[v9,2/7] powerpc/mce: Fix MCE handling for huge pages
diff mbox series

Message ID 20190812092236.16648-3-santosh@fossix.org
State Superseded
Headers show
Series
  • powerpc: implement machine check safe memcpy
Related show

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Context Check Description
snowpatch_ozlabs/checkpatch warning total: 0 errors, 0 warnings, 2 checks, 126 lines checked
snowpatch_ozlabs/apply_patch success Successfully applied on branch next (da206bd46848568e1aaf35f00e2d78bf9bc94f95)

Commit Message

Santosh Sivaraj Aug. 12, 2019, 9:22 a.m. UTC
From: Balbir Singh <bsingharora@gmail.com>

The current code would fail on huge pages addresses, since the shift would
be incorrect. Use the correct page shift value returned by
__find_linux_pte() to get the correct physical address. The code is more
generic and can handle both regular and compound pages.

Fixes: ba41e1e1ccb9 ("powerpc/mce: Hookup derror (load/store) UE errors")
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[arbab@linux.ibm.com: Fixup pseries_do_memory_failure()]
Signed-off-by: Reza Arbab <arbab@linux.ibm.com>
Co-developed-by: Santosh Sivaraj <santosh@fossix.org>
Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
Tested-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # v4.15+
---
 arch/powerpc/include/asm/mce.h       |  2 +-
 arch/powerpc/kernel/mce_power.c      | 55 ++++++++++++++--------------
 arch/powerpc/platforms/pseries/ras.c |  9 ++---
 3 files changed, 32 insertions(+), 34 deletions(-)

Comments

Sasha Levin Aug. 12, 2019, 1:55 p.m. UTC | #1
Hi,

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag,
fixing commit: ba41e1e1ccb9 powerpc/mce: Hookup derror (load/store) UE errors.

The bot has tested the following trees: v5.2.8, v4.19.66.

v5.2.8: Build OK!
v4.19.66: Failed to apply! Possible dependencies:
    360cae313702 ("KVM: PPC: Book3S HV: Nested guest entry via hypercall")
    41f4e631daf8 ("KVM: PPC: Book3S HV: Extract PMU save/restore operations as C-callable functions")
    884dfb722db8 ("KVM: PPC: Book3S HV: Simplify machine check handling")
    89329c0be8bd ("KVM: PPC: Book3S HV: Clear partition table entry on vm teardown")
    8e3f5fc1045d ("KVM: PPC: Book3S HV: Framework and hcall stubs for nested virtualization")
    95a6432ce903 ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests")
    a43c1590426c ("powerpc/pseries: Flush SLB contents on SLB MCE errors.")
    c05772018491 ("powerpc/64s: Better printing of machine check info for guest MCEs")
    d24ea8a7336a ("KVM: PPC: Book3S: Simplify external interrupt handling")
    df709a296ef7 ("KVM: PPC: Book3S HV: Simplify real-mode interrupt handling")
    f7035ce9f1df ("KVM: PPC: Book3S HV: Move interrupt delivery on guest entry to C code")


NOTE: The patch will not be queued to stable trees until it is upstream.

How should we proceed with this patch?

--
Thanks,
Sasha
Santosh Sivaraj Aug. 13, 2019, 12:40 a.m. UTC | #2
Sasha Levin <sashal@kernel.org> writes:

> Hi,
>
> [This is an automated email]
>
> This commit has been processed because it contains a "Fixes:" tag,
> fixing commit: ba41e1e1ccb9 powerpc/mce: Hookup derror (load/store) UE errors.
>
> The bot has tested the following trees: v5.2.8, v4.19.66.
>
> v5.2.8: Build OK!
> v4.19.66: Failed to apply! Possible dependencies:
>     360cae313702 ("KVM: PPC: Book3S HV: Nested guest entry via hypercall")
>     41f4e631daf8 ("KVM: PPC: Book3S HV: Extract PMU save/restore operations as C-callable functions")
>     884dfb722db8 ("KVM: PPC: Book3S HV: Simplify machine check handling")
>     89329c0be8bd ("KVM: PPC: Book3S HV: Clear partition table entry on vm teardown")
>     8e3f5fc1045d ("KVM: PPC: Book3S HV: Framework and hcall stubs for nested virtualization")
>     95a6432ce903 ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests")
>     a43c1590426c ("powerpc/pseries: Flush SLB contents on SLB MCE errors.")
>     c05772018491 ("powerpc/64s: Better printing of machine check info for guest MCEs")
>     d24ea8a7336a ("KVM: PPC: Book3S: Simplify external interrupt handling")
>     df709a296ef7 ("KVM: PPC: Book3S HV: Simplify real-mode interrupt handling")
>     f7035ce9f1df ("KVM: PPC: Book3S HV: Move interrupt delivery on guest entry to C code")
>
>
> NOTE: The patch will not be queued to stable trees until it is upstream.
>
> How should we proceed with this patch?

I will send a backport once this has been merged upstream.

