parisc: split syscall_trace into two halves

Instead of fiddling with gr[20], restructure code to return whether
or not to -ENOSYS. (Also do a bit of fiddling to let them take
pt_regs directly instead of re-computing it.)

Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>

diff --git a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c
index 2118ed0..08f6d2c 100644 (file)
--- a/arch/parisc/kernel/ptrace.c
+++ b/arch/parisc/kernel/ptrace.c
@@ -264,20 +264,19 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 }
 #endif
 
+long do_syscall_trace_enter(struct pt_regs *regs)
+{
+       if (test_thread_flag(TIF_SYSCALL_TRACE) &&
+           tracehook_report_syscall_entry(regs))
+               return -1L;
+
+       return regs->gr[20];
+}
 
-void syscall_trace(int why)
+void do_syscall_trace_exit(struct pt_regs *regs)
 {
-       struct pt_regs *regs = &current->thread.regs;
+       int stepping = !!(current->ptrace & (PT_SINGLESTEP|PT_BLOCKSTEP));
 
-       if (!test_thread_flag(TIF_SYSCALL_TRACE))
-               return;
-       /*
-        * Report the system call for tracing.  Entry tracing can
-        * decide to abort the call.  We handle that by setting an
-        * invalid syscall number (-1) to force an ENOSYS error.
-        */
-       if (why)
-               tracehook_report_syscall_exit(regs, 0);
-       else if (tracehook_report_syscall_entry(regs))
-               regs->gr[20] = -1;      /* force ENOSYS */
+       if (stepping || test_thread_flag(TIF_SYSCALL_TRACE))
+               tracehook_report_syscall_exit(regs, stepping);
 }

diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S
index 07de1bb..f5f9602 100644 (file)
--- a/arch/parisc/kernel/syscall.S
+++ b/arch/parisc/kernel/syscall.S
@@ -288,19 +288,23 @@ tracesys:
        STREG   %r18,PT_GR18(%r2)
        /* Finished saving things for the debugger */
 
-       ldi     0,%r26                          /* syscall entry */
-       ldil    L%syscall_trace,%r1
+       copy    %r2,%r26
+       ldil    L%do_syscall_trace_enter,%r1
        ldil    L%tracesys_next,%r2
-       be      R%syscall_trace(%sr7,%r1)
+       be      R%do_syscall_trace_enter(%sr7,%r1)
        ldo     R%tracesys_next(%r2),%r2
        
-tracesys_next: 
+tracesys_next:
+       /* do_syscall_trace_enter either returned the syscallno, or -1L,
+        *  so we skip restoring the PT_GR20 below, since we pulled it from
+        *  task->thread.regs.gr[20] above.
+        */
+       copy    %ret0,%r20
        ldil    L%sys_call_table,%r1
        ldo     R%sys_call_table(%r1), %r19
 
        ldo     -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1      /* get task ptr */
        LDREG   TI_TASK(%r1), %r1
-       LDREG   TASK_PT_GR20(%r1), %r20
        LDREG   TASK_PT_GR26(%r1), %r26         /* Restore the users args */
        LDREG   TASK_PT_GR25(%r1), %r25
        LDREG   TASK_PT_GR24(%r1), %r24
@@ -337,8 +341,8 @@ tracesys_exit:
 #ifdef CONFIG_64BIT
        ldo     -16(%r30),%r29                  /* Reference param save area */
 #endif
-       ldi     1,%r26                          /* syscall exit */
-       bl      syscall_trace, %r2
+       ldo     TASK_REGS(%r1),%r26
+       bl      do_syscall_trace_exit,%r2
        STREG   %r28,TASK_PT_GR28(%r1)          /* save return value now */
        ldo     -THREAD_SZ_ALGN-FRAME_SIZE(%r30),%r1      /* get task ptr */
        LDREG   TI_TASK(%r1), %r1
@@ -359,8 +363,8 @@ tracesys_sigexit:
 #ifdef CONFIG_64BIT
        ldo     -16(%r30),%r29                  /* Reference param save area */
 #endif
-       bl      syscall_trace, %r2
-       ldi     1,%r26                          /* syscall exit */
+       bl      do_syscall_trace_exit,%r2
+       ldo     TASK_REGS(%r1),%r26
 
        ldil    L%syscall_exit_rfi,%r1
        be,n    R%syscall_exit_rfi(%sr7,%r1)