Commit 293c2e27 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc/64s/exception: simplify hmi control flow 



Branch to the relocated 0xc000 address early (still in real mode), to
simplify subsequent branches. Have the virt mode handler avoid just
'windup' and redo the exception from scratch, rather than branching
back to the trampoline.

Rearrange the stack setup instruction location to match the system
reset handler (e.g., right before EXCEPTION_PROLOG_COMMON).

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent f34c9675

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

+10 −16
Original line number Diff line number Diff line
@@ -260,17 +260,6 @@ END_FTR_SECTION_NESTED(ftr,ftr,943) 
	mtctr	reg;							\

	bctr



#ifdef CONFIG_RELOCATABLE

#define BRANCH_LINK_TO_FAR(label)					\

	__LOAD_FAR_HANDLER(r12, label);					\

	mtctr	r12;							\

	bctrl



#else

#define BRANCH_LINK_TO_FAR(label)					\

	bl	label

#endif



#ifdef CONFIG_KVM_BOOK3S_64_HANDLER

#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE

/*
@@ -1713,22 +1702,26 @@ EXC_REAL_BEGIN(hmi_exception, 0xe60, 0x20) 
	EXCEPTION_PROLOG_0 PACA_EXGEN

	b	hmi_exception_early

EXC_REAL_END(hmi_exception, 0xe60, 0x20)

__TRAMP_REAL_OOL_MASKABLE_HV(hmi_exception, 0xe60, IRQS_DISABLED)

EXC_VIRT_NONE(0x4e60, 0x20)

TRAMP_KVM_HV(PACA_EXGEN, 0xe60)

TRAMP_REAL_BEGIN(hmi_exception_early)

	EXCEPTION_PROLOG_1 EXC_HV, PACA_EXGEN, 1, 0xe60, 0, 0, 0

	mfctr	r10			/* save ctr, even for !RELOCATABLE */

	BRANCH_TO_C000(r11, hmi_exception_early_common)



EXC_COMMON_BEGIN(hmi_exception_early_common)

	mtctr	r10			/* Restore ctr */

	mfspr	r11,SPRN_HSRR0		/* Save HSRR0 */

	mfspr	r12,SPRN_HSRR1		/* Save HSRR1 */

	mr	r10,r1			/* Save r1 */

	ld	r1,PACAEMERGSP(r13)	/* Use emergency stack for realmode */

	subi	r1,r1,INT_FRAME_SIZE	/* alloc stack frame		*/

	mfspr	r11,SPRN_HSRR0		/* Save HSRR0 */

	mfspr	r12,SPRN_HSRR1		/* Save HSRR1 */

	EXCEPTION_PROLOG_COMMON_1()

	/* We don't touch AMR here, we never go to virtual mode */

	EXCEPTION_PROLOG_COMMON_2(PACA_EXGEN)

	EXCEPTION_PROLOG_COMMON_3(0xe60)

	addi	r3,r1,STACK_FRAME_OVERHEAD

	BRANCH_LINK_TO_FAR(DOTSYM(hmi_exception_realmode)) /* Function call ABI */

	bl	hmi_exception_realmode

	cmpdi	cr0,r3,0

	bne	1f
@@ -1742,7 +1735,8 @@ TRAMP_REAL_BEGIN(hmi_exception_early) 
	 */

	EXCEPTION_RESTORE_REGS EXC_HV

	EXCEPTION_PROLOG_0 PACA_EXGEN

	b	tramp_real_hmi_exception

	EXCEPTION_PROLOG_1 EXC_HV, PACA_EXGEN, 1, 0xe60, 0, 0, IRQS_DISABLED

	EXCEPTION_PROLOG_2_REAL hmi_exception_common, EXC_HV, 1



EXC_COMMON_BEGIN(hmi_exception_common)

	EXCEPTION_COMMON(PACA_EXGEN, 0xe60)

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