[PATCH 1/3] nptl: Remove x86_64 cancellation assembly implementations
Adhemerval Zanella
adhemerval.zanella@linaro.org
Wed Apr 1 14:24:37 GMT 2020
All cancellable syscalls are done by C implementations, so there is no
no need to use a specialized implementation to optimize register usage.
Checked on x86_64-linux-gnu.
---
sysdeps/unix/sysv/linux/x86_64/cancellation.S | 104 ------------------
.../sysv/linux/x86_64/libc-cancellation.S | 21 ----
.../sysv/linux/x86_64/librt-cancellation.S | 21 ----
sysdeps/x86_64/nptl/tcb-offsets.sym | 7 --
4 files changed, 153 deletions(-)
delete mode 100644 sysdeps/unix/sysv/linux/x86_64/cancellation.S
delete mode 100644 sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S
delete mode 100644 sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S
diff --git a/sysdeps/unix/sysv/linux/x86_64/cancellation.S b/sysdeps/unix/sysv/linux/x86_64/cancellation.S
deleted file mode 100644
index 256529c9f6..0000000000
--- a/sysdeps/unix/sysv/linux/x86_64/cancellation.S
+++ /dev/null
@@ -1,104 +0,0 @@
-/* Copyright (C) 2009-2020 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, see
- <https://www.gnu.org/licenses/>. */
-
-#include <sysdep.h>
-#include <tcb-offsets.h>
-#include <kernel-features.h>
-#include <lowlevellock-futex.h>
-
-#define PTHREAD_UNWIND JUMPTARGET(__pthread_unwind)
-#if IS_IN (libpthread)
-# if defined SHARED && !defined NO_HIDDEN
-# undef PTHREAD_UNWIND
-# define PTHREAD_UNWIND __GI___pthread_unwind
-# endif
-#else
-# ifndef SHARED
- .weak __pthread_unwind
-# endif
-#endif
-
-
-#define LOAD_PRIVATE_FUTEX_WAIT(reg) \
- movl $(FUTEX_WAIT | FUTEX_PRIVATE_FLAG), reg
-
-/* 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: subq $8, %rsp
- cfi_adjust_cfa_offset(8)
- LP_OP(mov) $TCB_PTHREAD_CANCELED, %fs:RESULT
- lock
- orl $TCB_EXITING_BITMASK, %fs:CANCELHANDLING
- mov %fs:CLEANUP_JMP_BUF, %RDI_LP
- call PTHREAD_UNWIND
- 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
-
- movl %r11d, %eax
-3: 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: mov %fs:0, %RDI_LP
- movl $__NR_futex, %eax
- xorq %r10, %r10
- addq $CANCELHANDLING, %rdi
- LOAD_PRIVATE_FUTEX_WAIT (%esi)
- syscall
- movl %fs:CANCELHANDLING, %eax
- jmp 3b
-END(__pthread_disable_asynccancel)
diff --git a/sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S b/sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S
deleted file mode 100644
index 6c6b2a814d..0000000000
--- a/sysdeps/unix/sysv/linux/x86_64/libc-cancellation.S
+++ /dev/null
@@ -1,21 +0,0 @@
-/* Copyright (C) 2009-2020 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, see
- <https://www.gnu.org/licenses/>. */
-
-#define __pthread_enable_asynccancel __libc_enable_asynccancel
-#define __pthread_disable_asynccancel __libc_disable_asynccancel
-#include "cancellation.S"
diff --git a/sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S b/sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S
deleted file mode 100644
index 71ff1ca8ea..0000000000
--- a/sysdeps/unix/sysv/linux/x86_64/librt-cancellation.S
+++ /dev/null
@@ -1,21 +0,0 @@
-/* Copyright (C) 2009-2020 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, see
- <https://www.gnu.org/licenses/>. */
-
-#define __pthread_enable_asynccancel __librt_enable_asynccancel
-#define __pthread_disable_asynccancel __librt_disable_asynccancel
-#include "cancellation.S"
diff --git a/sysdeps/x86_64/nptl/tcb-offsets.sym b/sysdeps/x86_64/nptl/tcb-offsets.sym
index ae8034743b..037759eb4f 100644
--- a/sysdeps/x86_64/nptl/tcb-offsets.sym
+++ b/sysdeps/x86_64/nptl/tcb-offsets.sym
@@ -16,11 +16,4 @@ FEATURE_1_OFFSET offsetof (tcbhead_t, feature_1)
SSP_BASE_OFFSET offsetof (tcbhead_t, ssp_base)
-- 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
--
2.17.1
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