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BACKPORT: FROMGIT: irqchip/gic-v2, v3: Prevent SW resends entirely

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The GIC irqchips can now use a HW resend when a retrigger is invoked by
check_irq_resend(). However, should the HW resend fail, check_irq_resend()
will still attempt to trigger a SW resend, which is still a bad idea for
the GICs.

Prevent this from happening by setting IRQD_HANDLE_ENFORCE_IRQCTX on all
GIC IRQs. Technically per-cpu IRQs do not need this, as their flow handlers
never set IRQS_PENDING, but this aligns all IRQs wrt context enforcement:
this also forces all GIC IRQ handling to happen in IRQ context (as defined
by in_irq()).

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200730170321.31228-3-valentin.schneider@arm.com

Bug: 140053385
(cherry picked from commit 1b57d91b96
 https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git irq/gic-retrigger)
(resolved trivial merge conflict in drivers/irqchip/irq-gic.c)
Change-Id: I26d068ff58660627b4fd02f2d0483f81f0cd2094
Signed-off-by: Eric Biggers <ebiggers@google.com>
This commit is contained in:
Valentin Schneider
2020-07-30 18:03:21 +01:00
committed by Eric Biggers
parent 0dcd0fd8a7
commit 50f98784b1
2 changed files with 9 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/irqchip/irq-gic-v3.c
View File

@@ -1314,6 +1314,7 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hw)
{
struct irq_chip *chip = &gic_chip;
struct irq_data *irqd = irq_desc_get_irq_data(irq_to_desc(irq));
if (static_branch_likely(&supports_deactivate_key))
chip = &gic_eoimode1_chip;
@@ -1338,7 +1339,7 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq,
irq_domain_set_info(d, irq, hw, chip, d->host_data,
handle_fasteoi_irq, NULL, NULL);
irq_set_probe(irq);
irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(irq)));
irqd_set_single_target(irqd);
break;
case LPI_RANGE:
@@ -1352,6 +1353,8 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq,
return -EPERM;
}
/* Prevents SW retriggers which mess up the ACK/EOI ordering */
irqd_set_handle_enforce_irqctx(irqd);
return 0;
}

6
drivers/irqchip/irq-gic.c
View File

@@ -1002,6 +1002,7 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hw)
{
struct gic_chip_data *gic = d->host_data;
struct irq_data *irqd = irq_desc_get_irq_data(irq_to_desc(irq));
switch (hw) {
case 0 ... 15:
@@ -1019,9 +1020,12 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq,
irq_domain_set_info(d, irq, hw, &gic->chip, d->host_data,
handle_fasteoi_irq, NULL, NULL);
irq_set_probe(irq);
irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(irq)));
irqd_set_single_target(irqd);
break;
}
/* Prevents SW retriggers which mess up the ACK/EOI ordering */
irqd_set_handle_enforce_irqctx(irqd);
return 0;
}