From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-x243.google.com (mail-qt0-x243.google.com [IPv6:2607:f8b0:400d:c0d::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 3yVmhK5GzWzDq78 for ; Mon, 6 Nov 2017 19:59:13 +1100 (AEDT) Received: by mail-qt0-x243.google.com with SMTP id j58so10029230qtj.0 for ; Mon, 06 Nov 2017 00:59:13 -0800 (PST) Sender: Ram Pai From: Ram Pai To: mpe@ellerman.id.au, mingo@redhat.com, akpm@linux-foundation.org, corbet@lwn.net, arnd@arndb.de Cc: linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, dave.hansen@intel.com, benh@kernel.crashing.org, paulus@samba.org, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, hbabu@us.ibm.com, mhocko@kernel.org, bauerman@linux.vnet.ibm.com, ebiederm@xmission.com, linuxram@us.ibm.com Subject: [PATCH v9 19/51] powerpc: Handle exceptions caused by pkey violation Date: Mon, 6 Nov 2017 00:57:11 -0800 Message-Id: <1509958663-18737-20-git-send-email-linuxram@us.ibm.com> In-Reply-To: <1509958663-18737-1-git-send-email-linuxram@us.ibm.com> References: <1509958663-18737-1-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: , 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/mm/fault.c | 32 +++++++++++++++++++++++++++----- 1 files changed, 27 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 4797d08..dfcd0e4 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -145,6 +145,24 @@ static noinline int bad_area(struct pt_regs *regs, unsigned long address) return __bad_area(regs, address, SEGV_MAPERR); } +static int bad_page_fault_exception(struct pt_regs *regs, unsigned long address, + int si_code) +{ + int sig = SIGBUS; + int code = BUS_OBJERR; + +#ifdef CONFIG_PPC_MEM_KEYS + if (si_code & DSISR_KEYFAULT) { + perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); + sig = SIGSEGV; + code = SEGV_PKUERR; + } +#endif /* CONFIG_PPC_MEM_KEYS */ + + _exception(sig, regs, code, address); + return 0; +} + static int do_sigbus(struct pt_regs *regs, unsigned long address, unsigned int fault) { @@ -391,11 +409,9 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, return 0; if (unlikely(page_fault_is_bad(error_code))) { - if (is_user) { - _exception(SIGBUS, regs, BUS_OBJERR, address); - return 0; - } - return SIGBUS; + if (!is_user) + return SIGBUS; + return bad_page_fault_exception(regs, address, error_code); } /* Additional sanity check(s) */ @@ -498,6 +514,12 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, * the fault. */ fault = handle_mm_fault(vma, address, flags); + +#ifdef CONFIG_PPC_MEM_KEYS + if (unlikely(fault & VM_FAULT_SIGSEGV)) + return __bad_area(regs, address, SEGV_PKUERR); +#endif /* CONFIG_PPC_MEM_KEYS */ + major |= fault & VM_FAULT_MAJOR; /* -- 1.7.1