aarch64: Improve syscall-cancel stack frame

One push instead of N; use stp/ldp to halve the insns.

diff --git a/ChangeLog b/ChangeLog
index 3a20a65..26812de 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,15 @@
 2014-05-29  Richard Henderson  <rth@twiddle.net>
 
+       * sysdeps/unix/sysv/linux/aarch64/nptl/sysdep-cancel.h (PSEUDO):
+       Always allocate 64 bytes of stack frame.  Use ldp/stp to create
+       it and break it down.
+       (DOCARGS_0, DOCARGS_1): Do nothing.
+       (DOCARGS_2): Update to store into the new stack frame.
+       (DOCARGS_3, DOCARGS_4, DOCARGS_5, DOCARGS_6): Likewise.
+       (UNDOCARGS_1): Update to restore from the new stack frame.
+       (UNDOCARGS_2, UNDOCARGS_3, UNDOCARGS_4): Likewise.
+       (UNDOCARGS_5, UNDOCARGS_6): Likewise.
+
        * sysdeps/unix/sysv/linux/aarch64/nptl/sysdep-cancel.h
        (SINGLE_THREAD_P): New parameter for result regno.
        (PSEUDO): Update to match; use cbz instead of beq.

diff --git a/sysdeps/unix/sysv/linux/aarch64/nptl/sysdep-cancel.h b/sysdeps/unix/sysv/linux/aarch64/nptl/sysdep-cancel.h
index bdb5c73..0f5bb51 100644 (file)
--- a/sysdeps/unix/sysv/linux/aarch64/nptl/sysdep-cancel.h
+++ b/sysdeps/unix/sysv/linux/aarch64/nptl/sysdep-cancel.h
@@ -38,20 +38,22 @@ ENTRY (__##syscall_name##_nocancel);                                        \
 ENTRY (name);                                                          \
        SINGLE_THREAD_P(16);                                            \
        cbz     w16, .Lpseudo_nocancel;                                 \
-       DOCARGS_##args; /* save syscall args etc. around CENABLE.  */   \
+       /* Setup common stack frame no matter the number of args.       \
+          Also save the first arg, since it's basically free.  */      \
+       stp     x30, x0, [sp, -64]!;                                    \
+       cfi_adjust_cfa_offset (64);                                     \
+       cfi_rel_offset (x30, 0);                                        \
+       DOCARGS_##args;         /* save syscall args around CENABLE.  */ \
        CENABLE;                                                        \
-       mov     x16, x0;        /* put mask in safe place.  */          \
+       mov     x16, x0;        /* save mask around syscall.  */        \
        UNDOCARGS_##args;       /* restore syscall args.  */            \
-       mov     x8, SYS_ify (syscall_name);     /* do the call.  */     \
-       svc     0;                                                      \
-       str     x0, [sp, -16]!; /* save syscall return value.  */       \
-       cfi_adjust_cfa_offset (16);                                     \
-       mov     x0, x16;         /* get mask back.  */                  \
+       DO_CALL (syscall_name, args);                                   \
+       str     x0, [sp, 8];    /* save result around CDISABLE.  */     \
+       mov     x0, x16;        /* restore mask for CDISABLE.  */       \
        CDISABLE;                                                       \
-       ldr     x0, [sp], 16;                                           \
-       cfi_adjust_cfa_offset (-16);                                    \
-       ldr     x30, [sp], 16;                                          \
-       cfi_adjust_cfa_offset (-16);                                    \
+       /* Break down the stack frame, restoring result at once.  */    \
+       ldp     x30, x0, [sp], 64;                                      \
+       cfi_adjust_cfa_offset (-64);                                    \
        cfi_restore (x30);                                              \
        b       .Lpseudo_finish;                                        \
        cfi_endproc;                                                    \
@@ -63,83 +65,21 @@ ENTRY (name);                                                               \
        SYSCALL_ERROR_HANDLER;                                          \
        cfi_endproc
 
