[PATCH 0/6 v3] sycalls: Remove args i and n from syscall_get_arguments()

[PATCH 0/6 v3] sycalls: Remove args i and n from syscall_get_arguments()

[Steven Rostedt]

[ Looking for acks ]

Two and a half years ago I sent out 3 patches and a title letter that
had this[1]:

  At Linux Plumbers, 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.

  I haven't run the numbers (I can do that when I get some time), but since
  pretty much all use cases use 0 and 6 and that would allow these functions
  not to need strange logic to handle odd cases, I think this is still a win.

It received positive comments but also Linus asked to remove the separate
arg pointers and replace them with a single structure and fill that
instead. But for some reason, this got pushed aside and forgotten (probably,
had to do with the fact that I left Red Hat shortly after this).

Recently, it was brought back up again[2] and I decided to dust off these
patches and resubmit them. I also added one more patch to do the same
for syscall_set_arguments() that I did for syscall_get_arguments() even
though syscall_set_arguments() currently (and never has) had any callers.
But we are told that in the near future it may have one.

The changes do optimize the logic a little, but for most archs I just kept
the same logic (loops and such) as I don't have a way to test it, and
didn't want to break the logic.

I added a new struct syscall_info that holds seccomp_data and also
includes a stack pointer (sp) field. I would change seccomp_data,
but because its in include/uapi/linux/seccomp.h I didn't want to
touch it and break userspace. Perhaps we could add the field at the
end, but I didn't want to chance it (unless others say its OK).

I ran these through zero-day-bot and compiled tested these changes for
all architectures except for csky which I do not have a cross compiler
for.

Note the following archs fail normal builds, but they fail the same
with these patches:

   arc
   h8300
   parisc64

Note, you may notice that I have "(Red Hat)" as the author of the
first three patches (even though they are signed off by "(VMware)").
This is because those patches were originally written while I was
working for Red Hat. But as I forward ported them while working for
VMware, my signed-off-by reflects that.

[1] - https://lore.kernel.org/lkml/20161107212634.529267342@goodmis.org/T/#u
[2] - https://lore.kernel.org/lkml/20190326151244.GC16837@redhat.com/T/#u


Changes since v2:

 - Added Dmitry's two patches to fix riscv and csky
 - Rebased to handle the two new patches

Dmitry V. Levin (2):
      riscv: Fix syscall_get_arguments() and syscall_set_arguments()
      csky: Fix syscall_get_arguments() and syscall_set_arguments()

Steven Rostedt (Red Hat) (3):
      ptrace: Remove maxargs from task_current_syscall()
      tracing/syscalls: Pass in hardcoded 6 into syscall_get_arguments()
      syscalls: Remove start and number from syscall_get_arguments() args

Steven Rostedt (VMware) (1):
      syscalls: Remove start and number from syscall_set_arguments() args

----
 arch/arc/include/asm/syscall.h        |   7 +-
 arch/arm/include/asm/syscall.h        |  47 ++---------
 arch/arm64/include/asm/syscall.h      |  46 ++---------
 arch/c6x/include/asm/syscall.h        |  79 ++++---------------
 arch/csky/include/asm/syscall.h       |  26 ++-----
 arch/h8300/include/asm/syscall.h      |  34 ++------
 arch/hexagon/include/asm/syscall.h    |   4 +-
 arch/ia64/include/asm/syscall.h       |  13 +---
 arch/ia64/kernel/ptrace.c             |   7 +-
 arch/microblaze/include/asm/syscall.h |   8 +-
 arch/mips/include/asm/syscall.h       |   3 +-
 arch/mips/kernel/ptrace.c             |   2 +-
 arch/nds32/include/asm/syscall.h      |  62 +++------------
 arch/nios2/include/asm/syscall.h      |  84 ++++----------------
 arch/openrisc/include/asm/syscall.h   |  12 +--
 arch/parisc/include/asm/syscall.h     |  30 ++-----
 arch/powerpc/include/asm/syscall.h    |  15 ++--
 arch/riscv/include/asm/syscall.h      |  24 ++----
 arch/s390/include/asm/syscall.h       |  28 +++----
 arch/sh/include/asm/syscall_32.h      |  47 +++--------
 arch/sh/include/asm/syscall_64.h      |   8 +-
 arch/sparc/include/asm/syscall.h      |  11 ++-
 arch/um/include/asm/syscall-generic.h |  78 +++----------------
 arch/x86/include/asm/syscall.h        | 142 ++++++++--------------------------
 arch/xtensa/include/asm/syscall.h     |  33 ++------
 fs/proc/base.c                        |  17 ++--
 include/asm-generic/syscall.h         |  21 ++---
 include/linux/ptrace.h                |  11 ++-
 include/trace/events/syscalls.h       |   2 +-
 kernel/seccomp.c                      |   2 +-
 kernel/trace/trace_syscalls.c         |   9 ++-
 lib/syscall.c                         |  57 ++++++--------
 32 files changed, 247 insertions(+), 722 deletions(-)

[PATCH 1/6 v3] ptrace: Remove maxargs from task_current_syscall()

[Steven Rostedt]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

task_current_syscall() has a single user that passes in 6 for maxargs, which
is the maximum arguments that can be used to get system calls from
syscall_get_arguments(). Instead of passing in a number of arguments to
grab, just get 6 arguments. The args argument even specifies that it's an
array of 6 items.

This will also allow changing syscall_get_arguments() to not get a variable
number of arguments, but always grab 6.

Linus also suggested not passing in a bunch of arguments to
task_current_syscall() but to instead pass in a pointer to a structure, and
just fill the structure. struct seccomp_data has almost all the parameters
that is needed except for the stack pointer (sp). As seccomp_data is part of
uapi, and I'm afraid to change it, a new structure was created
"syscall_info", which includes seccomp_data and adds the "sp" field.

Link: http://lkml.kernel.org/r/20161107213233.466776454@goodmis.org

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 fs/proc/base.c         | 17 +++++++------
 include/linux/ptrace.h | 11 +++++---
 lib/syscall.c          | 57 ++++++++++++++++++------------------------
 3 files changed, 42 insertions(+), 43 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index ddef482f1334..6a803a0b75df 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -616,24 +616,25 @@ static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
 static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
 			    struct pid *pid, struct task_struct *task)
 {
-	long nr;
-	unsigned long args[6], sp, pc;
+	struct syscall_info info;
+	u64 *args = &info.data.args[0];
 	int res;
 
 	res = lock_trace(task);
 	if (res)
 		return res;
 
-	if (task_current_syscall(task, &nr, args, 6, &sp, &pc))
+	if (task_current_syscall(task, &info))
 		seq_puts(m, "running\n");
-	else if (nr < 0)
-		seq_printf(m, "%ld 0x%lx 0x%lx\n", nr, sp, pc);
+	else if (info.data.nr < 0)
+		seq_printf(m, "%d 0x%llx 0x%llx\n",
+			   info.data.nr, info.sp, info.data.instruction_pointer);
 	else
 		seq_printf(m,
-		       "%ld 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n",
-		       nr,
+		       "%d 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx\n",
+		       info.data.nr,
 		       args[0], args[1], args[2], args[3], args[4], args[5],
-		       sp, pc);
+		       info.sp, info.data.instruction_pointer);
 	unlock_trace(task);
 
 	return 0;
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index edb9b040c94c..d5084ebd9f03 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -9,6 +9,13 @@
 #include <linux/bug.h>			/* For BUG_ON.  */
 #include <linux/pid_namespace.h>	/* For task_active_pid_ns.  */
 #include <uapi/linux/ptrace.h>
+#include <linux/seccomp.h>
+
+/* Add sp to seccomp_data, as seccomp is user API, we don't want to modify it */
+struct syscall_info {
+	__u64			sp;
+	struct seccomp_data	data;
+};
 
 extern int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
 			    void *buf, int len, unsigned int gup_flags);
@@ -407,9 +414,7 @@ static inline void user_single_step_report(struct pt_regs *regs)
 #define current_user_stack_pointer() user_stack_pointer(current_pt_regs())
 #endif
 
-extern int task_current_syscall(struct task_struct *target, long *callno,
-				unsigned long args[6], unsigned int maxargs,
-				unsigned long *sp, unsigned long *pc);
+extern int task_current_syscall(struct task_struct *target, struct syscall_info *info);
 
 extern void sigaction_compat_abi(struct k_sigaction *act, struct k_sigaction *oact);
 #endif
diff --git a/lib/syscall.c b/lib/syscall.c
index 1a7077f20eae..e8467e17b9a2 100644
--- a/lib/syscall.c
+++ b/lib/syscall.c
@@ -5,16 +5,14 @@
 #include <linux/export.h>
 #include <asm/syscall.h>
 
-static int collect_syscall(struct task_struct *target, long *callno,
-			   unsigned long args[6], unsigned int maxargs,
-			   unsigned long *sp, unsigned long *pc)
+static int collect_syscall(struct task_struct *target, struct syscall_info *info)
 {
 	struct pt_regs *regs;
 
 	if (!try_get_task_stack(target)) {
 		/* Task has no stack, so the task isn't in a syscall. */
-		*sp = *pc = 0;
-		*callno = -1;
+		memset(info, 0, sizeof(*info));
+		info->data.nr = -1;
 		return 0;
 	}
 
@@ -24,12 +22,13 @@ static int collect_syscall(struct task_struct *target, long *callno,
 		return -EAGAIN;
 	}
 
-	*sp = user_stack_pointer(regs);
-	*pc = instruction_pointer(regs);
+	info->sp = user_stack_pointer(regs);
+	info->data.instruction_pointer = instruction_pointer(regs);
 
