Messages in this thread | | | From | Andy Lutomirski <> | Date | Wed, 11 Feb 2015 12:36:36 -0800 | Subject | Re: [PATCH 02/11] x86: code shrink in paranoid_exit |
| |
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? (Yes, this could be a followup, but it could be easier to spot now by changing macros like RESTORE_XYZ.)
--Andy
| |