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

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()

2 files changed, 7 insertions, 4 deletions

diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 54a0347ca812..df27e499956a 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -149,7 +149,7 @@ static void populate_seccomp_data(struct seccomp_data *sd)
 
 	sd->nr = syscall_get_nr(task, regs);
 	sd->arch = syscall_get_arch();
-	syscall_get_arguments(task, regs, 0, 6, args);
+	syscall_get_arguments(task, regs, args);
 	sd->args[0] = args[0];
 	sd->args[1] = args[1];
 	sd->args[2] = args[2];
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index f93a56d2db27..fa8fbff736d6 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -314,6 +314,7 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
 	struct ring_buffer_event *event;
 	struct ring_buffer *buffer;
 	unsigned long irq_flags;
+	unsigned long args[6];
 	int pc;
 	int syscall_nr;
 	int size;
@@ -347,7 +348,8 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
 
 	entry = ring_buffer_event_data(event);
 	entry->nr = syscall_nr;
-	syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
+	syscall_get_arguments(current, regs, args);
+	memcpy(entry->args, args, sizeof(unsigned long) * sys_data->nb_args);
 
 	event_trigger_unlock_commit(trace_file, buffer, event, entry,
 				    irq_flags, pc);
@@ -583,6 +585,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
 	struct syscall_metadata *sys_data;
 	struct syscall_trace_enter *rec;
 	struct hlist_head *head;
+	unsigned long args[6];
 	bool valid_prog_array;
 	int syscall_nr;
 	int rctx;
@@ -613,8 +616,8 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
 		return;
 
 	rec->nr = syscall_nr;
-	syscall_get_arguments(current, regs, 0, sys_data->nb_args,
-			       (unsigned long *)&rec->args);
+	syscall_get_arguments(current, regs, args);
+	memcpy(&rec->args, args, sizeof(unsigned long) * sys_data->nb_args);
 
 	if ((valid_prog_array &&
 	     !perf_call_bpf_enter(sys_data->enter_event, regs, sys_data, rec)) ||