-	*callno = syscall_get_nr(target, regs);
-	if (*callno != -1L && maxargs > 0)
-		syscall_get_arguments(target, regs, 0, maxargs, args);
+	info->data.nr = syscall_get_nr(target, regs);
+	if (info->data.nr != -1L)
+		syscall_get_arguments(target, regs, 0, 6,
+				      (unsigned long *)&info->data.args[0]);
 
 	put_task_stack(target);
 	return 0;
@@ -38,41 +37,35 @@ static int collect_syscall(struct task_struct *target, long *callno,
 /**
  * task_current_syscall - Discover what a blocked task is doing.
  * @target:		thread to examine
- * @callno:		filled with system call number or -1
- * @args:		filled with @maxargs system call arguments
- * @maxargs:		number of elements in @args to fill
- * @sp:			filled with user stack pointer
- * @pc:			filled with user PC
+ * @info:		structure with the following fields:
+ *			 .sp        - filled with user stack pointer
+ *			 .data.nr   - filled with system call number or -1
+ *			 .data.args - filled with @maxargs system call arguments
+ *			 .data.instruction_pointer - filled with user PC
  *
- * If @target is blocked in a system call, returns zero with *@callno
- * set to the the call's number and @args filled in with its arguments.
- * Registers not used for system call arguments may not be available and
- * it is not kosher to use &struct user_regset calls while the system
+ * If @target is blocked in a system call, returns zero with @info.data.nr
+ * set to the the call's number and @info.data.args filled in with its
+ * arguments. Registers not used for system call arguments may not be available
+ * and it is not kosher to use &struct user_regset calls while the system
  * call is still in progress.  Note we may get this result if @target
  * has finished its system call but not yet returned to user mode, such
  * as when it's stopped for signal handling or syscall exit tracing.
  *
  * If @target is blocked in the kernel during a fault or exception,
- * returns zero with *@callno set to -1 and does not fill in @args.
- * If so, it's now safe to examine @target using &struct user_regset
- * get() calls as long as we're sure @target won't return to user mode.
+ * returns zero with *@info.data.nr set to -1 and does not fill in
+ * @info.data.args. If so, it's now safe to examine @target using
+ * &struct user_regset get() calls as long as we're sure @target won't return
+ * to user mode.
  *
  * Returns -%EAGAIN if @target does not remain blocked.
- *
- * Returns -%EINVAL if @maxargs is too large (maximum is six).
  */
-int task_current_syscall(struct task_struct *target, long *callno,
-			 unsigned long args[6], unsigned int maxargs,
-			 unsigned long *sp, unsigned long *pc)
+int task_current_syscall(struct task_struct *target, struct syscall_info *info)
 {
 	long state;
 	unsigned long ncsw;
 
-	if (unlikely(maxargs > 6))
-		return -EINVAL;
-
 	if (target == current)
-		return collect_syscall(target, callno, args, maxargs, sp, pc);
+		return collect_syscall(target, info);
 
 	state = target->state;
 	if (unlikely(!state))
@@ -80,7 +73,7 @@ int task_current_syscall(struct task_struct *target, long *callno,
 
 	ncsw = wait_task_inactive(target, state);
 	if (unlikely(!ncsw) ||
-	    unlikely(collect_syscall(target, callno, args, maxargs, sp, pc)) ||
+	    unlikely(collect_syscall(target, info)) ||
 	    unlikely(wait_task_inactive(target, state) != ncsw))
 		return -EAGAIN;
 
-- 
2.20.1

[PATCH 2/6 v3] tracing/syscalls: Pass in hardcoded 6 into syscall_get_arguments()

[Steven Rostedt]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

The only users that calls syscall_get_arguments() with a variable and not a
hard coded '6' is ftrace_syscall_enter(). syscall_get_arguments() can be
optimized by removing a variable input, and always grabbing 6 arguments
regardless of what the system call actually uses.

Change ftrace_syscall_enter() to pass the 6 args into a local stack array
and copy the necessary arguments into the trace event as needed.

This is needed to remove two parameters from syscall_get_arguments().

Link: http://lkml.kernel.org/r/20161107213233.627583542@goodmis.org

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_syscalls.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index f93a56d2db27..e9f5bbbad6d9 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, 0, 6, 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, 0, 6, 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)) ||
-- 
2.20.1

[PATCH 3/6 v3] riscv: Fix syscall_get_arguments() and syscall_set_arguments()

[Steven Rostedt]

From: "Dmitry V. Levin" <ldv@altlinux.org>

RISC-V syscall arguments are located in orig_a0,a1..a5 fields
of struct pt_regs.

Due to an off-by-one bug and a bug in pointer arithmetic
syscall_get_arguments() was reading s3..s7 fields instead of a1..a5.
Likewise, syscall_set_arguments() was writing s3..s7 fields
instead of a1..a5.

Link: http://lkml.kernel.org/r/20190329171221.GA32456@altlinux.org

Fixes: e2c0cdfba7f69 ("RISC-V: User-facing API")
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org
Cc: stable@vger.kernel.org # v4.15+
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 arch/riscv/include/asm/syscall.h | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h
index bba3da6ef157..6ea9e1804233 100644
--- a/arch/riscv/include/asm/syscall.h
+++ b/arch/riscv/include/asm/syscall.h
@@ -79,10 +79,11 @@ static inline void syscall_get_arguments(struct task_struct *task,
 	if (i == 0) {
 		args[0] = regs->orig_a0;
 		args++;
-		i++;
 		n--;
+	} else {
+		i--;
 	}
-	memcpy(args, &regs->a1 + i * sizeof(regs->a1), n * sizeof(args[0]));
+	memcpy(args, &regs->a1 + i, n * sizeof(args[0]));
 }
 
 static inline void syscall_set_arguments(struct task_struct *task,
@@ -94,10 +95,11 @@ static inline void syscall_set_arguments(struct task_struct *task,
         if (i == 0) {
                 regs->orig_a0 = args[0];
                 args++;
-                i++;
                 n--;
-        }
-	memcpy(&regs->a1 + i * sizeof(regs->a1), args, n * sizeof(regs->a0));
+	} else {
+		i--;
+	}
+	memcpy(&regs->a1 + i, args, n * sizeof(regs->a1));
 }
 
 static inline int syscall_get_arch(void)
-- 
2.20.1

[PATCH 4/6 v3] csky: Fix syscall_get_arguments() and syscall_set_arguments()

[Steven Rostedt]

From: "Dmitry V. Levin" <ldv@altlinux.org>

C-SKY syscall arguments are located in orig_a0,a1,a2,a3,regs[0],regs[1]
fields of struct pt_regs.

Due to an off-by-one bug and a bug in pointer arithmetic
syscall_get_arguments() was reading orig_a0,regs[1..5] fields instead.
Likewise, syscall_set_arguments() was writing orig_a0,regs[1..5] fields
instead.

Link: http://lkml.kernel.org/r/20190329171230.GB32456@altlinux.org

Fixes: 4859bfca11c7d ("csky: System Call")
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 arch/csky/include/asm/syscall.h | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/csky/include/asm/syscall.h b/arch/csky/include/asm/syscall.h
index d637445737b7..9a9cd81e66c1 100644
--- a/arch/csky/include/asm/syscall.h
+++ b/arch/csky/include/asm/syscall.h
@@ -49,10 +49,11 @@ syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
 	if (i == 0) {
 		args[0] = regs->orig_a0;
 		args++;
-		i++;
 		n--;
+	} else {
+		i--;
 	}
-	memcpy(args, &regs->a1 + i * sizeof(regs->a1), n * sizeof(args[0]));
+	memcpy(args, &regs->a1 + i, n * sizeof(args[0]));
 }
 
 static inline void
@@ -63,10 +64,11 @@ syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
 	if (i == 0) {
 		regs->orig_a0 = args[0];
 		args++;
-		i++;
 		n--;
+	} else {
+		i--;
 	}
-	memcpy(&regs->a1 + i * sizeof(regs->a1), args, n * sizeof(regs->a0));
+	memcpy(&regs->a1 + i, args, n * sizeof(regs->a1));
 }
 
 static inline int
-- 
2.20.1

[PATCH 5/6 v3] syscalls: Remove start and number from syscall_get_arguments() args

[Steven Rostedt]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

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: Thomas Gleixner <tglx@linutronix.de>
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
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 arch/arc/include/asm/syscall.h        |  7 ++-
 arch/arm/include/asm/syscall.h        | 23 ++-------
 arch/arm64/include/asm/syscall.h      | 22 ++------
 arch/c6x/include/asm/syscall.h        | 41 +++------------
 arch/csky/include/asm/syscall.h       | 14 ++---
 arch/h8300/include/asm/syscall.h      | 34 +++----------
 arch/hexagon/include/asm/syscall.h    |  4 +-
 arch/ia64/include/asm/syscall.h       |  5 +-
 arch/microblaze/include/asm/syscall.h |  4 +-
 arch/mips/include/asm/syscall.h       |  3 +-
 arch/mips/kernel/ptrace.c             |  2 +-
 arch/nds32/include/asm/syscall.h      | 33 +++---------
 arch/nios2/include/asm/syscall.h      | 42 +++------------
 arch/openrisc/include/asm/syscall.h   |  6 +--
 arch/parisc/include/asm/syscall.h     | 30 +++--------
 arch/powerpc/include/asm/syscall.h    |  8 ++-
 arch/riscv/include/asm/syscall.h      | 13 ++---
 arch/s390/include/asm/syscall.h       | 17 ++-----
 arch/sh/include/asm/syscall_32.h      | 26 +++-------
 arch/sh/include/asm/syscall_64.h      |  4 +-
 arch/sparc/include/asm/syscall.h      |  4 +-
 arch/um/include/asm/syscall-generic.h | 39 +++-----------
 arch/x86/include/asm/syscall.h        | 73 +++++++--------------------
 arch/xtensa/include/asm/syscall.h     | 16 ++----
 include/asm-generic/syscall.h         | 11 ++--
 include/trace/events/syscalls.h       |  2 +-
 kernel/seccomp.c                      |  2 +-
 kernel/trace/trace_syscalls.c         |  4 +-
 lib/syscall.c                         |  2 +-
 29 files changed, 113 insertions(+), 378 deletions(-)

diff --git a/arch/arc/include/asm/syscall.h b/arch/arc/include/asm/syscall.h
index 29de09804306..c7a4201ed62b 100644
--- a/arch/arc/include/asm/syscall.h
+++ b/arch/arc/include/asm/syscall.h
@@ -55,12 +55,11 @@ syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
  */
 static inline void
 syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
-		      unsigned int i, unsigned int n, unsigned long *args)
+		      unsigned long *args)
 {
 	unsigned long *inside_ptregs = &(regs->r0);
-	inside_ptregs -= i;
-
-	BUG_ON((i + n) > 6);
+	unsigned int n = 6;
+	unsigned int i = 0;
 
 	while (n--) {
 		args[i++] = (*inside_ptregs);
diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h
index 06dea6bce293..db969a2972ae 100644
--- a/arch/arm/include/asm/syscall.h
+++ b/arch/arm/include/asm/syscall.h
@@ -55,29 +55,12 @@ 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)
 {
-	if (n == 0)
-		return;
-
-	if (i + n > SYSCALL_MAX_ARGS) {
-		unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
-		unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
-		pr_warn("%s called with max args %d, handling only %d\n",
-			__func__, i + n, SYSCALL_MAX_ARGS);
-		memset(args_bad, 0, n_bad * sizeof(args[0]));
-		n = SYSCALL_MAX_ARGS - i;
-	}
-
-	if (i == 0) {
-		args[0] = regs->ARM_ORIG_r0;
-		args++;
-		i++;
-		n--;
-	}
+	args[0] = regs->ARM_ORIG_r0;
+	args++;
 
