powerpc/64: provide a helper macro to load r2 with the kernel TOC

A later change stops the kernel using r2 and loads it with a poison
value.  Provide a PACATOC loading abstraction which can hide this
detail.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220926034057.2360083-5-npiggin@gmail.com

arch/powerpc/include/asm/ppc_asm.h

@@ -327,6 +327,12 @@ GLUE(.,name):
 
 #ifdef __powerpc64__
 
+#define __LOAD_PACA_TOC(reg)			\
+	ld	reg,PACATOC(r13)
+
+#define LOAD_PACA_TOC()				\
+	__LOAD_PACA_TOC(r2)
+
 #define LOAD_REG_IMMEDIATE(reg, expr) __LOAD_REG_IMMEDIATE reg, expr
 
 #define LOAD_REG_IMMEDIATE_SYM(reg, tmp, expr)	\

arch/powerpc/kernel/exceptions-64e.S

@@ -371,7 +371,7 @@ exc_##n##_common:							    \
 	ld	r4,excf+EX_R11(r13);	/* get back r11 */		    \
 	mfspr	r5,scratch;		/* get back r13 */		    \
 	SAVE_GPR(12, r1);		/* save r12 in stackframe */	    \
-	ld	r2,PACATOC(r13);	/* get kernel TOC into r2 */	    \
+	LOAD_PACA_TOC();		/* get kernel TOC into r2 */	    \
 	mflr	r6;			/* save LR in stackframe */	    \
 	mfctr	r7;			/* save CTR in stackframe */	    \
 	mfspr	r8,SPRN_XER;		/* save XER in stackframe */	    \
@@ -687,7 +687,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
 	beq+	1f
 
 #ifdef CONFIG_RELOCATABLE
-	ld	r15,PACATOC(r13)
+	__LOAD_PACA_TOC(r15)
 	ld	r14,interrupt_base_book3e@got(r15)
 	ld	r15,__end_interrupts@got(r15)
 	cmpld	cr0,r10,r14
@@ -758,7 +758,7 @@ kernel_dbg_exc:
 	beq+	1f
 
 #ifdef CONFIG_RELOCATABLE
-	ld	r15,PACATOC(r13)
+	__LOAD_PACA_TOC(r15)
 	ld	r14,interrupt_base_book3e@got(r15)
 	ld	r15,__end_interrupts@got(r15)
 	cmpld	cr0,r10,r14
@@ -883,7 +883,7 @@ kernel_dbg_exc:
 
 .macro SEARCH_RESTART_TABLE
 #ifdef CONFIG_RELOCATABLE
-	ld	r11,PACATOC(r13)
+	__LOAD_PACA_TOC(r11)
 	ld	r14,__start___restart_table@got(r11)
 	ld	r15,__stop___restart_table@got(r11)
 #else
@@ -1061,7 +1061,7 @@ bad_stack_book3e:
 	std	r11,0(r1)
 	ZEROIZE_GPR(12)
 	std	r12,0(r11)
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 1:	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	kernel_bad_stack
 	b	1b
@@ -1302,7 +1302,7 @@ a2_tlbinit_after_linear_map:
 
 	/* Now we branch the new virtual address mapped by this entry */
 #ifdef CONFIG_RELOCATABLE
-	ld	r5,PACATOC(r13)
+	__LOAD_PACA_TOC(r5)
 	ld	r3,1f@got(r5)
 #else
 	LOAD_REG_IMMEDIATE_SYM(r3, r5, 1f)

arch/powerpc/kernel/exceptions-64s.S

@@ -580,7 +580,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
 	std	r2,GPR2(r1)		/* save r2 in stackframe	*/
 	SAVE_GPRS(3, 8, r1)		/* save r3 - r8 in stackframe   */
 	mflr	r9			/* Get LR, later save to stack	*/
-	ld	r2,PACATOC(r13)		/* get kernel TOC into r2	*/
+	LOAD_PACA_TOC()			/* get kernel TOC into r2	*/
 	std	r9,_LINK(r1)
 	lbz	r10,PACAIRQSOFTMASK(r13)
 	mfspr	r11,SPRN_XER		/* save XER in stackframe	*/
@@ -610,7 +610,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
 .macro SEARCH_RESTART_TABLE
 #ifdef CONFIG_RELOCATABLE
 	mr	r12,r2
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 	LOAD_REG_ADDR(r9, __start___restart_table)
 	LOAD_REG_ADDR(r10, __stop___restart_table)
 	mr	r2,r12
@@ -640,7 +640,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
 .macro SEARCH_SOFT_MASK_TABLE
 #ifdef CONFIG_RELOCATABLE
 	mr	r12,r2
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 	LOAD_REG_ADDR(r9, __start___soft_mask_table)
 	LOAD_REG_ADDR(r10, __stop___soft_mask_table)
 	mr	r2,r12

arch/powerpc/kernel/head_64.S

@@ -841,7 +841,7 @@ __secondary_start:
  * before going into C code.
  */
 start_secondary_prolog:
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 	li	r3,0
 	std	r3,0(r1)		/* Zero the stack frame pointer	*/
 	bl	start_secondary
@@ -981,7 +981,7 @@ start_here_common:
 	std	r1,PACAKSAVE(r13)
 
