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author | Huacai Chen <chenhuacai@loongson.cn> | 2024-03-19 10:50:34 +0300 |
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committer | Huacai Chen <chenhuacai@loongson.cn> | 2024-03-19 10:50:34 +0300 |
commit | c87e12e0e8c1241410e758e181ca6bf23efa5b5b (patch) | |
tree | 74f5b6d31808d62e6c9dcbe82cf8e67d6c54a56d /Documentation/gpu | |
parent | f48ad26e5e57016b447461f22ecf7c3ed8337353 (diff) | |
download | linux-c87e12e0e8c1241410e758e181ca6bf23efa5b5b.tar.xz |
LoongArch: Change __my_cpu_offset definition to avoid mis-optimization
From GCC commit 3f13154553f8546a ("df-scan: remove ad-hoc handling of
global regs in asms"), global registers will no longer be forced to add
to the def-use chain. Then current_thread_info(), current_stack_pointer
and __my_cpu_offset may be lifted out of the loop because they are no
longer treated as "volatile variables".
This optimization is still correct for the current_thread_info() and
current_stack_pointer usages because they are associated to a thread.
However it is wrong for __my_cpu_offset because it is associated to a
CPU rather than a thread: if the thread migrates to a different CPU in
the loop, __my_cpu_offset should be changed.
Change __my_cpu_offset definition to treat it as a "volatile variable",
in order to avoid such a mis-optimization.
Cc: stable@vger.kernel.org
Reported-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Reported-by: Miao Wang <shankerwangmiao@gmail.com>
Signed-off-by: Xing Li <lixing@loongson.cn>
Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn>
Signed-off-by: Rui Wang <wangrui@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'Documentation/gpu')
0 files changed, 0 insertions, 0 deletions