syscalls: Remove start and number from syscall_get_arguments() args

At Linux Plumbers, Andy Lutomirski approached me and pointed out that the
function call syscall_get_arguments() implemented in x86 was horribly
written and not optimized for the standard case of passing in 0 and 6 for
the starting index and the number of system calls to get. When looking at
all the users of this function, I discovered that all instances pass in only
0 and 6 for these arguments. Instead of having this function handle
different cases that are never used, simply rewrite it to return the first 6
arguments of a system call.

This should help out the performance of tracing system calls by ptrace,
ftrace and perf.

Link: http://lkml.kernel.org/r/20161107213233.754809394@goodmis.org
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Dave Martin <dave.martin@arm.com>
Cc: "Dmitry V. Levin" <ldv@altlinux.org>
Cc: x86@kernel.org
Cc: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: uclinux-h8-devel@lists.sourceforge.jp
Cc: linux-hexagon@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: nios2-dev@lists.rocketboards.org
Cc: openrisc@lists.librecores.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linux-um@lists.infradead.org
Cc: linux-xtensa@linux-xtensa.org
Cc: linux-arch@vger.kernel.org
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS parts
Acked-by: Max Filippov <jcmvbkbc@gmail.com> # For xtensa changes
Acked-by: Will Deacon <will.deacon@arm.com> # For the arm64 bits
Reviewed-by: Thomas Gleixner <tglx@linutronix.de> # for x86
Reviewed-by: Dmitry V. Levin <ldv@altlinux.org>
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/arch/arc/include/asm/syscall.h b/arch/arc/include/asm/syscall.h
index 29de098043064a20112dd7ffd02f86059261ae44..c7a4201ed62ba70f9f37275475be215b0e7fb6d1 100644 (file)
--- 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 06dea6bce293b934e1146d26aa316ea8e36e80b5..db969a2972aedbb767fc9797c999cba5e7fd7248 100644 (file)
--- 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 ad8be16a39c9d18bdbd406f522c02432529c4cf6..55b2dab21023428bdc2d1763948b2c04e523988b 100644 (file)
--- 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 ae2be315ee9c98d8440f4409be8b67cc261f8858..06db3251926b9ba93e126be167c3e21a00d38e1b 100644 (file)
--- 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 9a9cd81e66c1157c2df53e1ff350569b2d87dcb2..c691fe92edc6efdae78b02254df30b9b76dfe588 100644 (file)
--- 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 924990401237126585ea8fd105e4b57e8f9e5b24..ddd483c6ca95c9df50e9ed7b8c820c9884afcbeb 100644 (file)
--- 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 4af9c7b6f13af9490e4bee7b9f608c7d467cecb3..ae3a1e24fabd7193ff7d3dc142c4ca7d123f56e6 100644 (file)
--- 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 1d0b875fec44fc0fd8a70876e8ee6191f66f6005..8204c1ff70ce4829faf5f98b751c546f5d7a0106 100644 (file)
--- 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 220decd605a4aded46a99b445e54bf27c4adc821..4b23e44e5c3c069a59361ea0109c4a7f8b7943e2 100644 (file)
--- 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 6cf8ffb5367ec3fb725aac26c701d0ae5d81923c..a2b4748655df4d1466d037b971855c8046c589e8 100644 (file)
--- 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 0057c910bc2f34de0f518c43d2e234c845db0da1..3a62f80958e170527a93f4058d60f5372d5773ee 100644 (file)
--- 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 f7e5e86765fe8efe51283d7c350a6a4ab8b73863..89a6ec8731d8bd84cb5ad0b9447c5540eba5f839 100644 (file)
--- 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 9de220854c4ad88f43ea579cbcf51c250cb6e688..792bd449d83940abf53bc45fed700cf828e13dc6 100644 (file)
--- 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 2db9f1cf0694c0f2c6bdaec77953f62fb4fe6372..72607860cd559b835c39d34d55eaabeb1c496cce 100644 (file)
--- 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 8bff1a58c97f1b107dabf79e172f5ecb56c5db2d..62a6d477fae0197cdba9d62044e31104f1b05192 100644 (file)
--- 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 1a0e7a8b1c811cf5d089c5ac68eb96d189ad702d..5c9b9dc82b7ea8fc1c6546e5d9f113b16a7a9837 100644 (file)
--- 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 6ea9e180423318a18fd1957bacbf393b13d6c55b..6adca1804be1063638e26225aba6290d0ae3a997 100644 (file)
--- 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 96f9a9151fde02fc6f76633d76d292f47512d364..ee0b1f6aa36d3b769b3ce58403a5428e5e7e30b0 100644 (file)
--- 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 6e118799831c32dc37b8cf21960d284c5bec3646..2bf1199a05953642bd95808b554e33124b86fbef 100644 (file)
--- 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 43882580c7f99bec93e519f1b4182c1daad2fbf0..4e8f6460c703c4ec19466aa3b66e03e36ad6c8b4 100644 (file)
--- 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 053989e3f6a6f1435323873ea010723ac09736bd..872dfee852d640d308c1fa45f19881b906d4d37e 100644 (file)
--- 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 9fb9cf8cd39a3b29f45a80d1a4281d2abd82a262..25d00acd1322cf5152e971b201d04d12aee1e4b4 100644 (file)
--- 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 d653139857af2a1121f877b611c8d56d4e4690f0..8dbb5c379450be0bcf0338f3638ac530a611f7ec 100644 (file)
--- 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 a168bf81c7f4701a036abaa251fa5dce7fad6c19..1504ce9a233ad5228e2baac62c94f5a4ec8deace 100644 (file)
--- 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 0c938a4354f6f58f67e0bb3555dca24460afadb7..269e9412ef4210465f35e890a438b041948c34e3 100644 (file)
--- 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 44a3259ed4a5bde50e231a982624b0893e5bb0eb..b6e0cbc2c71f16df87380860e88544acb6d80a40 100644 (file)
--- 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 54a0347ca8128f09cdbbcc83e2e8f8eea633a7ab..df27e499956a1a5a816fd31081c15292cdeb6777 100644 (file)
--- 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 e9f5bbbad6d94cf1e6c3ee284b79e2a86c897cda..fa8fbff736d684734e89f05fb149c4e83436d8f4 100644 (file)
--- 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 e8467e17b9a20b049922f37d418de69275e991a1..fb328e7ccb0893136e949f3581cc8b647f414de2 100644 (file)
--- 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);