-	memcpy(args, &regs->ARM_r0 + i, n * sizeof(args[0]));
+	memcpy(args, &regs->ARM_r0 + 1, 5 * sizeof(args[0]));
 }
 
 static inline void syscall_set_arguments(struct task_struct *task,
diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h
index ad8be16a39c9..55b2dab21023 100644
--- a/arch/arm64/include/asm/syscall.h
+++ b/arch/arm64/include/asm/syscall.h
@@ -65,28 +65,12 @@ 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)
 {
-	if (n == 0)
-		return;
-
-	if (i + n > SYSCALL_MAX_ARGS) {
-		unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
-		unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
-		pr_warning("%s called with max args %d, handling only %d\n",
-			   __func__, i + n, SYSCALL_MAX_ARGS);
-		memset(args_bad, 0, n_bad * sizeof(args[0]));
-	}
-
-	if (i == 0) {
-		args[0] = regs->orig_x0;
-		args++;
-		i++;
-		n--;
-	}
+	args[0] = regs->orig_x0;
+	args++;
 
-	memcpy(args, &regs->regs[i], n * sizeof(args[0]));
+	memcpy(args, &regs->regs[1], 5 * sizeof(args[0]));
 }
 
 static inline void syscall_set_arguments(struct task_struct *task,
diff --git a/arch/c6x/include/asm/syscall.h b/arch/c6x/include/asm/syscall.h
index ae2be315ee9c..06db3251926b 100644
--- a/arch/c6x/include/asm/syscall.h
+++ b/arch/c6x/include/asm/syscall.h
@@ -46,40 +46,15 @@ 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)
+					 struct pt_regs *regs,
+					 unsigned long *args)
 {
-	switch (i) {
-	case 0:
-		if (!n--)
-			break;
-		*args++ = regs->a4;
-	case 1:
-		if (!n--)
-			break;
-		*args++ = regs->b4;
-	case 2:
-		if (!n--)
-			break;
-		*args++ = regs->a6;
-	case 3:
-		if (!n--)
-			break;
-		*args++ = regs->b6;
-	case 4:
-		if (!n--)
-			break;
-		*args++ = regs->a8;
-	case 5:
-		if (!n--)
-			break;
-		*args++ = regs->b8;
-	case 6:
-		if (!n--)
-			break;
-	default:
-		BUG();
-	}
+	*args++ = regs->a4;
+	*args++ = regs->b4;
+	*args++ = regs->a6;
+	*args++ = regs->b6;
+	*args++ = regs->a8;
+	*args   = regs->b8;
 }
 
 static inline void syscall_set_arguments(struct task_struct *task,
diff --git a/arch/csky/include/asm/syscall.h b/arch/csky/include/asm/syscall.h
index 9a9cd81e66c1..c691fe92edc6 100644
--- a/arch/csky/include/asm/syscall.h
+++ b/arch/csky/include/asm/syscall.h
@@ -43,17 +43,11 @@ syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
 
 static inline void
 syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
-		      unsigned int i, unsigned int n, unsigned long *args)
+		      unsigned long *args)
 {
-	BUG_ON(i + n > 6);
-	if (i == 0) {
-		args[0] = regs->orig_a0;
-		args++;
-		n--;
-	} else {
-		i--;
-	}
-	memcpy(args, &regs->a1 + i, n * sizeof(args[0]));
+	args[0] = regs->orig_a0;
+	args++;
+	memcpy(args, &regs->a1, 5 * sizeof(args[0]));
 }
 
 static inline void
diff --git a/arch/h8300/include/asm/syscall.h b/arch/h8300/include/asm/syscall.h
index 924990401237..ddd483c6ca95 100644
--- a/arch/h8300/include/asm/syscall.h
+++ b/arch/h8300/include/asm/syscall.h
@@ -17,34 +17,14 @@ syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
 
 static inline void
 syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
-		      unsigned int i, unsigned int n, unsigned long *args)
+		      unsigned long *args)
 {
-	BUG_ON(i + n > 6);
-
-	while (n > 0) {
-		switch (i) {
-		case 0:
-			*args++ = regs->er1;
-			break;
-		case 1:
-			*args++ = regs->er2;
-			break;
-		case 2:
-			*args++ = regs->er3;
-			break;
-		case 3:
-			*args++ = regs->er4;
-			break;
-		case 4:
-			*args++ = regs->er5;
-			break;
-		case 5:
-			*args++ = regs->er6;
-			break;
-		}
-		i++;
-		n--;
-	}
+	*args++ = regs->er1;
+	*args++ = regs->er2;
+	*args++ = regs->er3;
+	*args++ = regs->er4;
+	*args++ = regs->er5;
+	*args   = regs->er6;
 }
 
 
diff --git a/arch/hexagon/include/asm/syscall.h b/arch/hexagon/include/asm/syscall.h
index 4af9c7b6f13a..ae3a1e24fabd 100644
--- a/arch/hexagon/include/asm/syscall.h
+++ b/arch/hexagon/include/asm/syscall.h
@@ -37,10 +37,8 @@ static inline long syscall_get_nr(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);
-	memcpy(args, &(&regs->r00)[i], n * sizeof(args[0]));
+	memcpy(args, &(&regs->r00)[0], 6 * sizeof(args[0]));
 }
 #endif
diff --git a/arch/ia64/include/asm/syscall.h b/arch/ia64/include/asm/syscall.h
index 1d0b875fec44..8204c1ff70ce 100644
--- a/arch/ia64/include/asm/syscall.h
+++ b/arch/ia64/include/asm/syscall.h
@@ -63,12 +63,9 @@ extern void ia64_syscall_get_set_arguments(struct task_struct *task,
 	unsigned long *args, int rw);
 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);
-
-	ia64_syscall_get_set_arguments(task, regs, i, n, args, 0);
+	ia64_syscall_get_set_arguments(task, regs, 0, 6, args, 0);
 }
 
 static inline void syscall_set_arguments(struct task_struct *task,
diff --git a/arch/microblaze/include/asm/syscall.h b/arch/microblaze/include/asm/syscall.h
index 220decd605a4..4b23e44e5c3c 100644
--- a/arch/microblaze/include/asm/syscall.h
+++ b/arch/microblaze/include/asm/syscall.h
@@ -82,9 +82,11 @@ static inline void microblaze_set_syscall_arg(struct pt_regs *regs,
 
 static inline void syscall_get_arguments(struct task_struct *task,
 					 struct pt_regs *regs,
-					 unsigned int i, unsigned int n,
 					 unsigned long *args)
 {
+	unsigned int i = 0;
+	unsigned int n = 6;
+
 	while (n--)
 		*args++ = microblaze_get_syscall_arg(regs, i++);
 }
diff --git a/arch/mips/include/asm/syscall.h b/arch/mips/include/asm/syscall.h
index 6cf8ffb5367e..a2b4748655df 100644
--- a/arch/mips/include/asm/syscall.h
+++ b/arch/mips/include/asm/syscall.h
@@ -116,9 +116,10 @@ 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)
 {
+	unsigned int i = 0;
+	unsigned int n = 6;
 	int ret;
 
 	/* O32 ABI syscall() */
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index 0057c910bc2f..3a62f80958e1 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -1419,7 +1419,7 @@ asmlinkage long syscall_trace_enter(struct pt_regs *regs, long syscall)
 
 		sd.nr = syscall;
 		sd.arch = syscall_get_arch();
-		syscall_get_arguments(current, regs, 0, 6, args);
+		syscall_get_arguments(current, regs, args);
 		for (i = 0; i < 6; i++)
 			sd.args[i] = args[i];
 		sd.instruction_pointer = KSTK_EIP(current);
diff --git a/arch/nds32/include/asm/syscall.h b/arch/nds32/include/asm/syscall.h
index f7e5e86765fe..89a6ec8731d8 100644
--- a/arch/nds32/include/asm/syscall.h
+++ b/arch/nds32/include/asm/syscall.h
@@ -108,42 +108,21 @@ void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
  * syscall_get_arguments - extract system call parameter values
  * @task:	task of interest, must be blocked
  * @regs:	task_pt_regs() of @task
- * @i:		argument index [0,5]
- * @n:		number of arguments; n+i must be [1,6].
  * @args:	array filled with argument values
  *
- * Fetches @n arguments to the system call starting with the @i'th argument
- * (from 0 through 5).  Argument @i is stored in @args[0], and so on.
- * An arch inline version is probably optimal when @i and @n are constants.
+ * Fetches 6 arguments to the system call (from 0 through 5). The first
+ * argument is stored in @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.
  */
 #define SYSCALL_MAX_ARGS 6
 void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
-			   unsigned int i, unsigned int n, unsigned long *args)
+			   unsigned long *args)
 {
-	if (n == 0)
-		return;
-	if (i + n > SYSCALL_MAX_ARGS) {
-		unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
-		unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
-		pr_warning("%s called with max args %d, handling only %d\n",
-			   __func__, i + n, SYSCALL_MAX_ARGS);
-		memset(args_bad, 0, n_bad * sizeof(args[0]));
-		memset(args_bad, 0, n_bad * sizeof(args[0]));
-	}
-
-	if (i == 0) {
-		args[0] = regs->orig_r0;
-		args++;
-		i++;
-		n--;
-	}
-
-	memcpy(args, &regs->uregs[0] + i, n * sizeof(args[0]));
+	args[0] = regs->orig_r0;
+	args++;
+	memcpy(args, &regs->uregs[0] + 1, 5 * sizeof(args[0]));
 }
 
