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arm64: smp: avoid NMI IPIs with broken MediaTek FW

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Some MediaTek devices have broken firmware which corrupts some GICR
registers behind the back of the OS, and pseudo-NMIs cannot be used on
these devices. For more details see commit:

  44bd78dd2b ("irqchip/gic-v3: Disable pseudo NMIs on Mediatek devices w/ firmware issues")

We did not take this problem into account in commit:

  331a1b3a83 ("arm64: smp: Add arch support for backtrace using pseudo-NMI")

Since that commit arm64's SMP code will try to setup some IPIs as
pseudo-NMIs, even on systems with broken FW. The GICv3 code will
(rightly) reject attempts to request interrupts as pseudo-NMIs,
resulting in boot-time failures.

Avoid the problem by taking the broken FW into account when deciding to
request IPIs as pseudo-NMIs. The GICv3 driver maintains a static_key
named "supports_pseudo_nmis" which is false on systems with broken FW,
and we can consult this within ipi_should_be_nmi().

Fixes: 331a1b3a83 ("arm64: smp: Add arch support for backtrace using pseudo-NMI")
Reported-by: Chen-Yu Tsai <wenst@chromium.org>
Closes: https://issuetracker.google.com/issues/197061987#comment68
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Rutland 2023-10-02 18:00:36 +01:00 committed by Catalin Marinas
parent 62817d5ba2
commit a07a594152
2 changed files with 5 additions and 2 deletions
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5
arch/arm64/kernel/smp.c
View file

@ -964,7 +964,10 @@ static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
static bool ipi_should_be_nmi(enum ipi_msg_type ipi)
{
if (!system_uses_irq_prio_masking())
DECLARE_STATIC_KEY_FALSE(supports_pseudo_nmis);
if (!system_uses_irq_prio_masking() ||
!static_branch_likely(&supports_pseudo_nmis))
return false;
switch (ipi) {

2
drivers/irqchip/irq-gic-v3.c
View file

@ -106,7 +106,7 @@ static DEFINE_STATIC_KEY_TRUE(supports_deactivate_key);
* - Figure 4-7 Secure read of the priority field for a Non-secure Group 1
* interrupt.
*/
static DEFINE_STATIC_KEY_FALSE(supports_pseudo_nmis);
DEFINE_STATIC_KEY_FALSE(supports_pseudo_nmis);
DEFINE_STATIC_KEY_FALSE(gic_nonsecure_priorities);
EXPORT_SYMBOL(gic_nonsecure_priorities);