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authorUlrich Drepper <drepper@redhat.com>2009-08-04 11:03:46 -0700
committerUlrich Drepper <drepper@redhat.com>2009-08-04 11:03:46 -0700
commit421665c40ae002f74130eb4e0b19cb22d97860cf (patch)
tree78e155aac7fd869030ddad548afbf9dfaed6df0c /nptl
parent4a1377672ca5472fac9096b4da72d26226b4aa59 (diff)
downloadglibc-421665c40ae002f74130eb4e0b19cb22d97860cf.zip
glibc-421665c40ae002f74130eb4e0b19cb22d97860cf.tar.gz
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Optimize x86-64 syscall cancellation handling.
The syscall wrappers had to save and restore the syscall parameter values and return value when calling the functions to enable/disable cancellation were called. Not anymore. The called functions are special and don't modify any unexpected registers.
Diffstat (limited to 'nptl')
-rw-r--r--nptl/ChangeLog12
-rw-r--r--nptl/sysdeps/unix/sysv/linux/x86_64/cancellation.S114
-rw-r--r--nptl/sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S22
-rw-r--r--nptl/sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S22
-rw-r--r--nptl/sysdeps/unix/sysv/linux/x86_64/sysdep-cancel.h55
-rw-r--r--nptl/sysdeps/x86_64/tcb-offsets.sym10
6 files changed, 191 insertions, 44 deletions
diff --git a/nptl/ChangeLog b/nptl/ChangeLog
index 3ebe841..3a74b5f 100644
--- a/nptl/ChangeLog
+++ b/nptl/ChangeLog
@@ -1,3 +1,15 @@
+2009-08-04 Ulrich Drepper <drepper@redhat.com>
+
+ * sysdeps/unix/sysv/linux/x86_64/cancellation.S: New file.
+ * sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S: New file.
+ * sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S: New file.
+ * sysdeps/unix/sysv/linux/x86_64/sysdep-cancel.h (PSEUDO): Optimize
+ since we can assume the special __*_{en,dis}able_asynccancel
+ functions.
+ (PUSHARGS_*, POPARGS_*, SAVESTK_*, RESTSTK_*): Removed.
+ * sysdeps/x86_64/tcb-offsets.sym: Add cancellation-related bits
+ and PTHREAD_CANCELED.
+
2009-07-31 Ulrich Drepper <drepper@redhat.com>
* descr.h: Better definition of *_BITMASK macros for cancellation.
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/cancellation.S b/nptl/sysdeps/unix/sysv/linux/x86_64/cancellation.S
new file mode 100644
index 0000000..a51df3e
--- /dev/null
+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/cancellation.S
@@ -0,0 +1,114 @@
+/* Copyright (C) 2009 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2009.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <sysdep.h>
+#include <tcb-offsets.h>
+#include <kernel-features.h>
+
+#ifdef IS_IN_libpthread
+# ifdef SHARED
+# define __pthread_unwind __GI___pthread_unwind
+# endif
+#else
+# ifndef SHARED
+ .weak __pthread_unwind
+# endif
+#endif
+
+
+#ifdef __ASSUME_PRIVATE_FUTEX
+# define LOAD_PRIVATE_FUTEX_WAIT(reg) \
+ movl $(FUTEX_WAIT | FUTEX_PRIVATE_FLAG), reg
+#else
+# if FUTEX_WAIT == 0
+# define LOAD_PRIVATE_FUTEX_WAIT(reg) \
+ movl %fs:PRIVATE_FUTEX, reg
+# else
+# define LOAD_PRIVATE_FUTEX_WAIT(reg) \
+ movl %fs:PRIVATE_FUTEX, reg ; \
+ orl $FUTEX_WAIT, reg
+# endif
+#endif
+
+/* It is crucial that the functions in this file don't modify registers
+ other than %rax and %r11. The syscall wrapper code depends on this
