[PATCH -v2 0/6] AMD MCE injection improvs

[PATCH -v2 0/6] AMD MCE injection improvs

[Borislav Petkov]

From: Borislav Petkov <borislav.petkov@amd.com>

v2: Address all comments from last round.

v1:

So this basically moves the mce-inject module to arch/x86/ras/ and adds
a bunch of features to it.

More importantly, though, it creates all the glue to add the
arch/x86/ras/ directory to Kconfig. The idea is to gradually collect
RAS-related stuff there.

Tony, please take a look and let me know how do you find the general
layout, etc.

Thanks.

Borislav Petkov (6):
  x86, RAS: Add a barebones RAS subtree
  x86, RAS: Move AMD MCE injection code into ras/
  x86, RAS: Convert mce-inject module to debugfs
  x86, RAS: Add function enabling direct writes to MCE MSRs
  x86, RAS: Add attributes needed for HW injection
  x86, RAS: Add an injector function

 arch/x86/Kconfig              |   8 ++
 arch/x86/Makefile             |   3 +
 arch/x86/ras/Kconfig          |  14 +++
 arch/x86/ras/Makefile         |   1 +
 arch/x86/ras/amd/Makefile     |   3 +
 arch/x86/ras/amd/mce-inject.c | 274 ++++++++++++++++++++++++++++++++++++++++++
 drivers/edac/Kconfig          |  10 --
 drivers/edac/mce_amd_inj.c    | 173 --------------------------
 8 files changed, 303 insertions(+), 183 deletions(-)
 create mode 100644 arch/x86/ras/Kconfig
 create mode 100644 arch/x86/ras/Makefile
 create mode 100644 arch/x86/ras/amd/Makefile
 create mode 100644 arch/x86/ras/amd/mce-inject.c
 delete mode 100644 drivers/edac/mce_amd_inj.c

-- 
1.8.0.rc2.4.g42e55a5

[PATCH -v2 1/6] x86, RAS: Add a barebones RAS subtree

[Borislav Petkov]

From: Borislav Petkov <borislav.petkov@amd.com>

This should collect all x86 RAS-related stuff.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
 arch/x86/Kconfig  | 6 ++++++
 arch/x86/Makefile | 3 +++
 2 files changed, 9 insertions(+)
 create mode 100644 arch/x86/ras/Makefile

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1ae94bcae5d9..e882fc64ffb3 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -660,6 +660,12 @@ config X86_CYCLONE_TIMER
 	def_bool y
 	depends on X86_SUMMIT
 
+config X86_RAS
+	bool "X86 RAS features"
+	---help---
+	A collection of Reliability, Availability and Serviceability software
+	features which enable hardware error logging and reporting.
+
 source "arch/x86/Kconfig.cpu"
 
 config HPET_TIMER
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 58790bd85c1d..2810e50b670d 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -163,6 +163,9 @@ libs-y  += arch/x86/lib/
 # See arch/x86/Kbuild for content of core part of the kernel
 core-y += arch/x86/
 
+# RAS support
+core-$(CONFIG_X86_RAS)		+= arch/x86/ras/
+
 # drivers-y are linked after core-y
 drivers-$(CONFIG_MATH_EMULATION) += arch/x86/math-emu/
 drivers-$(CONFIG_PCI)            += arch/x86/pci/
diff --git a/arch/x86/ras/Makefile b/arch/x86/ras/Makefile
new file mode 100644
index 000000000000..e69de29bb2d1
-- 
1.8.0.rc2.4.g42e55a5

[PATCH -v2 2/6] x86, RAS: Move AMD MCE injection code into ras/

[Borislav Petkov]

From: Borislav Petkov <borislav.petkov@amd.com>

This is the code collecting all AMD MCE injection methods.

