From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932097Ab2IJPvT (ORCPT ); Mon, 10 Sep 2012 11:51:19 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:45067 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757547Ab2IJPvP (ORCPT ); Mon, 10 Sep 2012 11:51:15 -0400 Date: Mon, 10 Sep 2012 16:50:33 +0100 From: Catalin Marinas To: Arnd Bergmann Cc: Al Viro , "linux-arch@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v3 17/31] arm64: System calls handling Message-ID: <20120910155033.GF27042@arm.com> References: <1347035226-18649-1-git-send-email-catalin.marinas@arm.com> <201209101351.52902.arnd@arndb.de> <20120910140148.GD27042@arm.com> <201209101424.21344.arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201209101424.21344.arnd@arndb.de> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 10, 2012 at 03:24:21PM +0100, Arnd Bergmann wrote: > On Monday 10 September 2012, Catalin Marinas wrote: > > > > On Mon, Sep 10, 2012 at 02:51:52PM +0100, Arnd Bergmann wrote: > > > On Monday 10 September 2012, Catalin Marinas wrote: > > > > Yes, I've seen these but since Al's patches are not in mainline, I don't > > > > want to add additional dependencies to the arm64 patches (currently > > > > based on 3.6-rc4). Once they get into mainline, I'll add a patch that > > > > converts arm64 to the generic functions above. > > > > > > > > For kernel_execve(), I think I can simplify it further and not rely on > > > > Al's patches (similar to other architectures doing an SVC from kernel): > > > > > > Hmm, I thought one of the reasons for Al to do his series was to discourage > > > people from doing syscalls from kernel space, but I may be misremembering > > > things. Al? > > > > If that was the aim, I'm happy to change the code similar to the > > arch/arm one. But as I said I would wait until Al's patches get into > > mainline. > > Ok. Another point: I wouldn't be too worried about dependencies for new > code, because it's not possible to bisect through your series anyway > (one needs all the patches before anything starts working really), > so from my point of view you could also write your code in a way that > expects Al's patches to get merged first. It's not about bisectability but rather a way to test the branch that I publish. On its own, my branch wouldn't even compile. Anyway, here's the update (tested on a local branch with Al's execve2 branch merged): arm64: Switch to generic sys_execve/kernel_execve This patch converts the arm64 port to use the generic sys_execve and kernel_execve() functions. It introduces the ret_from_kernel_execve() function for starting the new user context and removes the (compat_)sys_execve_wrapper() functions. Signed-off-by: Catalin Marinas Cc: Al Viro diff --git a/arch/arm64/include/asm/syscalls.h b/arch/arm64/include/asm/syscalls.h index 09ff335..81680a0 100644 --- a/arch/arm64/include/asm/syscalls.h +++ b/arch/arm64/include/asm/syscalls.h @@ -23,9 +23,6 @@ /* * System call wrappers implemented in kernel/entry.S. */ -asmlinkage long sys_execve_wrapper(const char __user *filename, - const char __user *const __user *argv, - const char __user *const __user *envp); asmlinkage long sys_clone_wrapper(unsigned long clone_flags, unsigned long newsp, void __user *parent_tid, diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h index fe18a68..948cfb1 100644 --- a/arch/arm64/include/asm/unistd.h +++ b/arch/arm64/include/asm/unistd.h @@ -24,4 +24,7 @@ #include #endif +#define __ARCH_WANT_SYS_EXECVE +#define __ARCH_WANT_KERNEL_EXECVE + #endif /* __ASM_UNISTD_H */ diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 38cf853..5e0b28c 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -592,7 +592,7 @@ work_resched: /* * "slow" syscall return path. */ -ENTRY(ret_to_user) +ret_to_user: disable_irq // disable interrupts ldr x1, [tsk, #TI_FLAGS] and x2, x1, #_TIF_WORK_MASK @@ -614,6 +614,22 @@ ENTRY(ret_from_fork) ENDPROC(ret_from_fork) /* + * ret_from_kernel_execve(struct pt_regs *normal, struct pt_regs *new) + * + * Turn a kernel thread into a user process. + */ +ENTRY(ret_from_kernel_execve) + str xzr, [x1, #S_X0] // returning 0 + mov x2, #-1 + str x2, [x1, #S_SYSCALLNO] // not a