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| author | Maciej W. Rozycki <macro@linux-mips.org> | 2015-05-12 15:20:57 +0100 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2015-05-12 23:15:49 +0200 |
| commit | 03dce595270f22d59a6f37e9170287c1afd94bc2 (patch) | |
| tree | 68e8ae5e92d6dda9b32be45d72025b095913671d /arch/mips/kernel/ptrace.c | |
| parent | 620b155034570f577470cf5309f741bac6a6e32b (diff) | |
| download | linux-03dce595270f22d59a6f37e9170287c1afd94bc2.tar.bz2 | |
MIPS: Fix a preemption issue with thread's FPU defaults
Fix "BUG: using smp_processor_id() in preemptible" reported in accesses
to thread's FPU defaults: the value to initialise FSCR to at program
startup, the FCSR r/w mask and the contents of FIR in full FPU
emulation, removing a regression introduced with 9b26616c [MIPS: Respect
the ISA level in FCSR handling] and f6843626 [MIPS: math-emu: Set FIR
feature flags for full emulation].
Use `boot_cpu_data' to obtain the data from, following the approach that
`cpu_has_*' macros take and avoiding the call to `smp_processor_id' made
in the reference to `current_cpu_data'. The contents of FSCR have to be
consistent across processors in an SMP system, the settings there must
not change as a thread is migrated across processors. And the contents
of FIR are guaranteed to be consistent in FPU emulation, by definition.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Tested-by: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Tested-by: Paul Martin <paul.martin@codethink.co.uk>
Cc: Markos Chandras <Markos.Chandras@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10030/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel/ptrace.c')
| -rw-r--r-- | arch/mips/kernel/ptrace.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index d544e774eea6..e933a309f2ea 100644 --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -176,7 +176,7 @@ int ptrace_setfpregs(struct task_struct *child, __u32 __user *data) __get_user(value, data + 64); fcr31 = child->thread.fpu.fcr31; - mask = current_cpu_data.fpu_msk31; + mask = boot_cpu_data.fpu_msk31; child->thread.fpu.fcr31 = (value & ~mask) | (fcr31 & mask); /* FIR may not be written. */ |