git/linux-cryptodev-2.6
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git synced 2026-04-25 00:52:45 -04:00
Code Issues Packages Projects Releases Wiki Activity

powerpc/64: Fix msr_check_and_set/clear MSR[EE] race

Browse Source 
irq soft-masking means that when Linux irqs are disabled, the MSR[EE]
value can change from 1 to 0 asynchronously: if a masked interrupt of
the PACA_IRQ_MUST_HARD_MASK variety fires while irqs are disabled,
the masked handler will return with MSR[EE]=0.

This means a sequence like mtmsr(mfmsr() | MSR_FP) is racy if it can
be called with local irqs disabled, unless a hard_irq_disable has been
done.

Reported-by: Sachin Sant <sachinp@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221004051157.308999-2-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin
2022-10-04 15:11:57 +10:00
committed by Michael Ellerman
parent 8154850b28
commit 0fa6831811
2 changed files with 26 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
arch/powerpc/kernel/process.c
View File

@@ -127,7 +127,7 @@ unsigned long notrace msr_check_and_set(unsigned long bits)
newmsr |= MSR_VSX;
if (oldmsr != newmsr)
mtmsr_isync(newmsr);
newmsr = mtmsr_isync_irqsafe(newmsr);
return newmsr;
}
@@ -145,7 +145,7 @@ void notrace __msr_check_and_clear(unsigned long bits)
newmsr &= ~MSR_VSX;
if (oldmsr != newmsr)
mtmsr_isync(newmsr);
mtmsr_isync_irqsafe(newmsr);
}
EXPORT_SYMBOL(__msr_check_and_clear);