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MIPS: Fix mips_atomic_set() retry condition

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commit 2ec420b26f7b6ff332393f0bb5a7d245f7ad87f0 upstream.

The inline asm retry check in the MIPS_ATOMIC_SET operation of the
sysmips system call has been backwards since commit f1e39a4a61 ("MIPS:
Rewrite sysmips(MIPS_ATOMIC_SET, ...) in C with inline assembler")
merged in v2.6.32, resulting in the non R10000_LLSC_WAR case retrying
until the operation was inatomic, before returning the new value that
was probably just written multiple times instead of the old value.

Invert the branch condition to fix that particular issue.

Fixes: f1e39a4a61 ("MIPS: Rewrite sysmips(MIPS_ATOMIC_SET, ...) in C with inline assembler")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16148/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
James Hogan 2017-05-31 16:19:47 +01:00 • committed by Greg Kroah-Hartman
parent 75202d3ffc
commit de34c0799d
1 changed files with 1 additions and 1 deletions
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2
arch/mips/kernel/syscall.c
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@ -141,7 +141,7 @@ static inline int mips_atomic_set(unsigned long addr, unsigned long new)
"1: ll %[old], (%[addr]) \n"
" move %[tmp], %[new] \n"
"2: sc %[tmp], (%[addr]) \n"
" bnez %[tmp], 4f \n"
" beqz %[tmp], 4f \n"
"3: \n"
" .insn \n"
" .subsection 2 \n"