[PATCH 08/38] x86, NMI, NMI injecting support

[Huang Ying]

This patch implements trigger NMI on specified CPUs. At the same time,
the NMI reason (contents of port 0x61) can be faked too. This can be
used to debug and test the NMI handler.

Signed-off-by: Huang Ying <ying.huang@xxxxxxxxx>
---
 arch/x86/Kconfig.debug            |   10 +++
 arch/x86/include/asm/mach_traps.h |    9 +++-
 arch/x86/kernel/Makefile          |    1 +
 arch/x86/kernel/nmi_inject.c      |  117 +++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/traps.c           |   34 ++++++++++-
 5 files changed, 167 insertions(+), 4 deletions(-)
 create mode 100644 arch/x86/kernel/nmi_inject.c

diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 7508508..d6bb833 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -299,4 +299,14 @@ config DEBUG_STRICT_USER_COPY_CHECKS
 
 	  If unsure, or if you run an older (pre 4.4) gcc, say N.
 
+config NMI_INJECT
+	tristate "NMI injecting support"
+	depends on DEBUG_KERNEL
+	---help---
+	  This can be used to trigger NMI on specified CPUs. And the
+	  reason of NMI (contents of port 0x61) can be faked
+	  too. This can be used to debug and test the NMI handler.
+
+	  If unsure, say N.
+
 endmenu
diff --git a/arch/x86/include/asm/mach_traps.h b/arch/x86/include/asm/mach_traps.h
index 72a8b52..4235bb3 100644
--- a/arch/x86/include/asm/mach_traps.h
+++ b/arch/x86/include/asm/mach_traps.h
@@ -17,7 +17,7 @@
 #define NMI_REASON_CLEAR_IOCHK	0x08
 #define NMI_REASON_CLEAR_MASK	0x0f
 
-static inline unsigned char get_nmi_reason(void)
+static inline unsigned char __get_nmi_reason(void)
 {
 	return inb(NMI_REASON_PORT);
 }
@@ -40,4 +40,11 @@ static inline void reassert_nmi(void)
 		unlock_cmos();
 }
 
+struct nmi_reason_inject_data {
+	unsigned char reason;
+	unsigned char valid : 1;
+};
+
+extern struct nmi_reason_inject_data nmi_reason_inject_data;
+
 #endif /* _ASM_X86_MACH_DEFAULT_MACH_TRAPS_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 2dde3c7..5f98f33 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -119,6 +119,7 @@ obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o
 obj-$(CONFIG_SWIOTLB)			+= pci-swiotlb.o
 
