From patchwork Mon Jul 26 14:11:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 12399593 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F5C0C43214 for ; Mon, 26 Jul 2021 14:11:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 93AE560F44 for ; Mon, 26 Jul 2021 14:11:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 93AE560F44 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id F41CE8E0002; Mon, 26 Jul 2021 10:11:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DB8AD8E0001; Mon, 26 Jul 2021 10:11:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CA82C8E0002; Mon, 26 Jul 2021 10:11:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0018.hostedemail.com [216.40.44.18]) by kanga.kvack.org (Postfix) with ESMTP id ADC3B8E0001 for ; Mon, 26 Jul 2021 10:11:56 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 45B941826526A for ; Mon, 26 Jul 2021 14:11:56 +0000 (UTC) X-FDA: 78404927832.24.0B5FFF9 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf08.hostedemail.com (Postfix) with ESMTP id D3B2430000B4 for ; Mon, 26 Jul 2021 14:11:55 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 9A9B460F9D; Mon, 26 Jul 2021 14:11:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627308715; bh=Lzb0rI8ezKQ/fVredrC1398NDBNvAdJ5u5ejW/DHsXk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sTg05R2g9pqjCuxEEH5ZiQzNKE76zEqQvKr1GsizTDii1s2zsKda+s7AKDdzusPst esUwO3T4gVTOR9znMBhSzQEJ9OjMMeS4sDeCo2SWJQ93PXVVHrYzfqc93ak8blDXzY 0mfyOm5wM6qq/W+xuKZYz1leIfYVAP1a/uafMaZPRjO5owWZlEoyxKu6On2pJXUko8 XVrzwjPVV9TJWOUlRsFaOVoa1sPoyKfo/pD0Pdloj80el3PIvqzn/prcg3zujFgfqP D8xMpYqG5wN2K7/MzuODsQ/3ktkRALfVkdbH4wFT0FADx2DsvRwgwXmpVfptbC8C68 D89sDQqLV3QTw== From: Arnd Bergmann To: Russell King Cc: Arnd Bergmann , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, Alexander Viro , Linus Walleij Subject: [PATCH v5 04/10] ARM: syscall: always store thread_info->abi_syscall Date: Mon, 26 Jul 2021 16:11:35 +0200 Message-Id: <20210726141141.2839385-5-arnd@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210726141141.2839385-1-arnd@kernel.org> References: <20210726141141.2839385-1-arnd@kernel.org> MIME-Version: 1.0 Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=sTg05R2g; spf=pass (imf08.hostedemail.com: domain of arnd@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=arnd@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: D3B2430000B4 X-Stat-Signature: 5ndrptithd91kozd8bgyzhbuydzfwtpc X-HE-Tag: 1627308715-841203 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Arnd Bergmann The system call number is used in a a couple of places, in particular ptrace, seccomp and /proc//syscall. The last one apparently never worked reliably on ARM for tasks that are not currently getting traced. Storing the syscall number in the normal entry path makes it work, as well as allowing us to see if the current system call is for OABI compat mode, which is the next thing I want to hook into. Since the thread_info->syscall field is not just the number any more, it is now renamed to abi_syscall. In kernels that enable both OABI and EABI, the upper bits of this field encode 0x900000 (__NR_OABI_SYSCALL_BASE) for OABI tasks, while normal EABI tasks do not set the upper bits. This makes it possible to implement the in_oabi_syscall() helper later. All other users of thread_info->syscall go through the syscall_get_nr() helper, which in turn filters out the ABI bits. Note that the ABI information is lost with PTRACE_SET_SYSCALL, so one cannot set the internal number to a particular version, but this was already the case. We could change it to let gdb encode the ABI type along with the syscall in a CONFIG_OABI_COMPAT-enabled kernel, but that itself would be a (backwards-compatible) ABI change, so I don't do it here. Signed-off-by: Arnd Bergmann --- arch/arm/include/asm/syscall.h | 5 ++++- arch/arm/include/asm/thread_info.h | 2 +- arch/arm/include/uapi/asm/unistd.h | 1 + arch/arm/kernel/asm-offsets.c | 1 + arch/arm/kernel/entry-common.S | 8 ++++++-- arch/arm/kernel/ptrace.c | 14 ++++++++------ 6 files changed, 21 insertions(+), 10 deletions(-) diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h index fd02761ba06c..f055e846a5cc 100644 --- a/arch/arm/include/asm/syscall.h +++ b/arch/arm/include/asm/syscall.h @@ -22,7 +22,10 @@ extern const unsigned long sys_call_table[]; static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs) { - return task_thread_info(task)->syscall; + if (IS_ENABLED(CONFIG_AEABI) && !IS_ENABLED(CONFIG_OABI_COMPAT)) + return task_thread_info(task)->abi_syscall; + + return task_thread_info(task)->abi_syscall & __NR_SYSCALL_MASK; } static inline void syscall_rollback(struct task_struct *task, diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h index 70d4cbc49ae1..17c56051747b 100644 --- a/arch/arm/include/asm/thread_info.h +++ b/arch/arm/include/asm/thread_info.h @@ -62,7 +62,7 @@ struct thread_info { unsigned long stack_canary; #endif struct cpu_context_save cpu_context; /* cpu context */ - __u32 syscall; /* syscall number */ + __u32 abi_syscall; /* ABI type and syscall nr */ __u8 used_cp[16]; /* thread used copro */ unsigned long tp_value[2]; /* TLS registers */ #ifdef CONFIG_CRUNCH diff --git a/arch/arm/include/uapi/asm/unistd.h b/arch/arm/include/uapi/asm/unistd.h index ae7749e15726..a1149911464c 100644 --- a/arch/arm/include/uapi/asm/unistd.h +++ b/arch/arm/include/uapi/asm/unistd.h @@ -15,6 +15,7 @@ #define _UAPI__ASM_ARM_UNISTD_H #define __NR_OABI_SYSCALL_BASE 0x900000 +#define __NR_SYSCALL_MASK 0x0fffff #if defined(__thumb__) || defined(__ARM_EABI__) #define __NR_SYSCALL_BASE 0 diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c index 70993af22d80..a0945b898ca3 100644 --- a/arch/arm/kernel/asm-offsets.c +++ b/arch/arm/kernel/asm-offsets.c @@ -48,6 +48,7 @@ int main(void) DEFINE(TI_CPU, offsetof(struct thread_info, cpu)); DEFINE(TI_CPU_DOMAIN, offsetof(struct thread_info, cpu_domain)); DEFINE(TI_CPU_SAVE, offsetof(struct thread_info, cpu_context)); + DEFINE(TI_ABI_SYSCALL, offsetof(struct thread_info, abi_syscall)); DEFINE(TI_USED_CP, offsetof(struct thread_info, used_cp)); DEFINE(TI_TP_VALUE, offsetof(struct thread_info, tp_value)); DEFINE(TI_FPSTATE, offsetof(struct thread_info, fpstate)); diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 7f0b7aba1498..e837af90cd44 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -226,6 +226,7 @@ ENTRY(vector_swi) /* saved_psr and saved_pc are now dead */ uaccess_disable tbl + get_thread_info tsk adr tbl, sys_call_table @ load syscall table pointer @@ -237,13 +238,17 @@ ENTRY(vector_swi) * get the old ABI syscall table address. */ bics r10, r10, #0xff000000 + strne r10, [tsk, #TI_ABI_SYSCALL] + streq scno, [tsk, #TI_ABI_SYSCALL] eorne scno, r10, #__NR_OABI_SYSCALL_BASE ldrne tbl, =sys_oabi_call_table #elif !defined(CONFIG_AEABI) bic scno, scno, #0xff000000 @ mask off SWI op-code + str scno, [tsk, #TI_ABI_SYSCALL] eor scno, scno, #__NR_SYSCALL_BASE @ check OS number +#else + str scno, [tsk, #TI_ABI_SYSCALL] #endif - get_thread_info tsk /* * Reload the registers that may have been corrupted on entry to * the syscall assembly (by tracing or context tracking.) @@ -288,7 +293,6 @@ ENDPROC(vector_swi) * context switches, and waiting for our parent to respond. */ __sys_trace: - mov r1, scno add r0, sp, #S_OFF bl syscall_trace_enter mov scno, r0 diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c index 2771e682220b..d886ea8910cb 100644 --- a/arch/arm/kernel/ptrace.c +++ b/arch/arm/kernel/ptrace.c @@ -25,6 +25,7 @@ #include #include +#include #include #define CREATE_TRACE_POINTS @@ -811,7 +812,8 @@ long arch_ptrace(struct task_struct *child, long request, break; case PTRACE_SET_SYSCALL: - task_thread_info(child)->syscall = data; + task_thread_info(child)->abi_syscall = data & + __NR_SYSCALL_MASK; ret = 0; break; @@ -880,14 +882,14 @@ static void tracehook_report_syscall(struct pt_regs *regs, if (dir == PTRACE_SYSCALL_EXIT) tracehook_report_syscall_exit(regs, 0); else if (tracehook_report_syscall_entry(regs)) - current_thread_info()->syscall = -1; + current_thread_info()->abi_syscall = -1; regs->ARM_ip = ip; } -asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno) +asmlinkage int syscall_trace_enter(struct pt_regs *regs) { - current_thread_info()->syscall = scno; + int scno; if (test_thread_flag(TIF_SYSCALL_TRACE)) tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER); @@ -898,11 +900,11 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno) return -1; #else /* XXX: remove this once OABI gets fixed */ - secure_computing_strict(current_thread_info()->syscall); + secure_computing_strict(syscall_get_nr(current, regs)); #endif /* Tracer or seccomp may have changed syscall. */ - scno = current_thread_info()->syscall; + scno = syscall_get_nr(current, regs); if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) trace_sys_enter(regs, scno);