 	/* Load the TOC (virtual address) */
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 
 	/* Mark interrupts soft and hard disabled (they might be enabled
 	 * in the PACA when doing hotplug)

arch/powerpc/kernel/interrupt_64.S

@@ -57,7 +57,7 @@ _ASM_NOKPROBE_SYMBOL(system_call_vectored_\name)
 	std	r0,GPR0(r1)
 	std	r10,GPR1(r1)
 	std	r2,GPR2(r1)
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 	mfcr	r12
 	li	r11,0
 	/* Save syscall parameters in r3-r8 */
@@ -174,7 +174,7 @@ syscall_vectored_\name\()_restart:
 _ASM_NOKPROBE_SYMBOL(syscall_vectored_\name\()_restart)
 	GET_PACA(r13)
 	ld	r1,PACA_EXIT_SAVE_R1(r13)
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 	ld	r3,RESULT(r1)
 	addi	r4,r1,STACK_FRAME_OVERHEAD
 	li	r11,IRQS_ALL_DISABLED
@@ -224,7 +224,7 @@ START_BTB_FLUSH_SECTION
 	BTB_FLUSH(r10)
 END_BTB_FLUSH_SECTION
 #endif
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 	mfcr	r12
 	li	r11,0
 	/* Save syscall parameters in r3-r8 */
@@ -355,7 +355,7 @@ syscall_restart:
 _ASM_NOKPROBE_SYMBOL(syscall_restart)
 	GET_PACA(r13)
 	ld	r1,PACA_EXIT_SAVE_R1(r13)
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 	ld	r3,RESULT(r1)
 	addi	r4,r1,STACK_FRAME_OVERHEAD
 	li	r11,IRQS_ALL_DISABLED
@@ -502,7 +502,7 @@ interrupt_return_\srr\()_user_restart:
 _ASM_NOKPROBE_SYMBOL(interrupt_return_\srr\()_user_restart)
 	GET_PACA(r13)
 	ld	r1,PACA_EXIT_SAVE_R1(r13)
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	li	r11,IRQS_ALL_DISABLED
 	stb	r11,PACAIRQSOFTMASK(r13)
@@ -663,7 +663,7 @@ interrupt_return_\srr\()_kernel_restart:
 _ASM_NOKPROBE_SYMBOL(interrupt_return_\srr\()_kernel_restart)
 	GET_PACA(r13)
 	ld	r1,PACA_EXIT_SAVE_R1(r13)
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	li	r11,IRQS_ALL_DISABLED
 	stb	r11,PACAIRQSOFTMASK(r13)

arch/powerpc/kernel/optprobes_head.S

@@ -73,7 +73,7 @@ optprobe_template_entry:
 	 * further below.
 	 */
 #ifdef CONFIG_PPC64
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 #endif
 
 	.global optprobe_template_op_address

arch/powerpc/kernel/trace/ftrace_low.S

@@ -48,7 +48,7 @@ _GLOBAL(return_to_handler)
 	 * We might be called from a module.
 	 * Switch to our TOC to run inside the core kernel.
 	 */
-	ld	r2, PACATOC(r13)
+	LOAD_PACA_TOC()
 #else
 	stwu	r1, -16(r1)
 	stw	r3, 8(r1)

arch/powerpc/kernel/trace/ftrace_mprofile.S

@@ -83,8 +83,7 @@
 #ifdef CONFIG_PPC64
 	/* Save callee's TOC in the ABI compliant location */
 	std	r2, STK_GOT(r1)
-	ld	r2,PACATOC(r13)	/* get kernel TOC in r2 */
-
+	LOAD_PACA_TOC()		/* get kernel TOC in r2 */
 	LOAD_REG_ADDR(r3, function_trace_op)
 	ld	r5,0(r3)
 #else

arch/powerpc/kvm/book3s_64_entry.S

@@ -315,7 +315,7 @@ kvmppc_p9_exit_interrupt:
 	reg = reg + 1
 	.endr
 
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 
 	mflr	r4
 	std	r4,VCPU_LR(r3)

arch/powerpc/kvm/book3s_hv_rmhandlers.S

@@ -1024,7 +1024,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 
 	/* Restore R1/R2 so we can handle faults */
 	ld	r1, HSTATE_HOST_R1(r13)
-	ld	r2, PACATOC(r13)
+	LOAD_PACA_TOC()
 
 	mfspr	r10, SPRN_SRR0
 	mfspr	r11, SPRN_SRR1
@@ -2727,7 +2727,7 @@ kvmppc_bad_host_intr:
 	std	r4, _CTR(r1)
 	std	r5, _XER(r1)
 	std	r6, SOFTE(r1)
-	ld	r2, PACATOC(r13)
+	LOAD_PACA_TOC()
 	LOAD_REG_IMMEDIATE(3, 0x7265677368657265)
 	std	r3, STACK_FRAME_OVERHEAD-16(r1)
 

arch/powerpc/kvm/tm.S

@@ -110,7 +110,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_P9_TM_HV_ASSIST)
 	mtmsrd	r2, 1
 
 	/* Reload TOC pointer. */
-	ld	r2, PACATOC(r13)
+	LOAD_PACA_TOC()
 
 	/* Save all but r0-r2, r9 & r13 */
 	reg = 3

arch/powerpc/mm/nohash/tlb_low_64e.S

@@ -1118,7 +1118,7 @@ tlb_load_linear:
 	 * we only use 1G pages for now. That might have to be changed in a
 	 * final implementation, especially when dealing with hypervisors
 	 */
-	ld	r11,PACATOC(r13)
+	__LOAD_PACA_TOC(r11)
 	ld	r11,linear_map_top@got(r11)
 	ld	r10,0(r11)
 	tovirt(10,10)

arch/powerpc/platforms/powernv/opal-wrappers.S

@@ -57,7 +57,7 @@ opal_return:
 	.long 0xa64b7b7d /* mthsrr1 r11				*/
 	.long 0x2402004c /* hrfid				*/
 #endif
-	ld	r2,PACATOC(r13)
+	LOAD_PACA_TOC()
 	ld	r0,PPC_LR_STKOFF(r1)
 	mtlr	r0
 	blr