capture AMR register contents, and save it in paca
whenever a pkey violation is detected.

This value will be needed to deliver pkey-violation
signal to the task.

Signed-off-by: Ram Pai <linux...@us.ibm.com>
---
 arch/powerpc/include/asm/paca.h   |    3 +++
 arch/powerpc/kernel/asm-offsets.c |    5 +++++
 arch/powerpc/mm/fault.c           |    2 ++
 3 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
index 1c09f8f..c8bd1fc 100644
--- a/arch/powerpc/include/asm/paca.h
+++ b/arch/powerpc/include/asm/paca.h
@@ -92,6 +92,9 @@ struct paca_struct {
        struct dtl_entry *dispatch_log_end;
 #endif /* CONFIG_PPC_STD_MMU_64 */
        u64 dscr_default;               /* per-CPU default DSCR */
+#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
+       u64 paca_amr;                   /* value of amr at exception */
+#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 709e234..17f5d8a 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -241,6 +241,11 @@ int main(void)
        OFFSET(PACAHWCPUID, paca_struct, hw_cpu_id);
        OFFSET(PACAKEXECSTATE, paca_struct, kexec_state);
        OFFSET(PACA_DSCR_DEFAULT, paca_struct, dscr_default);
+
+#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
+       OFFSET(PACA_AMR, paca_struct, paca_amr);
+#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
+
        OFFSET(ACCOUNT_STARTTIME, paca_struct, accounting.starttime);
        OFFSET(ACCOUNT_STARTTIME_USER, paca_struct, accounting.starttime_user);
        OFFSET(ACCOUNT_USER_TIME, paca_struct, accounting.utime);
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index ea74fe2..a6710f5 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -264,6 +264,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long 
address,
 #ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
        if (error_code & DSISR_KEYFAULT) {
                code = SEGV_PKUERR;
+               get_paca()->paca_amr = read_amr();
                goto bad_area_nosemaphore;
        }
 #endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
@@ -451,6 +452,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long 
address,
 #ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
        if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE,
                        is_exec, 0)) {
+               get_paca()->paca_amr = read_amr();
                code = SEGV_PKUERR;
                goto bad_area;
        }
-- 
1.7.1

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