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    Subject[RFC v5 32/38] powerpc: capture the violated protection key on fault
    Date
    Capture the protection key that got violated in paca.
    This value will be used by used to inform the signal
    handler.

    Signed-off-by: Ram Pai <linuxram@us.ibm.com>
    ---
    arch/powerpc/include/asm/paca.h | 1 +
    arch/powerpc/kernel/asm-offsets.c | 1 +
    arch/powerpc/mm/fault.c | 3 +++
    3 files changed, 5 insertions(+), 0 deletions(-)

    diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
    index c8bd1fc..0c06188 100644
    --- a/arch/powerpc/include/asm/paca.h
    +++ b/arch/powerpc/include/asm/paca.h
    @@ -94,6 +94,7 @@ struct paca_struct {
    u64 dscr_default; /* per-CPU default DSCR */
    #ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
    u64 paca_amr; /* value of amr at exception */
    + u16 paca_pkey; /* exception causing pkey */
    #endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */

    #ifdef CONFIG_PPC_STD_MMU_64
    diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
    index 17f5d8a..7dff862 100644
    --- a/arch/powerpc/kernel/asm-offsets.c
    +++ b/arch/powerpc/kernel/asm-offsets.c
    @@ -244,6 +244,7 @@ int main(void)

    #ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
    OFFSET(PACA_AMR, paca_struct, paca_amr);
    + OFFSET(PACA_PKEY, paca_struct, paca_pkey);
    #endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */

    OFFSET(ACCOUNT_STARTTIME, paca_struct, accounting.starttime);
    diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
    index a6710f5..c8674a7 100644
    --- a/arch/powerpc/mm/fault.c
    +++ b/arch/powerpc/mm/fault.c
    @@ -265,6 +265,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
    if (error_code & DSISR_KEYFAULT) {
    code = SEGV_PKUERR;
    get_paca()->paca_amr = read_amr();
    + get_paca()->paca_pkey = get_pte_pkey(current->mm, address);
    goto bad_area_nosemaphore;
    }
    #endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
    @@ -290,6 +291,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,

    perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);

    +
    /*
    * We want to do this outside mmap_sem, because reading code around nip
    * can result in fault, which will cause a deadlock when called with
    @@ -453,6 +455,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
    if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE,
    is_exec, 0)) {
    get_paca()->paca_amr = read_amr();
    + get_paca()->paca_pkey = vma_pkey(vma);
    code = SEGV_PKUERR;
    goto bad_area;
    }
    --
    1.7.1
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