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History log of /src/common/lib/libc/arch/arm/atomic/sync_fetch_and_and_8.S
RevisionDateAuthorComments
 1.6  28-Jul-2021  skrll Remove memory barriers from the atomic_ops(3) atomic operations. They're
not needed for correctness.

Add the correct memory barriers to the gcc legacy __sync built-in
functions for atomic memory access. From the gcc documentation:

In most cases, these built-in functions are considered a full barrier.
That is, no memory operand is moved across the operation, either forward
or backward. Further, instructions are issued as necessary to prevent the
processor from speculating loads across the operation and from queuing
stores after the operation.

type __sync_lock_test_and_set (type *ptr, type value, ...)

This built-in function is not a full barrier, but rather an acquire
barrier. This means that references after the operation cannot move to
(or be speculated to) before the operation, but previous memory stores
may not be globally visible yet, and previous memory loads may not yet
be satisfied.

void __sync_lock_release (type *ptr, ...)

This built-in function is not a full barrier, but rather a release
barrier. This means that all previous memory stores are globally
visible, and all previous memory loads have been satisfied, but
following memory reads are not prevented from being speculated to
before the barrier.
 1.5  17-May-2015  justin branches: 1.5.16; 1.5.18;
Move arm sync_* changes to Makefile.inc
 1.4  17-May-2015  justin Do not build arm toolchain symbols in the rump kernel

These symbols will be provided at link time and will be
duplicate symbols in rump kernel and libc if defined.

Many have been fixed previously, but these were missed
as did not have a test.
 1.3  23-Jun-2014  joerg branches: 1.3.4;
Add aliases for the builtins used to implement C11/C++11 atomics.
 1.2  30-Nov-2013  joerg branches: 1.2.2; 1.2.4;
Use explicit form of register pair operations by specifying both.
 1.1  08-Nov-2013  matt Add support for the gcc __sync builtins.
Note that these need earmv6 or later to get the ldrex/strex instructions
 1.2.4.2  22-May-2014  yamt sync with head.

for a reference, the tree before this commit was tagged
as yamt-pagecache-tag8.

this commit was splitted into small chunks to avoid
a limitation of cvs. ("Protocol error: too many arguments")
 1.2.4.1  30-Nov-2013  yamt file sync_fetch_and_and_8.S was added on branch yamt-pagecache on 2014-05-22 11:26:28 +0000
 1.2.2.1  10-Aug-2014  tls Rebase.
 1.3.4.2  19-Aug-2014  tls Rebase to HEAD as of a few days ago.
 1.3.4.1  23-Jun-2014  tls file sync_fetch_and_and_8.S was added on branch tls-maxphys on 2014-08-19 23:45:12 +0000
 1.5.18.1  11-Aug-2021  martin Pull up following revision(s) (requested by skrll in ticket #1330):

