x86/ras/mce_amd_inj: Inject bank 4 errors on the NBC

Bank 4 MCEs are logged and reported only on the node base core
(NBC) in a socket. Refer to the D18F3x44[NbMcaToMstCpuEn] field
in Fam10h and later BKDGs. The node base core (NBC) is the
lowest numbered core in the node.

This patch ensures that we inject the error on the NBC for bank
4 errors. Otherwise, triggering #MC or APIC interrupts on a core
which is not the NBC would not have any effect on the system,
i.e. we would not see any relevant output on kernel logs for the
error we just injected.

Signed-off-by: Aravind Gopalakrishnan <[e-mail]>
[ Cleanup comments. ]
[ Add a missing dependency on AMD_NB caught by Randy Dunlap. ]
Signed-off-by: Borislav Petkov <[e-mail]>
Acked-by: Randy Dunlap <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: H. Peter Anvin <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Tony Luck <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/ras/Kconfig

···
 config AMD_MCE_INJ
 	tristate "Simple MCE injection interface for AMD processors"
-	depends on RAS && EDAC_DECODE_MCE && DEBUG_FS
+	depends on RAS && EDAC_DECODE_MCE && DEBUG_FS && AMD_NB
 	default n
 	help
 	  This is a simple debugfs interface to inject MCEs and test different
 	  aspects of the MCE handling code.
 
 	  WARNING: Do not even assume this interface is staying stable!
-
-

arch/x86/ras/mce_amd_inj.c

···
 #include <linux/cpu.h>
 #include <linux/string.h>
 #include <linux/uaccess.h>
+#include <linux/pci.h>
 
 #include <asm/mce.h>
+#include <asm/amd_nb.h>
 #include <asm/irq_vectors.h>
 
 #include "../kernel/cpu/mcheck/mce-internal.h"
···
 static u8 n_banks;
 
 #define MAX_FLAG_OPT_SIZE	3
+#define NBCFG			0x44
 
 enum injection_type {
 	SW_INJ = 0,	/* SW injection, simply decode the error */
···
 	asm volatile("int %0" :: "i" (THRESHOLD_APIC_VECTOR));
 }
 
+static u32 get_nbc_for_node(int node_id)
+{
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+	u32 cores_per_node;
+
+	cores_per_node = c->x86_max_cores / amd_get_nodes_per_socket();
+
+	return cores_per_node * node_id;
+}
+
+static void toggle_nb_mca_mst_cpu(u16 nid)
+{
+	struct pci_dev *F3 = node_to_amd_nb(nid)->misc;
+	u32 val;
+	int err;
+
+	if (!F3)
+		return;
+
+	err = pci_read_config_dword(F3, NBCFG, &val);
+	if (err) {
+		pr_err("%s: Error reading F%dx%03x.\n",
+		       __func__, PCI_FUNC(F3->devfn), NBCFG);
+		return;
+	}
+
+	if (val & BIT(27))
+		return;
+
+	pr_err("%s: Set D18F3x44[NbMcaToMstCpuEn] which BIOS hasn't done.\n",
+	       __func__);
+
+	val |= BIT(27);
+	err = pci_write_config_dword(F3, NBCFG, val);
+	if (err)
+		pr_err("%s: Error writing F%dx%03x.\n",
+		       __func__, PCI_FUNC(F3->devfn), NBCFG);
+}
+
 static void do_inject(void)
 {
 	u64 mcg_status = 0;
···
 	if (inj_type == DFR_INT_INJ) {
 		i_mce.status |= MCI_STATUS_DEFERRED;
 		i_mce.status |= (i_mce.status & ~MCI_STATUS_UC);
+	}
+
+	/*
+	 * For multi node CPUs, logging and reporting of bank 4 errors happens
+	 * only on the node base core. Refer to D18F3x44[NbMcaToMstCpuEn] for
+	 * Fam10h and later BKDGs.
+	 */
+	if (static_cpu_has(X86_FEATURE_AMD_DCM) && b == 4) {
+		toggle_nb_mca_mst_cpu(amd_get_nb_id(cpu));
+		cpu = get_nbc_for_node(amd_get_nb_id(cpu));
 	}
 
 	get_online_cpus();