 /**
diff --git a/arch/nios2/include/asm/syscall.h b/arch/nios2/include/asm/syscall.h
index 9de220854c4a..792bd449d839 100644
--- a/arch/nios2/include/asm/syscall.h
+++ b/arch/nios2/include/asm/syscall.h
@@ -58,42 +58,14 @@ 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)
+	struct pt_regs *regs, unsigned long *args)
 {
-	BUG_ON(i + n > 6);
-
-	switch (i) {
-	case 0:
-		if (!n--)
-			break;
-		*args++ = regs->r4;
-	case 1:
-		if (!n--)
-			break;
-		*args++ = regs->r5;
-	case 2:
-		if (!n--)
-			break;
-		*args++ = regs->r6;
-	case 3:
-		if (!n--)
-			break;
-		*args++ = regs->r7;
-	case 4:
-		if (!n--)
-			break;
-		*args++ = regs->r8;
-	case 5:
-		if (!n--)
-			break;
-		*args++ = regs->r9;
-	case 6:
-		if (!n--)
-			break;
-	default:
-		BUG();
-	}
+	*args++ = regs->r4;
+	*args++ = regs->r5;
+	*args++ = regs->r6;
+	*args++ = regs->r7;
+	*args++ = regs->r8;
+	*args   = regs->r9;
 }
 
 static inline void syscall_set_arguments(struct task_struct *task,
diff --git a/arch/openrisc/include/asm/syscall.h b/arch/openrisc/include/asm/syscall.h
index 2db9f1cf0694..72607860cd55 100644
--- a/arch/openrisc/include/asm/syscall.h
+++ b/arch/openrisc/include/asm/syscall.h
@@ -56,11 +56,9 @@ syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
 
 static inline void
 syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
-		      unsigned int i, unsigned int n, unsigned long *args)
+		      unsigned long *args)
 {
-	BUG_ON(i + n > 6);
-
-	memcpy(args, &regs->gpr[3 + i], n * sizeof(args[0]));
+	memcpy(args, &regs->gpr[3], 6 * sizeof(args[0]));
 }
 
 static inline void
diff --git a/arch/parisc/include/asm/syscall.h b/arch/parisc/include/asm/syscall.h
index 8bff1a58c97f..62a6d477fae0 100644
--- a/arch/parisc/include/asm/syscall.h
+++ b/arch/parisc/include/asm/syscall.h
@@ -18,29 +18,15 @@ static inline long syscall_get_nr(struct task_struct *tsk,
 }
 
 static inline void syscall_get_arguments(struct task_struct *tsk,
-					 struct pt_regs *regs, unsigned int i,
-					 unsigned int n, unsigned long *args)
+					 struct pt_regs *regs,
+					 unsigned long *args)
 {
-	BUG_ON(i);
-
-	switch (n) {
-	case 6:
-		args[5] = regs->gr[21];
-	case 5:
-		args[4] = regs->gr[22];
-	case 4:
-		args[3] = regs->gr[23];
-	case 3:
-		args[2] = regs->gr[24];
-	case 2:
-		args[1] = regs->gr[25];
-	case 1:
-		args[0] = regs->gr[26];
-	case 0:
-		break;
-	default:
-		BUG();
-	}
+	args[5] = regs->gr[21];
+	args[4] = regs->gr[22];
+	args[3] = regs->gr[23];
+	args[2] = regs->gr[24];
+	args[1] = regs->gr[25];
+	args[0] = regs->gr[26];
 }
 
 static inline long syscall_get_return_value(struct task_struct *task,
diff --git a/arch/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h
index 1a0e7a8b1c81..5c9b9dc82b7e 100644
--- a/arch/powerpc/include/asm/syscall.h
+++ b/arch/powerpc/include/asm/syscall.h
@@ -65,22 +65,20 @@ 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)
 {
 	unsigned long val, mask = -1UL;
-
-	BUG_ON(i + n > 6);
+	unsigned int n = 6;
 
 #ifdef CONFIG_COMPAT
 	if (test_tsk_thread_flag(task, TIF_32BIT))
 		mask = 0xffffffff;
 #endif
 	while (n--) {
-		if (n == 0 && i == 0)
+		if (n == 0)
 			val = regs->orig_gpr3;
 		else
-			val = regs->gpr[3 + i + n];
+			val = regs->gpr[3 + n];
 
 		args[n] = val & mask;
 	}
diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h
index 6ea9e1804233..6adca1804be1 100644
--- a/arch/riscv/include/asm/syscall.h
+++ b/arch/riscv/include/asm/syscall.h
@@ -72,18 +72,11 @@ 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++;
-		n--;
-	} else {
-		i--;
-	}
-	memcpy(args, &regs->a1 + i, 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,
diff --git a/arch/s390/include/asm/syscall.h b/arch/s390/include/asm/syscall.h
index 96f9a9151fde..ee0b1f6aa36d 100644
--- a/arch/s390/include/asm/syscall.h
+++ b/arch/s390/include/asm/syscall.h
@@ -56,27 +56,20 @@ 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)
 {
 	unsigned long mask = -1UL;
+	unsigned int n = 6;
 
-	/*
-	 * No arguments for this syscall, there's nothing to do.
-	 */
-	if (!n)
-		return;
-
-	BUG_ON(i + n > 6);
 #ifdef CONFIG_COMPAT
 	if (test_tsk_thread_flag(task, TIF_31BIT))
 		mask = 0xffffffff;
 #endif
 	while (n-- > 0)
-		if (i + n > 0)
-			args[n] = regs->gprs[2 + i + n] & mask;
-	if (i == 0)
-		args[0] = regs->orig_gpr2 & mask;
+		if (n > 0)
+			args[n] = regs->gprs[2 + n] & mask;
+
+	args[0] = regs->orig_gpr2 & mask;
 }
 
 static inline void syscall_set_arguments(struct task_struct *task,
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,
diff --git a/arch/sh/include/asm/syscall_64.h b/arch/sh/include/asm/syscall_64.h
index 43882580c7f9..4e8f6460c703 100644
--- a/arch/sh/include/asm/syscall_64.h
+++ b/arch/sh/include/asm/syscall_64.h
@@ -47,11 +47,9 @@ 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);
-	memcpy(args, &regs->regs[2 + i], n * sizeof(args[0]));
+	memcpy(args, &regs->regs[2], 6 * sizeof(args[0]));
 }
 
 static inline void syscall_set_arguments(struct task_struct *task,
diff --git a/arch/sparc/include/asm/syscall.h b/arch/sparc/include/asm/syscall.h
index 053989e3f6a6..872dfee852d6 100644
--- a/arch/sparc/include/asm/syscall.h
+++ b/arch/sparc/include/asm/syscall.h
@@ -96,11 +96,11 @@ 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)
 {
 	int zero_extend = 0;
 	unsigned int j;
+	unsigned int n = 6;
 
 #ifdef CONFIG_SPARC64
 	if (test_tsk_thread_flag(task, TIF_32BIT))
@@ -108,7 +108,7 @@ static inline void syscall_get_arguments(struct task_struct *task,
 #endif
 
 	for (j = 0; j < n; j++) {
-		unsigned long val = regs->u_regs[UREG_I0 + i + j];
+		unsigned long val = regs->u_regs[UREG_I0 + j];
 
 		if (zero_extend)
 			args[j] = (u32) val;
diff --git a/arch/um/include/asm/syscall-generic.h b/arch/um/include/asm/syscall-generic.h
index 9fb9cf8cd39a..25d00acd1322 100644
--- a/arch/um/include/asm/syscall-generic.h
+++ b/arch/um/include/asm/syscall-generic.h
@@ -53,43 +53,16 @@ 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)
 {
 	const struct uml_pt_regs *r = &regs->regs;
 
-	switch (i) {
-	case 0:
-		if (!n--)
-			break;
-		*args++ = UPT_SYSCALL_ARG1(r);
-	case 1:
-		if (!n--)
-			break;
-		*args++ = UPT_SYSCALL_ARG2(r);
-	case 2:
-		if (!n--)
-			break;
-		*args++ = UPT_SYSCALL_ARG3(r);
-	case 3:
-		if (!n--)
-			break;
-		*args++ = UPT_SYSCALL_ARG4(r);
-	case 4:
-		if (!n--)
-			break;
-		*args++ = UPT_SYSCALL_ARG5(r);
-	case 5:
-		if (!n--)
-			break;
-		*args++ = UPT_SYSCALL_ARG6(r);
-	case 6:
-		if (!n--)
-			break;
-	default:
-		BUG();
-		break;
-	}
+	*args++ = UPT_SYSCALL_ARG1(r);
+	*args++ = UPT_SYSCALL_ARG2(r);
+	*args++ = UPT_SYSCALL_ARG3(r);
+	*args++ = UPT_SYSCALL_ARG4(r);
+	*args++ = UPT_SYSCALL_ARG5(r);
+	*args   = UPT_SYSCALL_ARG6(r);
 }
 
 static inline void syscall_set_arguments(struct task_struct *task,
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index d653139857af..8dbb5c379450 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -91,11 +91,9 @@ 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);
-	memcpy(args, &regs->bx + i, n * sizeof(args[0]));
+	memcpy(args, &regs->bx, 6 * sizeof(args[0]));
 }
 
 static inline void syscall_set_arguments(struct task_struct *task,
@@ -116,63 +114,26 @@ static inline int syscall_get_arch(void)
 
 static inline void syscall_get_arguments(struct task_struct *task,
 					 struct pt_regs *regs,
-					 unsigned int i, unsigned int n,
 					 unsigned long *args)
 {
 # ifdef CONFIG_IA32_EMULATION
-	if (task->thread_info.status & TS_COMPAT)
-		switch (i) {
-		case 0:
-			if (!n--) break;
-			*args++ = regs->bx;
-		case 1:
-			if (!n--) break;
-			*args++ = regs->cx;
-		case 2:
-			if (!n--) break;
-			*args++ = regs->dx;
-		case 3:
-			if (!n--) break;
-			*args++ = regs->si;
-		case 4:
-			if (!n--) break;
-			*args++ = regs->di;
-		case 5:
-			if (!n--) break;
-			*args++ = regs->bp;
-		case 6:
-			if (!n--) break;
-		default:
-			BUG();
-			break;
-		}
-	else
+	if (task->thread_info.status & TS_COMPAT) {
+		*args++ = regs->bx;
+		*args++ = regs->cx;
+		*args++ = regs->dx;
+		*args++ = regs->si;
+		*args++ = regs->di;
+		*args   = regs->bp;
+	} else
 # endif
-		switch (i) {
-		case 0:
-			if (!n--) break;
-			*args++ = regs->di;
-		case 1:
-			if (!n--) break;
-			*args++ = regs->si;
-		case 2:
-			if (!n--) break;
-			*args++ = regs->dx;
-		case 3:
-			if (!n--) break;
-			*args++ = regs->r10;
-		case 4:
-			if (!n--) break;
-			*args++ = regs->r8;
-		case 5:
-			if (!n--) break;
-			*args++ = regs->r9;
-		case 6:
-			if (!n--) break;
-		default:
-			BUG();
-			break;
-		}
+	{
+		*args++ = regs->di;
+		*args++ = regs->si;
+		*args++ = regs->dx;
+		*args++ = regs->r10;
+		*args++ = regs->r8;
+		*args   = regs->r9;
+	}
 }
 
 static inline void syscall_set_arguments(struct task_struct *task,
diff --git a/arch/xtensa/include/asm/syscall.h b/arch/xtensa/include/asm/syscall.h
index a168bf81c7f4..1504ce9a233a 100644
--- a/arch/xtensa/include/asm/syscall.h
+++ b/arch/xtensa/include/asm/syscall.h
@@ -59,23 +59,13 @@ 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)
 {
 	static const unsigned int reg[] = XTENSA_SYSCALL_ARGUMENT_REGS;
-	unsigned int j;
-
-	if (n == 0)
-		return;
-
-	WARN_ON_ONCE(i + n > SYSCALL_MAX_ARGS);
+	unsigned int i;
 
