Commit 5b1c9a0d authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/32: Tag DAR in EXCEPTION_PROLOG_2 for the 8xx 



8xx requires to tag the DAR with a magic value in order to
fixup DAR on faults generated by 'dcbX', as the 8xx
forgets to update the DAR for those faults.

Do the tagging as early as possible, that is before enabling MMU.

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/853a2e28ca7c5fc85617037030f99fe6070c9536.1615552867.git.christophe.leroy@csgroup.eu
parent 7aa8dd67

arch/powerpc/kernel/head_32.h

+6 −0
Original line number Diff line number Diff line
@@ -57,6 +57,12 @@ 
.endm



.macro EXCEPTION_PROLOG_2 handle_dar_dsisr=0

#ifdef CONFIG_PPC_8xx

	.if	\handle_dar_dsisr

	li	r11, RPN_PATTERN

	mtspr	SPRN_DAR, r11	/* Tag DAR, to be used in DTLB Error */

	.endif

#endif

	LOAD_REG_IMMEDIATE(r11, MSR_KERNEL & ~(MSR_IR | MSR_RI)) /* can take DTLB miss */

	mtmsr	r11

	isync

arch/powerpc/kernel/head_8xx.S

+6 −12
Original line number Diff line number Diff line
@@ -30,6 +30,12 @@ 
#include <asm/export.h>

#include <asm/code-patching-asm.h>



/*

 * Value for the bits that have fixed value in RPN entries.

 * Also used for tagging DAR for DTLBerror.

 */

#define RPN_PATTERN	0x00f0



#include "head_32.h"



.macro compare_to_kernel_boundary scratch, addr
@@ -42,12 +48,6 @@ 
#endif

.endm



/*

 * Value for the bits that have fixed value in RPN entries.

 * Also used for tagging DAR for DTLBerror.

 */

#define RPN_PATTERN	0x00f0



#define PAGE_SHIFT_512K		19

#define PAGE_SHIFT_8M		23
@@ -124,8 +124,6 @@ instruction_counter: 
	. = 0x200

MachineCheck:

	EXCEPTION_PROLOG handle_dar_dsisr=1

	li	r6, RPN_PATTERN

	mtspr	SPRN_DAR, r6	/* Tag DAR, to be used in DTLB Error */

	addi r3,r1,STACK_FRAME_OVERHEAD

	EXC_XFER_STD(0x200, machine_check_exception)
@@ -136,8 +134,6 @@ MachineCheck: 
	. = 0x600

Alignment:

	EXCEPTION_PROLOG handle_dar_dsisr=1

	li	r6, RPN_PATTERN

	mtspr	SPRN_DAR, r6	/* Tag DAR, to be used in DTLB Error */

	addi	r3,r1,STACK_FRAME_OVERHEAD

	b	.Lalignment_exception_ool
@@ -331,8 +327,6 @@ DataTLBError: 
	cmpwi	cr1, r11, RPN_PATTERN

	beq-	cr1, FixupDAR	/* must be a buggy dcbX, icbi insn. */

DARFixed:/* Return from dcbx instruction bug workaround */

	li	r11, RPN_PATTERN

	mtspr	SPRN_DAR, r11	/* Tag DAR, to be used in DTLB Error */

	EXCEPTION_PROLOG_1

	EXCEPTION_PROLOG_2 handle_dar_dsisr=1

	lwz	r4, _DAR(r11)