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Merge tag 'trace-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

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Pull syscall-get-arguments cleanup and fixes from Steven Rostedt:
 "Andy Lutomirski approached me to tell me that the
  syscall_get_arguments() implementation in x86 was horrible and gcc
  certainly gets it wrong.

  He said that since the tracepoints only pass in 0 and 6 for i and n
  repectively, it should be optimized for that case. Inspecting the
  kernel, I discovered that all users pass in 0 for i and only one file
  passing in something other than 6 for the number of arguments. That
  code happens to be my own code used for the special syscall tracing.

  That can easily be converted to just using 0 and 6 as well, and only
  copying what is needed. Which is probably the faster path anyway for
  that case.

  Along the way, a couple of real fixes came from this as the
  syscall_get_arguments() function was incorrect for csky and riscv.

  x86 has been optimized to for the new interface that removes the
  variable number of arguments, but the other architectures could still
  use some loving and take more advantage of the simpler interface"

* tag 'trace-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  syscalls: Remove start and number from syscall_set_arguments() args
  syscalls: Remove start and number from syscall_get_arguments() args
  csky: Fix syscall_get_arguments() and syscall_set_arguments()
  riscv: Fix syscall_get_arguments() and syscall_set_arguments()
  tracing/syscalls: Pass in hardcoded 6 into syscall_get_arguments()
  ptrace: Remove maxargs from task_current_syscall()
This commit is contained in:
Linus Torvalds
2019-04-05 13:15:57 -10:00
parent 7f46774c64 32d9258662
commit 970b766cfd
32 changed files with 243 additions and 718 deletions
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24
arch/riscv/include/asm/syscall.h
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@@ -72,32 +72,20 @@ 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)
{
BUG_ON(i + n > 6);
if (i == 0) {
args[0] = regs->orig_a0;
args++;
i++;
n--;
}
memcpy(args, &regs->a1 + i * sizeof(regs->a1), n * sizeof(args[0]));
args[0] = regs->orig_a0;
args++;
memcpy(args, &regs->a1, 5 * sizeof(args[0]));
}
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);
if (i == 0) {
regs->orig_a0 = args[0];
args++;
i++;
n--;
}
memcpy(&regs->a1 + i * sizeof(regs->a1), args, n * sizeof(regs->a0));
regs->orig_a0 = args[0];
args++;
memcpy(&regs->a1, args, 5 * sizeof(regs->a1));
}
static inline int syscall_get_arch(void)