No functionality change.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
 arch/x86/Kconfig                                            |  2 ++
 arch/x86/ras/Kconfig                                        | 11 +++++++++++
 arch/x86/ras/Makefile                                       |  1 +
 arch/x86/ras/amd/Makefile                                   |  3 +++
 drivers/edac/mce_amd_inj.c => arch/x86/ras/amd/mce-inject.c |  2 +-
 drivers/edac/Kconfig                                        | 10 ----------
 6 files changed, 18 insertions(+), 11 deletions(-)
 create mode 100644 arch/x86/ras/Kconfig
 create mode 100644 arch/x86/ras/amd/Makefile
 rename drivers/edac/mce_amd_inj.c => arch/x86/ras/amd/mce-inject.c (99%)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e882fc64ffb3..f2f704af9f86 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -666,6 +666,8 @@ config X86_RAS
 	A collection of Reliability, Availability and Serviceability software
 	features which enable hardware error logging and reporting.
 
+source "arch/x86/ras/Kconfig"
+
 source "arch/x86/Kconfig.cpu"
 
 config HPET_TIMER
diff --git a/arch/x86/ras/Kconfig b/arch/x86/ras/Kconfig
new file mode 100644
index 000000000000..9362f54bfe0f
--- /dev/null
+++ b/arch/x86/ras/Kconfig
@@ -0,0 +1,11 @@
+menu "AMD RAS features"
+	depends on X86_RAS && CPU_SUP_AMD
+
+config X86_AMD_MCE_INJECT
+	tristate "Simple MCE injection interface over /sysfs"
+	default n
+	help
+	  This is a simple interface to inject MCEs over /sysfs and test
+	  the MCE decoding code.
+
+endmenu
diff --git a/arch/x86/ras/Makefile b/arch/x86/ras/Makefile
index e69de29bb2d1..dd7a321e4b5e 100644
--- a/arch/x86/ras/Makefile
+++ b/arch/x86/ras/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_X86_MCE)		+= amd/
diff --git a/arch/x86/ras/amd/Makefile b/arch/x86/ras/amd/Makefile
new file mode 100644
index 000000000000..74f2a1e676b4
--- /dev/null
+++ b/arch/x86/ras/amd/Makefile
@@ -0,0 +1,3 @@
+amd_mce_inject-y				:= mce-inject.o
+obj-$(CONFIG_X86_AMD_MCE_INJECT)		+= amd_mce_inject.o
+
diff --git a/drivers/edac/mce_amd_inj.c b/arch/x86/ras/amd/mce-inject.c
similarity index 99%
rename from drivers/edac/mce_amd_inj.c
rename to arch/x86/ras/amd/mce-inject.c
index 66b5151c1080..90aa317b09a6 100644
--- a/drivers/edac/mce_amd_inj.c
+++ b/arch/x86/ras/amd/mce-inject.c
@@ -16,7 +16,7 @@
 #include <linux/module.h>
 #include <asm/mce.h>
 
-#include "mce_amd.h"
+#include "../../../drivers/edac/mce_amd.h"
 
 struct edac_mce_attr {
 	struct attribute attr;
diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
index 409b92b8d346..96c1f6f4b6a1 100644
--- a/drivers/edac/Kconfig
+++ b/drivers/edac/Kconfig
@@ -59,16 +59,6 @@ config EDAC_DECODE_MCE
 	  which occur really early upon boot, before the module infrastructure
 	  has been initialized.
 
-config EDAC_MCE_INJ
-	tristate "Simple MCE injection interface over /sysfs"
-	depends on EDAC_DECODE_MCE
-	default n
-	help
-	  This is a simple interface to inject MCEs over /sysfs and test
-	  the MCE decoding code in EDAC.
-
-	  This is currently AMD-only.
-
 config EDAC_MM_EDAC
 	tristate "Main Memory EDAC (Error Detection And Correction) reporting"
 	help
-- 
1.8.0.rc2.4.g42e55a5

[PATCH -v2 3/6] x86, RAS: Convert mce-inject module to debugfs

[Borislav Petkov]

From: Borislav Petkov <borislav.petkov@amd.com>

This is a module which is used for debugging MCE decoding paths so its
userspace interface should go to debugfs, where it belongs conceptually.

