lutomirski wrote: > On Wed, Jan 14, 2015 at 1:48 PM, Denys Vlasenko <dvlasenk@redhat.com> wrote: >> RESTORE_EXTRA_REGS + RESTORE_C_REGS looks small, but it's >> a lot of instructions (fourteen). Let's reuse them. >> >> 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 >> --- >> arch/x86/kernel/entry_64.S | 6 ++---- >> 1 file changed, 2 insertions(+), 4 deletions(-) >> >> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S >> index a21b5b3..f5e815e 100644 >> --- a/arch/x86/kernel/entry_64.S >> +++ b/arch/x86/kernel/entry_64.S >> @@ -1270,12 +1270,10 @@ ENTRY(paranoid_exit) >> jnz paranoid_restore >> TRACE_IRQS_IRETQ 0 >> SWAPGS_UNSAFE_STACK >> - RESTORE_EXTRA_REGS >> - RESTORE_C_REGS >> - REMOVE_PT_GPREGS_FROM_STACK 8 >> - INTERRUPT_RETURN >> + jmp paranoid_restore1 >> paranoid_restore: >> TRACE_IRQS_IRETQ_DEBUG 0 >> +paranoid_restore1: >> RESTORE_EXTRA_REGS >> RESTORE_C_REGS >> REMOVE_PT_GPREGS_FROM_STACK 8 > > This is sort of a reply to the wrong thread, but wouldn't it be nicer > if we could pop a bunch of regs instead of using mov followed by add?
I like this (pop instead of mov) too.
> (Yes, this could be a followup, but it could be easier to spot now by > changing macros like RESTORE_XYZ.)
I don't understand what this means. "Let's switch to pops now, in this patch"? Or something else?
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