Raul Rangel has uploaded this change for review.

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libpayload/x86/exception: Add ability to ignore unknown interrupts

This will make enabling the APIC safer by ignoring unknown interrupts
and not halting the system. Once all interrupt sources have been found
and handled DIE_ON_UNKNOWN_INTERRUPT can be set if desired.

BUG=b:116777191
TEST=Booted grunt, halted the kernel, and pushed the power button while
in S5. Verified that depthcharge logged the unknown exception.

APIC Init Started
APIC Configured
Ignoring interrupt vector 39

Change-Id: If4ed566ec284d69786c369f37e4e331d7f892c74
Signed-off-by: Raul E Rangel <rrangel@chromium.org>
---
M payloads/libpayload/arch/x86/Kconfig
M payloads/libpayload/arch/x86/exception.c
2 files changed, 32 insertions(+), 3 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/82/28882/1

diff --git a/payloads/libpayload/arch/x86/Kconfig b/payloads/libpayload/arch/x86/Kconfig
index cbb21cb..129ff5f 100644
--- a/payloads/libpayload/arch/x86/Kconfig
+++ b/payloads/libpayload/arch/x86/Kconfig
@@ -37,4 +37,21 @@
 config ENABLE_APIC
 	bool "Enables the Local APIC"
 
+choice
+	prompt "Interrupt Handling"
+	default LOG_UNKNOWN_INTERRUPTS if ENABLE_APIC
+	default DIE_ON_UNKNOWN_INTERRUPT
+
+config IGNORE_UNKNOWN_INTERRUPTS
+	bool "Ignore unknown user defined interrupts"
+
+config LOG_UNKNOWN_INTERRUPTS
+	bool "Logs unknown user defined interrupts to the console"
+
+config DIE_ON_UNKNOWN_INTERRUPT
+	bool "Die if an unknown user defined interrupt is encountered"
+
+endchoice
+
+
 endif
diff --git a/payloads/libpayload/arch/x86/exception.c b/payloads/libpayload/arch/x86/exception.c
index 1fa1304..983a9f3 100644
--- a/payloads/libpayload/arch/x86/exception.c
+++ b/payloads/libpayload/arch/x86/exception.c
@@ -171,9 +171,14 @@
 
 	if (handlers[vec]) {
 		handlers[vec](vec);
-		if (IS_ENABLED(CONFIG_LP_ENABLE_APIC))
-			apic_eoi(vec);
-		return;
+		goto success;
+	} else if (vec >= EXC_COUNT
+		   && IS_ENABLED(CONFIG_LP_IGNORE_UNKNOWN_INTERRUPTS)) {
+		goto success;
+	} else if (vec >= EXC_COUNT
+		   && IS_ENABLED(CONFIG_LP_LOG_UNKNOWN_INTERRUPTS)) {
+		printf("Ignoring interrupt vector %u\n", vec);
+		goto success;
 	}
 
 	die_if(vec >= EXC_COUNT || !names[vec], "Bad exception vector %u\n",
@@ -181,7 +186,14 @@
 
 	dump_exception_state();
 	dump_stack(exception_state->regs.esp, 512);
+	/* We don't call apic_eoi because we don't want to ack the interrupt and
+	   allow another interrupt to wake the processor. */
 	halt();
+	return;
+
+success:
+	if (IS_ENABLED(CONFIG_LP_ENABLE_APIC))
+		apic_eoi(vec);
 }
 
 void exception_init(void)

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