Thanks,
Santosh

>
> --
> Thanks,
> Sasha

Patch
diff mbox series

diff --git a/arch/powerpc/include/asm/mce.h b/arch/powerpc/include/asm/mce.h
index a4c6a74ad2fb..f3a6036b6bc0 100644
--- a/arch/powerpc/include/asm/mce.h
+++ b/arch/powerpc/include/asm/mce.h
@@ -209,7 +209,7 @@  extern void release_mce_event(void);
 extern void machine_check_queue_event(void);
 extern void machine_check_print_event_info(struct machine_check_event *evt,
 					   bool user_mode, bool in_guest);
-unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr);
+unsigned long addr_to_phys(struct pt_regs *regs, unsigned long addr);
 #ifdef CONFIG_PPC_BOOK3S_64
 void flush_and_reload_slb(void);
 #endif /* CONFIG_PPC_BOOK3S_64 */
diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c
index a814d2dfb5b0..e74816f045f8 100644
--- a/arch/powerpc/kernel/mce_power.c
+++ b/arch/powerpc/kernel/mce_power.c
@@ -20,13 +20,14 @@ 
 #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.
+ * Convert an address related to an mm to a physical address.
+ * NOTE: we are in real mode, we could potentially race with page table updates.
  */
-unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
+unsigned long addr_to_phys(struct pt_regs *regs, unsigned long addr)
 {
-	pte_t *ptep;
-	unsigned long flags;
+	pte_t *ptep, pte;
+	unsigned int shift;
+	unsigned long flags, phys_addr;
 	struct mm_struct *mm;
 
 	if (user_mode(regs))
@@ -35,14 +36,21 @@  unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
 		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);
+	ptep = __find_linux_pte(mm->pgd, addr, NULL, &shift);
 	local_irq_restore(flags);
+
 	if (!ptep || pte_special(*ptep))
 		return ULONG_MAX;
-	return pte_pfn(*ptep);
+
+	pte = *ptep;
+	if (shift > PAGE_SHIFT) {
+		unsigned long rpnmask = (1ul << shift) - PAGE_SIZE;
+
+		pte = __pte(pte_val(pte) | (addr & rpnmask));
+	}
+	phys_addr = pte_pfn(pte) << PAGE_SHIFT;
+
+	return phys_addr;
 }
 
 /* flush SLBs and reload */
@@ -344,7 +352,7 @@  static const struct mce_derror_table mce_p9_derror_table[] = {
   MCE_INITIATOR_CPU,   MCE_SEV_SEVERE, true },
 { 0, false, 0, 0, 0, 0, 0 } };
 
-static int mce_find_instr_ea_and_pfn(struct pt_regs *regs, uint64_t *addr,
+static int mce_find_instr_ea_and_phys(struct pt_regs *regs, uint64_t *addr,
 					uint64_t *phys_addr)
 {
 	/*
@@ -354,18 +362,16 @@  static int mce_find_instr_ea_and_pfn(struct pt_regs *regs, uint64_t *addr,
 	 * faults
 	 */
 	int instr;
-	unsigned long pfn, instr_addr;
+	unsigned long 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_addr = addr_to_phys(regs, regs->nip) + (regs->nip & ~PAGE_MASK);
+	if (instr_addr != ULONG_MAX) {
 		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);
+			*phys_addr = addr_to_phys(regs, op.ea);
 			return 0;
 		}
 		/*
@@ -440,15 +446,9 @@  static int mce_handle_ierror(struct pt_regs *regs,
 			*addr = regs->nip;
 			if (mce_err->sync_error &&
 				table[i].error_type == MCE_ERROR_TYPE_UE) {
-				unsigned long pfn;
-
-				if (get_paca()->in_mce < MAX_MCE_DEPTH) {
-					pfn = addr_to_pfn(regs, regs->nip);
-					if (pfn != ULONG_MAX) {
-						*phys_addr =
-							(pfn << PAGE_SHIFT);
-					}
-				}
+				if (get_paca()->in_mce < MAX_MCE_DEPTH)
+					*phys_addr = addr_to_phys(regs,
+								 regs->nip);
 			}
 		}
 		return handled;
@@ -541,7 +541,8 @@  static int mce_handle_derror(struct pt_regs *regs,
 			 * kernel/exception-64s.h
 			 */
 			if (get_paca()->in_mce < MAX_MCE_DEPTH)
-				mce_find_instr_ea_and_pfn(regs, addr, phys_addr);
+				mce_find_instr_ea_and_phys(regs, addr,
+							   phys_addr);
 		}
 		found = 1;
 	}
diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
index f16fdd0f71f7..5743f6353638 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -739,13 +739,10 @@  static void pseries_do_memory_failure(struct pt_regs *regs,
 	if (mce_log->sub_err_type & UE_LOGICAL_ADDR_PROVIDED) {
 		paddr = be64_to_cpu(mce_log->logical_address);
 	} else if (mce_log->sub_err_type & UE_EFFECTIVE_ADDR_PROVIDED) {
-		unsigned long pfn;
-
-		pfn = addr_to_pfn(regs,
-				  be64_to_cpu(mce_log->effective_address));
-		if (pfn == ULONG_MAX)
+		paddr = addr_to_phys(regs,
+				     be64_to_cpu(mce_log->effective_address));
+		if (paddr == ULONG_MAX)
 			return;
-		paddr = pfn << PAGE_SHIFT;
 	} else {
 		return;
 	}