While at it, add a warning to the Kconfig text that this interface is
unstable and no userspace scripts should rely all too much on it.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
 arch/x86/ras/Kconfig          |  11 ++-
 arch/x86/ras/amd/mce-inject.c | 182 ++++++++++++++++++------------------------
 2 files changed, 86 insertions(+), 107 deletions(-)

diff --git a/arch/x86/ras/Kconfig b/arch/x86/ras/Kconfig
index 9362f54bfe0f..4334ab92b3b0 100644
--- a/arch/x86/ras/Kconfig
+++ b/arch/x86/ras/Kconfig
@@ -2,10 +2,13 @@ menu "AMD RAS features"
 	depends on X86_RAS && CPU_SUP_AMD
 
 config X86_AMD_MCE_INJECT
-	tristate "Simple MCE injection interface over /sysfs"
+	tristate "Inject MCEs"
+	depends on DEBUG_FS
 	default n
-	help
-	  This is a simple interface to inject MCEs over /sysfs and test
-	  the MCE decoding code.
+	---help---
+	  This is a simple debugfs interface to inject MCEs and test different
+	  aspects of the MCE handling code.
+
+	  WARNING: Do not even assume that this interface is staying stable!
 
 endmenu
diff --git a/arch/x86/ras/amd/mce-inject.c b/arch/x86/ras/amd/mce-inject.c
index 90aa317b09a6..66969eab5591 100644
--- a/arch/x86/ras/amd/mce-inject.c
+++ b/arch/x86/ras/amd/mce-inject.c
@@ -1,173 +1,149 @@
 /*
- * A simple MCE injection facility for testing the MCE decoding code. This
- * driver should be built as module so that it can be loaded on production
- * kernels for testing purposes.
+ * A simple MCE injection facility for testing different aspects of the RAS
+ * code. This driver should be built as module so that it can be loaded
+ * on production kernels for testing purposes.
  *
  * This file may be distributed under the terms of the GNU General Public
  * License version 2.
  *
- * Copyright (c) 2010:  Borislav Petkov <borislav.petkov@amd.com>
- *			Advanced Micro Devices Inc.
+ * Copyright (c) 2010-12:  Borislav Petkov <borislav.petkov@amd.com>
+ *			   Advanced Micro Devices Inc.
  */
 
 #include <linux/kobject.h>
+#include <linux/debugfs.h>
 #include <linux/device.h>
-#include <linux/edac.h>
 #include <linux/module.h>
 #include <asm/mce.h>
 
 #include "../../../drivers/edac/mce_amd.h"
 
-struct edac_mce_attr {
-	struct attribute attr;
-	ssize_t (*show) (struct kobject *kobj, struct edac_mce_attr *attr, char *buf);
-	ssize_t (*store)(struct kobject *kobj, struct edac_mce_attr *attr,
-			 const char *buf, size_t count);
-};
-
-#define EDAC_MCE_ATTR(_name, _mode, _show, _store)			\
-static struct edac_mce_attr mce_attr_##_name = __ATTR(_name, _mode, _show, _store)
-
-static struct kobject *mce_kobj;
-
 /*
  * Collect all the MCi_XXX settings
  */
 static struct mce i_mce;
+static struct dentry *dfs_inj;
 
-#define MCE_INJECT_STORE(reg)						\
-static ssize_t edac_inject_##reg##_store(struct kobject *kobj,		\
-					 struct edac_mce_attr *attr,	\
-					 const char *data, size_t count)\
+#define MCE_INJECT_SET(reg)						\
+static int inj_##reg##_set(void *data, u64 val)				\
 {									\
-	int ret = 0;							\
-	unsigned long value;						\
-									\
-	ret = strict_strtoul(data, 16, &value);				\
-	if (ret < 0)							\
-		printk(KERN_ERR "Error writing MCE " #reg " field.\n");	\
-									\
-	i_mce.reg = value;						\
+	struct mce *m = (struct mce *)data;				\
 									\
-	return count;							\
+	m->reg = val;							\
+	return 0;							\
 }
 
