From c76c6c4ecbec0deb56a4f9e932b26866024a508f Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 12 Apr 2023 09:50:20 +0100 Subject: 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 Reviewed-by: Linus Walleij Tested-by: Guenter Roeck Signed-off-by: Russell King (Oracle) --- arch/arm/include/asm/assembler.h | 13 ------------- 1 file changed, 13 deletions(-) (limited to 'arch/arm/include/asm/assembler.h') 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"; \ -- cgit v1.2.3