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| author | Maciej W. Rozycki <macro@imgtec.com> | 2016-05-12 10:18:27 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-06-07 18:23:34 -0700 |
| commit | 664ebbd2b71918abe54b137f0ab3876bb3d4519c (patch) | |
| tree | 451dba0fe943417b2478d129b7ee8d06ad58138c | |
| parent | a2f8254a071f9890eff771ff8e4f4e0cb9bcde18 (diff) | |
| download | lwn-664ebbd2b71918abe54b137f0ab3876bb3d4519c.tar.gz lwn-664ebbd2b71918abe54b137f0ab3876bb3d4519c.zip | |
MIPS: ptrace: Fix FP context restoration FCSR regression
commit 4249548454f7ba4581aeee26bd83f42b48a14d15 upstream.
Fix a floating-point context restoration regression introduced with
commit 9b26616c8d9d ("MIPS: Respect the ISA level in FCSR handling")
that causes a Floating Point exception and consequently a kernel oops
with hard float configurations when one or more FCSR Enable and their
corresponding Cause bits are set both at a time via a ptrace(2) call.
To do so reinstate Cause bit masking originally introduced with commit
b1442d39fac2 ("MIPS: Prevent user from setting FCSR cause bits") to
address this exact problem and then inadvertently removed from the
PTRACE_SETFPREGS request with the commit referred above.
Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13238/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/mips/kernel/ptrace.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index a5279b2f3198..d1d7852dadfb 100644 --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -176,6 +176,7 @@ int ptrace_setfpregs(struct task_struct *child, __u32 __user *data) } __get_user(value, data + 64); + value &= ~FPU_CSR_ALL_X; fcr31 = child->thread.fpu.fcr31; mask = boot_cpu_data.fpu_msk31; child->thread.fpu.fcr31 = (value & ~mask) | (fcr31 & mask); |