-MCE_INJECT_STORE(status);
-MCE_INJECT_STORE(misc);
-MCE_INJECT_STORE(addr);
+MCE_INJECT_SET(status);
+MCE_INJECT_SET(misc);
+MCE_INJECT_SET(addr);
 
-#define MCE_INJECT_SHOW(reg)						\
-static ssize_t edac_inject_##reg##_show(struct kobject *kobj,		\
-					struct edac_mce_attr *attr,	\
-					char *buf)			\
+#define MCE_INJECT_GET(reg)						\
+static int inj_##reg##_get(void *data, u64 *val)			\
 {									\
-	return sprintf(buf, "0x%016llx\n", i_mce.reg);			\
+	struct mce *m = (struct mce *)data;				\
+									\
+	*val = m->reg;							\
+	return 0;							\
 }
 
-MCE_INJECT_SHOW(status);
-MCE_INJECT_SHOW(misc);
-MCE_INJECT_SHOW(addr);
+MCE_INJECT_GET(status);
+MCE_INJECT_GET(misc);
+MCE_INJECT_GET(addr);
 
-EDAC_MCE_ATTR(status, 0644, edac_inject_status_show, edac_inject_status_store);
-EDAC_MCE_ATTR(misc, 0644, edac_inject_misc_show, edac_inject_misc_store);
-EDAC_MCE_ATTR(addr, 0644, edac_inject_addr_show, edac_inject_addr_store);
+DEFINE_SIMPLE_ATTRIBUTE(status_fops, inj_status_get, inj_status_set, "%llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(misc_fops, inj_misc_get, inj_misc_set, "%llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(addr_fops, inj_addr_get, inj_addr_set, "%llx\n");
 
 /*
  * This denotes into which bank we're injecting and triggers
  * the injection, at the same time.
  */
-static ssize_t edac_inject_bank_store(struct kobject *kobj,
-				      struct edac_mce_attr *attr,
-				      const char *data, size_t count)
+static int inj_bank_set(void *data, u64 val)
 {
-	int ret = 0;
-	unsigned long value;
+	struct mce *m = (struct mce *)data;
 
-	ret = strict_strtoul(data, 10, &value);
-	if (ret < 0) {
-		printk(KERN_ERR "Invalid bank value!\n");
-		return -EINVAL;
-	}
-
-	if (value > 5)
-		if (boot_cpu_data.x86 != 0x15 || value > 6) {
-			printk(KERN_ERR "Non-existent MCE bank: %lu\n", value);
+	if (val > 5) {
+		if (boot_cpu_data.x86 != 0x15 || val > 6) {
+			pr_err("Non-existent MCE bank: %llu\n", val);
 			return -EINVAL;
 		}
+	}
 
-	i_mce.bank = value;
+	m->bank = val;
 
-	amd_decode_mce(NULL, 0, &i_mce);
+	amd_decode_mce(NULL, 0, m);
 
-	return count;
+	return 0;
 }
 
-static ssize_t edac_inject_bank_show(struct kobject *kobj,
-				     struct edac_mce_attr *attr, char *buf)
+static int inj_bank_get(void *data, u64 *val)
 {
-	return sprintf(buf, "%d\n", i_mce.bank);
-}
+	struct mce *m = (struct mce *)data;
 
-EDAC_MCE_ATTR(bank, 0644, edac_inject_bank_show, edac_inject_bank_store);
+	*val = m->bank;
+	return 0;
+}
 