+ because it doesn't explicitly save the other registers which hold
+ relevant values. */
+ .text
+
+ .hidden __pthread_enable_asynccancel
+ENTRY(__pthread_enable_asynccancel)
+ movl %fs:CANCELHANDLING, %eax
+2: movl %eax, %r11d
+ orl $TCB_CANCELTYPE_BITMASK, %r11d
+ cmpl %eax, %r11d
+ je 1f
+
+ lock
+ cmpxchgl %r11d, %fs:CANCELHANDLING
+ jnz 2b
+
+ andl $(TCB_CANCELSTATE_BITMASK|TCB_CANCELTYPE_BITMASK|TCB_CANCELED_BITMASK|TCB_EXITING_BITMASK|TCB_CANCEL_RESTMASK|TCB_TERMINATED_BITMASK), %r11d
+ cmpl $(TCB_CANCELTYPE_BITMASK|TCB_CANCELED_BITMASK), %r11d
+ je 3f
+
+1: ret
+
+3: movq $TCB_PTHREAD_CANCELED, %fs:RESULT
+ lock
+ orl $TCB_EXITING_BITMASK, %fs:CANCELHANDLING
+ movq %fs:CLEANUP_JMP_BUF, %rdi
+#ifdef SHARED
+ call __pthread_unwind@PLT
+#else
+ call __pthread_unwind
+#endif
+ hlt
+END(__pthread_enable_asynccancel)
+
+
+ .hidden __pthread_disable_asynccancel
+ENTRY(__pthread_disable_asynccancel)
+ testl $TCB_CANCELTYPE_BITMASK, %edi
+ jnz 1f
+
+ movl %fs:CANCELHANDLING, %eax
+2: movl %eax, %r11d
+ andl $~TCB_CANCELTYPE_BITMASK, %r11d
+ lock
+ cmpxchgl %r11d, %fs:CANCELHANDLING
+ jnz 2b
+
+3: movl %r11d, %eax
+ andl $(TCB_CANCELING_BITMASK|TCB_CANCELED_BITMASK), %eax
+ cmpl $TCB_CANCELING_BITMASK, %eax
+ je 4f
+1: ret
+
+ /* Performance doesn't matter in this loop. We will
+ delay until the thread is canceled. And we will unlikely
+ enter the loop twice. */
+4: movq %fs:0, %rdi
+ movl $__NR_futex, %eax
+ xorq %r10, %r10
+ addq $CANCELHANDLING, %rdi
+ LOAD_PRIVATE_FUTEX_WAIT (%esi)
+ syscall
+ jmp 3b
+END(__pthread_disable_asynccancel)
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S b/nptl/sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S
new file mode 100644
index 0000000..1100588
--- /dev/null
+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S
@@ -0,0 +1,22 @@
+/* Copyright (C) 2009 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2009.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#define __pthread_enable_asynccancel __libc_enable_asynccancel
+#define __pthread_disable_asynccancel __libc_disable_asynccancel
+#include "cancellation.S"
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S b/nptl/sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S
new file mode 100644
index 0000000..ce4192b
--- /dev/null
+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S
@@ -0,0 +1,22 @@
+/* Copyright (C) 2009 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2009.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#define __pthread_enable_asynccancel __librt_enable_asynccancel
+#define __pthread_disable_asynccancel __librt_disable_asynccancel
+#include "cancellation.S"
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/sysdep-cancel.h b/nptl/sysdeps/unix/sysv/linux/x86_64/sysdep-cancel.h
index 3e741da..1e92de1 100644
--- a/nptl/sysdeps/unix/sysv/linux/x86_64/sysdep-cancel.h
+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/sysdep-cancel.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+/* Copyright (C) 2002-2006, 2009 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek <jakub@redhat.com>, 2002.
