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| author | Ard Biesheuvel <ardb@kernel.org> | 2023-04-12 10:50:20 +0200 |
|---|---|---|
| committer | Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2023-04-12 11:04:56 +0200 |
| commit | c76c6c4ecbec0deb56a4f9e932b26866024a508f (patch) | |
| tree | e6da7ee937a9e9ee7b29dcab602a24d2ee974714 /arch/arm/include/asm/assembler.h | |
| parent | ARM: 9293/1: vfp: Pass successful return address via register R3 (diff) | |
| download | linux-c76c6c4ecbec0deb56a4f9e932b26866024a508f.tar.xz linux-c76c6c4ecbec0deb56a4f9e932b26866024a508f.zip | |
ARM: 9294/2: vfp: Fix broken softirq handling with instrumentation enabled
Commit 62b95a7b44d1 ("ARM: 9282/1: vfp: Manipulate task VFP state with
softirqs disabled") replaced the en/disable preemption calls inside the
VFP state handling code with en/disabling of soft IRQs, which is
necessary to allow kernel use of the VFP/SIMD unit when handling a soft
IRQ.
Unfortunately, when lockdep is enabled (or other instrumentation that
enables TRACE_IRQFLAGS), the disable path implemented in asm fails to
perform the lockdep and RCU related bookkeeping, resulting in spurious
warnings and other badness.
Set let's rework the VFP entry code a little bit so we can make the
local_bh_disable() call from C, with all the instrumentations that
happen to have been configured. Calling local_bh_enable() can be done
from asm, as it is a simple wrapper around __local_bh_enable_ip(), which
is always a callable function.
Link: https://lore.kernel.org/all/ZBBYCSZUJOWBg1s8@localhost.localdomain/
Fixes: 62b95a7b44d1 ("ARM: 9282/1: vfp: Manipulate task VFP state with softirqs disabled")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/include/asm/assembler.h')
| -rw-r--r-- | arch/arm/include/asm/assembler.h | 13 |
1 files changed, 0 insertions, 13 deletions
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index 06b48ce23e1c..505a306e0271 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -244,19 +244,6 @@ THUMB( fpreg .req r7 ) .endm #endif - .macro local_bh_disable, ti, tmp - ldr \tmp, [\ti, #TI_PREEMPT] - add \tmp, \tmp, #SOFTIRQ_DISABLE_OFFSET - str \tmp, [\ti, #TI_PREEMPT] - .endm - - .macro local_bh_enable_ti, ti, tmp - get_thread_info \ti - ldr \tmp, [\ti, #TI_PREEMPT] - sub \tmp, \tmp, #SOFTIRQ_DISABLE_OFFSET - str \tmp, [\ti, #TI_PREEMPT] - .endm - #define USERL(l, x...) \ 9999: x; \ .pushsection __ex_table,"a"; \ |