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[50.39.103.96]) by smtp.gmail.com with ESMTPSA id q46sm2290345qtc.54.2017.07.15.20.59.15 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 15 Jul 2017 20:59:17 -0700 (PDT) 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 Subject: [RFC v6 31/62] powerpc: Handle exceptions caused by pkey violation Date: Sat, 15 Jul 2017 20:56:33 -0700 Message-Id: <1500177424-13695-32-git-send-email-linuxram@us.ibm.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1500177424-13695-1-git-send-email-linuxram@us.ibm.com> References: <1500177424-13695-1-git-send-email-linuxram@us.ibm.com> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: arnd@arndb.de, corbet@lwn.net, linuxram@us.ibm.com, mhocko@kernel.org, dave.hansen@intel.com, mingo@redhat.com, paulus@samba.org, aneesh.kumar@linux.vnet.ibm.com, akpm@linux-foundation.org, khandual@linux.vnet.ibm.com Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Handle Data and Instruction exceptions caused by memory protection-key. The CPU will detect the key fault if the HPTE is already programmed with the key. However if the HPTE is not hashed, a key fault will not be detected by the hardware. The software will detect pkey violation in such a case. Signed-off-by: Ram Pai --- arch/powerpc/include/asm/reg.h | 3 ++- arch/powerpc/mm/fault.c | 21 +++++++++++++++++++++ 2 files changed, 23 insertions(+), 1 deletions(-) diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h index ee04bc0..b7cbc8c 100644 --- a/arch/powerpc/include/asm/reg.h +++ b/arch/powerpc/include/asm/reg.h @@ -286,7 +286,8 @@ #define DSISR_SET_RC 0x00040000 /* Failed setting of R/C bits */ #define DSISR_PGDIRFAULT 0x00020000 /* Fault on page directory */ #define DSISR_PAGE_FAULT_MASK (DSISR_BIT32 | DSISR_PAGEATTR_CONFLT | \ - DSISR_BADACCESS | DSISR_DABRMATCH | DSISR_BIT43) + DSISR_BADACCESS | DSISR_KEYFAULT | \ + DSISR_DABRMATCH | DSISR_BIT43) #define SPRN_TBRL 0x10C /* Time Base Read Lower Register (user, R/O) */ #define SPRN_TBRU 0x10D /* Time Base Read Upper Register (user, R/O) */ #define SPRN_CIR 0x11B /* Chip Information Register (hyper, R/0) */ diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 3a7d580..ea74fe2 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -261,6 +261,13 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, } #endif +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS + if (error_code & DSISR_KEYFAULT) { + code = SEGV_PKUERR; + goto bad_area_nosemaphore; + } +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */ + /* We restore the interrupt state now */ if (!arch_irq_disabled_regs(regs)) local_irq_enable(); @@ -441,6 +448,20 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, WARN_ON_ONCE(error_code & DSISR_PROTFAULT); #endif /* CONFIG_PPC_STD_MMU */ +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS + if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, + is_exec, 0)) { + code = SEGV_PKUERR; + goto bad_area; + } +#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */ + + + /* handle_mm_fault() needs to know if its a instruction access + * fault. + */ + if (is_exec) + flags |= FAULT_FLAG_INSTRUCTION; /* * If for any reason at all we couldn't handle the fault, * make sure we exit gracefully rather than endlessly redo