-	for (j = 0; j < n; ++j) {
-		if (i + j < SYSCALL_MAX_ARGS)
-			args[j] = regs->areg[reg[i + j]];
-		else
-			args[j] = 0;
-	}
+	for (i = 0; i < 6; ++i)
+		args[i] = regs->areg[reg[i]];
 }
 
 static inline void syscall_set_arguments(struct task_struct *task,
diff --git a/include/asm-generic/syscall.h b/include/asm-generic/syscall.h
index 0c938a4354f6..269e9412ef42 100644
--- a/include/asm-generic/syscall.h
+++ b/include/asm-generic/syscall.h
@@ -105,21 +105,16 @@ void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
  * syscall_get_arguments - extract system call parameter values
  * @task:	task of interest, must be blocked
  * @regs:	task_pt_regs() of @task
- * @i:		argument index [0,5]
- * @n:		number of arguments; n+i must be [1,6].
  * @args:	array filled with argument values
  *
- * Fetches @n arguments to the system call starting with the @i'th argument
- * (from 0 through 5).  Argument @i is stored in @args[0], and so on.
- * An arch inline version is probably optimal when @i and @n are constants.
+ * Fetches 6 arguments to the system call.  First argument is stored in
+*  @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_get_arguments(struct task_struct *task, struct pt_regs *regs,
-			   unsigned int i, unsigned int n, unsigned long *args);
+			   unsigned long *args);
 
 /**
  * syscall_set_arguments - change system call parameter value
diff --git a/include/trace/events/syscalls.h b/include/trace/events/syscalls.h
index 44a3259ed4a5..b6e0cbc2c71f 100644
--- a/include/trace/events/syscalls.h
+++ b/include/trace/events/syscalls.h
@@ -28,7 +28,7 @@ TRACE_EVENT_FN(sys_enter,
 
 	TP_fast_assign(
 		__entry->id	= id;
-		syscall_get_arguments(current, regs, 0, 6, __entry->args);
+		syscall_get_arguments(current, regs, __entry->args);
 	),
 
 	TP_printk("NR %ld (%lx, %lx, %lx, %lx, %lx, %lx)",
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 e9f5bbbad6d9..fa8fbff736d6 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -348,7 +348,7 @@ 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, 6, 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,
@@ -616,7 +616,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
 		return;
 
 	rec->nr = syscall_nr;
-	syscall_get_arguments(current, regs, 0, 6, args);
+	syscall_get_arguments(current, regs, args);
 	memcpy(&rec->args, args, sizeof(unsigned long) * sys_data->nb_args);
 
 	if ((valid_prog_array &&
diff --git a/lib/syscall.c b/lib/syscall.c
index e8467e17b9a2..fb328e7ccb08 100644
--- a/lib/syscall.c
+++ b/lib/syscall.c
@@ -27,7 +27,7 @@ static int collect_syscall(struct task_struct *target, struct syscall_info *info
 
 	info->data.nr = syscall_get_nr(target, regs);
 	if (info->data.nr != -1L)
-		syscall_get_arguments(target, regs, 0, 6,
+		syscall_get_arguments(target, regs,
 				      (unsigned long *)&info->data.args[0]);
 
 	put_task_stack(target);
-- 
2.20.1

[PATCH 6/6 v3] syscalls: Remove start and number from syscall_set_arguments() args

[Steven Rostedt]

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

Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
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
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 arch/arm/include/asm/syscall.h        | 22 ++-------
 arch/arm64/include/asm/syscall.h      | 22 ++-------
 arch/c6x/include/asm/syscall.h        | 38 +++------------
 arch/csky/include/asm/syscall.h       | 14 ++----
 arch/ia64/include/asm/syscall.h       | 10 ++--
 arch/ia64/kernel/ptrace.c             |  7 ++-
 arch/microblaze/include/asm/syscall.h |  4 +-
 arch/nds32/include/asm/syscall.h      | 29 ++---------
 arch/nios2/include/asm/syscall.h      | 42 +++-------------
 arch/openrisc/include/asm/syscall.h   |  6 +--
 arch/powerpc/include/asm/syscall.h    |  7 +--
 arch/riscv/include/asm/syscall.h      | 13 ++---
 arch/s390/include/asm/syscall.h       | 11 ++---
 arch/sh/include/asm/syscall_32.h      | 21 +++-----
 arch/sh/include/asm/syscall_64.h      |  4 +-
 arch/sparc/include/asm/syscall.h      |  7 ++-
 arch/um/include/asm/syscall-generic.h | 39 +++------------
 arch/x86/include/asm/syscall.h        | 69 +++++++--------------------
 arch/xtensa/include/asm/syscall.h     | 17 ++-----
 include/asm-generic/syscall.h         | 10 +---
 20 files changed, 88 insertions(+), 304 deletions(-)

diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h
index db969a2972ae..080ce70cab12 100644
--- a/arch/arm/include/asm/syscall.h
+++ b/arch/arm/include/asm/syscall.h
@@ -65,26 +65,12 @@ 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)
 {
-	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->ARM_ORIG_r0 = args[0];
-		args++;
-		i++;
-		n--;
-	}
-
-	memcpy(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
+	regs->ARM_ORIG_r0 = args[0];
+	args++;
+
+	memcpy(&regs->ARM_r0 + 1, args, 5 * sizeof(args[0]));
 }
 
 static inline int syscall_get_arch(void)
diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h
index 55b2dab21023..a179df3674a1 100644
--- a/arch/arm64/include/asm/syscall.h
+++ b/arch/arm64/include/asm/syscall.h
@@ -75,26 +75,12 @@ 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)
 {
-	if (n == 0)
-		return;
-
-	if (i + n > SYSCALL_MAX_ARGS) {
-		pr_warning("%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_x0 = args[0];
-		args++;
-		i++;
-		n--;
-	}
-
-	memcpy(&regs->regs[i], args, n * sizeof(args[0]));
+	regs->orig_x0 = args[0];
+	args++;
+
+	memcpy(&regs->regs[1], args, 5 * sizeof(args[0]));
 }
 
 /*
diff --git a/arch/c6x/include/asm/syscall.h b/arch/c6x/include/asm/syscall.h
index 06db3251926b..15ba8599858e 100644
--- a/arch/c6x/include/asm/syscall.h
+++ b/arch/c6x/include/asm/syscall.h
@@ -59,40 +59,14 @@ 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)
 {
-	switch (i) {
-	case 0:
-		if (!n--)
-			break;
-		regs->a4 = *args++;
-	case 1:
-		if (!n--)
-			break;
-		regs->b4 = *args++;
-	case 2:
-		if (!n--)
-			break;
-		regs->a6 = *args++;
-	case 3:
-		if (!n--)
-			break;
-		regs->b6 = *args++;
-	case 4:
-		if (!n--)
-			break;
-		regs->a8 = *args++;
-	case 5:
-		if (!n--)
-			break;
-		regs->a9 = *args++;
-	case 6:
-		if (!n)
-			break;
-	default:
-		BUG();
-	}
+	regs->a4 = *args++;
+	regs->b4 = *args++;
+	regs->a6 = *args++;
+	regs->b6 = *args++;
+	regs->a8 = *args++;
+	regs->a9 = *args;
 }
 
 #endif /* __ASM_C6X_SYSCALLS_H */
diff --git a/arch/csky/include/asm/syscall.h b/arch/csky/include/asm/syscall.h
index c691fe92edc6..bda0a446c63e 100644
--- a/arch/csky/include/asm/syscall.h
+++ b/arch/csky/include/asm/syscall.h
@@ -52,17 +52,11 @@ syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
 
 static inline void
 syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
-		      unsigned int i, unsigned int n, const unsigned long *args)
+		      const unsigned long *args)
 {
-	BUG_ON(i + n > 6);
-	if (i == 0) {
-		regs->orig_a0 = args[0];
-		args++;
-		n--;
-	} else {
-		i--;
-	}
-	memcpy(&regs->a1 + i, args, n * sizeof(regs->a1));
+	regs->orig_a0 = args[0];
+	args++;
+	memcpy(&regs->a1, args, 5 * sizeof(regs->a1));
 }
 
 static inline int
diff --git a/arch/ia64/include/asm/syscall.h b/arch/ia64/include/asm/syscall.h
index 8204c1ff70ce..0d9e7fab4a79 100644
--- a/arch/ia64/include/asm/syscall.h
+++ b/arch/ia64/include/asm/syscall.h
@@ -59,23 +59,19 @@ static inline void syscall_set_return_value(struct task_struct *task,
 }
 
 extern void ia64_syscall_get_set_arguments(struct task_struct *task,
-	struct pt_regs *regs, unsigned int i, unsigned int n,
-	unsigned long *args, int rw);
+	struct pt_regs *regs, unsigned long *args, int rw);
 static inline void syscall_get_arguments(struct task_struct *task,
 					 struct pt_regs *regs,
 					 unsigned long *args)
 {
-	ia64_syscall_get_set_arguments(task, regs, 0, 6, args, 0);
+	ia64_syscall_get_set_arguments(task, regs, args, 0);
 }
 
 static inline void syscall_set_arguments(struct task_struct *task,
 					 struct pt_regs *regs,
-					 unsigned int i, unsigned int n,
 					 unsigned long *args)
 {
-	BUG_ON(i + n > 6);
-
-	ia64_syscall_get_set_arguments(task, regs, i, n, args, 1);
+	ia64_syscall_get_set_arguments(task, regs, args, 1);
 }
 
 static inline int syscall_get_arch(void)
diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
index 6d50ede0ed69..bf9c24d9ce84 100644
--- a/arch/ia64/kernel/ptrace.c
+++ b/arch/ia64/kernel/ptrace.c
@@ -2179,12 +2179,11 @@ static void syscall_get_set_args_cb(struct unw_frame_info *info, void *data)
 }
 
