[PATCH] ARM: pt_regs offsets

Generate pt_regs S_xx offsets from the structure itself instead
of #defining them.
Signed-off-by: Russell King <rmk@arm.linux.org.uk>

arch/arm/kernel/asm-offsets.c

@@ -64,6 +64,26 @@ int main(void)
   DEFINE(TI_VFPSTATE,		offsetof(struct thread_info, vfpstate));
   DEFINE(TI_IWMMXT_STATE,	(offsetof(struct thread_info, fpstate)+4)&~7);
   BLANK();
+  DEFINE(S_R0,			offsetof(struct pt_regs, ARM_r0));
+  DEFINE(S_R1,			offsetof(struct pt_regs, ARM_r1));
+  DEFINE(S_R2,			offsetof(struct pt_regs, ARM_r2));
+  DEFINE(S_R3,			offsetof(struct pt_regs, ARM_r3));
+  DEFINE(S_R4,			offsetof(struct pt_regs, ARM_r4));
+  DEFINE(S_R5,			offsetof(struct pt_regs, ARM_r5));
+  DEFINE(S_R6,			offsetof(struct pt_regs, ARM_r6));
+  DEFINE(S_R7,			offsetof(struct pt_regs, ARM_r7));
+  DEFINE(S_R8,			offsetof(struct pt_regs, ARM_r8));
+  DEFINE(S_R9,			offsetof(struct pt_regs, ARM_r9));
+  DEFINE(S_R10,			offsetof(struct pt_regs, ARM_r10));
+  DEFINE(S_FP,			offsetof(struct pt_regs, ARM_fp));
+  DEFINE(S_IP,			offsetof(struct pt_regs, ARM_ip));
+  DEFINE(S_SP,			offsetof(struct pt_regs, ARM_sp));
+  DEFINE(S_LR,			offsetof(struct pt_regs, ARM_lr));
+  DEFINE(S_PC,			offsetof(struct pt_regs, ARM_pc));
+  DEFINE(S_PSR,			offsetof(struct pt_regs, ARM_cpsr));
+  DEFINE(S_OLD_R0,		offsetof(struct pt_regs, ARM_ORIG_r0));
+  DEFINE(S_FRAME_SIZE,		sizeof(struct pt_regs));
+  BLANK();
 #if __LINUX_ARM_ARCH__ >= 6
   DEFINE(MM_CONTEXT_ID,		offsetof(struct mm_struct, context.id));
   BLANK();

arch/arm/kernel/entry-common.S

@@ -15,13 +15,6 @@
 
 #include "entry-header.S"
 
-/* 
- * We rely on the fact that R0 is at the bottom of the stack (due to
- * slow/fast restore user regs).
- */
-#if S_R0 != 0
-#error "Please fix"
-#endif
 
 	.align	5
 /*

arch/arm/kernel/entry-header.S

@@ -39,30 +39,19 @@
 #define ARMSWI_OFFSET	0x000f0000
 
 @
-@ Stack format (ensured by USER_* and SVC_*)
+@ Most of the stack format comes from struct pt_regs, but with
+@ the addition of 8 bytes for storing syscall args 5 and 6.
 @
-#define S_FRAME_SIZE	72
-#define S_OLD_R0	68
-#define S_PSR		64
-
-#define S_PC		60
-#define S_LR		56
-#define S_SP		52
-#define S_IP		48
-#define S_FP		44
-#define S_R10		40
-#define S_R9		36
-#define S_R8		32
-#define S_R7		28
-#define S_R6		24
-#define S_R5		20
-#define S_R4		16
-#define S_R3		12
-#define S_R2		8
-#define S_R1		4
-#define S_R0		0
 #define S_OFF		8
 
+/* 
+ * The SWI code relies on the fact that R0 is at the bottom of the stack
+ * (due to slow/fast restore user regs).
+ */
+#if S_R0 != 0
+#error "Please fix"
+#endif
+
 #if __LINUX_ARM_ARCH__ >= 6
 	.macro	disable_irq
 	cpsid	i