From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-x243.google.com (mail-qk0-x243.google.com [IPv6:2607:f8b0:400d:c09::243]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3x9CNb1RKczDqmV for ; Sun, 16 Jul 2017 13:59:27 +1000 (AEST) Received: by mail-qk0-x243.google.com with SMTP id a66so16022788qkb.0 for ; Sat, 15 Jul 2017 20:59:27 -0700 (PDT) Sender: Ram Pai From: Ram Pai To: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, dave.hansen@intel.com, hbabu@us.ibm.com, linuxram@us.ibm.com, arnd@arndb.de, akpm@linux-foundation.org, corbet@lwn.net, mingo@redhat.com, mhocko@kernel.org Subject: [RFC v6 34/62] powerpc: capture the violated protection key on fault Date: Sat, 15 Jul 2017 20:56:36 -0700 Message-Id: <1500177424-13695-35-git-send-email-linuxram@us.ibm.com> In-Reply-To: <1500177424-13695-1-git-send-email-linuxram@us.ibm.com> References: <1500177424-13695-1-git-send-email-linuxram@us.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Capture the protection key that got violated in paca. This value will be later used to inform the signal handler. Signed-off-by: Ram Pai --- arch/powerpc/include/asm/paca.h | 1 + arch/powerpc/kernel/asm-offsets.c | 1 + arch/powerpc/mm/fault.c | 8 ++++++++ 3 files changed, 10 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..6423277 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 */ @@ -453,6 +454,13 @@ 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(); + /* + * The pgd-pdt...pmd-pte tree may not have been fully setup. + * Hence we cannot walk the tree to locate the pte, to locate + * the key. Hence lets call vma_pkey() to get the key here + * instead of get_pte_pkey(). + */ + get_paca()->paca_pkey = vma_pkey(vma); code = SEGV_PKUERR; goto bad_area; } -- 1.7.1