 void ia64_syscall_get_set_arguments(struct task_struct *task,
-	struct pt_regs *regs, unsigned int i, unsigned int n,
-	unsigned long *args, int rw)
+	struct pt_regs *regs, unsigned long *args, int rw)
 {
 	struct syscall_get_set_args data = {
-		.i = i,
-		.n = n,
+		.i = 0,
+		.n = 6,
 		.args = args,
 		.regs = regs,
 		.rw = rw,
diff --git a/arch/microblaze/include/asm/syscall.h b/arch/microblaze/include/asm/syscall.h
index 4b23e44e5c3c..833d3a53dab3 100644
--- a/arch/microblaze/include/asm/syscall.h
+++ b/arch/microblaze/include/asm/syscall.h
@@ -93,9 +93,11 @@ 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)
 {
+	unsigned int i = 0;
+	unsigned int n = 6;
+
 	while (n--)
 		microblaze_set_syscall_arg(regs, i++, *args++);
 }
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(&regs->uregs[0] + i, args, n * sizeof(args[0]));
+	memcpy(&regs->uregs[0] + 1, args, 5 * sizeof(args[0]));
 }
 #endif /* _ASM_NDS32_SYSCALL_H */
diff --git a/arch/nios2/include/asm/syscall.h b/arch/nios2/include/asm/syscall.h
index 792bd449d839..d7624ed06efb 100644
--- a/arch/nios2/include/asm/syscall.h
+++ b/arch/nios2/include/asm/syscall.h
@@ -69,42 +69,14 @@ 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)
+	struct pt_regs *regs, const unsigned long *args)
 {
-	BUG_ON(i + n > 6);
-
-	switch (i) {
-	case 0:
-		if (!n--)
-			break;
-		regs->r4 = *args++;
-	case 1:
-		if (!n--)
-			break;
-		regs->r5 = *args++;
-	case 2:
-		if (!n--)
-			break;
-		regs->r6 = *args++;
-	case 3:
-		if (!n--)
-			break;
-		regs->r7 = *args++;
-	case 4:
-		if (!n--)
-			break;
-		regs->r8 = *args++;
-	case 5:
-		if (!n--)
-			break;
-		regs->r9 = *args++;
-	case 6:
-		if (!n)
-			break;
-	default:
-		BUG();
-	}
+	regs->r4 = *args++;
+	regs->r5 = *args++;
+	regs->r6 = *args++;
+	regs->r7 = *args++;
+	regs->r8 = *args++;
+	regs->r9 = *args;
 }
 
 #endif
diff --git a/arch/openrisc/include/asm/syscall.h b/arch/openrisc/include/asm/syscall.h
index 72607860cd55..b4ff07c1baed 100644
--- a/arch/openrisc/include/asm/syscall.h
+++ b/arch/openrisc/include/asm/syscall.h
@@ -63,11 +63,9 @@ syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
 
 static inline void
 syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
-		      unsigned int i, unsigned int n, const unsigned long *args)
+		      const unsigned long *args)
 {
-	BUG_ON(i + n > 6);
-
-	memcpy(&regs->gpr[3 + i], args, n * sizeof(args[0]));
+	memcpy(&regs->gpr[3], args, 6 * sizeof(args[0]));
 }
 
 static inline int syscall_get_arch(void)
diff --git a/arch/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h
index 5c9b9dc82b7e..1243045bad2d 100644
--- a/arch/powerpc/include/asm/syscall.h
+++ b/arch/powerpc/include/asm/syscall.h
@@ -86,15 +86,12 @@ 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);
-	memcpy(&regs->gpr[3 + i], args, n * sizeof(args[0]));
+	memcpy(&regs->gpr[3], args, 6 * sizeof(args[0]));
 
 	/* Also copy the first argument into orig_gpr3 */
-	if (i == 0 && n > 0)
-		regs->orig_gpr3 = args[0];
+	regs->orig_gpr3 = args[0];
 }
 
 static inline int syscall_get_arch(void)
diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h
index 6adca1804be1..a3d5273ded7c 100644
--- a/arch/riscv/include/asm/syscall.h
+++ b/arch/riscv/include/asm/syscall.h
@@ -81,18 +81,11 @@ 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);
-        if (i == 0) {
-                regs->orig_a0 = args[0];
-                args++;
-                n--;
-	} else {
-		i--;
-	}
-	memcpy(&regs->a1 + i, args, n * sizeof(regs->a1));
+	regs->orig_a0 = args[0];
+	args++;
+	memcpy(&regs->a1, args, 5 * sizeof(regs->a1));
 }
 
 static inline int syscall_get_arch(void)
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];
 }
 
 static inline int syscall_get_arch(void)
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)
diff --git a/arch/sh/include/asm/syscall_64.h b/arch/sh/include/asm/syscall_64.h
index 4e8f6460c703..22fad97da066 100644
--- a/arch/sh/include/asm/syscall_64.h
+++ b/arch/sh/include/asm/syscall_64.h
@@ -54,11 +54,9 @@ 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);
-	memcpy(&regs->regs[2 + i], args, n * sizeof(args[0]));
+	memcpy(&regs->regs[2], args, 6 * sizeof(args[0]));
 }
 
 static inline int syscall_get_arch(void)
diff --git a/arch/sparc/include/asm/syscall.h b/arch/sparc/include/asm/syscall.h
index 872dfee852d6..4d075434e816 100644
--- a/arch/sparc/include/asm/syscall.h
+++ b/arch/sparc/include/asm/syscall.h
@@ -119,13 +119,12 @@ 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)
 {
-	unsigned int j;
+	unsigned int i;
 
-	for (j = 0; j < n; j++)
-		regs->u_regs[UREG_I0 + i + j] = args[j];
+	for (i = 0; i < 6; i++)
+		regs->u_regs[UREG_I0 + i] = args[i];
 }
 
 static inline int syscall_get_arch(void)
diff --git a/arch/um/include/asm/syscall-generic.h b/arch/um/include/asm/syscall-generic.h
index 25d00acd1322..98e50c50c12e 100644
--- a/arch/um/include/asm/syscall-generic.h
+++ b/arch/um/include/asm/syscall-generic.h
@@ -67,43 +67,16 @@ 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)
 {
 	struct uml_pt_regs *r = &regs->regs;
 
-	switch (i) {
-	case 0:
-		if (!n--)
-			break;
-		UPT_SYSCALL_ARG1(r) = *args++;
-	case 1:
-		if (!n--)
-			break;
-		UPT_SYSCALL_ARG2(r) = *args++;
-	case 2:
-		if (!n--)
-			break;
-		UPT_SYSCALL_ARG3(r) = *args++;
-	case 3:
-		if (!n--)
-			break;
-		UPT_SYSCALL_ARG4(r) = *args++;
-	case 4:
-		if (!n--)
-			break;
-		UPT_SYSCALL_ARG5(r) = *args++;
-	case 5:
-		if (!n--)
-			break;
-		UPT_SYSCALL_ARG6(r) = *args++;
-	case 6:
-		if (!n--)
-			break;
-	default:
-		BUG();
-		break;
-	}
+	UPT_SYSCALL_ARG1(r) = *args++;
+	UPT_SYSCALL_ARG2(r) = *args++;
+	UPT_SYSCALL_ARG3(r) = *args++;
+	UPT_SYSCALL_ARG4(r) = *args++;
+	UPT_SYSCALL_ARG5(r) = *args++;
+	UPT_SYSCALL_ARG6(r) = *args;
 }
 
 /* See arch/x86/um/asm/syscall.h for syscall_get_arch() definition. */
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index 8dbb5c379450..4c305471ec33 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -138,63 +138,26 @@ 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)
 {
 # ifdef CONFIG_IA32_EMULATION
-	if (task->thread_info.status & TS_COMPAT)
-		switch (i) {
-		case 0:
-			if (!n--) break;
-			regs->bx = *args++;
-		case 1:
-			if (!n--) break;
-			regs->cx = *args++;
-		case 2:
-			if (!n--) break;
-			regs->dx = *args++;
-		case 3:
-			if (!n--) break;
-			regs->si = *args++;
-		case 4:
-			if (!n--) break;
-			regs->di = *args++;
-		case 5:
-			if (!n--) break;
-			regs->bp = *args++;
-		case 6:
-			if (!n--) break;
-		default:
-			BUG();
-			break;
-		}
-	else
+	if (task->thread_info.status & TS_COMPAT) {
+		regs->bx = *args++;
+		regs->cx = *args++;
+		regs->dx = *args++;
+		regs->si = *args++;
+		regs->di = *args++;
+		regs->bp = *args;
+	} else
 # endif
-		switch (i) {
-		case 0:
-			if (!n--) break;
-			regs->di = *args++;
-		case 1:
-			if (!n--) break;
-			regs->si = *args++;
-		case 2:
-			if (!n--) break;
-			regs->dx = *args++;
-		case 3:
-			if (!n--) break;
-			regs->r10 = *args++;
-		case 4:
-			if (!n--) break;
-			regs->r8 = *args++;
-		case 5:
-			if (!n--) break;
-			regs->r9 = *args++;
-		case 6:
-			if (!n--) break;
-		default:
-			BUG();
-			break;
-		}
+	{
+		regs->di = *args++;
+		regs->si = *args++;
+		regs->dx = *args++;
+		regs->r10 = *args++;
+		regs->r8 = *args++;
+		regs->r9 = *args;
+	}
 }
 
 static inline int syscall_get_arch(void)
diff --git a/arch/xtensa/include/asm/syscall.h b/arch/xtensa/include/asm/syscall.h
index 1504ce9a233a..91dc06d58060 100644
--- a/arch/xtensa/include/asm/syscall.h
+++ b/arch/xtensa/include/asm/syscall.h
@@ -70,24 +70,13 @@ 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)
 {
 	static const unsigned int reg[] = XTENSA_SYSCALL_ARGUMENT_REGS;
-	unsigned int j;
-
-	if (n == 0)
-		return;
-
-	if (WARN_ON_ONCE(i + n > SYSCALL_MAX_ARGS)) {
-		if (i < SYSCALL_MAX_ARGS)
-			n = SYSCALL_MAX_ARGS - i;
-		else
-			return;
-	}
+	unsigned int i;
 
-	for (j = 0; j < n; ++j)
-		regs->areg[reg[i + j]] = args[j];
+	for (i = 0; i < 6; ++i)
+		regs->areg[reg[i]] = args[i];
 }
 
 asmlinkage long xtensa_rt_sigreturn(struct pt_regs*);
diff --git a/include/asm-generic/syscall.h b/include/asm-generic/syscall.h
index 269e9412ef42..b88239e9efe4 100644
--- a/include/asm-generic/syscall.h
+++ b/include/asm-generic/syscall.h
@@ -120,21 +120,15 @@ 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);
 
 /**
-- 
2.20.1

Re: [PATCH 1/6 v3] ptrace: Remove maxargs from task_current_syscall()