-static struct edac_mce_attr *sysfs_attrs[] = { &mce_attr_status, &mce_attr_misc,
-					       &mce_attr_addr, &mce_attr_bank
+DEFINE_SIMPLE_ATTRIBUTE(bank_fops, inj_bank_get, inj_bank_set, "%llu\n");
+
+struct dfs_node {
+	char *name;
+	struct dentry *d;
+	const struct file_operations *fops;
+} dfs_fls[] = {
+	{ .name = "status",	.fops = &status_fops },
+	{ .name = "misc",	.fops = &misc_fops },
+	{ .name = "addr",	.fops = &addr_fops },
+	{ .name = "bank",	.fops = &bank_fops },
 };
 
-static int __init edac_init_mce_inject(void)
+static int __init init_mce_inject(void)
 {
-	struct bus_type *edac_subsys = NULL;
-	int i, err = 0;
+	int i;
 
-	edac_subsys = edac_get_sysfs_subsys();
-	if (!edac_subsys)
+	dfs_inj = debugfs_create_dir("mce-inject", NULL);
+	if (!dfs_inj)
 		return -EINVAL;
 
-	mce_kobj = kobject_create_and_add("mce", &edac_subsys->dev_root->kobj);
-	if (!mce_kobj) {
-		printk(KERN_ERR "Error creating a mce kset.\n");
-		err = -ENOMEM;
-		goto err_mce_kobj;
-	}
+	for (i = 0; i < ARRAY_SIZE(dfs_fls); i++) {
+		dfs_fls[i].d = debugfs_create_file(dfs_fls[i].name,
+						    S_IRUSR | S_IWUSR,
+						    dfs_inj,
+						    &i_mce,
+						    dfs_fls[i].fops);
 
-	for (i = 0; i < ARRAY_SIZE(sysfs_attrs); i++) {
-		err = sysfs_create_file(mce_kobj, &sysfs_attrs[i]->attr);
-		if (err) {
-			printk(KERN_ERR "Error creating %s in sysfs.\n",
-					sysfs_attrs[i]->attr.name);
-			goto err_sysfs_create;
-		}
+		if (!dfs_fls[i].d)
+			goto err_dfs_add;
 	}
+
 	return 0;
 
-err_sysfs_create:
+err_dfs_add:
 	while (--i >= 0)
-		sysfs_remove_file(mce_kobj, &sysfs_attrs[i]->attr);
+		debugfs_remove(dfs_fls[i].d);
 
-	kobject_del(mce_kobj);
+	debugfs_remove(dfs_inj);
+	dfs_inj = NULL;
 
-err_mce_kobj:
-	edac_put_sysfs_subsys();
-
-	return err;
+	return -ENOMEM;
 }
 
-static void __exit edac_exit_mce_inject(void)
+static void __exit exit_mce_inject(void)
 {
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(sysfs_attrs); i++)
-		sysfs_remove_file(mce_kobj, &sysfs_attrs[i]->attr);
+	for (i = 0; i < ARRAY_SIZE(dfs_fls); i++)
+		debugfs_remove(dfs_fls[i].d);
 
-	kobject_del(mce_kobj);
+	memset(&dfs_fls, 0, sizeof(dfs_fls));
 
-	edac_put_sysfs_subsys();
+	debugfs_remove(dfs_inj);
+	dfs_inj = NULL;
 }
-
-module_init(edac_init_mce_inject);
-module_exit(edac_exit_mce_inject);
+module_init(init_mce_inject);
+module_exit(exit_mce_inject);
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Borislav Petkov <borislav.petkov@amd.com>");
 MODULE_AUTHOR("AMD Inc.");
-MODULE_DESCRIPTION("MCE injection facility for testing MCE decoding");
+MODULE_DESCRIPTION("MCE injection facility for RAS testing");
-- 
1.8.0.rc2.4.g42e55a5

[PATCH -v2 4/6] x86, RAS: Add function enabling direct writes to MCE MSRs

[Borislav Petkov]

