diff options
Diffstat (limited to 'arch/x86/entry/vdso/vdso32/system_call.S')
| -rw-r--r-- | arch/x86/entry/vdso/vdso32/system_call.S | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/arch/x86/entry/vdso/vdso32/system_call.S b/arch/x86/entry/vdso/vdso32/system_call.S new file mode 100644 index 000000000000..93bd8452383f --- /dev/null +++ b/arch/x86/entry/vdso/vdso32/system_call.S @@ -0,0 +1,57 @@ +/* + * Code for the vDSO. This version uses the old int $0x80 method. +*/ + +#include <asm/dwarf2.h> +#include <asm/cpufeature.h> +#include <asm/alternative-asm.h> + +/* + * First get the common code for the sigreturn entry points. + * This must come first. + */ +#include "sigreturn.S" + + .text + .globl __kernel_vsyscall + .type __kernel_vsyscall,@function + ALIGN +__kernel_vsyscall: + CFI_STARTPROC + /* + * Reshuffle regs so that all of any of the entry instructions + * will preserve enough state. + */ + pushl %edx + CFI_ADJUST_CFA_OFFSET 4 + CFI_REL_OFFSET edx, 0 + pushl %ecx + CFI_ADJUST_CFA_OFFSET 4 + CFI_REL_OFFSET ecx, 0 + movl %esp, %ecx + +#ifdef CONFIG_X86_64 + /* If SYSENTER (Intel) or SYSCALL32 (AMD) is available, use it. */ + ALTERNATIVE_2 "", "sysenter", X86_FEATURE_SYSENTER32, \ + "syscall", X86_FEATURE_SYSCALL32 +#else + ALTERNATIVE "", "sysenter", X86_FEATURE_SEP +#endif + + /* Enter using int $0x80 */ + movl (%esp), %ecx + int $0x80 +GLOBAL(int80_landing_pad) + + /* Restore ECX and EDX in case they were clobbered. */ + popl %ecx + CFI_RESTORE ecx + CFI_ADJUST_CFA_OFFSET -4 + popl %edx + CFI_RESTORE edx + CFI_ADJUST_CFA_OFFSET -4 + ret + CFI_ENDPROC + + .size __kernel_vsyscall,.-__kernel_vsyscall + .previous |