x86/entry/64: Merge the POP_C_REGS and POP_EXTRA_REGS macros into a single POP_REGS macro

The two special, opencoded cases for POP_C_REGS can be handled by ASM
macros.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dan.j.williams@intel.com
Link: http://lkml.kernel.org/r/20180211104949.12992-3-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 15 insertions, 26 deletions

diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h
index 8907a6593b42..3bda31736a7b 100644
--- a/arch/x86/entry/calling.h
+++ b/arch/x86/entry/calling.h
@@ -139,25 +139,32 @@ For 32-bit we have the following conventions - kernel is built with
         xorq %r15, %r15
         .endm
 
-        .macro POP_EXTRA_REGS
+        .macro POP_REGS pop_rdi=1 skip_r11rcx=0
         popq %r15
         popq %r14
         popq %r13
         popq %r12
         popq %rbp
         popq %rbx
-        .endm
-
-        .macro POP_C_REGS
+        .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
         popq %rdi
+        .endif
         .endm
 
         .macro icebp
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 1a6fc0136225..7351c91fb7df 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -334,15 +334,7 @@ GLOBAL(entry_SYSCALL_64_after_hwframe)
 syscall_return_via_sysret:
         /* rcx and r11 are already restored (see code above) */
         UNWIND_HINT_EMPTY
-        POP_EXTRA_REGS
-        popq    %rsi    /* skip r11 */
-        popq    %r10
-        popq    %r9
-        popq    %r8
-        popq    %rax
-        popq    %rsi    /* skip rcx */
-        popq    %rdx
-        popq    %rsi
+        POP_REGS pop_rdi=0 skip_r11rcx=1
 
         /*
          * Now all regs are restored except RSP and RDI.
@@ -635,15 +627,7 @@ GLOBAL(swapgs_restore_regs_and_return_to_usermode)
         ud2
 1:
 #endif
-        POP_EXTRA_REGS
-        popq    %r11
-        popq    %r10
-        popq    %r9
-        popq    %r8
-        popq    %rax
-        popq    %rcx
-        popq    %rdx
-        popq    %rsi
+        POP_REGS pop_rdi=0
 
         /*
          * The stack is now user RDI, orig_ax, RIP, CS, EFLAGS, RSP, SS.
@@ -701,8 +685,7 @@ GLOBAL(restore_regs_and_return_to_kernel)
         ud2
 1:
 #endif
-        POP_EXTRA_REGS
-        POP_C_REGS
+        POP_REGS
         addq    $8, %rsp        /* skip regs->orig_ax */
         INTERRUPT_RETURN
 
@@ -1661,8 +1644,7 @@ end_repeat_nmi:
 nmi_swapgs:
         SWAPGS_UNSAFE_STACK
 nmi_restore:
-        POP_EXTRA_REGS
-        POP_C_REGS
+        POP_REGS
 
         /*
          * Skip orig_ax and the "outermost" frame to point RSP at the "iret"