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Subject[tip:x86/cpu] x86, msr: CFI annotations, cleanups for msr-reg.S
Commit-ID:  79c5dca3619d6ae15815eec14cd7a43db5f38b47
Gitweb: http://git.kernel.org/tip/79c5dca3619d6ae15815eec14cd7a43db5f38b47
Author: H. Peter Anvin <hpa@zytor.com>
AuthorDate: Mon, 31 Aug 2009 13:59:53 -0700
Committer: H. Peter Anvin <hpa@zytor.com>
CommitDate: Mon, 31 Aug 2009 15:14:47 -0700

x86, msr: CFI annotations, cleanups for msr-reg.S

Add CFI annotations for native_{rd,wr}msr_safe_regs().
Simplify the 64-bit implementation: we don't allow the upper half
registers to be set, and so we can use them to carry state across the
operation.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <petkovbb@gmail.com>
LKML-Reference: <1251705011-18636-1-git-send-email-petkovbb@gmail.com>


---
arch/x86/lib/msr-reg.S | 80 +++++++++++++++++++++++++-----------------------
1 files changed, 42 insertions(+), 38 deletions(-)
diff --git a/arch/x86/lib/msr-reg.S b/arch/x86/lib/msr-reg.S
index 51f1bb3..9e8cdcf 100644
--- a/arch/x86/lib/msr-reg.S
+++ b/arch/x86/lib/msr-reg.S
@@ -1,5 +1,6 @@
#include <linux/linkage.h>
#include <linux/errno.h>
+#include <asm/dwarf2.h>
#include <asm/asm.h>
#include <asm/msr.h>

@@ -12,10 +13,11 @@
*/
.macro op_safe_regs op:req
ENTRY(native_\op\()_safe_regs)
- push %rbx
- push %rbp
- push $0 /* Return value */
- push %rdi
+ CFI_STARTPROC
+ pushq_cfi %rbx
+ pushq_cfi %rbp
+ movq %rdi, %r10 /* Save pointer */
+ xorl %r11d, %r11d /* Return value */
movl (%rdi), %eax
movl 4(%rdi), %ecx
movl 8(%rdi), %edx
@@ -23,27 +25,26 @@ ENTRY(native_\op\()_safe_regs)
movl 20(%rdi), %ebp
movl 24(%rdi), %esi
movl 28(%rdi), %edi
+ CFI_REMEMBER_STATE
1: \op
-2: movl %edi, %r10d
- pop %rdi
- movl %eax, (%rdi)
- movl %ecx, 4(%rdi)
- movl %edx, 8(%rdi)
- movl %ebx, 12(%rdi)
- movl %ebp, 20(%rdi)
- movl %esi, 24(%rdi)
- movl %r10d, 28(%rdi)
- pop %rax
- pop %rbp
- pop %rbx
+2: movl %eax, (%r10)
+ movl %r11d, %eax /* Return value */
+ movl %ecx, 4(%r10)
+ movl %edx, 8(%r10)
+ movl %ebx, 12(%r10)
+ movl %ebp, 20(%r10)
+ movl %esi, 24(%r10)
+ movl %edi, 28(%r10)
+ popq_cfi %rbp
+ popq_cfi %rbx
ret
3:
- movq $-EIO, 8(%rsp)
+ CFI_RESTORE_STATE
+ movl $-EIO, %r11d
jmp 2b
- .section __ex_table,"ax"
- .balign 4
- .quad 1b, 3b
- .previous
+
+ _ASM_EXTABLE(1b, 3b)
+ CFI_ENDPROC
ENDPROC(native_\op\()_safe_regs)
.endm

@@ -51,12 +52,13 @@ ENDPROC(native_\op\()_safe_regs)

.macro op_safe_regs op:req
ENTRY(native_\op\()_safe_regs)
- push %ebx
- push %ebp
- push %esi
- push %edi
- push $0 /* Return value */
- push %eax
+ CFI_STARTPROC
+ pushl_cfi %ebx
+ pushl_cfi %ebp
+ pushl_cfi %esi
+ pushl_cfi %edi
+ pushl_cfi $0 /* Return value */
+ pushl_cfi %eax
movl 4(%eax), %ecx
movl 8(%eax), %edx
movl 12(%eax), %ebx
@@ -64,30 +66,32 @@ ENTRY(native_\op\()_safe_regs)
movl 24(%eax), %esi
movl 28(%eax), %edi
movl (%eax), %eax
+ CFI_REMEMBER_STATE
1: \op
-2: push %eax
+2: pushl_cfi %eax
movl 4(%esp), %eax
- pop (%eax)
+ popl_cfi (%eax)
addl $4, %esp
+ CFI_ADJUST_CFA_OFFSET -4
movl %ecx, 4(%eax)
movl %edx, 8(%eax)
movl %ebx, 12(%eax)
movl %ebp, 20(%eax)
movl %esi, 24(%eax)
movl %edi, 28(%eax)
- pop %eax
- pop %edi
- pop %esi
- pop %ebp
- pop %ebx
+ popl_cfi %eax
+ popl_cfi %edi
+ popl_cfi %esi
+ popl_cfi %ebp
+ popl_cfi %ebx
ret
3:
+ CFI_RESTORE_STATE
movl $-EIO, 4(%esp)
jmp 2b
- .section __ex_table,"ax"
- .balign 4
- .long 1b, 3b
- .previous
+
+ _ASM_EXTABLE(1b, 3b)
+ CFI_ENDPROC
ENDPROC(native_\op\()_safe_regs)
.endm


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