[Xen-changelog] [xen stable-4.9] x86/entry: Use 32bit xors rater than 64bit xors for clearing GPRs

[patchbot@xxxxxxx]

commit 1ab9bae78de85906df0b933b2b0e067810c6fa00
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Mar 6 16:02:23 2018 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Mar 6 16:02:23 2018 +0100

    x86/entry: Use 32bit xors rater than 64bit xors for clearing GPRs
    
    Intel's Silvermont/Knights Landing architecture treats them as full ALU
    operations, rather than zeroing idoms.
    
    No functional change, and no change in code volume (only changing the bit
    selection in the REX prefix).
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
    master commit: eb1d3a3f04b85d596862a4c9dcf796e67ab4dc09
    master date: 2018-02-15 11:08:27 +0000
---
 xen/include/asm-x86/asm_defns.h | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/xen/include/asm-x86/asm_defns.h b/xen/include/asm-x86/asm_defns.h
index ba96b0e823..77bc2ec157 100644
--- a/xen/include/asm-x86/asm_defns.h
+++ b/xen/include/asm-x86/asm_defns.h
@@ -271,10 +271,10 @@ static always_inline void stac(void)
         movq  %r10,UREGS_r10(%rsp)
         movq  %r11,UREGS_r11(%rsp)
 .endif
-        xor   %r8, %r8
-        xor   %r9, %r9
-        xor   %r10, %r10
-        xor   %r11, %r11
+        xor   %r8d, %r8d
+        xor   %r9d, %r9d
+        xor   %r10d, %r10d
+        xor   %r11d, %r11d
         movq  %rbx,UREGS_rbx(%rsp)
         xor   %ebx, %ebx
         movq  %rbp,UREGS_rbp(%rsp)
@@ -291,10 +291,10 @@ static always_inline void stac(void)
         movq  %r14,UREGS_r14(%rsp)
         movq  %r15,UREGS_r15(%rsp)
 .endif
-        xor   %r12, %r12
-        xor   %r13, %r13
-        xor   %r14, %r14
-        xor   %r15, %r15
+        xor   %r12d, %r12d
+        xor   %r13d, %r13d
+        xor   %r14d, %r14d
+        xor   %r15d, %r15d
 .endm
 
 #define LOAD_ONE_REG(reg, compat) \
@@ -319,10 +319,10 @@ static always_inline void stac(void)
         movq  UREGS_r13(%rsp), %r13
         movq  UREGS_r12(%rsp), %r12
 .else
-        xor %r15, %r15
-        xor %r14, %r14
-        xor %r13, %r13
-        xor %r12, %r12
+        xor %r15d, %r15d
+        xor %r14d, %r14d
+        xor %r13d, %r13d
+        xor %r12d, %r12d
 .endif
         LOAD_ONE_REG(bp, \compat)
         LOAD_ONE_REG(bx, \compat)
@@ -332,10 +332,10 @@ static always_inline void stac(void)
         movq  UREGS_r9(%rsp),%r9
         movq  UREGS_r8(%rsp),%r8
 .else
-        xor %r11, %r11
-        xor %r10, %r10
-        xor %r9, %r9
-        xor %r8, %r8
+        xor %r11d, %r11d
+        xor %r10d, %r10d
+        xor %r9d, %r9d
+        xor %r8d, %r8d
 .endif
         LOAD_ONE_REG(ax, \compat)
         LOAD_ONE_REG(cx, \compat)
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.9

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