common/lib/libc/arch/arm/atomic/atomic_swap.S: revision 1.18
common/lib/libc/arch/arm/atomic/atomic_and_16.S: revision 1.5
common/lib/libc/arch/arm/atomic/atomic_swap.S: revision 1.19
common/lib/libc/arch/arm/atomic/atomic_xor_64.S: revision 1.6
common/lib/libc/arch/arm/atomic/atomic_inc_32.S: revision 1.8
common/lib/libc/arch/arm/atomic/atomic_and_32.S: revision 1.9
common/lib/libc/arch/arm/atomic/atomic_add_8.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_xor_64.S: revision 1.7
common/lib/libc/arch/arm/atomic/atomic_inc_32.S: revision 1.9
common/lib/libc/arch/arm/atomic/atomic_cas_up.S: revision 1.8
common/lib/libc/arch/arm/atomic/atomic_add_8.S: revision 1.5
common/lib/libc/arch/arm/atomic/atomic_op_asm.h: revision 1.9
common/lib/libc/arch/arm/atomic/membar_ops.S: revision 1.8
common/lib/libc/arch/arm/atomic/membar_ops.S: revision 1.9
common/lib/libc/arch/arm/atomic/atomic_op_asm.h: revision 1.10
common/lib/libc/arch/arm/atomic/atomic_and_32.S: revision 1.10
common/lib/libc/arch/arm/atomic/atomic_cas_16.S: revision 1.3
common/lib/libc/arch/arm/atomic/sync_fetch_and_and_8.S: revision 1.6
common/lib/libc/arch/arm/atomic/atomic_xor_32.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_xor_32.S: revision 1.5
common/lib/libc/arch/arm/atomic/atomic_nand_64.S: revision 1.6
common/lib/libc/arch/arm/atomic/atomic_xor_16.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_swap_16.S: revision 1.6
common/lib/libc/arch/arm/atomic/atomic_nand_64.S: revision 1.7
common/lib/libc/arch/arm/atomic/atomic_cas_32.S: revision 1.8
common/lib/libc/arch/arm/atomic/atomic_xor_16.S: revision 1.5
common/lib/libc/arch/arm/atomic/atomic_swap_16.S: revision 1.7
common/lib/libc/arch/arm/atomic/atomic_add_32.S: revision 1.10
common/lib/libc/arch/arm/atomic/sync_fetch_and_add_8.S: revision 1.6
common/lib/libc/arch/arm/atomic/atomic_dec_64.S: revision 1.8
common/lib/libc/arch/arm/atomic/atomic_add_16.S: revision 1.4
common/lib/libc/arch/arm/atomic/sync_fetch_and_sub_8.S: revision 1.6
common/lib/libc/arch/arm/atomic/atomic_xor_8.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_dec_64.S: revision 1.9
common/lib/libc/arch/arm/atomic/atomic_add_16.S: revision 1.5
common/lib/libc/arch/arm/atomic/atomic_xor_8.S: revision 1.5
common/lib/libc/arch/arm/atomic/atomic_or_64.S: revision 1.13
common/lib/libc/arch/arm/atomic/atomic_add_32.S: revision 1.9
common/lib/libc/arch/arm/atomic/atomic_or_64.S: revision 1.14
common/lib/libc/arch/arm/atomic/atomic_or_16.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_or_16.S: revision 1.5
common/lib/libc/arch/arm/atomic/sync_fetch_and_nand_8.S: revision 1.6
common/lib/libc/arch/arm/atomic/atomic_nand_16.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_nand_16.S: revision 1.5
common/lib/libc/arch/arm/atomic/sync_fetch_and_or_8.S: revision 1.6
common/lib/libc/arch/arm/atomic/atomic_nand_32.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_or_32.S: revision 1.9
common/lib/libc/arch/arm/atomic/atomic_nand_32.S: revision 1.5
common/lib/libc/arch/arm/atomic/atomic_cas_8.S: revision 1.9
common/lib/libc/arch/arm/atomic/atomic_inc_64.S: revision 1.10
common/lib/libc/arch/arm/atomic/atomic_inc_64.S: revision 1.11
common/lib/libc/arch/arm/atomic/atomic_cas_64.S: revision 1.12
common/lib/libc/arch/arm/atomic/sync_bool_compare_and_swap_8.S: revision 1.5
common/lib/libc/arch/arm/atomic/atomic_or_8.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_dec_32.S: revision 1.6
common/lib/libc/arch/arm/atomic/atomic_or_8.S: revision 1.5
common/lib/libc/arch/arm/atomic/atomic_dec_32.S: revision 1.7
common/lib/libc/arch/arm/atomic/atomic_sub_64.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_sub_64.S: revision 1.5
common/lib/libc/arch/arm/atomic/sync_fetch_and_xor_8.S: revision 1.6
common/lib/libc/arch/arm/atomic/sync_bool_compare_and_swap_4.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_and_64.S: revision 1.12
common/lib/libc/arch/arm/atomic/atomic_or_32.S: revision 1.10
common/lib/libc/arch/arm/atomic/atomic_and_64.S: revision 1.13
common/lib/libc/arch/arm/atomic/sync_bool_compare_and_swap_2.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_swap_64.S: revision 1.14
common/lib/libc/arch/arm/atomic/sync_bool_compare_and_swap_1.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_nand_8.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_and_8.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_add_64.S: revision 1.13
common/lib/libc/arch/arm/atomic/atomic_nand_8.S: revision 1.5
common/lib/libc/arch/arm/atomic/atomic_and_8.S: revision 1.5
common/lib/libc/arch/arm/atomic/atomic_and_16.S: revision 1.4
common/lib/libc/arch/arm/atomic/atomic_add_64.S: revision 1.14

Give the thumb atomic ops a chance of working

s/ifdef _ARM_ARCH_6/if defined(_ARM_ARCH_6)/ for consistency. NFCI.

Remove memory barriers from the atomic_ops(3) atomic operations. They're
not needed for correctness.

Add the correct memory barriers to the gcc legacy __sync built-in
functions for atomic memory access. From the gcc documentation:

In most cases, these built-in functions are considered a full barrier.

That is, no memory operand is moved across the operation, either forward
or backward. Further, instructions are issued as necessary to prevent the
processor from speculating loads across the operation and from queuing
stores after the operation.

type __sync_lock_test_and_set (type *ptr, type value, ...)
This built-in function is not a full barrier, but rather an acquire
barrier. This means that references after the operation cannot move to
(or be speculated to) before the operation, but previous memory stores
may not be globally visible yet, and previous memory loads may not yet
be satisfied.

void __sync_lock_release (type *ptr, ...)
This built-in function is not a full barrier, but rather a release
barrier. This means that all previous memory stores are globally
visible, and all previous memory loads have been satisfied, but
following memory reads are not prevented from being speculated to
before the barrier.
 1.5.16.2  21-Apr-2020  martin Ooops, restore accidently removed files from merge mishap
 1.5.16.1  21-Apr-2020  martin Sync with HEAD

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