x86/entry: Remove skip_r11rcx

commit 1b331eeea7b8676fc5dbdf80d0a07e41be226177 upstream.

Yes, r11 and rcx have been restored previously, but since they're being
popped anyway (into rsi) might as well pop them into their own regs --
setting them to the value they already are.

Less magical code.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220506121631.365070674@infradead.org
[bwh: Backported to 5.10: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 07a9331d55e73ddf846c595ebdbd3800db25c43c..2be2595e4458d5444895818322c9fb67ed594caf 100644 (file)
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -146,27 +146,19 @@ For 32-bit we have the following conventions - kernel is built with
 
 .endm
 
-.macro POP_REGS pop_rdi=1 skip_r11rcx=0
+.macro POP_REGS pop_rdi=1
        popq %r15
        popq %r14
        popq %r13
        popq %r12
        popq %rbp
        popq %rbx
-       .if \skip_r11rcx
-       popq %rsi
-       .else
        popq %r11
-       .endif
        popq %r10
        popq %r9
        popq %r8
        popq %rax
-       .if \skip_r11rcx
-       popq %rsi
-       .else
        popq %rcx
-       .endif
        popq %rdx
        popq %rsi
        .if \pop_rdi

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index fb77ef8ecde5c40b750b8849fa98919405986e7f..afdc4f5370c3b09dd6f4ca2e93ea1c94ace1360b 100644 (file)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -191,8 +191,7 @@ SYM_INNER_LABEL(entry_SYSCALL_64_after_hwframe, SYM_L_GLOBAL)
         * perf profiles. Nothing jumps here.
         */
 syscall_return_via_sysret:
-       /* rcx and r11 are already restored (see code above) */
-       POP_REGS pop_rdi=0 skip_r11rcx=1
+       POP_REGS pop_rdi=0
 
        /*
         * Now all regs are restored except RSP and RDI.