[PATCH] arm64: irqflags: Fix Pseudo-NMI state assertion failure during vpanic

[Jinjie Ruan]

When CONFIG_ARM64_DEBUG_PRIORITY_MASKING is enabled, triggering an LKDTM
HARDLOCKUP induces a warning at __pmr_local_irq_disable() inside
vpanic().

This occurs because a Pseudo-NMI interrupts the locked-up CPU and updates
ICC_PMR_EL1 to a transient composite state:
	GIC_PRIO_IRQON | GICV3_PRIO_PSR_I_SET (0xf0).

Then, vpanic() unconditionally calls local_irq_disable(), triggering
the strict assertion which only expects pure IRQON or IRQOFF.

Fix this by expanding the debugging whitelist in __pmr_local_irq_disable()
to explicitly permit this valid Pseudo-NMI context flag where DAIF.IF is
set to prevent NMI nesting.

	# echo HARDLOCKUP > /sys/kernel/debug/provoke-crash/DIRECT
	lkdtm: Performing direct entry HARDLOCKUP
	watchdog: CPU3: Watchdog detected hard LOCKUP on cpu 3
	...

	CPU: 3 UID: 0 PID: 219 Comm: sh Not tainted 7.2.0-rc1 #341 PREEMPT
	Hardware name: linux,dummy-virt (DT)
	pstate: 00002005 (nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
	pc : lkdtm_HARDLOCKUP+0x64/0x78
	lr : lkdtm_HARDLOCKUP+0x64/0x78
	sp : ffffffc080b33ac0
	pmr: 000000c0
	x29: ffffffc080b33ac0 x28: ffffff80c3d61ac0 x27: 0000000000000000
	x26: 0000000000000000 x25: ffffff80c0f24800 x24: ffffff80c05495f0
	x23: ffffffc080b33c30 x22: ffffffc080b33c30 x21: ffffffed82f60bb0
	x20: 000000000000000b x19: ffffff80c339d000 x18: 0000000000000001
	x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000028
	x14: 0000000000000000 x13: 0000000000008000 x12: 0000000000000161
	x11: ffffffed837fb000 x10: 0000000000000000 x9 : 0000000000000001
	x8 : ffffffc080b339c8 x7 : ffffffc080b33ab0 x6 : ffffffc080b33a40
	x5 : ffffffc080b33a28 x4 : ffffffc080b34000 x3 : 0000000000000000
	x2 : 0000000100000000 x1 : 0000000100000000 x0 : 0000000000000001
	Call trace:
	 lkdtm_HARDLOCKUP+0x64/0x78 (P)
	 lkdtm_do_action+0x1c/0x38
	 direct_entry+0xd0/0x164
	 full_proxy_write+0x6c/0xa8
	 vfs_write+0xd0/0x354
	 ksys_write+0x68/0xfc
	 __arm64_sys_write+0x1c/0x28
	 invoke_syscall+0x9c/0x10c
	 el0_svc_common.constprop.0+0x40/0xe8
	 do_el0_svc+0x20/0x2c
	 el0_svc+0x5c/0x44c
	 el0t_64_sync_handler+0xa0/0xe4
	 el0t_64_sync+0x1ac/0x1b0
	Sending NMI from CPU 3 to CPUs 0-2,4-7:
	...
	------------[ cut here ]------------
	WARNING: arch/arm64/include/asm/irqflags.h:63 at vpanic+0x3a8/0x574, CPU#3: sh/219
	Modules linked in:
	CPU: 3 UID: 0 PID: 219 Comm: sh Not tainted 7.2.0-rc1 #341 PREEMPT
	Hardware name: linux,dummy-virt (DT)
	pstate: 200020c5 (nzCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
	pc : vpanic+0x3a8/0x574
	lr : do_panic_on_target_cpu+0x0/0x1c
	sp : ffffffc08001bb10
	pmr: 000000f0
	x29: ffffffc08001bb10 x28: 00000000000000f0 x27: 0000000000000003
	x26: 0000000000000000 x25: ffffffed82b902f0 x24: ffffffed81cbba08
	x23: ffffffed830e2000 x22: ffffffed830e21a0 x21: ffffffc08001bbc0
	x20: ffffffed82b94078 x19: ffffffed8225fff8 x18: 00000000ffffffff
	x17: 666f735f6f645f5f x16: 205d3e3832353031 x15: ffffffed83b5bf3b
	x14: 0000000000000001 x13: ffffffed82bba668 x12: 0000000000000188
	x11: 0000000000000498 x10: ffffffed82c2a650 x9 : 0000000100110001
	x8 : ffffff80c3d61ac0 x7 : 0000000000000001 x6 : ffffffed81cbaca8
	x5 : ffffffc080b33980 x4 : ffffffc08001bc50 x3 : 0000000000000001
	x2 : ffffffed82b8f000 x1 : 00000000000000d0 x0 : 0000000000000001
	Call trace:
	 vpanic+0x3a8/0x574 (P)
	 do_panic_on_target_cpu+0x0/0x1c
	 add_taint+0x0/0xbc
	 watchdog_hardlockup_check+0x32c/0x3f8
	 watchdog_overflow_callback+0x34/0x44
	 __perf_event_overflow+0xfc/0x4ec
	 perf_event_overflow+0x30/0xf4
	 armv8pmu_handle_irq+0x114/0x1fc
	 armpmu_dispatch_irq+0x2c/0x68
	 handle_percpu_devid_irq+0xd4/0x268
	 handle_irq_desc+0x40/0x58
	 generic_handle_domain_nmi+0x28/0x50
	 __gic_handle_nmi.constprop.0+0x4c/0xa0
	 gic_handle_irq+0x38/0x2bc
	 call_on_irq_stack+0x30/0x48
	 do_interrupt_handler+0x80/0x94
	 el1_interrupt+0x90/0xac
	 el1h_64_irq_handler+0x18/0x24
	 el1h_64_irq+0x80/0x84
	 lkdtm_HARDLOCKUP+0x64/0x78 (P)
	 lkdtm_do_action+0x1c/0x38
	 direct_entry+0xd0/0x164
	 full_proxy_write+0x6c/0xa8
	 vfs_write+0xd0/0x354
	 ksys_write+0x68/0xfc
	 __arm64_sys_write+0x1c/0x28
	 invoke_syscall+0x9c/0x10c
	 el0_svc_common.constprop.0+0x40/0xe8
	 do_el0_svc+0x20/0x2c
	 el0_svc+0x5c/0x44c
	 el0t_64_sync_handler+0xa0/0xe4
	 el0t_64_sync+0x1ac/0x1b0

Cc: catalin.marinas@xxxxxxx
Cc: will@xxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 48ce8f80f5901 ("arm64: irqflags: Introduce explicit debugging for IRQ priorities")
Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
---
 arch/arm64/include/asm/irqflags.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h
index a8cb5a5c93b7..c5e3e9fe19a4 100644
--- a/arch/arm64/include/asm/irqflags.h
+++ b/arch/arm64/include/asm/irqflags.h
@@ -60,7 +60,8 @@ static __always_inline void __pmr_local_irq_disable(void)
 {
 	if (IS_ENABLED(CONFIG_ARM64_DEBUG_PRIORITY_MASKING)) {
 		u32 pmr = read_sysreg_s(SYS_ICC_PMR_EL1);
-		WARN_ON_ONCE(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF);
+		WARN_ON_ONCE(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF &&
+			     pmr != (GIC_PRIO_IRQON | GICV3_PRIO_PSR_I_SET));
 	}
 
 	barrier();
-- 
2.34.1