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-rw-r--r--arch/x86/lib/msr-reg.S102
1 files changed, 102 insertions, 0 deletions
diff --git a/arch/x86/lib/msr-reg.S b/arch/x86/lib/msr-reg.S
new file mode 100644
index 000000000000..69fa10623f21
--- /dev/null
+++ b/arch/x86/lib/msr-reg.S
@@ -0,0 +1,102 @@
+#include <linux/linkage.h>
+#include <linux/errno.h>
+#include <asm/dwarf2.h>
+#include <asm/asm.h>
+#include <asm/msr.h>
+
+#ifdef CONFIG_X86_64
+/*
+ * int native_{rdmsr,wrmsr}_safe_regs(u32 gprs[8]);
+ *
+ * reg layout: u32 gprs[eax, ecx, edx, ebx, esp, ebp, esi, edi]
+ *
+ */
+.macro op_safe_regs op
+ENTRY(native_\op\()_safe_regs)
+ 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
+ movl 12(%rdi), %ebx
+ movl 20(%rdi), %ebp
+ movl 24(%rdi), %esi
+ movl 28(%rdi), %edi
+ CFI_REMEMBER_STATE
+1: \op
+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:
+ CFI_RESTORE_STATE
+ movl $-EIO, %r11d
+ jmp 2b
+
+ _ASM_EXTABLE(1b, 3b)
+ CFI_ENDPROC
+ENDPROC(native_\op\()_safe_regs)
+.endm
+
+#else /* X86_32 */
+
+.macro op_safe_regs op
+ENTRY(native_\op\()_safe_regs)
+ 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
+ movl 20(%eax), %ebp
+ movl 24(%eax), %esi
+ movl 28(%eax), %edi
+ movl (%eax), %eax
+ CFI_REMEMBER_STATE
+1: \op
+2: pushl_cfi %eax
+ movl 4(%esp), %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)
+ 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
+
+ _ASM_EXTABLE(1b, 3b)
+ CFI_ENDPROC
+ENDPROC(native_\op\()_safe_regs)
+.endm
+
+#endif
+
+op_safe_regs rdmsr
+op_safe_regs wrmsr
+