sched, x86: Optimize the preempt_schedule() call

[mirror_ubuntu-artful-kernel.git] / arch / x86 / include / asm / calling.h

diff --git a/arch/x86/include/asm/calling.h b/arch/x86/include/asm/calling.h
index 0fa67503391257d89d1b55016c07e97fba7fa667..cb4c73bfeb48169056001d1c8426492a3ad4af79 100644 (file)
--- a/arch/x86/include/asm/calling.h
+++ b/arch/x86/include/asm/calling.h
@@ -48,6 +48,8 @@ For 32-bit we have the following conventions - kernel is built with
 
 #include <asm/dwarf2.h>
 
+#ifdef CONFIG_X86_64
+
 /*
  * 64-bit system call stack frame layout defines and helpers,
  * for assembly code:
@@ -192,3 +194,51 @@ For 32-bit we have the following conventions - kernel is built with
        .macro icebp
        .byte 0xf1
        .endm
+
+#else /* CONFIG_X86_64 */
+
+/*
+ * For 32bit only simplified versions of SAVE_ALL/RESTORE_ALL. These
+ * are different from the entry_32.S versions in not changing the segment
+ * registers. So only suitable for in kernel use, not when transitioning
+ * from or to user space. The resulting stack frame is not a standard
+ * pt_regs frame. The main use case is calling C code from assembler
+ * when all the registers need to be preserved.
+ */
+
+       .macro SAVE_ALL
+       pushl_cfi %eax
+       CFI_REL_OFFSET eax, 0
+       pushl_cfi %ebp
+       CFI_REL_OFFSET ebp, 0
+       pushl_cfi %edi
+       CFI_REL_OFFSET edi, 0
+       pushl_cfi %esi
+       CFI_REL_OFFSET esi, 0
+       pushl_cfi %edx
+       CFI_REL_OFFSET edx, 0
+       pushl_cfi %ecx
+       CFI_REL_OFFSET ecx, 0
+       pushl_cfi %ebx
+       CFI_REL_OFFSET ebx, 0
+       .endm
+
+       .macro RESTORE_ALL
+       popl_cfi %ebx
+       CFI_RESTORE ebx
+       popl_cfi %ecx
+       CFI_RESTORE ecx
+       popl_cfi %edx
+       CFI_RESTORE edx
+       popl_cfi %esi
+       CFI_RESTORE esi
+       popl_cfi %edi
+       CFI_RESTORE edi
+       popl_cfi %ebp
+       CFI_RESTORE ebp
+       popl_cfi %eax
+       CFI_RESTORE eax
+       .endm
+
+#endif /* CONFIG_X86_64 */
+