On Sun, 19 Aug 2018 22:38:39 +0530 Mahesh J Salgaonkar <mah...@linux.vnet.ibm.com> wrote:
> From: Mahesh Salgaonkar <mah...@linux.vnet.ibm.com> > > Now that other platforms also implements real mode mce handler, > lets consolidate the code by sharing existing powernv machine check > early code. Rename machine_check_powernv_early to > machine_check_common_early and reuse the code. > > Signed-off-by: Mahesh Salgaonkar <mah...@linux.vnet.ibm.com> > --- > arch/powerpc/kernel/exceptions-64s.S | 155 > ++++++---------------------------- > 1 file changed, 28 insertions(+), 127 deletions(-) > > diff --git a/arch/powerpc/kernel/exceptions-64s.S > b/arch/powerpc/kernel/exceptions-64s.S > index 12f056179112..2f85a7baf026 100644 > --- a/arch/powerpc/kernel/exceptions-64s.S > +++ b/arch/powerpc/kernel/exceptions-64s.S > @@ -243,14 +243,13 @@ EXC_REAL_BEGIN(machine_check, 0x200, 0x100) > SET_SCRATCH0(r13) /* save r13 */ > EXCEPTION_PROLOG_0(PACA_EXMC) > BEGIN_FTR_SECTION > - b machine_check_powernv_early > + b machine_check_common_early > FTR_SECTION_ELSE > b machine_check_pSeries_0 > ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE) > EXC_REAL_END(machine_check, 0x200, 0x100) > EXC_VIRT_NONE(0x4200, 0x100) > -TRAMP_REAL_BEGIN(machine_check_powernv_early) > -BEGIN_FTR_SECTION > +TRAMP_REAL_BEGIN(machine_check_common_early) > EXCEPTION_PROLOG_1(PACA_EXMC, NOTEST, 0x200) > /* > * Register contents: > @@ -306,7 +305,9 @@ BEGIN_FTR_SECTION > /* Save r9 through r13 from EXMC save area to stack frame. */ > EXCEPTION_PROLOG_COMMON_2(PACA_EXMC) > mfmsr r11 /* get MSR value */ > +BEGIN_FTR_SECTION > ori r11,r11,MSR_ME /* turn on ME bit */ > +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 > @@ -325,7 +326,6 @@ BEGIN_FTR_SECTION > andc r11,r11,r10 /* Turn off MSR_ME */ > b 1b > b . /* prevent speculative execution */ > -END_FTR_SECTION_IFSET(CPU_FTR_HVMODE) > > TRAMP_REAL_BEGIN(machine_check_pSeries) > .globl machine_check_fwnmi > @@ -333,7 +333,7 @@ machine_check_fwnmi: > SET_SCRATCH0(r13) /* save r13 */ > EXCEPTION_PROLOG_0(PACA_EXMC) > BEGIN_FTR_SECTION > - b machine_check_pSeries_early > + b machine_check_common_early > END_FTR_SECTION_IFCLR(CPU_FTR_HVMODE) > machine_check_pSeries_0: > EXCEPTION_PROLOG_1(PACA_EXMC, KVMTEST_PR, 0x200) > @@ -346,103 +346,6 @@ machine_check_pSeries_0: > > TRAMP_KVM_SKIP(PACA_EXMC, 0x200) > > -TRAMP_REAL_BEGIN(machine_check_pSeries_early) > -BEGIN_FTR_SECTION > - EXCEPTION_PROLOG_1(PACA_EXMC, NOTEST, 0x200) > - mr r10,r1 /* Save r1 */ > - lhz r11,PACA_IN_MCE(r13) > - cmpwi r11,0 /* Are we in nested machine check */ > - bne 0f /* Yes, we are. */ > - /* First machine check entry */ > - ld r1,PACAMCEMERGSP(r13) /* Use MC emergency stack */ > -0: subi r1,r1,INT_FRAME_SIZE /* alloc stack frame */ > - addi r11,r11,1 /* increment paca->in_mce */ > - sth r11,PACA_IN_MCE(r13) > - /* Limit nested MCE to level 4 to avoid stack overflow */ > - cmpwi r11,MAX_MCE_DEPTH > - bgt 1f /* Check if we hit limit of 4 */ > - mfspr r11,SPRN_SRR0 /* Save SRR0 */ > - mfspr r12,SPRN_SRR1 /* Save SRR1 */ > - EXCEPTION_PROLOG_COMMON_1() > - EXCEPTION_PROLOG_COMMON_2(PACA_EXMC) > - EXCEPTION_PROLOG_COMMON_3(0x200) > - addi r3,r1,STACK_FRAME_OVERHEAD > - BRANCH_LINK_TO_FAR(machine_check_early) /* Function call ABI */ > - ld r12,_MSR(r1) > - andi. r11,r12,MSR_PR /* See if coming from user. */ > - bne 2f /* continue in V mode if we are. */ > - > - /* > - * At this point we are not sure about what context we come from. > - * We may be in the middle of swithing stack. r1 may not be valid. > - * Hence stay on emergency stack, call machine_check_exception and > - * return from the interrupt. > - * But before that, check if this is an un-recoverable exception. > - * If yes, then stay on emergency stack and panic. > - */ > - andi. r11,r12,MSR_RI > - beq 1f > - > - /* > - * Check if we have successfully handled/recovered from error, if not > - * then stay on emergency