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powerpc/64s/exception: machine check move unrecoverable handling out of line
Similarly to the previous change, all callers of the unrecoverable handler run relocated so can reach it with a direct branch. This makes it easy to move out of line, which makes the "normal" path less cluttered and easier to follow. MSR[ME] manipulation still requires the rfi, so that is moved out of line to its own function. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190802105709.27696-15-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin
Michael Ellerman
parent
296e753fb4
commit
b7d9ccec30
1 changed files with 44 additions and 43 deletions
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@ -992,9 +992,9 @@ EXC_COMMON_BEGIN(machine_check_early_common)
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bne 1f
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/* First machine check entry */
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ld r1,PACAMCEMERGSP(r13) /* Use MC emergency stack */
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1: subi r1,r1,INT_FRAME_SIZE /* alloc stack frame */
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/* Limit nested MCE to level 4 to avoid stack overflow */
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bge cr1,2f /* Check if we hit limit of 4 */
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1: /* Limit nested MCE to level 4 to avoid stack overflow */
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bgt cr1,unrecoverable_mce /* Check if we hit limit of 4 */
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subi r1,r1,INT_FRAME_SIZE /* alloc stack frame */
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EXCEPTION_PROLOG_COMMON_1()
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/* We don't touch AMR here, we never go to virtual mode */
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@ -1013,21 +1013,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
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mtmsrd r10,1
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b machine_check_handle_early
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2:
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/* Stack overflow. Stay on emergency stack and panic.
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* Keep the ME bit off while panic-ing, so that if we hit
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* another machine check we checkstop.
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*/
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addi r1,r1,INT_FRAME_SIZE /* go back to previous stack frame */
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ld r11,PACAKMSR(r13)
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LOAD_HANDLER(r12, unrecover_mce)
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li r10,MSR_ME
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andc r11,r11,r10 /* Turn off MSR_ME */
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mtspr SPRN_SRR0,r12
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mtspr SPRN_SRR1,r11
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RFI_TO_KERNEL
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b . /* prevent speculative execution */
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EXC_COMMON_BEGIN(machine_check_common)
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/*
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* Machine check is different because we use a different
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@ -1141,32 +1126,15 @@ END_FTR_SECTION_IFSET(CPU_FTR_HVMODE | CPU_FTR_ARCH_206)
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* If yes, then stay on emergency stack and panic.
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*/
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andi. r11,r12,MSR_RI
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bne 2f
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1: mfspr r11,SPRN_SRR0
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LOAD_HANDLER(r10,unrecover_mce)
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mtspr SPRN_SRR0,r10
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ld r10,PACAKMSR(r13)
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/*
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* We are going down. But there are chances that we might get hit by
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* another MCE during panic path and we may run into unstable state
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* with no way out. Hence, turn ME bit off while going down, so that
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* when another MCE is hit during panic path, system will checkstop
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* and hypervisor will get restarted cleanly by SP.
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*/
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li r3,MSR_ME
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andc r10,r10,r3 /* Turn off MSR_ME */
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mtspr SPRN_SRR1,r10
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RFI_TO_KERNEL
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b .
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2:
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beq unrecoverable_mce
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/*
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* Check if we have successfully handled/recovered from error, if not
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* then stay on emergency stack and panic.
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*/
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ld r3,RESULT(r1) /* Load result */
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cmpdi r3,0 /* see if we handled MCE successfully */
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beq 1b /* if !handled then panic */
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beq unrecoverable_mce /* if !handled then panic */
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/*
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* Return from MC interrupt.
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@ -1189,17 +1157,35 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
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EXCEPTION_PROLOG_1 EXC_STD, PACA_EXMC, 1, 0x200, 1, 1, 0
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EXCEPTION_PROLOG_2_REAL machine_check_common, EXC_STD, 0
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EXC_COMMON_BEGIN(unrecover_mce)
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EXC_COMMON_BEGIN(unrecoverable_mce)
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/*
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* We are going down. But there are chances that we might get hit by
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* another MCE during panic path and we may run into unstable state
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* with no way out. Hence, turn ME bit off while going down, so that
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* when another MCE is hit during panic path, system will checkstop
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* and hypervisor will get restarted cleanly by SP.
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*/
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BEGIN_FTR_SECTION
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li r10,0 /* clear MSR_RI */
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mtmsrd r10,1
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bl disable_machine_check
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END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
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ld r10,PACAKMSR(r13)
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li r3,MSR_ME
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andc r10,r10,r3
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mtmsrd r10
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/* Invoke machine_check_exception to print MCE event and panic. */
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addi r3,r1,STACK_FRAME_OVERHEAD
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bl machine_check_exception
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/*
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* We will not reach here. Even if we did, there is no way out. Call
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* unrecoverable_exception and die.
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* We will not reach here. Even if we did, there is no way out.
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* Call unrecoverable_exception and die.
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*/
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1: addi r3,r1,STACK_FRAME_OVERHEAD
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addi r3,r1,STACK_FRAME_OVERHEAD
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bl unrecoverable_exception
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b 1b
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b .
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EXC_REAL_BEGIN(data_access, 0x300, 0x80)
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@ -2282,6 +2268,21 @@ enable_machine_check:
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1: mtlr r0
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blr
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/* MSR[RI] should be clear because this uses SRR[01] */
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disable_machine_check:
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mflr r0
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bcl 20,31,$+4
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0: mflr r3
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addi r3,r3,(1f - 0b)
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mtspr SPRN_SRR0,r3
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mfmsr r3
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li r4,MSR_ME
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andc r3,r3,r4
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mtspr SPRN_SRR1,r3
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RFI_TO_KERNEL
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1: mtlr r0
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blr
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/*
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* Hash table stuff
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*/
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