b35f549df1
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 <oleg@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Dave Martin <dave.martin@arm.com> Cc: "Dmitry V. Levin" <ldv@altlinux.org> 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 <paul.burton@mips.com> # MIPS parts Acked-by: Max Filippov <jcmvbkbc@gmail.com> # For xtensa changes Acked-by: Will Deacon <will.deacon@arm.com> # For the arm64 bits Reviewed-by: Thomas Gleixner <tglx@linutronix.de> # for x86 Reviewed-by: Dmitry V. Levin <ldv@altlinux.org> Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
94 lines
2.1 KiB
C
94 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_SH_SYSCALL_32_H
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#define __ASM_SH_SYSCALL_32_H
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#include <uapi/linux/audit.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/err.h>
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#include <asm/ptrace.h>
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/* The system call number is given by the user in R3 */
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static inline long syscall_get_nr(struct task_struct *task,
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struct pt_regs *regs)
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{
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return (regs->tra >= 0) ? regs->regs[3] : -1L;
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}
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static inline void syscall_rollback(struct task_struct *task,
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struct pt_regs *regs)
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{
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/*
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* XXX: This needs some thought. On SH we don't
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* save away the original r0 value anywhere.
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*/
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}
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static inline long syscall_get_error(struct task_struct *task,
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struct pt_regs *regs)
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{
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return IS_ERR_VALUE(regs->regs[0]) ? regs->regs[0] : 0;
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}
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static inline long syscall_get_return_value(struct task_struct *task,
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struct pt_regs *regs)
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{
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return regs->regs[0];
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}
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static inline void syscall_set_return_value(struct task_struct *task,
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struct pt_regs *regs,
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int error, long val)
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{
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if (error)
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regs->regs[0] = -error;
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else
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regs->regs[0] = val;
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}
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static inline void syscall_get_arguments(struct task_struct *task,
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struct pt_regs *regs,
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unsigned long *args)
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{
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/* Argument pattern is: R4, R5, R6, R7, R0, R1 */
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args[5] = regs->regs[1];
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args[4] = regs->regs[0];
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args[3] = regs->regs[7];
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args[2] = regs->regs[6];
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args[1] = regs->regs[5];
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args[0] = regs->regs[4];
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}
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static inline void syscall_set_arguments(struct task_struct *task,
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struct pt_regs *regs,
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unsigned int i, unsigned int n,
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const unsigned long *args)
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{
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/* Same note as above applies */
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BUG_ON(i);
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switch (n) {
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case 6: regs->regs[1] = args[5];
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case 5: regs->regs[0] = args[4];
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case 4: regs->regs[7] = args[3];
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case 3: regs->regs[6] = args[2];
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case 2: regs->regs[5] = args[1];
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case 1: regs->regs[4] = args[0];
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break;
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default:
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BUG();
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}
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}
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static inline int syscall_get_arch(void)
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{
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int arch = AUDIT_ARCH_SH;
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#ifdef CONFIG_CPU_LITTLE_ENDIAN
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arch |= __AUDIT_ARCH_LE;
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#endif
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return arch;
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}
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#endif /* __ASM_SH_SYSCALL_32_H */
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