[Thomas Gleixner]

On Mon, 1 Apr 2019, Steven Rostedt wrote:

> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> 
> task_current_syscall() has a single user that passes in 6 for maxargs, which
> is the maximum arguments that can be used to get system calls from
> syscall_get_arguments(). Instead of passing in a number of arguments to
> grab, just get 6 arguments. The args argument even specifies that it's an
> array of 6 items.
> 
> This will also allow changing syscall_get_arguments() to not get a variable
> number of arguments, but always grab 6.
> 
> Linus also suggested not passing in a bunch of arguments to
> task_current_syscall() but to instead pass in a pointer to a structure, and
> just fill the structure. struct seccomp_data has almost all the parameters
> that is needed except for the stack pointer (sp). As seccomp_data is part of
> uapi, and I'm afraid to change it, a new structure was created
> "syscall_info", which includes seccomp_data and adds the "sp" field.
> 
> Link: http://lkml.kernel.org/r/20161107213233.466776454@goodmis.org
> 
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Alexey Dobriyan <adobriyan@gmail.com>
> Cc: Oleg Nesterov <oleg@redhat.com>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> Cc: linux-fsdevel@vger.kernel.org
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

Re: [PATCH 5/6 v3] syscalls: Remove start and number from syscall_get_arguments() args

[Thomas Gleixner]

On Mon, 1 Apr 2019, Steven Rostedt wrote:

> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> 
> 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

For x86:

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

Re: [PATCH 6/6 v3] syscalls: Remove start and number from syscall_set_arguments() args

[Thomas Gleixner]

On Mon, 1 Apr 2019, 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

For x86:

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

Re: [PATCH 0/6 v3] sycalls: Remove args i and n from syscall_get_arguments()

[Steven Rostedt]

On Mon, 01 Apr 2019 09:41:04 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> [ Looking for acks ]
> 

I got a couple.

> Two and a half years ago I sent out 3 patches and a title letter that
> had this[1]:

Linus,

Is this something that can go into this -rc release or would you want
me to wait till the next merge window?

The reason I ask, is that there's two arch patches in this series that
have stable tags attached to them. But I moved things around such that
they are applied before the global arch patches are and can be applied
independently.

Should I move those two patches up front and just add those to this
release cycle, or would you like the entire series now?

-- Steve


> ----
>  arch/arc/include/asm/syscall.h        |   7 +-
>  arch/arm/include/asm/syscall.h        |  47 ++---------
>  arch/arm64/include/asm/syscall.h      |  46 ++---------
>  arch/c6x/include/asm/syscall.h        |  79 ++++---------------
>  arch/csky/include/asm/syscall.h       |  26 ++-----
>  arch/h8300/include/asm/syscall.h      |  34 ++------
>  arch/hexagon/include/asm/syscall.h    |   4 +-
>  arch/ia64/include/asm/syscall.h       |  13 +---
>  arch/ia64/kernel/ptrace.c             |   7 +-
>  arch/microblaze/include/asm/syscall.h |   8 +-
>  arch/mips/include/asm/syscall.h       |   3 +-
>  arch/mips/kernel/ptrace.c             |   2 +-
>  arch/nds32/include/asm/syscall.h      |  62 +++------------
>  arch/nios2/include/asm/syscall.h      |  84 ++++----------------
>  arch/openrisc/include/asm/syscall.h   |  12 +--
>  arch/parisc/include/asm/syscall.h     |  30 ++-----
>  arch/powerpc/include/asm/syscall.h    |  15 ++--
>  arch/riscv/include/asm/syscall.h      |  24 ++----
>  arch/s390/include/asm/syscall.h       |  28 +++----
>  arch/sh/include/asm/syscall_32.h      |  47 +++--------
>  arch/sh/include/asm/syscall_64.h      |   8 +-
>  arch/sparc/include/asm/syscall.h      |  11 ++-
>  arch/um/include/asm/syscall-generic.h |  78 +++----------------
>  arch/x86/include/asm/syscall.h        | 142 ++++++++--------------------------
>  arch/xtensa/include/asm/syscall.h     |  33 ++------
>  fs/proc/base.c                        |  17 ++--
>  include/asm-generic/syscall.h         |  21 ++---
>  include/linux/ptrace.h                |  11 ++-
>  include/trace/events/syscalls.h       |   2 +-
>  kernel/seccomp.c                      |   2 +-
>  kernel/trace/trace_syscalls.c         |   9 ++-
>  lib/syscall.c                         |  57 ++++++--------
>  32 files changed, 247 insertions(+), 722 deletions(-)

Re: [PATCH 4/6 v3] csky: Fix syscall_get_arguments() and syscall_set_arguments()

[Dmitry V. Levin]

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On Mon, Apr 01, 2019 at 09:41:08AM -0400, Steven Rostedt wrote:
> From: "Dmitry V. Levin" <ldv@altlinux.org>
> 
> C-SKY syscall arguments are located in orig_a0,a1,a2,a3,regs[0],regs[1]
> fields of struct pt_regs.
> 
> Due to an off-by-one bug and a bug in pointer arithmetic
> syscall_get_arguments() was reading orig_a0,regs[1..5] fields instead.
> Likewise, syscall_set_arguments() was writing orig_a0,regs[1..5] fields
> instead.
> 
> Link: http://lkml.kernel.org/r/20190329171230.GB32456@altlinux.org
> 
> Fixes: 4859bfca11c7d ("csky: System Call")
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Will Drewry <wad@chromium.org>
> Cc: Guo Ren <guoren@kernel.org>
> Cc: stable@vger.kernel.org # v4.20+
> Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

According to
https://lore.kernel.org/lkml/20190330004949.GA15705@guoren-Inspiron-7460/
the following tags could be added to this patch:

Tested-by: Guo Ren <ren_guo@c-sky.com>
Acked-by: Guo Ren <ren_guo@c-sky.com>


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Re: [PATCH 3/6 v3] riscv: Fix syscall_get_arguments() and syscall_set_arguments()

[Dmitry V. Levin]

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On Mon, Apr 01, 2019 at 09:41:07AM -0400, Steven Rostedt wrote:
> From: "Dmitry V. Levin" <ldv@altlinux.org>
> 
> RISC-V syscall arguments are located in orig_a0,a1..a5 fields
> of struct pt_regs.
> 
> Due to an off-by-one bug and a bug in pointer arithmetic
> syscall_get_arguments() was reading s3..s7 fields instead of a1..a5.
> Likewise, syscall_set_arguments() was writing s3..s7 fields
> instead of a1..a5.
> 
> Link: http://lkml.kernel.org/r/20190329171221.GA32456@altlinux.org
> 
> Fixes: e2c0cdfba7f69 ("RISC-V: User-facing API")
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Andy Lutomirski <luto@amacapital.net>
> Cc: Will Drewry <wad@chromium.org>
> Cc: Palmer Dabbelt <palmer@sifive.com>
> Cc: Albert Ou <aou@eecs.berkeley.edu>
> Cc: linux-riscv@lists.infradead.org
> Cc: stable@vger.kernel.org # v4.15+
> Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

According to
https://lore.kernel.org/lkml/mhng-8e9b547b-7fe3-43d2-9dea-b217de923605@palmer-si-x1c4/
the following tag could be added to this patch:
 
Acked-by: Palmer Dabbelt <palmer@sifive.com>


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Re: [PATCH 3/6 v3] riscv: Fix syscall_get_arguments() and syscall_set_arguments()

[Steven Rostedt]

On Thu, 4 Apr 2019 17:02:10 +0300
"Dmitry V. Levin" <ldv@altlinux.org> wrote:

> On Mon, Apr 01, 2019 at 09:41:07AM -0400, Steven Rostedt wrote:
> > From: "Dmitry V. Levin" <ldv@altlinux.org>
> > 
> > RISC-V syscall arguments are located in orig_a0,a1..a5 fields
> > of struct pt_regs.
> > 
> > Due to an off-by-one bug and a bug in pointer arithmetic
> > syscall_get_arguments() was reading s3..s7 fields instead of a1..a5.
> > Likewise, syscall_set_arguments() was writing s3..s7 fields
> > instead of a1..a5.
> > 
> > Link: http://lkml.kernel.org/r/20190329171221.GA32456@altlinux.org
> > 
> > Fixes: e2c0cdfba7f69 ("RISC-V: User-facing API")
> > Cc: Ingo Molnar <mingo@redhat.com>
> > Cc: Kees Cook <keescook@chromium.org>
> > Cc: Andy Lutomirski <luto@amacapital.net>
> > Cc: Will Drewry <wad@chromium.org>
> > Cc: Palmer Dabbelt <palmer@sifive.com>
> > Cc: Albert Ou <aou@eecs.berkeley.edu>
> > Cc: linux-riscv@lists.infradead.org
> > Cc: stable@vger.kernel.org # v4.15+
> > Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
> > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>  
> 
> According to
> https://lore.kernel.org/lkml/mhng-8e9b547b-7fe3-43d2-9dea-b217de923605@palmer-si-x1c4/
> the following tag could be added to this patch:
>  
> Acked-by: Palmer Dabbelt <palmer@sifive.com>

That link isn't actually an ack. Palmer, you OK if I add it?

-- Steve

Re: [PATCH 4/6 v3] csky: Fix syscall_get_arguments() and syscall_set_arguments()

[Steven Rostedt]

On Thu, 4 Apr 2019 17:02:01 +0300
"Dmitry V. Levin" <ldv@altlinux.org> wrote:
> According to
> https://lore.kernel.org/lkml/20190330004949.GA15705@guoren-Inspiron-7460/
> the following tags could be added to this patch:
> 
> Tested-by: Guo Ren <ren_guo@c-sky.com>
> Acked-by: Guo Ren <ren_guo@c-sky.com>

Thanks! Added.

-- Steve

Re: [PATCH 5/6 v3] syscalls: Remove start and number from syscall_get_arguments() args

[Dmitry V. Levin]

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On Mon, Apr 01, 2019 at 09:41:09AM -0400, Steven Rostedt wrote:
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> 
> 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

FWIW, you can add
Reviewed-by: Dmitry V. Levin <ldv@altlinux.org>

There are several places listed below where I'd prefer to see more readable
equivalents, but feel free to leave it to respective arch maintainers.

