From b35f549df1d7520d37ba1e6d4a8d4df6bd52d136 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 7 Nov 2016 16:26:37 -0500 Subject: syscalls: Remove start and number from syscall_get_arguments() args At Linux Plumbers, Andy Lutomirski approached me and pointed out that the function call syscall_get_arguments() implemented in x86 was horribly written and not optimized for the standard case of passing in 0 and 6 for the starting index and the number of system calls to get. When looking at all the users of this function, I discovered that all instances pass in only 0 and 6 for these arguments. Instead of having this function handle different cases that are never used, simply rewrite it to return the first 6 arguments of a system call. This should help out the performance of tracing system calls by ptrace, ftrace and perf. Link: http://lkml.kernel.org/r/20161107213233.754809394@goodmis.org Cc: Oleg Nesterov Cc: Kees Cook Cc: Andy Lutomirski Cc: Dominik Brodowski Cc: Dave Martin Cc: "Dmitry V. Levin" Cc: x86@kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-c6x-dev@linux-c6x.org Cc: uclinux-h8-devel@lists.sourceforge.jp Cc: linux-hexagon@vger.kernel.org Cc: linux-ia64@vger.kernel.org Cc: linux-mips@vger.kernel.org Cc: nios2-dev@lists.rocketboards.org Cc: openrisc@lists.librecores.org Cc: linux-parisc@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-riscv@lists.infradead.org Cc: linux-s390@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: sparclinux@vger.kernel.org Cc: linux-um@lists.infradead.org Cc: linux-xtensa@linux-xtensa.org Cc: linux-arch@vger.kernel.org Acked-by: Paul Burton # MIPS parts Acked-by: Max Filippov # For xtensa changes Acked-by: Will Deacon # For the arm64 bits Reviewed-by: Thomas Gleixner # for x86 Reviewed-by: Dmitry V. Levin Reported-by: Andy Lutomirski Signed-off-by: Steven Rostedt (VMware) --- arch/sh/include/asm/syscall_32.h | 26 ++++++-------------------- 1 file changed, 6 insertions(+), 20 deletions(-) (limited to 'arch/sh/include/asm/syscall_32.h') diff --git a/arch/sh/include/asm/syscall_32.h b/arch/sh/include/asm/syscall_32.h index 6e118799831c..2bf1199a0595 100644 --- a/arch/sh/include/asm/syscall_32.h +++ b/arch/sh/include/asm/syscall_32.h @@ -48,30 +48,16 @@ static inline void syscall_set_return_value(struct task_struct *task, static inline void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs, - unsigned int i, unsigned int n, unsigned long *args) { - /* - * Do this simply for now. If we need to start supporting - * fetching arguments from arbitrary indices, this will need some - * extra logic. Presently there are no in-tree users that depend - * on this behaviour. - */ - BUG_ON(i); /* Argument pattern is: R4, R5, R6, R7, R0, R1 */ - switch (n) { - case 6: args[5] = regs->regs[1]; - case 5: args[4] = regs->regs[0]; - case 4: args[3] = regs->regs[7]; - case 3: args[2] = regs->regs[6]; - case 2: args[1] = regs->regs[5]; - case 1: args[0] = regs->regs[4]; - case 0: - break; - default: - BUG(); - } + args[5] = regs->regs[1]; + args[4] = regs->regs[0]; + args[3] = regs->regs[7]; + args[2] = regs->regs[6]; + args[1] = regs->regs[5]; + args[0] = regs->regs[4]; } static inline void syscall_set_arguments(struct task_struct *task, -- cgit From 32d92586629a8b3637a3c9361709818e25f327ad Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Wed, 27 Mar 2019 20:07:31 -0400 Subject: syscalls: Remove start and number from syscall_set_arguments() args After removing the start and count arguments of syscall_get_arguments() it seems reasonable to remove them from syscall_set_arguments(). Note, as of today, there are no users of syscall_set_arguments(). But we are told that there will be soon. But for now, at least make it consistent with syscall_get_arguments(). Link: http://lkml.kernel.org/r/20190327222014.GA32540@altlinux.org Cc: Oleg Nesterov Cc: Kees Cook Cc: Andy Lutomirski Cc: Dominik Brodowski Cc: Dave Martin Cc: "Dmitry V. Levin" Cc: x86@kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-c6x-dev@linux-c6x.org Cc: uclinux-h8-devel@lists.sourceforge.jp Cc: linux-hexagon@vger.kernel.org Cc: linux-ia64@vger.kernel.org Cc: linux-mips@vger.kernel.org Cc: nios2-dev@lists.rocketboards.org Cc: openrisc@lists.librecores.org Cc: linux-parisc@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-riscv@lists.infradead.org Cc: linux-s390@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: sparclinux@vger.kernel.org Cc: linux-um@lists.infradead.org Cc: linux-xtensa@linux-xtensa.org Cc: linux-arch@vger.kernel.org Acked-by: Max Filippov # For xtensa changes Acked-by: Will Deacon # For the arm64 bits Reviewed-by: Thomas Gleixner # for x86 Reviewed-by: Dmitry V. Levin Signed-off-by: Steven Rostedt (VMware) --- arch/sh/include/asm/syscall_32.h | 21 ++++++--------------- 1 file changed, 6 insertions(+), 15 deletions(-) (limited to 'arch/sh/include/asm/syscall_32.h') diff --git a/arch/sh/include/asm/syscall_32.h b/arch/sh/include/asm/syscall_32.h index 2bf1199a0595..8c9d7e5e5dcc 100644 --- a/arch/sh/include/asm/syscall_32.h +++ b/arch/sh/include/asm/syscall_32.h @@ -62,23 +62,14 @@ static inline void syscall_get_arguments(struct task_struct *task, static inline void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs, - unsigned int i, unsigned int n, const unsigned long *args) { - /* Same note as above applies */ - BUG_ON(i); - - switch (n) { - case 6: regs->regs[1] = args[5]; - case 5: regs->regs[0] = args[4]; - case 4: regs->regs[7] = args[3]; - case 3: regs->regs[6] = args[2]; - case 2: regs->regs[5] = args[1]; - case 1: regs->regs[4] = args[0]; - break; - default: - BUG(); - } + regs->regs[1] = args[5]; + regs->regs[0] = args[4]; + regs->regs[7] = args[3]; + regs->regs[6] = args[2]; + regs->regs[5] = args[1]; + regs->regs[4] = args[0]; } static inline int syscall_get_arch(void) -- cgit