powerpc: Reduce the number of non volatiles GPRs to 8

This requires a hacked gcc.

Signed-off-by: Anton Blanchard <anton@samba.org>
--

Index: linux.junk/arch/powerpc/include/asm/exception-64s.h
===================================================================
--- linux.junk.orig/arch/powerpc/include/asm/exception-64s.h
+++ linux.junk/arch/powerpc/include/asm/exception-64s.h
@@ -336,6 +336,7 @@ do_kvm_##n:								\
 	std	r2,GPR2(r1);		/* save r2 in stackframe	*/ \
 	SAVE_4GPRS(3, r1);		/* save r3 - r6 in stackframe   */ \
 	SAVE_2GPRS(7, r1);		/* save r7, r8 in stackframe	*/ \
+	SAVE_10GPRS(14, r1);						   \
 	mflr	r9;			/* Get LR, later save to stack	*/ \
 	ld	r2,PACATOC(r13);	/* get kernel TOC into r2	*/ \
 	std	r9,_LINK(r1);						   \
Index: linux.junk/arch/powerpc/include/asm/ppc_asm.h
===================================================================
--- linux.junk.orig/arch/powerpc/include/asm/ppc_asm.h
+++ linux.junk/arch/powerpc/include/asm/ppc_asm.h
@@ -77,8 +77,8 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLP
 #ifdef __powerpc64__
 #define SAVE_GPR(n, base)	std	n,GPR0+8*(n)(base)
 #define REST_GPR(n, base)	ld	n,GPR0+8*(n)(base)
-#define SAVE_NVGPRS(base)	SAVE_8GPRS(14, base); SAVE_10GPRS(22, base)
-#define REST_NVGPRS(base)	REST_8GPRS(14, base); REST_10GPRS(22, base)
+#define SAVE_NVGPRS(base)	SAVE_8GPRS(24, base)
+#define REST_NVGPRS(base)	REST_8GPRS(24, base)
 #else
 #define SAVE_GPR(n, base)	stw	n,GPR0+4*(n)(base)
 #define REST_GPR(n, base)	lwz	n,GPR0+4*(n)(base)
Index: linux.junk/arch/powerpc/kernel/asm-offsets.c
===================================================================
--- linux.junk.orig/arch/powerpc/kernel/asm-offsets.c
+++ linux.junk/arch/powerpc/kernel/asm-offsets.c
@@ -289,7 +289,6 @@ int main(void)
 	DEFINE(GPR11, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, gpr[11]));
 	DEFINE(GPR12, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, gpr[12]));
 	DEFINE(GPR13, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, gpr[13]));
-#ifndef CONFIG_PPC64
 	DEFINE(GPR14, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, gpr[14]));
 	DEFINE(GPR15, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, gpr[15]));
 	DEFINE(GPR16, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, gpr[16]));
@@ -308,7 +307,6 @@ int main(void)
 	DEFINE(GPR29, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, gpr[29]));
 	DEFINE(GPR30, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, gpr[30]));
 	DEFINE(GPR31, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, gpr[31]));
-#endif /* CONFIG_PPC64 */
 	/*
 	 * Note: these symbols include _ because they overlap with special
 	 * register names
Index: linux.junk/arch/powerpc/kernel/entry_64.S
===================================================================
--- linux.junk.orig/arch/powerpc/kernel/entry_64.S
+++ linux.junk/arch/powerpc/kernel/entry_64.S
@@ -86,6 +86,18 @@ END_FTR_SECTION_IFSET(CPU_FTR_TM)
 	std	r11,_XER(r1)
 	std	r11,_CTR(r1)
 	std	r9,GPR13(r1)
+
+	std	r14,GPR14(r1)
+	std	r15,GPR15(r1)
+	std	r16,GPR16(r1)
+	std	r17,GPR17(r1)
+	std	r18,GPR18(r1)
+	std	r19,GPR19(r1)
+	std	r20,GPR20(r1)
+	std	r21,GPR21(r1)
+	std	r22,GPR22(r1)
+	std	r23,GPR23(r1)
+
 	mflr	r10
 	/*
 	 * This clears CR0.SO (bit 28), which is the error indication on
@@ -112,6 +124,7 @@ BEGIN_FW_FTR_SECTION
 	cmpd	cr1,r11,r10
 	beq+	cr1,33f
 	bl	accumulate_stolen_time
+	trap
 	REST_GPR(0,r1)
 	REST_4GPRS(3,r1)
 	REST_2GPRS(7,r1)
@@ -225,7 +238,9 @@ END_FTR_SECTION_IFCLR(CPU_FTR_STCX_CHECK
 	ACCOUNT_CPU_USER_EXIT(r11, r12)
 	HMT_MEDIUM_LOW_HAS_PPR
 	ld	r13,GPR13(r1)	/* only restore r13 if returning to usermode */
-1:	ld	r2,GPR2(r1)
+1:
+	REST_10GPRS(14, r1)
+	ld	r2,GPR2(r1)
 	ld	r1,GPR1(r1)
 	mtlr	r4
 	mtcr	r5
@@ -405,10 +420,10 @@ _GLOBAL(ret_from_fork)
 _GLOBAL(ret_from_kernel_thread)
 	bl	schedule_tail
 	REST_NVGPRS(r1)
-	mtlr	r14
-	mr	r3,r15
+	mtlr	r24
+	mr	r3,r25
 #if defined(_CALL_ELF) && _CALL_ELF == 2
-	mr	r12,r14
+	mr	r12,r24
 #endif
 	blrl
 	li	r3,0
@@ -540,8 +555,7 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEG
 	mtcrf	0xFF,r6
 
 	/* r3-r13 are destroyed -- Cort */
-	REST_8GPRS(14, r1)
-	REST_10GPRS(22, r1)
+	REST_8GPRS(24, r1)
 
 	/* convert old thread to its task_struct for return value */
 	addi	r3,r3,-THREAD
@@ -771,6 +785,7 @@ fast_exception_return:
 	mtspr	SPRN_XER,r4
 
 	REST_8GPRS(5, r1)
+	REST_10GPRS(14, r1)
 
 	andi.	r0,r3,MSR_RI
 	beq-	unrecov_restore
Index: linux.junk/arch/powerpc/kernel/process.c
===================================================================
--- linux.junk.orig/arch/powerpc/kernel/process.c
+++ linux.junk/arch/powerpc/kernel/process.c
@@ -1207,12 +1207,12 @@ int copy_thread(unsigned long clone_flag
 		childregs->gpr[1] = sp + sizeof(struct pt_regs);
 		/* function */
 		if (usp)
-			childregs->gpr[14] = ppc_function_entry((void *)usp);
+			childregs->gpr[24] = ppc_function_entry((void *)usp);
 #ifdef CONFIG_PPC64
 		clear_tsk_thread_flag(p, TIF_32BIT);
 		childregs->softe = 1;
 #endif
-		childregs->gpr[15] = kthread_arg;
+		childregs->gpr[25] = kthread_arg;
 		p->thread.regs = NULL;	/* no user register state */
 		ti->flags |= _TIF_RESTOREALL;
 		f = ret_from_kernel_thread;