From: Chen-Yu Tsai wenst@chromium.org
[ Upstream commit 8d474deaba2c4dd33a5e2f5be82e6798ffa6b8a5 ]
When non-secure priorities are used, compared to the raw priority set, the value read back from RPR is also right-shifted by one and the highest bit set.
Add a macro to do the modifications to the raw priority when doing the comparison against the RPR value. This corrects the pseudo-NMI behavior when non-secure priorities in the GIC are used. Tested on 5.10 with the "IPI as pseudo-NMI" series [1] applied on MT8195.
[1] https://lore.kernel.org/linux-arm-kernel/1604317487-14543-1-git-send-email-s...
Fixes: 336780590990 ("irqchip/gic-v3: Support pseudo-NMIs when SCR_EL3.FIQ == 0") Reviewed-by: Alexandru Elisei alexandru.elisei@arm.com Signed-off-by: Chen-Yu Tsai wenst@chromium.org [maz: Added comment contributed by Alex] Signed-off-by: Marc Zyngier maz@kernel.org Link: https://lore.kernel.org/r/20210811171505.1502090-1-wenst@chromium.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/irqchip/irq-gic-v3.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index 66d623f91678..20a2d606b4c9 100644 --- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -100,6 +100,27 @@ EXPORT_SYMBOL(gic_pmr_sync); DEFINE_STATIC_KEY_FALSE(gic_nonsecure_priorities); EXPORT_SYMBOL(gic_nonsecure_priorities);
+/* + * When the Non-secure world has access to group 0 interrupts (as a + * consequence of SCR_EL3.FIQ == 0), reading the ICC_RPR_EL1 register will + * return the Distributor's view of the interrupt priority. + * + * When GIC security is enabled (GICD_CTLR.DS == 0), the interrupt priority + * written by software is moved to the Non-secure range by the Distributor. + * + * If both are true (which is when gic_nonsecure_priorities gets enabled), + * we need to shift down the priority programmed by software to match it + * against the value returned by ICC_RPR_EL1. + */ +#define GICD_INT_RPR_PRI(priority) \ + ({ \ + u32 __priority = (priority); \ + if (static_branch_unlikely(&gic_nonsecure_priorities)) \ + __priority = 0x80 | (__priority >> 1); \ + \ + __priority; \ + }) + /* ppi_nmi_refs[n] == number of cpus having ppi[n + 16] set as NMI */ static refcount_t *ppi_nmi_refs;
@@ -687,7 +708,7 @@ static asmlinkage void __exception_irq_entry gic_handle_irq(struct pt_regs *regs return;
if (gic_supports_nmi() && - unlikely(gic_read_rpr() == GICD_INT_NMI_PRI)) { + unlikely(gic_read_rpr() == GICD_INT_RPR_PRI(GICD_INT_NMI_PRI))) { gic_handle_nmi(irqnr, regs); return; }