c6bfe5c4d7
I've moved the ARM port from ports to the main sysdeps hierarchy. Beyond the README update, the move of the files was simply git mv ports/sysdeps/arm sysdeps/arm git mv ports/sysdeps/unix/arm sysdeps/unix/arm git mv ports/sysdeps/unix/sysv/linux/arm sysdeps/unix/sysv/linux/arm and in addition to the ChangeLog entries here, I put a note at the top of ports/ChangeLog.arm similar to that at the top of ChangeLog.powerpc. There is deliberately no NEWS change, as I think it makes the most sense to put in a general note above all ports having moved if we can achieve that for 2.20. Tested that disassembly of installed shared libraries for arm is the same before and after this patch, except for data (not instructions) in ld.so (there are assertions in sysdeps/arm/dl-machine.h, and the path by which that file is found, and so by which it appears in the assertion message, changes as a result of the move). * sysdeps/arm: Move directory from ports/sysdeps/arm. * sysdeps/unix/arm: Move directory from ports/sysdeps/unix/arm. * sysdeps/unix/sysv/linux/arm: Move directory from ports/sysdeps/unix/sysv/linux/arm. * README: Update listing for arm-*-linux-gnueabi. ports/ChangeLog.arm: * sysdeps/arm: Move directory to ../sysdeps/arm. * sysdeps/unix/arm: Move directory to ../sysdeps.arm. * sysdeps/unix/sysv/linux/arm: Move directory to ../sysdeps/unix/sysv/linux/arm.
108 lines
4.9 KiB
C
108 lines
4.9 KiB
C
/* Atomic operations. ARM/Linux version.
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Copyright (C) 2002-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#include <stdint.h>
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/* If the compiler doesn't provide a primitive, we'll use this macro
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to get assistance from the kernel. */
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#ifdef __thumb2__
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# define __arm_assisted_full_barrier() \
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__asm__ __volatile__ \
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("movw\tip, #0x0fa0\n\t" \
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"movt\tip, #0xffff\n\t" \
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"blx\tip" \
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: : : "ip", "lr", "cc", "memory");
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#else
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# define __arm_assisted_full_barrier() \
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__asm__ __volatile__ \
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("mov\tip, #0xffff0fff\n\t" \
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"mov\tlr, pc\n\t" \
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"add\tpc, ip, #(0xffff0fa0 - 0xffff0fff)" \
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: : : "ip", "lr", "cc", "memory");
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#endif
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/* Atomic compare and exchange. This sequence relies on the kernel to
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provide a compare and exchange operation which is atomic on the
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current architecture, either via cleverness on pre-ARMv6 or via
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ldrex / strex on ARMv6.
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It doesn't matter what register is used for a_oldval2, but we must
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specify one to work around GCC PR rtl-optimization/21223. Otherwise
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it may cause a_oldval or a_tmp to be moved to a different register.
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We use the union trick rather than simply using __typeof (...) in the
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declarations of A_OLDVAL et al because when NEWVAL or OLDVAL is of the
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form *PTR and PTR has a 'volatile ... *' type, then __typeof (*PTR) has
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a 'volatile ...' type and this triggers -Wvolatile-register-var to
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complain about 'register volatile ... asm ("reg")'. */
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#ifdef __thumb2__
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/* Thumb-2 has ldrex/strex. However it does not have barrier instructions,
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so we still need to use the kernel helper. */
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# define __arm_assisted_compare_and_exchange_val_32_acq(mem, newval, oldval) \
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({ union { __typeof (oldval) a; uint32_t v; } oldval_arg = { .a = (oldval) };\
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union { __typeof (newval) a; uint32_t v; } newval_arg = { .a = (newval) };\
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register uint32_t a_oldval asm ("r0"); \
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register uint32_t a_newval asm ("r1") = newval_arg.v; \
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register __typeof (mem) a_ptr asm ("r2") = (mem); \
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register uint32_t a_tmp asm ("r3"); \
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register uint32_t a_oldval2 asm ("r4") = oldval_arg.v; \
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__asm__ __volatile__ \
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("0:\tldr\t%[tmp],[%[ptr]]\n\t" \
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"cmp\t%[tmp], %[old2]\n\t" \
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"bne\t1f\n\t" \
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"mov\t%[old], %[old2]\n\t" \
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"movw\t%[tmp], #0x0fc0\n\t" \
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"movt\t%[tmp], #0xffff\n\t" \
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"blx\t%[tmp]\n\t" \
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"bcc\t0b\n\t" \
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"mov\t%[tmp], %[old2]\n\t" \
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"1:" \
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: [old] "=&r" (a_oldval), [tmp] "=&r" (a_tmp) \
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: [new] "r" (a_newval), [ptr] "r" (a_ptr), \
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[old2] "r" (a_oldval2) \
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: "ip", "lr", "cc", "memory"); \
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(__typeof (oldval)) a_tmp; })
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#else
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# define __arm_assisted_compare_and_exchange_val_32_acq(mem, newval, oldval) \
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({ union { __typeof (oldval) a; uint32_t v; } oldval_arg = { .a = (oldval) };\
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union { __typeof (newval) a; uint32_t v; } newval_arg = { .a = (newval) };\
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register uint32_t a_oldval asm ("r0"); \
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register uint32_t a_newval asm ("r1") = newval_arg.v; \
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register __typeof (mem) a_ptr asm ("r2") = (mem); \
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register uint32_t a_tmp asm ("r3"); \
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register uint32_t a_oldval2 asm ("r4") = oldval_arg.v; \
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__asm__ __volatile__ \
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("0:\tldr\t%[tmp],[%[ptr]]\n\t" \
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"cmp\t%[tmp], %[old2]\n\t" \
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"bne\t1f\n\t" \
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"mov\t%[old], %[old2]\n\t" \
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"mov\t%[tmp], #0xffff0fff\n\t" \
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"mov\tlr, pc\n\t" \
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"add\tpc, %[tmp], #(0xffff0fc0 - 0xffff0fff)\n\t" \
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"bcc\t0b\n\t" \
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"mov\t%[tmp], %[old2]\n\t" \
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"1:" \
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: [old] "=&r" (a_oldval), [tmp] "=&r" (a_tmp) \
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: [new] "r" (a_newval), [ptr] "r" (a_ptr), \
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[old2] "r" (a_oldval2) \
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: "ip", "lr", "cc", "memory"); \
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(__typeof (oldval)) a_tmp; })
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#endif
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#include <sysdeps/arm/bits/atomic.h>
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