stack and panic. > - */ > - cmpdi r3,0 /* see if we handled MCE successfully */ > - beq 1f /* if !handled then panic */ > - > - /* Stay on emergency stack and return from interrupt. */ > - LOAD_HANDLER(r10,mce_return) > - mtspr SPRN_SRR0,r10 > - ld r10,PACAKMSR(r13) > - mtspr SPRN_SRR1,r10 > - RFI_TO_KERNEL > - b . > - > -1: LOAD_HANDLER(r10,unrecover_mce) > - mtspr SPRN_SRR0,r10 > - ld r10,PACAKMSR(r13) > - /* > - * We are going down. But there are chances that we might get hit by > - * another MCE during panic path and we may run into unstable state > - * with no way out. Hence, turn ME bit off while going down, so that > - * when another MCE is hit during panic path, hypervisor will > - * power cycle the lpar, instead of getting into MCE loop. > - */ > - li r3,MSR_ME > - andc r10,r10,r3 /* Turn off MSR_ME */ > - mtspr SPRN_SRR1,r10 > - RFI_TO_KERNEL > - b . > - > - /* Move original SRR0 and SRR1 into the respective regs */ > -2: ld r9,_MSR(r1) > - mtspr SPRN_SRR1,r9 > - ld r3,_NIP(r1) > - mtspr SPRN_SRR0,r3 > - ld r9,_CTR(r1) > - mtctr r9 > - ld r9,_XER(r1) > - mtxer r9 > - ld r9,_LINK(r1) > - mtlr r9 > - REST_GPR(0, r1) > - REST_8GPRS(2, r1) > - REST_GPR(10, r1) > - ld r11,_CCR(r1) > - mtcr r11 > - /* Decrement paca->in_mce. */ > - lhz r12,PACA_IN_MCE(r13) > - subi r12,r12,1 > - sth r12,PACA_IN_MCE(r13) > - REST_GPR(11, r1) > - REST_2GPRS(12, r1) > - /* restore original r1. */ > - ld r1,GPR1(r1) > - SET_SCRATCH0(r13) /* save r13 */ > - EXCEPTION_PROLOG_0(PACA_EXMC) > - b machine_check_pSeries_0 > -END_FTR_SECTION_IFCLR(CPU_FTR_HVMODE) > - > EXC_COMMON_BEGIN(machine_check_common) > /* > * Machine check is different because we use a different > @@ -541,6 +444,9 @@ EXC_COMMON_BEGIN(machine_check_handle_early) > bl machine_check_early > std r3,RESULT(r1) /* Save result */ > ld r12,_MSR(r1) > +BEGIN_FTR_SECTION > + b 4f > +END_FTR_SECTION_IFCLR(CPU_FTR_HVMODE) > > #ifdef CONFIG_PPC_P7_NAP > /* > @@ -564,10 +470,11 @@ EXC_COMMON_BEGIN(machine_check_handle_early) > */ > rldicl. r11,r12,4,63 /* See if MC hit while in HV mode. */ > beq 5f > - andi. r11,r12,MSR_PR /* See if coming from user. */ > +4: andi. r11,r12,MSR_PR /* See if coming from user. */ > bne 9f /* continue in V mode if we are. */ > > 5: > +BEGIN_FTR_SECTION > #ifdef CONFIG_KVM_BOOK3S_64_HANDLER > /* > * We are coming from kernel context. Check if we are coming from > @@ -578,6 +485,7 @@ EXC_COMMON_BEGIN(machine_check_handle_early) > cmpwi r11,0 /* Check if coming from guest */ > bne 9f /* continue if we are. */ > #endif > +END_FTR_SECTION_IFSET(CPU_FTR_HVMODE) Put these inside the ifdef? > /* > * At this point we are not sure about what context we come from. > * Queue up the MCE event and return from the interrupt. > @@ -611,6 +519,7 @@ EXC_COMMON_BEGIN(machine_check_handle_early) > cmpdi r3,0 /* see if we handled MCE successfully */ > > beq 1b /* if !handled then panic */ > +BEGIN_FTR_SECTION > /* > * Return from MC interrupt. > * Queue up the MCE event so that we can log it later, while > @@ -619,10 +528,24 @@ EXC_COMMON_BEGIN(machine_check_handle_early) > bl machine_check_queue_event > MACHINE_CHECK_HANDLER_WINDUP > RFI_TO_USER_OR_KERNEL > +FTR_SECTION_ELSE > + /* > + * pSeries: Return from MC interrupt. Before that stay on emergency > + * stack and call machine_check_exception to log the MCE event. > + */ > + LOAD_HANDLER(r10,mce_return) > + mtspr SPRN_SRR0,r10 > + ld r10,PACAKMSR(r13) > + mtspr SPRN_SRR1,r10 > + RFI_TO_KERNEL > + b . > +ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE) Do you still need mce_return? Why can't you consolidate it as well? ... Hmm, okay so now I look back at patch 2, I don't think you should call machine_check_exception there. You're supposed to call machine_check_queue_event here and it will be handled by irq work. I think when you do that more of this code should fall out and be consolidated. Sorry for not picking that up earlier. Thanks, Nick