> diff --git a/arch/hexagon/include/asm/syscall.h b/arch/hexagon/include/asm/syscall.h
> index 4af9c7b6f13a..ae3a1e24fabd 100644
> --- a/arch/hexagon/include/asm/syscall.h
> +++ b/arch/hexagon/include/asm/syscall.h
> @@ -37,10 +37,8 @@ static inline long syscall_get_nr(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);
> -	memcpy(args, &(&regs->r00)[i], n * sizeof(args[0]));
> +	memcpy(args, &(&regs->r00)[0], 6 * sizeof(args[0]));

A shorter and slightly more readable equivalent is

	memcpy(args, &regs->r00, 6 * sizeof(args[0]));

> diff --git a/arch/nds32/include/asm/syscall.h b/arch/nds32/include/asm/syscall.h
> index f7e5e86765fe..89a6ec8731d8 100644
> --- a/arch/nds32/include/asm/syscall.h
> +++ b/arch/nds32/include/asm/syscall.h
> @@ -108,42 +108,21 @@ void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
>   * syscall_get_arguments - extract system call parameter values
>   * @task:	task of interest, must be blocked
>   * @regs:	task_pt_regs() of @task
> - * @i:		argument index [0,5]
> - * @n:		number of arguments; n+i must be [1,6].
>   * @args:	array filled with argument values
>   *
> - * Fetches @n arguments to the system call starting with the @i'th argument
> - * (from 0 through 5).  Argument @i is stored in @args[0], and so on.
> - * An arch inline version is probably optimal when @i and @n are constants.
> + * Fetches 6 arguments to the system call (from 0 through 5). The first
> + * argument is stored in @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.
>   */
>  #define SYSCALL_MAX_ARGS 6
>  void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
> -			   unsigned int i, unsigned int n, unsigned long *args)
> +			   unsigned long *args)
>  {
> -	if (n == 0)
> -		return;
> -	if (i + n > SYSCALL_MAX_ARGS) {
> -		unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
> -		unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
> -		pr_warning("%s called with max args %d, handling only %d\n",
> -			   __func__, i + n, SYSCALL_MAX_ARGS);
> -		memset(args_bad, 0, n_bad * sizeof(args[0]));
> -		memset(args_bad, 0, n_bad * sizeof(args[0]));
> -	}
> -
> -	if (i == 0) {
> -		args[0] = regs->orig_r0;
> -		args++;
> -		i++;
> -		n--;
> -	}
> -
> -	memcpy(args, &regs->uregs[0] + i, n * sizeof(args[0]));
> +	args[0] = regs->orig_r0;
> +	args++;
> +	memcpy(args, &regs->uregs[0] + 1, 5 * sizeof(args[0]));
>  }

A shorter and slightly more readable equivalent of the last memcpy is

	memcpy(args, &regs->uregs[1], 5 * sizeof(args[0]));

> diff --git a/arch/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h
> index 1a0e7a8b1c81..5c9b9dc82b7e 100644
> --- a/arch/powerpc/include/asm/syscall.h
> +++ b/arch/powerpc/include/asm/syscall.h
> @@ -65,22 +65,20 @@ 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)
>  {
>  	unsigned long val, mask = -1UL;
> -
> -	BUG_ON(i + n > 6);
> +	unsigned int n = 6;
>  
>  #ifdef CONFIG_COMPAT
>  	if (test_tsk_thread_flag(task, TIF_32BIT))
>  		mask = 0xffffffff;
>  #endif
>  	while (n--) {
> -		if (n == 0 && i == 0)
> +		if (n == 0)
>  			val = regs->orig_gpr3;
>  		else
> -			val = regs->gpr[3 + i + n];
> +			val = regs->gpr[3 + n];
>  
>  		args[n] = val & mask;
>  	}

A shorter and slightly more readable equivalent of the loop is

	while (--n)
		args[n] = regs->gpr[3 + n] & mask;
	args[0] = regs->orig_gpr3 & mask;

> diff --git a/arch/s390/include/asm/syscall.h b/arch/s390/include/asm/syscall.h
> index 96f9a9151fde..ee0b1f6aa36d 100644
> --- a/arch/s390/include/asm/syscall.h
> +++ b/arch/s390/include/asm/syscall.h
> @@ -56,27 +56,20 @@ 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)
>  {
>  	unsigned long mask = -1UL;
> +	unsigned int n = 6;
>  
> -	/*
> -	 * No arguments for this syscall, there's nothing to do.
> -	 */
> -	if (!n)
> -		return;
> -
> -	BUG_ON(i + n > 6);
>  #ifdef CONFIG_COMPAT
>  	if (test_tsk_thread_flag(task, TIF_31BIT))
>  		mask = 0xffffffff;
>  #endif
>  	while (n-- > 0)
> -		if (i + n > 0)
> -			args[n] = regs->gprs[2 + i + n] & mask;
> -	if (i == 0)
> -		args[0] = regs->orig_gpr2 & mask;
> +		if (n > 0)
> +			args[n] = regs->gprs[2 + n] & mask;
> +
> +	args[0] = regs->orig_gpr2 & mask;

A shorter and slightly more readable equivalent of the loop is

	while (--n > 0)
		args[n] = regs->gprs[2 + n] & mask;


-- 
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Re: [PATCH 6/6 v3] syscalls: Remove start and number from syscall_set_arguments() args

[Dmitry V. Levin]

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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 <ldv@altlinux.org>
 
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.

> 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(&regs->uregs[0] + i, args, n * sizeof(args[0]));
> +	memcpy(&regs->uregs[0] + 1, args, 5 * sizeof(args[0]));
>  }

A shorter and slightly more readable equivalent of the last memcpy is

	memcpy(&regs->uregs[1], args, 5 * sizeof(args[0]));

> 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];


-- 
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Re: [PATCH 6/6 v3] syscalls: Remove start and number from syscall_set_arguments() args

[Max Filippov]

On Mon, Apr 1, 2019 at 6:45 AM Steven Rostedt <rostedt@goodmis.org> 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().

[...]

>  arch/xtensa/include/asm/syscall.h     | 17 ++-----

For xtensa changes:
Acked-by: Max Filippov <jcmvbkbc@gmail.com>

-- 
Thanks.
-- Max

Re: [PATCH 5/6 v3] syscalls: Remove start and number from syscall_get_arguments() args

[Max Filippov]

On Mon, Apr 1, 2019 at 6:45 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
>
> 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.

[...]

>  arch/xtensa/include/asm/syscall.h     | 16 ++----

For xtensa changes:
Acked-by: Max Filippov <jcmvbkbc@gmail.com>

-- 
Thanks.
-- Max

Re: [PATCH 5/6 v3] syscalls: Remove start and number from syscall_get_arguments() args

[Steven Rostedt]

On Thu, 4 Apr 2019 21:17:58 +0300
"Dmitry V. Levin" <ldv@altlinux.org> wrote:

> There are several places listed below where I'd prefer to see more readable
> equivalents, but feel free to leave it to respective arch maintainers.

I was going to do similar changes, but figured I'd do just that (let
the arch maintainers further optimize the code). I made this more about
fixing the interface and less about the optimization and clean ups that
it can allow.

-- Steve

Re: [PATCH 3/6 v3] riscv: Fix syscall_get_arguments() and syscall_set_arguments()

[Palmer Dabbelt]

On Thu, 04 Apr 2019 07:26:53 PDT (-0700), rostedt@goodmis.org wrote:
> On Thu, 4 Apr 2019 17:02:10 +0300
> "Dmitry V. Levin" <ldv@altlinux.org> wrote:
>
>> On Mon, Apr 01, 2019 at 09:41:07AM -0400, Steven Rostedt wrote:
>> > From: "Dmitry V. Levin" <ldv@altlinux.org>
>> >
>> > RISC-V syscall arguments are located in orig_a0,a1..a5 fields
>> > of struct pt_regs.
>> >
>> > Due to an off-by-one bug and a bug in pointer arithmetic
>> > syscall_get_arguments() was reading s3..s7 fields instead of a1..a5.
>> > Likewise, syscall_set_arguments() was writing s3..s7 fields
>> > instead of a1..a5.
>> >
>> > Link: http://lkml.kernel.org/r/20190329171221.GA32456@altlinux.org
>> >
>> > Fixes: e2c0cdfba7f69 ("RISC-V: User-facing API")
>> > Cc: Ingo Molnar <mingo@redhat.com>
>> > Cc: Kees Cook <keescook@chromium.org>
>> > Cc: Andy Lutomirski <luto@amacapital.net>
>> > Cc: Will Drewry <wad@chromium.org>
>> > Cc: Palmer Dabbelt <palmer@sifive.com>
>> > Cc: Albert Ou <aou@eecs.berkeley.edu>
>> > Cc: linux-riscv@lists.infradead.org
>> > Cc: stable@vger.kernel.org # v4.15+
>> > Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
>> > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
>>
>> According to
>> https://lore.kernel.org/lkml/mhng-8e9b547b-7fe3-43d2-9dea-b217de923605@palmer-si-x1c4/
>> the following tag could be added to this patch:
>>
>> Acked-by: Palmer Dabbelt <palmer@sifive.com>
>
> That link isn't actually an ack. Palmer, you OK if I add it?

Acked-by: Palmer Dabbelt <palmer@sifive.com> (for the RISC-V parts)

Thanks!

Re: [PATCH 0/6 v3] sycalls: Remove args i and n from syscall_get_arguments()

[Linus Torvalds]

On Thu, Apr 4, 2019 at 3:28 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> Is this something that can go into this -rc release or would you want
> me to wait till the next merge window?
>
> The reason I ask, is that there's two arch patches in this series that
> have stable tags attached to them. But I moved things around such that
> they are applied before the global arch patches are and can be applied
> independently.
>
> Should I move those two patches up front and just add those to this
> release cycle, or would you like the entire series now?

I think I can take the entire series. It's removing code and fixing a
couple of bugs in the process. Even if not all changes are pure fixes,
it looks good to me.

I assume you've actually used this and can trace system calls with
arguments properly, so that it's all tested at least on x86-64?

                    Linus

Re: [PATCH 0/6 v3] sycalls: Remove args i and n from syscall_get_arguments()

[Will Deacon]

On Mon, Apr 01, 2019 at 09:41:04AM -0400, Steven Rostedt wrote:
> [ Looking for acks ]

For the arm64 bits:

Acked-by: Will Deacon <will.deacon@arm.com>

Will

Re: [PATCH 0/6 v3] sycalls: Remove args i and n from syscall_get_arguments()

[Steven Rostedt]

On Thu, 4 Apr 2019 15:24:16 -1000
Linus Torvalds <torvalds@linux-foundation.org> wrote:


> I assume you've actually used this and can trace system calls with
> arguments properly, so that it's all tested at least on x86-64?
>

Yep, and even tested it against strace. Looks fine. I also ran it
through my entire ftrace test suite (takes around 10 hours or more),
and it all passed.

I'll collect the last bit of acks and then send you a pull request.

-- Steve