This is a note to let you know that I've just added the patch titled
MIPS: ptrace: Fix FP context restoration FCSR regression
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mips-ptrace-fix-fp-context-restoration-fcsr-regression.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4249548454f7ba4581aeee26bd83f42b48a14d15 Mon Sep 17 00:00:00 2001
From: "Maciej W. Rozycki" <macro@xxxxxxxxxx>
Date: Thu, 12 May 2016 10:18:27 +0100
Subject: MIPS: ptrace: Fix FP context restoration FCSR regression
From: Maciej W. Rozycki <macro@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Patchwork: https://patchwork.linux-mips.org/patch/13238/
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/mips/kernel/ptrace.c | 1 +
1 file changed, 1 insertion(+)
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -176,6 +176,7 @@ int ptrace_setfpregs(struct task_struct
}
__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);
Patches currently in stable-queue which might be from macro@xxxxxxxxxx are
queue-4.4/mips-disable-preemption-during-prctl-pr_set_fp_mode.patch
queue-4.4/mips-ptrace-prevent-writes-to-read-only-fcsr-bits.patch
queue-4.4/mips-msa-fix-a-link-error-on-_init_msa_upper-with-older-gcc.patch
queue-4.4/mips-ptrace-fix-fp-context-restoration-fcsr-regression.patch
queue-4.4/mips-vdso-build-with-fno-strict-aliasing.patch
queue-4.4/mips-math-emu-fix-jalr-emulation-when-rd-0.patch
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