From: Borislav Petkov <borislav.petkov@amd.com>

Normally, writing to MCE MSRs causes a #GP. Add a function to enable
direct accesses to those MSRs.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
 arch/x86/ras/amd/mce-inject.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/arch/x86/ras/amd/mce-inject.c b/arch/x86/ras/amd/mce-inject.c
index 66969eab5591..c0c811579ce9 100644
--- a/arch/x86/ras/amd/mce-inject.c
+++ b/arch/x86/ras/amd/mce-inject.c
@@ -55,6 +55,30 @@ DEFINE_SIMPLE_ATTRIBUTE(misc_fops, inj_misc_get, inj_misc_set, "%llx\n");
 DEFINE_SIMPLE_ATTRIBUTE(addr_fops, inj_addr_get, inj_addr_set, "%llx\n");
 
 /*
+ * Caller needs to be make sure this cpu doesn't disappear
+ * from under us, i.e.: get_cpu/put_cpu.
+ */
+static int toggle_hw_mce_inject(unsigned int cpu, bool enable)
+{
+	u32 l, h;
+	int err;
+
+	err = rdmsr_on_cpu(cpu, MSR_K7_HWCR, &l, &h);
+	if (err) {
+		pr_err("%s: error reading HWCR\n", __func__);
+		return err;
+	}
+
+	enable ? (l |= BIT(18)) : (l &= ~BIT(18));
+
+	err = wrmsr_on_cpu(cpu, MSR_K7_HWCR, l, h);
+	if (err)
+		pr_err("%s: error writing HWCR\n", __func__);
+
+	return err;
+}
+
+/*
  * This denotes into which bank we're injecting and triggers
  * the injection, at the same time.
  */
-- 
1.8.0.rc2.4.g42e55a5

[PATCH -v2 5/6] x86, RAS: Add attributes needed for HW injection

[Borislav Petkov]

From: Borislav Petkov <borislav.petkov@amd.com>

hw_inject denotes whether we want to do a hardware or a software
injection and, in the case of hardware injection, we want to do that on
a particular cpu, thus the 'cpu' attribute.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
 arch/x86/ras/amd/mce-inject.c | 55 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/arch/x86/ras/amd/mce-inject.c b/arch/x86/ras/amd/mce-inject.c
index c0c811579ce9..b55d69fbd6e3 100644
--- a/arch/x86/ras/amd/mce-inject.c
+++ b/arch/x86/ras/amd/mce-inject.c
@@ -79,6 +79,59 @@ static int toggle_hw_mce_inject(unsigned int cpu, bool enable)
 }
 
 /*
+ * HW or SW injection
+ */
+static int hw_inj_get(void *data, u64 *val)
+{
+	struct mce *m = (struct mce *)data;
+
+	*val = !!(m->inject_flags & MCJ_EXCEPTION);
+
+	return 0;
+}
+
+static int hw_inj_set(void *data, u64 val)
+{
+	struct mce *m = (struct mce *)data;
+
+	switch (val) {
+	case 0:
+		m->inject_flags &= (u8)~MCJ_EXCEPTION;
+		break;
+
+	case 1:
+		m->inject_flags |= MCJ_EXCEPTION;
+		break;
+
+	default:
+		pr_err("%s: Only 0 or 1 allowed!\n", __func__);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(hw_inj_fops, hw_inj_get, hw_inj_set, "%llu\n");
+
+/*
+ * On which CPU to inject?
+ */
+MCE_INJECT_GET(extcpu);
+
+static int inj_extcpu_set(void *data, u64 val)
+{
+	struct mce *m = (struct mce *)data;
+
+	if (val >= nr_cpu_ids || !cpu_online(val)) {
+		pr_err("%s: Invalid CPU: %llu\n", __func__, val);
+		return -EINVAL;
+	}
+	m->extcpu = val;
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(extcpu_fops, inj_extcpu_get, inj_extcpu_set, "%llu\n");
+
+/*
  * This denotes into which bank we're injecting and triggers
  * the injection, at the same time.
  */
@@ -119,6 +172,8 @@ struct dfs_node {
 	{ .name = "misc",	.fops = &misc_fops },
 	{ .name = "addr",	.fops = &addr_fops },
 	{ .name = "bank",	.fops = &bank_fops },
+	{ .name = "hw_inject",	.fops = &hw_inj_fops },
+	{ .name = "cpu",	.fops = &extcpu_fops },
 };
 
