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| author | Ralf Baechle <ralf@linux-mips.org> | 2013-03-14 18:49:26 +0100 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2013-04-11 15:39:51 +0200 |
| commit | 1186e4e904839955e5d2be94f50e0a363cb5651b (patch) | |
| tree | d27e3c3d9ee05b5c9afb18dcfbfb7522060b5280 /arch/mips/kernel/traps.c | |
| parent | 02b849f7613003fe5f9e58bf233d49b0ebd4a5e8 (diff) | |
| download | blackbird-op-linux-1186e4e904839955e5d2be94f50e0a363cb5651b.tar.gz blackbird-op-linux-1186e4e904839955e5d2be94f50e0a363cb5651b.zip | |
MIPS: Avoid overoptimization by GCC.
Without this, it's possible that LTO will discard the calls to
set_except_vector() in the probe for the DADDI overflow bug resulting in a
kernel crash like this:
[...]
Mount-cache hash table entries: 256
Checking for the daddi bug... Integer overflow[#1]:
Cpu 0
$ 0 : 0000000000000000 0000000010008ce1 0000000000000001 0000000000000000
$ 4 : 7fffffffffffedcd ffffffff81410000 0000000000000030 000000000000003f
[...]
There are other similar places in the kernel so we've just been lucky
that GCC's been tolerant.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel/traps.c')
| -rw-r--r-- | arch/mips/kernel/traps.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 165b4f0bb7db..feb42c072384 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -1390,9 +1390,8 @@ unsigned long vi_handlers[64]; void __init *set_except_vector(int n, void *addr) { unsigned long handler = (unsigned long) addr; - unsigned long old_handler = exception_handlers[n]; + unsigned long old_handler = xchg(&exception_handlers[n], handler); - exception_handlers[n] = handler; if (n == 0 && cpu_has_divec) { unsigned long jump_mask = ~((1 << 28) - 1); u32 *buf = (u32 *)(ebase + 0x200); |