-# define DOCARGS_0                                                     \
-       str x30, [sp, -16]!;                                            \
-       cfi_adjust_cfa_offset (16);                                     \
-       cfi_rel_offset (x30, 0)
+# define DOCARGS_0
+# define DOCARGS_1
+# define DOCARGS_2     str x1, [sp, 16]
+# define DOCARGS_3     stp x1, x2, [sp, 16]
+# define DOCARGS_4     DOCARGS_3; str x3, [sp, 32]
+# define DOCARGS_5     DOCARGS_3; stp x3, x4, [sp, 32]
+# define DOCARGS_6     DOCARGS_5; str x5, [sp, 48]
 
 # define UNDOCARGS_0
-
-# define DOCARGS_1                                                     \
-       DOCARGS_0;                                                      \
-       str x0, [sp, -16]!;                                             \
-       cfi_adjust_cfa_offset (16);                                     \
-       cfi_rel_offset (x0, 0)
-
-# define UNDOCARGS_1                                                   \
-       ldr x0, [sp], 16;                                               \
-       cfi_restore (x0);                                               \
-       cfi_adjust_cfa_offset (-16);                                    \
-
-# define DOCARGS_2                                                     \
-       DOCARGS_1;                                                      \
-       str x1, [sp, -16]!;                                             \
-       cfi_adjust_cfa_offset (16);                                     \
-       cfi_rel_offset (x1, 0)
-
-# define UNDOCARGS_2                                                   \
-       ldr x1, [sp], 16;                                               \
-       cfi_restore (x1);                                               \
-       cfi_adjust_cfa_offset (-16);                                    \
-       UNDOCARGS_1
-
-# define DOCARGS_3                                                     \
-       DOCARGS_2;                                                      \
-       str x2, [sp, -16]!;                                             \
-       cfi_adjust_cfa_offset (16);                                     \
-       cfi_rel_offset (x2, 0)
-
-# define UNDOCARGS_3                                                   \
-       ldr x2, [sp], 16;                                               \
-       cfi_restore (x2);                                               \
-       cfi_adjust_cfa_offset (-16);                                    \
-       UNDOCARGS_2
-
-# define DOCARGS_4                                                     \
-       DOCARGS_3;                                                      \
-       str x3, [sp, -16]!;                                             \
-       cfi_adjust_cfa_offset (16);                                     \
-       cfi_rel_offset (x3, 0)
-
-# define UNDOCARGS_4                                                   \
-       ldr x3, [sp], 16;                                               \
-       cfi_restore (x3);                                               \
-       cfi_adjust_cfa_offset (-16);                                    \
-       UNDOCARGS_3
-
-# define DOCARGS_5                                                     \
-       DOCARGS_4;                                                      \
-       str x4, [sp, -16]!;                                             \
-       cfi_adjust_cfa_offset (16);                                     \
-       cfi_rel_offset (x4, 0)
-
-# define UNDOCARGS_5                                                   \
-       ldr x4, [sp], 16;                                               \
-       cfi_restore (x4);                                               \
-       cfi_adjust_cfa_offset (-16);                                    \
-       UNDOCARGS_4
-
-# define DOCARGS_6                                                     \
-       DOCARGS_5;                                                      \
-       str x5, [sp, -16]!;                                             \
-       cfi_adjust_cfa_offset (16);                                     \
-       cfi_rel_offset (x5, 0)
-
-# define UNDOCARGS_6                                                   \
-       ldr x5, [sp], 16;                                               \
-       cfi_restore (x5);                                               \
-       cfi_adjust_cfa_offset (-16);                                    \
-       UNDOCARGS_5
+# define UNDOCARGS_1   ldr x0, [sp, 8]
+# define UNDOCARGS_2   ldp x0, x1, [sp, 8]
+# define UNDOCARGS_3   UNDOCARGS_1; ldp x1, x2, [sp, 16]
+# define UNDOCARGS_4   UNDOCARGS_2; ldp x2, x3, [sp, 24]
+# define UNDOCARGS_5   UNDOCARGS_3; ldp x3, x4, [sp, 32]
+# define UNDOCARGS_6   UNDOCARGS_4; ldp x4, x5, [sp, 40]
 
 # ifdef IS_IN_libpthread
 #  define CENABLE      bl __pthread_enable_asynccancel