[PATCH V2 2/3] RAS, mce_amd_inj: Add capability to trigger apic interrupts

[Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>]

With this extension to the flags attribute, deferred error interrupts
and threshold interrupts can be triggered to test the apic interrupt
handler functionality for these type of errors

Update README section about the same too.

Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
---
 arch/x86/ras/mce_amd_inj.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 43 insertions(+), 1 deletion(-)

diff --git a/arch/x86/ras/mce_amd_inj.c b/arch/x86/ras/mce_amd_inj.c
index 4fd8bb9..794ca1f 100644
--- a/arch/x86/ras/mce_amd_inj.c
+++ b/arch/x86/ras/mce_amd_inj.c
@@ -34,12 +34,16 @@ static u8 n_banks;
 enum injection_type {
 	SW_INJ = 0,	/* SW injection, simply decode the error */
 	HW_INJ,		/* Trigger a #MC */
+	DFR_INT_INJ,    /* Trigger Deferred error interrupt */
+	THR_INT_INJ,    /* Trigger threshold interrupt */
 	N_INJ_TYPES,
 };
 
 static const char * const flags_options[] = {
 	[SW_INJ] = "sw",
 	[HW_INJ] = "hw",
+	[DFR_INT_INJ] = "df",
+	[THR_INT_INJ] = "th",
 	NULL
 };
 
@@ -182,6 +186,16 @@ static void trigger_mce(void *info)
 	asm volatile("int $18");
 }
 
+static void trigger_dfr_int(void *info)
+{
+	asm volatile("int %0" :: "i" (DEFERRED_ERROR_VECTOR));
+}
+
+static void trigger_thr_int(void *info)
+{
+	asm volatile("int %0" :: "i" (THRESHOLD_APIC_VECTOR));
+}
+
 static void do_inject(void)
 {
 	u64 mcg_status = 0;
@@ -202,6 +216,20 @@ static void do_inject(void)
 	if (!(i_mce.status & MCI_STATUS_PCC))
 		mcg_status |= MCG_STATUS_RIPV;
 
+	if (inj_type == DFR_INT_INJ) {
+		/*
+		 * Ensure necessary status bits for deferred errors:
+		 * a. MCx_STATUS[Deferred] is set -
+		 *    This is to ensure the error will be handled by the
+		 *    interrupt handler
+		 * b. unset MCx_STATUS[UC]
+		 *    As deferred errors are _not_ UC
+		 */
+
+		i_mce.status |= MCI_STATUS_DEFERRED;
+		i_mce.status |= (i_mce.status & ~MCI_STATUS_UC);
+	}
+
 	get_online_cpus();
 	if (!cpu_online(cpu))
 		goto err;
@@ -222,7 +250,16 @@ static void do_inject(void)
 
 	toggle_hw_mce_inject(cpu, false);
 
-	smp_call_function_single(cpu, trigger_mce, NULL, 0);
+	switch (inj_type) {
+	case DFR_INT_INJ:
+		smp_call_function_single(cpu, trigger_dfr_int, NULL, 0);
+		break;
+	case THR_INT_INJ:
+		smp_call_function_single(cpu, trigger_thr_int, NULL, 0);
+		break;
+	default:
+		smp_call_function_single(cpu, trigger_mce, NULL, 0);
+	}
 
 err:
 	put_online_cpus();
@@ -287,6 +324,11 @@ static const char readme_msg[] =
 "\t    handle the error. Be warned: might cause system panic if MCi_STATUS[PCC] \n"
 "\t    is set. Therefore, consider setting (debugfs_mountpoint)/mce/fake_panic \n"
 "\t    before injecting.\n"
+"\t  - \"df\": Trigger APIC interrupt for Deferred error. Causes deferred \n"
+"\t    error APIC interrupt handler to handle the error if the feature is \n"
+"\t    is present in hardware. \n"
+"\t  - \"th\": Trigger APIC interrupt for Threshold errors. Causes threshold \n"
+"\t    APIC interrupt handler to handle the error. \n"
 "\n";
 
 static ssize_t
-- 
2.4.0