Commit e9f99704 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/32: Always save non volatile registers on exception entry 



In preparation of handling exception entry and exit in C,
in order to simplify the handling, always save non volatile registers
when entering an exception.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3ce8ced87a4f1467fa36fcc50763d53b45e466c1.1615552867.git.christophe.leroy@csgroup.eu
parent 0f2793e3

arch/powerpc/include/asm/ptrace.h

+2 −4
Original line number Diff line number Diff line
@@ -209,16 +209,14 @@ static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc) 
 */

#define TRAP_FLAGS_MASK		0x1F

#define TRAP(regs)		((regs)->trap & ~TRAP_FLAGS_MASK)

#define FULL_REGS(regs)		(((regs)->trap & 1) == 0)

#define SET_FULL_REGS(regs)	((regs)->trap &= ~1)

#define FULL_REGS(regs)		true

#define SET_FULL_REGS(regs)	do { } while (0)

#define IS_CRITICAL_EXC(regs)	(((regs)->trap & 2) != 0)

#define IS_MCHECK_EXC(regs)	(((regs)->trap & 4) != 0)

#define IS_DEBUG_EXC(regs)	(((regs)->trap & 8) != 0)

#define NV_REG_POISON		0xdeadbeef

#define CHECK_FULL_REGS(regs)						      \

do {									      \

	if ((regs)->trap & 1)						      \

		printk(KERN_CRIT "%s: partial register set\n", __func__); \

} while (0)

#endif /* __powerpc64__ */

arch/powerpc/kernel/entry_32.S

+1 −12
Original line number Diff line number Diff line
@@ -81,12 +81,12 @@ _ASM_NOKPROBE_SYMBOL(crit_transfer_to_handler) 
 */

	.globl	transfer_to_handler_full

transfer_to_handler_full:

	SAVE_NVGPRS(r11)

_ASM_NOKPROBE_SYMBOL(transfer_to_handler_full)

	/* fall through */



	.globl	transfer_to_handler

transfer_to_handler:

	SAVE_NVGPRS(r11)

	stw	r2,GPR2(r11)

	stw	r12,_NIP(r11)

	stw	r9,_MSR(r11)
@@ -234,10 +234,6 @@ handle_page_fault: 
	bl	do_page_fault

	cmpwi	r3,0

	beq+	ret_from_except

	SAVE_NVGPRS(r1)

	lwz	r0,_TRAP(r1)

	clrrwi	r0,r0,1

	stw	r0,_TRAP(r1)

	mr	r4,r3		/* err arg for bad_page_fault */

	addi	r3,r1,STACK_FRAME_OVERHEAD

	bl	__bad_page_fault
@@ -810,13 +806,6 @@ recheck: 
do_user_signal:			/* r10 contains MSR_KERNEL here */

	ori	r10,r10,MSR_EE

	mtmsr	r10		/* hard-enable interrupts */

	/* save r13-r31 in the exception frame, if not already done */

	lwz	r3,_TRAP(r1)

	andi.	r0,r3,1

	beq	2f

	SAVE_NVGPRS(r1)

	rlwinm	r3,r3,0,0,30

	stw	r3,_TRAP(r1)

2:	addi	r3,r1,STACK_FRAME_OVERHEAD

	mr	r4,r9

	bl	do_notify_resume

arch/powerpc/kernel/head_32.h

+1 −2
Original line number Diff line number Diff line
@@ -198,7 +198,7 @@ _ASM_NOKPROBE_SYMBOL(\name\()_virt) 
			  ret_from_except_full)



#define EXC_XFER_LITE(n, hdlr)		\

	EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, transfer_to_handler, \

	EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, transfer_to_handler, \

			  ret_from_except)



.macro vmap_stack_overflow_exception
@@ -215,7 +215,6 @@ _ASM_NOKPROBE_SYMBOL(\name\()_virt) 
	lwz	r1, emergency_ctx@l(r1)

	addi	r1, r1, THREAD_SIZE - INT_FRAME_SIZE

	EXCEPTION_PROLOG_2 vmap_stack_overflow

	SAVE_NVGPRS(r11)

	addi	r3, r1, STACK_FRAME_OVERHEAD

	EXC_XFER_STD(0, stack_overflow_exception)

.endm

arch/powerpc/kernel/head_booke.h

+1 −1
Original line number Diff line number Diff line
@@ -331,7 +331,7 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV) 
			  ret_from_except_full)



#define EXC_XFER_LITE(n, hdlr)		\

	EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, transfer_to_handler, \

	EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, transfer_to_handler, \

			  ret_from_except)



/* Check for a single step debug exception while in an exception