Commit 296e753f authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc/64s/exception: simplify machine check early path 



machine_check_handle_early_common can reach machine_check_handle_early
directly now that it runs at the relocated address, so just branch
directly.

The rfi sequence is required to enable MSR[ME] but that step is moved
into a helper function, making the code easier to follow.

Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190802105709.27696-14-npiggin@gmail.com
parent abd1f4ca

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

+22 −9
Original line number Diff line number Diff line
@@ -1006,16 +1006,13 @@ EXC_COMMON_BEGIN(machine_check_early_common) 
	std	r3,_DAR(r1)

	std	r4,_DSISR(r1)



	mfmsr	r11			/* get MSR value */

BEGIN_FTR_SECTION

	ori	r11,r11,MSR_ME		/* turn on ME bit */

	bl	enable_machine_check

END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)

	ori	r11,r11,MSR_RI		/* turn on RI bit */

	LOAD_HANDLER(r12, machine_check_handle_early)

1:	mtspr	SPRN_SRR0,r12

	mtspr	SPRN_SRR1,r11

	RFI_TO_KERNEL

	b	.	/* prevent speculative execution */

	li	r10,MSR_RI

	mtmsrd	r10,1

	b	machine_check_handle_early



2:

	/* Stack overflow. Stay on emergency stack and panic.

	 * Keep the ME bit off while panic-ing, so that if we hit
@@ -1026,7 +1023,9 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE) 
	LOAD_HANDLER(r12, unrecover_mce)

	li	r10,MSR_ME

	andc	r11,r11,r10		/* Turn off MSR_ME */

	b	1b

	mtspr	SPRN_SRR0,r12

	mtspr	SPRN_SRR1,r11

	RFI_TO_KERNEL

	b	.	/* prevent speculative execution */



EXC_COMMON_BEGIN(machine_check_common)
@@ -2269,6 +2268,20 @@ CLOSE_FIXED_SECTION(virt_trampolines); 


USE_TEXT_SECTION()



/* MSR[RI] should be clear because this uses SRR[01] */

enable_machine_check:

	mflr	r0

	bcl	20,31,$+4

0:	mflr	r3

	addi	r3,r3,(1f - 0b)

	mtspr	SPRN_SRR0,r3

	mfmsr	r3

	ori	r3,r3,MSR_ME

	mtspr	SPRN_SRR1,r3

	RFI_TO_KERNEL

1:	mtlr	r0

	blr



/*

 * Hash table stuff

 */

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