Santosh Sivaraj's on August 15, 2019 10:39 am:
> From: Balbir Singh <bsingharora@xxxxxxxxx>
>
> 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@xxxxxxxxx>
> [arbab@xxxxxxxxxxxxx: Fixup pseries_do_memory_failure()]
> Signed-off-by: Reza Arbab <arbab@xxxxxxxxxxxxx>
> Co-developed-by: Santosh Sivaraj <santosh@xxxxxxxxxx>
> Signed-off-by: Santosh Sivaraj <santosh@xxxxxxxxxx>
> Tested-by: Mahesh Salgaonkar <mahesh@xxxxxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # 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(-)
>
> 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;
> }
This should remain addr_to_pfn I think. None of the callers care what
size page the EA was mapped with. 'pfn' is referring to the Linux pfn,
which is the small page number.
if (shift > PAGE_SHIFT)
return (pte_pfn(*ptep) | ((addr & ((1UL << shift) - 1)) >> PAGE_SHIFT);
else
return pte_pfn(*ptep);
Something roughly like that, then you don't have to change any callers
or am I missing something?
Thanks,
Nick
