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Mon, 27 Apr 2020 08:06:17 +0000 Received: from b03ledav006.gho.boulder.ibm.com (b03ledav006.gho.boulder.ibm.com [9.17.130.237]) by b03cxnp08026.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 03R86F3g31326608 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 27 Apr 2020 08:06:16 GMT Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 609D0C6059; Mon, 27 Apr 2020 08:06:16 +0000 (GMT) Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3B783C6055; Mon, 27 Apr 2020 08:06:14 +0000 (GMT) Received: from skywalker.ibmuc.com (unknown [9.85.72.10]) by b03ledav006.gho.boulder.ibm.com (Postfix) with ESMTP; Mon, 27 Apr 2020 08:06:13 +0000 (GMT) From: "Aneesh Kumar K.V" To: linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au Subject: [RFC PATCH 20/25] powerpc/book3s64/kuap: Improve error reporting with KUAP Date: Mon, 27 Apr 2020 13:35:01 +0530 Message-Id: <20200427080507.1626327-21-aneesh.kumar@linux.ibm.com> X-Mailer: git-send-email 2.25.3 In-Reply-To: <20200427080507.1626327-1-aneesh.kumar@linux.ibm.com> References: <20200427080507.1626327-1-aneesh.kumar@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.676 definitions=2020-04-27_03:2020-04-24, 2020-04-27 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 lowpriorityscore=0 clxscore=1015 mlxlogscore=853 mlxscore=0 suspectscore=0 bulkscore=0 adultscore=0 impostorscore=0 phishscore=0 spamscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004270072 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Aneesh Kumar K.V" , linuxram@us.ibm.com, npiggin@gmail.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" With hash translation use DSISR_KEYFAULT to identify a wrong access. With Radix we look at the AMR value and type of fault. Signed-off-by: Aneesh Kumar K.V --- arch/powerpc/include/asm/book3s/64/kup.h | 7 ------ arch/powerpc/mm/fault.c | 27 +++++++++++++++++++++++- 2 files changed, 26 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h index 590c1d9455d1..f564d909e195 100644 --- a/arch/powerpc/include/asm/book3s/64/kup.h +++ b/arch/powerpc/include/asm/book3s/64/kup.h @@ -280,13 +280,6 @@ static inline void restore_user_access(unsigned long flags) set_kuap(flags); } -static inline bool -bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write) -{ - return WARN(mmu_has_feature(MMU_FTR_KUAP) && - (regs->kuap & (is_write ? AMR_KUAP_BLOCK_WRITE : AMR_KUAP_BLOCK_READ)), - "Bug: %s fault blocked by AMR!", is_write ? "Write" : "Read"); -} #else /* CONFIG_PPC_KUAP */ static inline void kuap_restore_amr(struct pt_regs *regs) { diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 84af6c8eecf7..4f866b11512c 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -198,6 +198,31 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr, return 0; } +#define RADIX_KUAP_BLOCK_READ UL(0x4000000000000000) +#define RADIX_KUAP_BLOCK_WRITE UL(0x8000000000000000) + +static bool bad_kuap_fault(struct pt_regs *regs, unsigned long address, + bool is_write, unsigned long error_code) +{ + if (!mmu_has_feature(MMU_FTR_KUAP)) + return false; + + if (radix_enabled()) { + /* + * Will be a storage protection fault. + * Only check the details of AMR[0] + */ + return WARN((regs->kuap & (is_write ? RADIX_KUAP_BLOCK_WRITE : RADIX_KUAP_BLOCK_READ)), + "Bug: %s fault blocked by AMR!", is_write ? "Write" : "Read"); + } + /* + * We don't want to WARN here because userspace can setup + * keys such that a kernel access to user address can cause + * fault + */ + return !!(error_code & DSISR_KEYFAULT); +} + /* Is this a bad kernel fault ? */ static bool bad_kernel_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address, bool is_write) @@ -233,7 +258,7 @@ static bool bad_kernel_fault(struct pt_regs *regs, unsigned long error_code, // Read/write fault in a valid region (the exception table search passed // above), but blocked by KUAP is bad, it can never succeed. - if (bad_kuap_fault(regs, address, is_write)) + if (bad_kuap_fault(regs, address, is_write, error_code)) return true; // What's left? Kernel fault on user in well defined regions (extable -- 2.25.3