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When irqs are soft-disabled, MSR[EE] is volatile and can change from 1 to 0 asynchronously (if a PACA_IRQ_MUST_HARD_MASK interrupt hits). So it can not be used to check hard IRQ enabled status, except to confirm it is disabled. ppc64_runlatch_on/off functions use MSR this way to decide whether to re-enable MSR[EE] after disabling it, which leads to MSR[EE] being enabled when it shouldn't be (when a PACA_IRQ_MUST_HARD_MASK had disabled it between reading the MSR and clearing EE). This has been tolerated in the kernel previously, and it doesn't seem to cause a problem, but it is unexpected and may trip warnings or cause other problems as we tighten up this state management. Fix this by only re-enabling if PACA_IRQ_HARD_DIS is clear. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220926054305.2671436-5-npiggin@gmail.com
44 lines
1.2 KiB
C
44 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
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*/
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#ifndef _ASM_POWERPC_RUNLATCH_H
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#define _ASM_POWERPC_RUNLATCH_H
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#ifdef CONFIG_PPC64
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extern void __ppc64_runlatch_on(void);
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extern void __ppc64_runlatch_off(void);
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/*
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* We manually hard enable-disable, this is called
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* in the idle loop and we don't want to mess up
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* with soft-disable/enable & interrupt replay.
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*/
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#define ppc64_runlatch_off() \
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do { \
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if (cpu_has_feature(CPU_FTR_CTRL) && \
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test_thread_local_flags(_TLF_RUNLATCH)) { \
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__hard_irq_disable(); \
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__ppc64_runlatch_off(); \
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if (!(local_paca->irq_happened & PACA_IRQ_HARD_DIS)) \
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__hard_irq_enable(); \
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} \
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} while (0)
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#define ppc64_runlatch_on() \
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do { \
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if (cpu_has_feature(CPU_FTR_CTRL) && \
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!test_thread_local_flags(_TLF_RUNLATCH)) { \
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__hard_irq_disable(); \
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__ppc64_runlatch_on(); \
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if (!(local_paca->irq_happened & PACA_IRQ_HARD_DIS)) \
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__hard_irq_enable(); \
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} \
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} while (0)
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#else
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#define ppc64_runlatch_on()
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#define ppc64_runlatch_off()
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#endif /* CONFIG_PPC64 */
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#endif /* _ASM_POWERPC_RUNLATCH_H */
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