From: Andi Kleen <a...@linux.intel.com>
Add 32bit versions of SAVE/RESTORE_ALL to calling.h. Needed for
the following patches. These are much simplified over both 64bit
and the 32bit entry* version, just saving and restoring all registers
without anything fancy.
These are different from the entry_32.S versions in not changing
the segment registers or cld. 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.
Signed-off-by: Andi Kleen <a...@linux.intel.com>
---
arch/x86/include/asm/calling.h | 49 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 49 insertions(+)
diff --git a/arch/x86/include/asm/calling.h b/arch/x86/include/asm/calling.h
index 0fa6750..3365cea 100644
--- 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 +194,50 @@ For 32-bit we have the following conventions - kernel is
built with
.macro icebp
.byte 0xf1
.endm
+
+#else
+
+/*
+ * 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
--
1.8.3.1
--
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