From: Liam Howlett <liam.howlett@oracle.com> To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Julien Grall <julien.grall@arm.com> Cc: Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>, Andrii Nakryiko <andrii@kernel.org>, Liam Howlett <liam.howlett@oracle.com>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "netdev@vger.kernel.org" <netdev@vger.kernel.org>, "bpf@vger.kernel.org" <bpf@vger.kernel.org> Subject: [PATCH 1/3] arm64: armv8_deprecated: Fix swp_handler() signal generation Date: Tue, 20 Apr 2021 16:50:12 +0000 [thread overview] Message-ID: <20210420165001.3790670-1-Liam.Howlett@Oracle.com> (raw) arm64_notify_segfault() was written to decide on the si_code from the assembly emulation of the swp_handler(), but was also used for the signal generation from failed access_ok() and unaligned instructions. When access_ok() fails, there is no need to search for the offending address in the VMA space. Instead, simply set the error to SIGSEGV with si_code SEGV_ACCERR. Change the return code from emulate_swpX() when there is an unaligned pointer so the caller can differentiate from the EFAULT. It is unnecessary to search the VMAs in the case of an unaligned pointer. This change uses SIGSEGV and SEGV_ACCERR instead of SIGBUS to keep with what was returned before. Fixes: bd35a4adc413 (arm64: Port SWP/SWPB emulation support from arm) Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> --- arch/arm64/kernel/armv8_deprecated.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index 0e86e8b9cedd..f424082b3455 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -324,7 +324,7 @@ static int emulate_swpX(unsigned int address, unsigned int *data, if ((type != TYPE_SWPB) && (address & 0x3)) { /* SWP to unaligned address not permitted */ pr_debug("SWP instruction on unaligned pointer!\n"); - return -EFAULT; + return -ENXIO; } while (1) { @@ -406,15 +406,17 @@ static int swp_handler(struct pt_regs *regs, u32 instr) user_ptr = (const void __user *)(unsigned long)(address & ~3); if (!access_ok(user_ptr, 4)) { pr_debug("SWP{B} emulation: access to 0x%08x not allowed!\n", - address); - goto fault; + address); + goto e_access; } res = emulate_swpX(address, &data, type); - if (res == -EFAULT) - goto fault; - else if (res == 0) + if (!res) regs->user_regs.regs[destreg] = data; + else if (res == -EFAULT) + goto e_fault; + else if (res = -ENXIO) /* Unaligned pointer */ + goto e_align; ret: if (type == TYPE_SWPB) @@ -428,10 +430,14 @@ static int swp_handler(struct pt_regs *regs, u32 instr) arm64_skip_faulting_instruction(regs, 4); return 0; -fault: +e_fault: pr_debug("SWP{B} emulation: access caused memory abort!\n"); arm64_notify_segfault(address); + return 0; +e_align: +e_access: + force_signal_inject(SIGSEGV, SEGV_ACCERR, address, 0); return 0; } -- 2.30.2
WARNING: multiple messages have this Message-ID (diff)
From: Liam Howlett <liam.howlett@oracle.com> To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Julien Grall <julien.grall@arm.com> Cc: Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>, Andrii Nakryiko <andrii@kernel.org>, Liam Howlett <liam.howlett@oracle.com>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "netdev@vger.kernel.org" <netdev@vger.kernel.org>, "bpf@vger.kernel.org" <bpf@vger.kernel.org> Subject: [PATCH 1/3] arm64: armv8_deprecated: Fix swp_handler() signal generation Date: Tue, 20 Apr 2021 16:50:12 +0000 [thread overview] Message-ID: <20210420165001.3790670-1-Liam.Howlett@Oracle.com> (raw) arm64_notify_segfault() was written to decide on the si_code from the assembly emulation of the swp_handler(), but was also used for the signal generation from failed access_ok() and unaligned instructions. When access_ok() fails, there is no need to search for the offending address in the VMA space. Instead, simply set the error to SIGSEGV with si_code SEGV_ACCERR. Change the return code from emulate_swpX() when there is an unaligned pointer so the caller can differentiate from the EFAULT. It is unnecessary to search the VMAs in the case of an unaligned pointer. This change uses SIGSEGV and SEGV_ACCERR instead of SIGBUS to keep with what was returned before. Fixes: bd35a4adc413 (arm64: Port SWP/SWPB emulation support from arm) Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> --- arch/arm64/kernel/armv8_deprecated.