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A single fix for GICv3 to not take an interrupt in an NMI context. 

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Merge tag 'irq_urgent_for_v5.13_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq fix from Borislav Petkov:
 "A single fix for GICv3 to not take an interrupt in an NMI context"

* tag 'irq_urgent_for_v5.13_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic-v3: Workaround inconsistent PMR setting on NMI entry
This commit is contained in:
Linus Torvalds 2021-06-20 09:38:14 -07:00
parent 8363e795eb a13d0f8d11
commit 9df7f15ee9
1 changed files with 35 additions and 1 deletions
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36
drivers/irqchip/irq-gic-v3.c
View File

@ -642,11 +642,45 @@ static inline void gic_handle_nmi(u32 irqnr, struct pt_regs *regs)
nmi_exit();
}
static u32 do_read_iar(struct pt_regs *regs)
{
u32 iar;
if (gic_supports_nmi() && unlikely(!interrupts_enabled(regs))) {
u64 pmr;
/*
* We were in a context with IRQs disabled. However, the
* entry code has set PMR to a value that allows any
* interrupt to be acknowledged, and not just NMIs. This can
* lead to surprising effects if the NMI has been retired in
* the meantime, and that there is an IRQ pending. The IRQ
* would then be taken in NMI context, something that nobody
* wants to debug twice.
*
* Until we sort this, drop PMR again to a level that will
* actually only allow NMIs before reading IAR, and then
* restore it to what it was.
*/
pmr = gic_read_pmr();
gic_pmr_mask_irqs();
isb();
iar = gic_read_iar();
gic_write_pmr(pmr);
} else {
iar = gic_read_iar();
}
return iar;
}
static asmlinkage void __exception_irq_entry gic_handle_irq(struct pt_regs *regs)
{
u32 irqnr;
irqnr = gic_read_iar();
irqnr = do_read_iar(regs);
/* Check for special IDs first */
if ((irqnr >= 1020 && irqnr <= 1023))