From patchwork Mon Jun 18 12:02:58 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 10471101 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B0F616032A for ; Mon, 18 Jun 2018 12:03:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A07D627BA5 for ; Mon, 18 Jun 2018 12:03:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9569D289B3; Mon, 18 Jun 2018 12:03:57 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0118627BA5 for ; Mon, 18 Jun 2018 12:03:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964851AbeFRMDz (ORCPT ); Mon, 18 Jun 2018 08:03:55 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:32816 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934643AbeFRMDq (ORCPT ); Mon, 18 Jun 2018 08:03:46 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A4FF7165D; Mon, 18 Jun 2018 05:03:45 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id B7D363F25D; Mon, 18 Jun 2018 05:03:43 -0700 (PDT) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will.deacon@arm.com Cc: dave.martin@arm.com, hch@infradead.org, james.morse@arm.com, linux@dominikbrodowski.net, linux-fsdevel@vger.kernel.org, marc.zyngier@arm.com, mark.rutland@arm.com, viro@zeniv.linux.org.uk Subject: [PATCHv3 07/19] arm64: remove sigreturn wrappers Date: Mon, 18 Jun 2018 13:02:58 +0100 Message-Id: <20180618120310.39527-8-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20180618120310.39527-1-mark.rutland@arm.com> References: <20180618120310.39527-1-mark.rutland@arm.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The arm64 sigreturn* syscall handlers are non-standard. Rather than taking a number of user parameters in registers as per the AAPCS, they expect the pt_regs as their sole argument. To make this work, we override the syscall definitions to invoke wrappers written in assembly, which mov the SP into x0, and branch to their respective C functions. On other architectures (such as x86), the sigreturn* functions take no argument and instead use current_pt_regs() to acquire the user registers. This requires less boilerplate code, and allows for other features such as interposing C code in this path. This patch takes the same approach for arm64. Signed-off-by: Mark Rutland Tentatively-reviewed-by: Dave Martin Cc: Catalin Marinas Cc: Will Deacon Reviewed-by: Catalin Marinas --- arch/arm64/include/asm/unistd32.h | 4 ++-- arch/arm64/kernel/entry.S | 8 -------- arch/arm64/kernel/entry32.S | 10 ---------- arch/arm64/kernel/signal.c | 3 ++- arch/arm64/kernel/signal32.c | 6 ++++-- arch/arm64/kernel/sys.c | 3 +-- arch/arm64/kernel/sys32.c | 4 ++-- 7 files changed, 11 insertions(+), 27 deletions(-) diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h index ef292160748c..ab95554b1734 100644 --- a/arch/arm64/include/asm/unistd32.h +++ b/arch/arm64/include/asm/unistd32.h @@ -260,7 +260,7 @@ __SYSCALL(117, sys_ni_syscall) #define __NR_fsync 118 __SYSCALL(__NR_fsync, sys_fsync) #define __NR_sigreturn 119 -__SYSCALL(__NR_sigreturn, compat_sys_sigreturn_wrapper) +__SYSCALL(__NR_sigreturn, compat_sys_sigreturn) #define __NR_clone 120 __SYSCALL(__NR_clone, sys_clone) #define __NR_setdomainname 121 @@ -368,7 +368,7 @@ __SYSCALL(__NR_getresgid, sys_getresgid16) #define __NR_prctl 172 __SYSCALL(__NR_prctl, sys_prctl) #define __NR_rt_sigreturn 173 -__SYSCALL(__NR_rt_sigreturn, compat_sys_rt_sigreturn_wrapper) +__SYSCALL(__NR_rt_sigreturn, compat_sys_rt_sigreturn) #define __NR_rt_sigaction 174 __SYSCALL(__NR_rt_sigaction, compat_sys_rt_sigaction) #define __NR_rt_sigprocmask 175 diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 28ad8799406f..62f2876f9c63 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -1138,14 +1138,6 @@ __entry_tramp_data_start: #endif /* CONFIG_UNMAP_KERNEL_AT_EL0 */ /* - * Special system call wrappers. - */ -ENTRY(sys_rt_sigreturn_wrapper) - mov x0, sp - b sys_rt_sigreturn -ENDPROC(sys_rt_sigreturn_wrapper) - -/* * Register switch for AArch64. The callee-saved registers need to be saved * and restored. On entry: * x0 = previous task_struct (must be preserved across the switch) diff --git a/arch/arm64/kernel/entry32.S b/arch/arm64/kernel/entry32.S index f332d5d1f6b4..f9461696dde4 100644 --- a/arch/arm64/kernel/entry32.S +++ b/arch/arm64/kernel/entry32.S @@ -30,16 +30,6 @@ * System call wrappers for the AArch32 compatibility layer. */ -ENTRY(compat_sys_sigreturn_wrapper) - mov x0, sp - b compat_sys_sigreturn -ENDPROC(compat_sys_sigreturn_wrapper) - -ENTRY(compat_sys_rt_sigreturn_wrapper) - mov x0, sp - b compat_sys_rt_sigreturn -ENDPROC(compat_sys_rt_sigreturn_wrapper) - ENTRY(compat_sys_statfs64_wrapper) mov w3, #84 cmp w1, #88 diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index 70287634706e..f03e664f773f 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -539,8 +539,9 @@ static int restore_sigframe(struct pt_regs *regs, return err; } -asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) +asmlinkage long sys_rt_sigreturn(void) { + struct pt_regs *regs = current_pt_regs(); struct rt_sigframe __user *frame; /* Always make any pending restarted system calls return -EINTR */ diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index 77b91f478995..cb10588a7cb2 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -282,8 +282,9 @@ static int compat_restore_sigframe(struct pt_regs *regs, return err; } -asmlinkage int compat_sys_sigreturn(struct pt_regs *regs) +asmlinkage int compat_sys_sigreturn(void) { + struct pt_regs *regs = current_pt_regs(); struct compat_sigframe __user *frame; /* Always make any pending restarted system calls return -EINTR */ @@ -312,8 +313,9 @@ asmlinkage int compat_sys_sigreturn(struct pt_regs *regs) return 0; } -asmlinkage int compat_sys_rt_sigreturn(struct pt_regs *regs) +asmlinkage int compat_sys_rt_sigreturn(void) { + struct pt_regs *regs = current_pt_regs(); struct compat_rt_sigframe __user *frame; /* Always make any pending restarted system calls return -EINTR */ diff --git a/arch/arm64/kernel/sys.c b/arch/arm64/kernel/sys.c index 72981bae10eb..31045f3fed92 100644 --- a/arch/arm64/kernel/sys.c +++ b/arch/arm64/kernel/sys.c @@ -48,8 +48,7 @@ SYSCALL_DEFINE1(arm64_personality, unsigned int, personality) /* * Wrappers to pass the pt_regs argument. */ -asmlinkage long sys_rt_sigreturn_wrapper(void); -#define sys_rt_sigreturn sys_rt_sigreturn_wrapper +asmlinkage long sys_rt_sigreturn(void); #define sys_personality sys_arm64_personality #undef __SYSCALL diff --git a/arch/arm64/kernel/sys32.c b/arch/arm64/kernel/sys32.c index a40b1343b819..1ef103c95410 100644 --- a/arch/arm64/kernel/sys32.c +++ b/arch/arm64/kernel/sys32.c @@ -25,8 +25,8 @@ #include #include -asmlinkage long compat_sys_sigreturn_wrapper(void); -asmlinkage long compat_sys_rt_sigreturn_wrapper(void); +asmlinkage long compat_sys_sigreturn(void); +asmlinkage long compat_sys_rt_sigreturn(void); asmlinkage long compat_sys_statfs64_wrapper(void); asmlinkage long compat_sys_fstatfs64_wrapper(void); asmlinkage long compat_sys_pread64_wrapper(void);