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index 0e86e8b9cedd..f424082b3455 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -324,7 +324,7 @@ static int emulate_swpX(unsigned int address, unsigned int *data, if ((type != TYPE_SWPB) && (address & 0x3)) { /* SWP to unaligned address not permitted */ pr_debug("SWP instruction on unaligned pointer!\n"); - return -EFAULT; + return -ENXIO; } while (1) { @@ -406,15 +406,17 @@ static int swp_handler(struct pt_regs *regs, u32 instr) user_ptr = (const void __user *)(unsigned long)(address & ~3); if (!access_ok(user_ptr, 4)) { pr_debug("SWP{B} emulation: access to 0x%08x not allowed!\n", - address); - goto fault; + address); + goto e_access; } res = emulate_swpX(address, &data, type); - if (res == -EFAULT) - goto fault; - else if (res == 0) + if (!res) regs->user_regs.regs[destreg] = data; + else if (res == -EFAULT) + goto e_fault; + else if (res = -ENXIO) /* Unaligned pointer */ + goto e_align; ret: if (type == TYPE_SWPB) @@ -428,10 +430,14 @@ static int swp_handler(struct pt_regs *regs, u32 instr) arm64_skip_faulting_instruction(regs, 4); return 0; -fault: +e_fault: pr_debug("SWP{B} emulation: access caused memory abort!\n"); arm64_notify_segfault(address); + return 0; +e_align: +e_access: + force_signal_inject(SIGSEGV, SEGV_ACCERR, address, 0); return 0; } -- 2.30.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2021-04-20 16:50 UTC|newest] Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-20 16:50 Liam Howlett [this message] 2021-04-20 16:50 ` [PATCH 1/3] arm64: armv8_deprecated: Fix swp_handler() signal generation Liam Howlett 2021-04-20 16:50 ` [PATCH 2/3] arm64: signal: sigreturn() and rt_sigreturn() sometime returns the wrong signals Liam Howlett 2021-04-20 16:50 ` Liam Howlett 2021-04-22 12:48 ` Will Deacon 2021-04-22 12:48 ` Will Deacon 2021-04-22 18:22 ` Eric W. Biederman 2021-04-22 18:22 ` Eric W. Biederman 2021-04-22 19:24 ` Liam Howlett 2021-04-22 19:24 ` Liam Howlett 2021-04-23 18:17 ` Eric W. Biederman 2021-04-23 18:17 ` Eric W. Biederman 2021-04-23 20:03 ` Liam Howlett 2021-04-23 20:03 ` Liam Howlett 2021-04-29 17:52 ` Eric W. Biederman 2021-04-29 17:52 ` Eric W. Biederman 2021-04-30 18:48 ` Liam Howlett 2021-04-30 18:48 ` Liam Howlett 2021-04-30 19:57 ` Eric W. Biederman 2021-04-30 19:57 ` Eric W. Biederman 2021-04-30 20:31 ` Liam Howlett 2021-04-30 20:31 ` Liam Howlett 2021-04-20 16:50 ` [PATCH 3/3] arch/arm64/kernel/traps: Use find_vma_intersection() in traps for setting si_code Liam Howlett 2021-04-20 16:50 ` Liam Howlett 2021-04-22 12:53 ` Will Deacon 2021-04-22 12:53 ` Will Deacon 2021-04-22 18:56 ` Liam Howlett 2021-04-22 18:56 ` Liam Howlett 2021-04-20 21:22 ` [PATCH 1/3] arm64: armv8_deprecated: Fix swp_handler() signal generation kernel test robot 2021-04-20 21:22 ` kernel test robot 2021-04-21 15:47 ` Liam Howlett 2021-04-21 15:47 ` Liam Howlett 2021-04-21 15:47 ` Liam Howlett 2021-04-22 12:59 ` Will Deacon 2021-04-22 12:59 ` Will Deacon 2021-04-23 1:00 ` Liam Howlett 2021-04-23 1:00 ` Liam Howlett
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20210420165001.3790670-1-Liam.Howlett@Oracle.com \ --to=liam.howlett@oracle.com \ --cc=andrii@kernel.org \ --cc=ast@kernel.org \ --cc=bpf@vger.kernel.org \ --cc=catalin.marinas@arm.com \ --cc=daniel@iogearbox.net \ --cc=julien.grall@arm.com \ --cc=linux-arm-kernel@lists.infradead.org \ --cc=linux-kernel@vger.kernel.org \ --cc=netdev@vger.kernel.org \ --cc=will@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.