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author | Balbir Singh <bsingharora@gmail.com> | 2017-09-29 14:26:53 +1000 |
---|---|---|
committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-10-16 23:12:01 +1100 |
commit | ba41e1e1ccb9771ce41a3b8e2121f95486e76ac9 (patch) | |
tree | a6ca6c4b6e2cd1ce5eabf605b9ec2884fbf912de /arch/powerpc/kernel | |
parent | 81b61fa7a065e639d097b09c303e3212e4264fac (diff) | |
download | op-kernel-dev-ba41e1e1ccb9771ce41a3b8e2121f95486e76ac9.zip op-kernel-dev-ba41e1e1ccb9771ce41a3b8e2121f95486e76ac9.tar.gz |
powerpc/mce: Hookup derror (load/store) UE errors
Extract physical_address for UE errors by walking the page
tables for the mm and address at the NIP, to extract the
instruction. Then use the instruction to find the effective
address via analyse_instr().
We might have page table walking races, but we expect them to
be rare, the physical address extraction is best effort. The idea
is to then hook up this infrastructure to memory failure eventually.
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel')
-rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 2 | ||||
-rw-r--r-- | arch/powerpc/kernel/mce.c | 6 | ||||
-rw-r--r-- | arch/powerpc/kernel/mce_power.c | 87 |
3 files changed, 88 insertions, 7 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 8c32dd4..ce04b1c 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -232,7 +232,7 @@ BEGIN_FTR_SECTION addi r10,r10,1 /* increment paca->in_mce */ sth r10,PACA_IN_MCE(r13) /* Limit nested MCE to level 4 to avoid stack overflow */ - cmpwi r10,4 + cmpwi r10,MAX_MCE_DEPTH bgt 2f /* Check if we hit limit of 4 */ std r11,GPR1(r1) /* Save r1 on the stack. */ std r11,0(r1) /* make stack chain pointer */ diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c index d1775bd..1af7c55 100644 --- a/arch/powerpc/kernel/mce.c +++ b/arch/powerpc/kernel/mce.c @@ -82,7 +82,7 @@ static void mce_set_error_info(struct machine_check_event *mce, */ void save_mce_event(struct pt_regs *regs, long handled, struct mce_error_info *mce_err, - uint64_t nip, uint64_t addr) + uint64_t nip, uint64_t addr, uint64_t phys_addr) { int index = __this_cpu_inc_return(mce_nest_count) - 1; struct machine_check_event *mce = this_cpu_ptr(&mce_event[index]); @@ -140,6 +140,10 @@ void save_mce_event(struct pt_regs *regs, long handled, } else if (mce->error_type == MCE_ERROR_TYPE_UE) { mce->u.ue_error.effective_address_provided = true; mce->u.ue_error.effective_address = addr; + if (phys_addr != ULONG_MAX) { + mce->u.ue_error.physical_address_provided = true; + mce->u.ue_error.physical_address = phys_addr; + } } return; } diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c index d37e612..e61b80e 100644 --- a/arch/powerpc/kernel/mce_power.c +++ b/arch/powerpc/kernel/mce_power.c @@ -27,6 +27,36 @@ #include <asm/mmu.h> #include <asm/mce.h> #include <asm/machdep.h> +#include <asm/pgtable.h> +#include <asm/pte-walk.h> +#include <asm/sstep.h> +#include <asm/exception-64s.h> + +/* + * Convert an address related to an mm to a PFN. NOTE: we are in real + * mode, we could potentially race with page table updates. + */ +static unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr) +{ + pte_t *ptep; + unsigned long flags; + struct mm_struct *mm; + + if (user_mode(regs)) + mm = current->mm; + else + mm = &init_mm; + + local_irq_save(flags); + if (mm == current->mm) + ptep = find_current_mm_pte(mm->pgd, addr, NULL, NULL); + else + ptep = find_init_mm_pte(addr, NULL); + local_irq_restore(flags); + if (!ptep || pte_special(*ptep)) + return ULONG_MAX; + return pte_pfn(*ptep); +} static void flush_tlb_206(unsigned int num_sets, unsigned int action) { @@ -421,6 +451,41 @@ static const struct mce_derror_table mce_p9_derror_table[] = { MCE_INITIATOR_CPU, MCE_SEV_ERROR_SYNC, }, { 0, false, 0, 0, 0, 0 } }; +static int mce_find_instr_ea_and_pfn(struct pt_regs *regs, uint64_t *addr, + uint64_t *phys_addr) +{ + /* + * Carefully look at the NIP to determine + * the instruction to analyse. Reading the NIP + * in real-mode is tricky and can lead to recursive + * faults + */ + int instr; + unsigned long pfn, instr_addr; + struct instruction_op op; + struct pt_regs tmp = *regs; + + pfn = addr_to_pfn(regs, regs->nip); + if (pfn != ULONG_MAX) { + instr_addr = (pfn << PAGE_SHIFT) + (regs->nip & ~PAGE_MASK); + instr = *(unsigned int *)(instr_addr); + if (!analyse_instr(&op, &tmp, instr)) { + pfn = addr_to_pfn(regs, op.ea); + *addr = op.ea; + *phys_addr = (pfn << PAGE_SHIFT); + return 0; + } + /* + * analyse_instr() might fail if the instruction + * is not a load/store, although this is unexpected + * for load/store errors or if we got the NIP + * wrong + */ + } + *addr = 0; + return -1; +} + static int mce_handle_ierror(struct pt_regs *regs, const struct mce_ierror_table table[], struct mce_error_info *mce_err, uint64_t *addr) @@ -489,7 +554,8 @@ static int mce_handle_ierror(struct pt_regs *regs, static int mce_handle_derror(struct pt_regs *regs, const struct mce_derror_table table[], - struct mce_error_info *mce_err, uint64_t *addr) + struct mce_error_info *mce_err, uint64_t *addr, + uint64_t *phys_addr) { uint64_t dsisr = regs->dsisr; int handled = 0; @@ -555,7 +621,17 @@ static int mce_handle_derror(struct pt_regs *regs, mce_err->initiator = table[i].initiator; if (table[i].dar_valid) *addr = regs->dar; - + else if (mce_err->severity == MCE_SEV_ERROR_SYNC && + table[i].error_type == MCE_ERROR_TYPE_UE) { + /* + * We do a maximum of 4 nested MCE calls, see + * kernel/exception-64s.h + */ + if (get_paca()->in_mce < MAX_MCE_DEPTH) + if (!mce_find_instr_ea_and_pfn(regs, addr, + phys_addr)) + handled = 1; + } found = 1; } @@ -592,19 +668,20 @@ static long mce_handle_error(struct pt_regs *regs, const struct mce_ierror_table itable[]) { struct mce_error_info mce_err = { 0 }; - uint64_t addr; + uint64_t addr, phys_addr; uint64_t srr1 = regs->msr; long handled; if (SRR1_MC_LOADSTORE(srr1)) - handled = mce_handle_derror(regs, dtable, &mce_err, &addr); + handled = mce_handle_derror(regs, dtable, &mce_err, &addr, + &phys_addr); else handled = mce_handle_ierror(regs, itable, &mce_err, &addr); if (!handled && mce_err.error_type == MCE_ERROR_TYPE_UE) handled = mce_handle_ue_error(regs); - save_mce_event(regs, handled, &mce_err, regs->nip, addr); + save_mce_event(regs, handled, &mce_err, regs->nip, addr, phys_addr); return handled; } |