Re: [PATCH 6/6 v3] syscalls: Remove start and number from syscall_set_arguments() args
From: Dmitry V. Levin <hidden>
Date: 2019-04-04 18:18:55
Also in:
linux-arch, linux-arm-kernel, linux-mips, linux-riscv, linux-s390, linux-sh, linux-um, lkml, sparclinux
On Mon, Apr 01, 2019 at 09:41:10AM -0400, Steven Rostedt wrote:
From: "Steven Rostedt (VMware)" <rostedt@goodmis.org> 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
FWIW, you can add Reviewed-by: Dmitry V. Levin <redacted> There are two places listed below where I'd prefer to see more readable equivalents, but feel free to leave it to respective arch maintainers.
quoted hunk ↗ jump to hunk
diff --git a/arch/nds32/include/asm/syscall.h b/arch/nds32/include/asm/syscall.h index 89a6ec8731d8..671ebd357496 100644 --- a/arch/nds32/include/asm/syscall.h +++ b/arch/nds32/include/asm/syscall.h@@ -129,39 +129,20 @@ void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs, * syscall_set_arguments - change system call parameter value * @task: task of interest, must be in system call entry tracing * @regs: task_pt_regs() of @task - * @i: argument index [0,5] - * @n: number of arguments; n+i must be [1,6]. * @args: array of argument values to store * - * Changes @n arguments to the system call starting with the @i'th argument. - * Argument @i gets value @args[0], and so on. - * An arch inline version is probably optimal when @i and @n are constants. + * Changes 6 arguments to the system call. The first argument gets value + * @args[0], and so on. * * It's only valid to call this when @task is stopped for tracing on * entry to a system call, due to %TIF_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT. - * It's invalid to call this with @i + @n > 6; we only support system calls - * taking up to 6 arguments. */ void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs, - unsigned int i, unsigned int n, const unsigned long *args) { - if (n == 0) - return; - - if (i + n > SYSCALL_MAX_ARGS) { - pr_warn("%s called with max args %d, handling only %d\n", - __func__, i + n, SYSCALL_MAX_ARGS); - n = SYSCALL_MAX_ARGS - i; - } - - if (i == 0) { - regs->orig_r0 = args[0]; - args++; - i++; - n--; - } + regs->orig_r0 = args[0]; + args++; - memcpy(®s->uregs[0] + i, args, n * sizeof(args[0])); + memcpy(®s->uregs[0] + 1, args, 5 * sizeof(args[0])); }
A shorter and slightly more readable equivalent of the last memcpy is memcpy(®s->uregs[1], args, 5 * sizeof(args[0]));
quoted hunk ↗ jump to hunk
diff --git a/arch/s390/include/asm/syscall.h b/arch/s390/include/asm/syscall.h index ee0b1f6aa36d..59c3e91f2cdb 100644 --- a/arch/s390/include/asm/syscall.h +++ b/arch/s390/include/asm/syscall.h@@ -74,15 +74,14 @@ 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) { - BUG_ON(i + n > 6); + unsigned int n = 6; + while (n-- > 0) - if (i + n > 0) - regs->gprs[2 + i + n] = args[n]; - if (i == 0) - regs->orig_gpr2 = args[0]; + if (n > 0) + regs->gprs[2 + n] = args[n]; + regs->orig_gpr2 = args[0]; }
A shorter and slightly more readable equivalent of the loop is while (--n > 0) regs->gprs[2 + n] = args[n]; -- ldv
Attachments
- signature.asc [application/pgp-signature] 801 bytes