 obj-y					+= hwerr.o
+obj-$(CONFIG_NMI_INJECT)		+= nmi_inject.o
 
 ###
 # 64 bit specific files
diff --git a/arch/x86/kernel/nmi_inject.c b/arch/x86/kernel/nmi_inject.c
new file mode 100644
index 0000000..2b61148
--- /dev/null
+++ b/arch/x86/kernel/nmi_inject.c
@@ -0,0 +1,117 @@
+/*
+ * NMI injector, for NMI handler testing
+ *
+ * Copyright 2010 Intel Corp.
+ *   Author: Huang Ying <ying.huang@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/debugfs.h>
+#include <linux/cpu.h>
+#include <asm/mach_traps.h>
+#include <asm/apic.h>
+
+static int nmi_reason_inject_get(void *data, u64 *val)
+{
+	if (nmi_reason_inject_data.valid)
+		*val = nmi_reason_inject_data.reason;
+	else
+		*val = ~0ULL;
+	return 0;
+}
+
+static int nmi_reason_inject_set(void *data, u64 val)
+{
+	nmi_reason_inject_data.reason = val;
+	nmi_reason_inject_data.valid = 1;
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(nmi_reason_inject_fops, nmi_reason_inject_get,
+			nmi_reason_inject_set, "0x%llx\n");
+
+static int nmi_reason_uninject_set(void *data, u64 val)
+{
+	nmi_reason_inject_data.valid = 0;
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(nmi_reason_uninject_fops, NULL,
+			nmi_reason_uninject_set, "%llu\n");
+
+static int nmi_inject_set(void *data, u64 val)
+{
+	int cpu;
+	cpumask_var_t cpu_mask;
+
+	alloc_cpumask_var(&cpu_mask, GFP_KERNEL);
+	cpumask_clear(cpu_mask);
+	for_each_online_cpu(cpu) {
+		if (cpu >= sizeof(val))
+			continue;
+		if (val & (1ULL << cpu))
+			cpumask_set_cpu(cpu, cpu_mask);
+	}
+	if (!cpumask_empty(cpu_mask))
+		apic->send_IPI_mask(cpu_mask, NMI_VECTOR);
+	free_cpumask_var(cpu_mask);
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(nmi_inject_fops, NULL, nmi_inject_set, "0x%llx\n");
+
+static struct dentry *nmi_debug_dir;
+
+static int __init nmi_inject_init(void)
+{
+	int rc;
+	struct dentry *de;
+
+	rc = -ENOMEM;
+	nmi_debug_dir = debugfs_create_dir("nmi", NULL);
+	if (!nmi_debug_dir)
+		return rc;
+	de = debugfs_create_file("inject", S_IWUSR, nmi_debug_dir,
+				 NULL, &nmi_inject_fops);
+	if (!de)
+		goto err;
+	de = debugfs_create_file("reason_inject", S_IRUSR | S_IWUSR,
+				 nmi_debug_dir, NULL, &nmi_reason_inject_fops);
+	if (!de)
+		goto err;
+	de = debugfs_create_file("reason_uninject", S_IWUSR,
+				 nmi_debug_dir, NULL, &nmi_reason_uninject_fops);
+	if (!de)
+		goto err;
+
+	return 0;
+err:
+	debugfs_remove_recursive(nmi_debug_dir);
+	return rc;
+}
+
+static void __exit nmi_inject_exit(void)
+{
+	debugfs_remove_recursive(nmi_debug_dir);
+}
+
+module_init(nmi_inject_init);
+module_exit(nmi_inject_exit);
+
+MODULE_AUTHOR("Huang Ying");
+MODULE_DESCRIPTION("NMI injecting support");
+MODULE_LICENSE("GPL");
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 42f16f7..acfb1a9 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -316,6 +316,34 @@ static int __init setup_unknown_nmi_panic(char *str)
 }
 __setup("unknown_nmi_panic", setup_unknown_nmi_panic);
 
+struct nmi_reason_inject_data nmi_reason_inject_data;
+EXPORT_SYMBOL_GPL(nmi_reason_inject_data);
+
+static inline unsigned char get_nmi_reason(void)
+{
+	if (nmi_reason_inject_data.valid)
+		return nmi_reason_inject_data.reason;
+	else
+		return __get_nmi_reason();
+}
+
+static inline void outb_nmi_reason(unsigned char reason)
+{
+	static unsigned char prev_reason;
+
+	if (nmi_reason_inject_data.valid) {
+		if (reason & NMI_REASON_CLEAR_SERR)
+			nmi_reason_inject_data.reason &= ~NMI_REASON_SERR;
+		if (prev_reason == (reason | NMI_REASON_CLEAR_IOCHK) &&
+		    !(reason & NMI_REASON_CLEAR_IOCHK))
+			nmi_reason_inject_data.reason &= ~NMI_REASON_IOCHK;
+		if (!nmi_reason_inject_data.reason)
+			nmi_reason_inject_data.valid = 0;
+		prev_reason = reason;
+	} else
+		outb(reason, NMI_REASON_PORT);
+}
+
 static notrace __kprobes void
 pci_serr_error(unsigned char reason, struct pt_regs *regs)
 {
@@ -340,7 +368,7 @@ pci_serr_error(unsigned char reason, struct pt_regs *regs)
 
 	/* Clear and disable the PCI SERR error line. */
 	reason = (reason & NMI_REASON_CLEAR_MASK) | NMI_REASON_CLEAR_SERR;
-	outb(reason, NMI_REASON_PORT);
+	outb_nmi_reason(reason);
 }
 
 static notrace __kprobes void
@@ -358,7 +386,7 @@ io_check_error(unsigned char reason, struct pt_regs *regs)
 
 	/* Re-enable the IOCK line, wait for a few seconds */
 	reason = (reason & NMI_REASON_CLEAR_MASK) | NMI_REASON_CLEAR_IOCHK;
-	outb(reason, NMI_REASON_PORT);
+	outb_nmi_reason(reason);
 
 	i = 20000;
 	while (--i) {
@@ -367,7 +395,7 @@ io_check_error(unsigned char reason, struct pt_regs *regs)
 	}
 
 	reason &= ~NMI_REASON_CLEAR_IOCHK;
-	outb(reason, NMI_REASON_PORT);
+	outb_nmi_reason(reason);
 }
 
 static notrace __kprobes void
-- 
1.7.1


--=-PRpPBi3cUmNxk8/MyeY8--

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