syscall + mov x2, #S_FRAME_SIZE + bl memmove // copy regs to the normal location + get_thread_info tsk + mov sp, x0 // normal pt_regs + b ret_to_user +ENDPROC(ret_from_kernel_execve) + +/* * SVC handler. */ .align 6 @@ -671,11 +687,6 @@ __sys_trace_return: /* * Special system call wrappers. */ -ENTRY(sys_execve_wrapper) - mov x3, sp - b sys_execve -ENDPROC(sys_execve_wrapper) - ENTRY(sys_clone_wrapper) mov x5, sp b sys_clone diff --git a/arch/arm64/kernel/sys.c b/arch/arm64/kernel/sys.c index 905fcfb..9c77c0b 100644 --- a/arch/arm64/kernel/sys.c +++ b/arch/arm64/kernel/sys.c @@ -41,70 +41,6 @@ asmlinkage long sys_clone(unsigned long clone_flags, unsigned long newsp, return do_fork(clone_flags, newsp, regs, 0, parent_tidptr, child_tidptr); } -/* - * sys_execve() executes a new program. - */ -asmlinkage long sys_execve(const char __user *filenamei, - const char __user *const __user *argv, - const char __user *const __user *envp, - struct pt_regs *regs) -{ - long error; - char * filename; - - filename = getname(filenamei); - error = PTR_ERR(filename); - if (IS_ERR(filename)) - goto out; - error = do_execve(filename, argv, envp, regs); - putname(filename); -out: - return error; -} - -int kernel_execve(const char *filename, - const char *const argv[], - const char *const envp[]) -{ - struct pt_regs regs; - int ret; - - memset(®s, 0, sizeof(struct pt_regs)); - ret = do_execve(filename, - (const char __user *const __user *)argv, - (const char __user *const __user *)envp, ®s); - if (ret < 0) - goto out; - - /* - * Save argc to the register structure for userspace. - */ - regs.regs[0] = ret; - - /* - * We were successful. We won't be returning to our caller, but - * instead to user space by manipulating the kernel stack. - */ - asm( "add x0, %0, %1\n\t" - "mov x1, %2\n\t" - "mov x2, %3\n\t" - "bl memmove\n\t" /* copy regs to top of stack */ - "mov x27, #0\n\t" /* not a syscall */ - "mov x28, %0\n\t" /* thread structure */ - "mov sp, x0\n\t" /* reposition stack pointer */ - "b ret_to_user" - : - : "r" (current_thread_info()), - "Ir" (THREAD_START_SP - sizeof(regs)), - "r" (®s), - "Ir" (sizeof(regs)) - : "x0", "x1", "x2", "x27", "x28", "x30", "memory"); - - out: - return ret; -} -EXPORT_SYMBOL(kernel_execve); - asmlinkage long sys_mmap(unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, unsigned long fd, off_t off) @@ -118,7 +54,6 @@ asmlinkage long sys_mmap(unsigned long addr, unsigned long len, /* * Wrappers to pass the pt_regs argument. */ -#define sys_execve sys_execve_wrapper #define sys_clone sys_clone_wrapper #define sys_rt_sigreturn sys_rt_sigreturn_wrapper #define sys_sigaltstack sys_sigaltstack_wrapper diff --git a/arch/arm64/kernel/sys32.S b/arch/arm64/kernel/sys32.S index 5e4dc93..903ba9d 100644 --- a/arch/arm64/kernel/sys32.S +++ b/arch/arm64/kernel/sys32.S @@ -36,11 +36,6 @@ compat_sys_vfork_wrapper: b compat_sys_vfork ENDPROC(compat_sys_vfork_wrapper) -compat_sys_execve_wrapper: - mov x3, sp - b compat_sys_execve -ENDPROC(compat_sys_execve_wrapper) - compat_sys_clone_wrapper: mov x5, sp b compat_sys_clone @@ -152,7 +147,7 @@ ENDPROC(compat_sys_fanotify_mark_wrapper) */ #define sys_fork compat_sys_fork_wrapper #define sys_open compat_sys_open -#define sys_execve compat_sys_execve_wrapper +#define sys_execve compat_sys_execve #define sys_lseek compat_sys_lseek_wrapper #define sys_mount compat_sys_mount #define sys_ptrace compat_sys_ptrace diff --git a/arch/arm64/kernel/sys_compat.c b/arch/arm64/kernel/sys_compat.c index 967e92f..d77ba8e 100644 --- a/arch/arm64/kernel/sys_compat.c +++ b/arch/arm64/kernel/sys_compat.c @@ -51,24 +51,6 @@ asmlinkage int compat_sys_vfork(struct pt_regs *regs) regs, 0, NULL, NULL); } -asmlinkage int compat_sys_execve(const char __user *filenamei, - compat_uptr_t argv, compat_uptr_t envp, - struct pt_regs *regs) -{ - int error; - char * filename; - - filename = getname(filenamei); - error = PTR_ERR(filename); - if (IS_ERR(filename)) - goto out; - error = compat_do_execve(filename, compat_ptr(argv), compat_ptr(envp), - regs); - putname(filename); -out: - return error; -} - asmlinkage int compat_sys_sched_rr_get_interval(compat_pid_t pid, struct compat_timespec __user *interval) {