@@ -25,6 +25,10 @@
#if !defined NOT_IN_libc || defined IS_IN_libpthread || defined IS_IN_librt
+/* The code to disable cancellation depends on the fact that the called
+ functions are special. They don't modify registers other than %rax
+ and %r11 if they return. Therefore we don't have to preserve other
+ registers around these calls. */
# undef PSEUDO
# define PSEUDO(name, syscall_name, args) \
.text; \
@@ -40,60 +44,23 @@
ret; \
.size __##syscall_name##_nocancel,.-__##syscall_name##_nocancel; \
L(pseudo_cancel): \
- /* Save registers that might get destroyed. */ \
- SAVESTK_##args \
- PUSHARGS_##args \
+ /* We always have to align the stack before calling a function. */ \
+ subq $8, %rsp; cfi_adjust_cfa_offset (8); \
CENABLE \
- /* Restore registers. */ \
- POPARGS_##args \
/* The return value from CENABLE is argument for CDISABLE. */ \
movq %rax, (%rsp); \
- movl $SYS_ify (syscall_name), %eax; \
- syscall; \
+ DO_CALL (syscall_name, args); \
movq (%rsp), %rdi; \
/* Save %rax since it's the error code from the syscall. */ \
- movq %rax, 8(%rsp); \
+ movq %rax, %rdx; \
CDISABLE \
- movq 8(%rsp), %rax; \
- RESTSTK_##args \
+ movq %rdx, %rax; \
+ addq $8,%rsp; cfi_adjust_cfa_offset (-8); \
cmpq $-4095, %rax; \
jae SYSCALL_ERROR_LABEL; \
L(pseudo_end):
-# define PUSHARGS_0 /* Nothing. */
-# define PUSHARGS_1 PUSHARGS_0 movq %rdi, 8(%rsp);
-# define PUSHARGS_2 PUSHARGS_1 movq %rsi, 16(%rsp);
-# define PUSHARGS_3 PUSHARGS_2 movq %rdx, 24(%rsp);
-# define PUSHARGS_4 PUSHARGS_3 movq %rcx, 32(%rsp);
-# define PUSHARGS_5 PUSHARGS_4 movq %r8, 40(%rsp);
-# define PUSHARGS_6 PUSHARGS_5 movq %r9, 48(%rsp);
-
-# define POPARGS_0 /* Nothing. */
-# define POPARGS_1 POPARGS_0 movq 8(%rsp), %rdi;
-# define POPARGS_2 POPARGS_1 movq 16(%rsp), %rsi;
-# define POPARGS_3 POPARGS_2 movq 24(%rsp), %rdx;
-# define POPARGS_4 POPARGS_3 movq 32(%rsp), %r10;
-# define POPARGS_5 POPARGS_4 movq 40(%rsp), %r8;
-# define POPARGS_6 POPARGS_5 movq 48(%rsp), %r9;
-
-/* We always have to align the stack before calling a function. */
-# define SAVESTK_0 subq $24, %rsp; cfi_adjust_cfa_offset (24);
-# define SAVESTK_1 SAVESTK_0
-# define SAVESTK_2 SAVESTK_1
-# define SAVESTK_3 subq $40, %rsp; cfi_adjust_cfa_offset (40);
-# define SAVESTK_4 SAVESTK_3
-# define SAVESTK_5 subq $56, %rsp; cfi_adjust_cfa_offset (56);
-# define SAVESTK_6 SAVESTK_5
-
-# define RESTSTK_0 addq $24,%rsp; cfi_adjust_cfa_offset (-24);
-# define RESTSTK_1 RESTSTK_0
-# define RESTSTK_2 RESTSTK_1
-# define RESTSTK_3 addq $40, %rsp; cfi_adjust_cfa_offset (-40);
-# define RESTSTK_4 RESTSTK_3
-# define RESTSTK_5 addq $56, %rsp; cfi_adjust_cfa_offset (-56);
-# define RESTSTK_6 RESTSTK_5
-
# ifdef IS_IN_libpthread
# define CENABLE call __pthread_enable_asynccancel;
# define CDISABLE call __pthread_disable_asynccancel;
diff --git a/nptl/sysdeps/x86_64/tcb-offsets.sym b/nptl/sysdeps/x86_64/tcb-offsets.sym
index 51f35c6..cf86375 100644
--- a/nptl/sysdeps/x86_64/tcb-offsets.sym
+++ b/nptl/sysdeps/x86_64/tcb-offsets.sym
@@ -16,3 +16,13 @@ VGETCPU_CACHE_OFFSET offsetof (tcbhead_t, vgetcpu_cache)
PRIVATE_FUTEX offsetof (tcbhead_t, private_futex)
#endif
RTLD_SAVESPACE_SSE offsetof (tcbhead_t, rtld_savespace_sse)
+
+-- Not strictly offsets, but these values are also used in the TCB.
+TCB_CANCELSTATE_BITMASK CANCELSTATE_BITMASK
+TCB_CANCELTYPE_BITMASK CANCELTYPE_BITMASK
+TCB_CANCELING_BITMASK CANCELING_BITMASK
+TCB_CANCELED_BITMASK CANCELED_BITMASK
+TCB_EXITING_BITMASK EXITING_BITMASK
+TCB_CANCEL_RESTMASK CANCEL_RESTMASK
+TCB_TERMINATED_BITMASK TERMINATED_BITMASK
+TCB_PTHREAD_CANCELED PTHREAD_CANCELED