 static int __init init_mce_inject(void)
-- 
1.8.0.rc2.4.g42e55a5

[PATCH -v2 6/6] x86, RAS: Add an injector function

[Borislav Petkov]

From: Borislav Petkov <borislav.petkov@amd.com>

Selectively inject either a real MCE or a sw-only version which
exercises the decoding code only. The hardware-injected MCE triggers a
machine check exception (#MC) so that the MCE handler can be bothered to
do something too.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
 arch/x86/ras/amd/mce-inject.c | 50 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 48 insertions(+), 2 deletions(-)

diff --git a/arch/x86/ras/amd/mce-inject.c b/arch/x86/ras/amd/mce-inject.c
index b55d69fbd6e3..24a1c870cd18 100644
--- a/arch/x86/ras/amd/mce-inject.c
+++ b/arch/x86/ras/amd/mce-inject.c
@@ -131,6 +131,53 @@ static int inj_extcpu_set(void *data, u64 val)
 
 DEFINE_SIMPLE_ATTRIBUTE(extcpu_fops, inj_extcpu_get, inj_extcpu_set, "%llu\n");
 
+static void trigger_mce(void *info)
+{
+	asm volatile("int $18");
+}
+
+static void do_inject(void)
+{
+	u64 mcg_status = 0;
+	unsigned int cpu = i_mce.extcpu;
+	int this_cpu;
+	u8 b = i_mce.bank;
+
+	if (!(i_mce.inject_flags & MCJ_EXCEPTION)) {
+		amd_decode_mce(NULL, 0, &i_mce);
+		return;
+	}
+
+	/* prep MCE global settings for the injection */
+	mcg_status = MCG_STATUS_MCIP | MCG_STATUS_EIPV;
+
+	if (!(i_mce.status & MCI_STATUS_PCC))
+		mcg_status |= MCG_STATUS_RIPV;
+
+	this_cpu = get_cpu();
+
+	toggle_hw_mce_inject(cpu, true);
+
+	wrmsr_on_cpu(cpu, MSR_IA32_MCG_STATUS,
+		     (u32)mcg_status, (u32)(mcg_status >> 32));
+
+	wrmsr_on_cpu(cpu, MSR_IA32_MCx_STATUS(b),
+		     (u32)i_mce.status, (u32)(i_mce.status >> 32));
+
+	wrmsr_on_cpu(cpu, MSR_IA32_MCx_ADDR(b),
+		     (u32)i_mce.addr, (u32)(i_mce.addr >> 32));
+
+	wrmsr_on_cpu(cpu, MSR_IA32_MCx_MISC(b),
+		     (u32)i_mce.misc, (u32)(i_mce.misc >> 32));
+
+	toggle_hw_mce_inject(cpu, false);
+
+	smp_call_function_single(cpu, trigger_mce, NULL, 0);
+
+	put_cpu();
+
+}
+
 /*
  * This denotes into which bank we're injecting and triggers
  * the injection, at the same time.
@@ -147,8 +194,7 @@ static int inj_bank_set(void *data, u64 val)
 	}
 
 	m->bank = val;
-
-	amd_decode_mce(NULL, 0, m);
+	do_inject();
 
 	return 0;
 }
-- 
1.8.0.rc2.4.g42e55a5

Re: [PATCH -v2 3/6] x86, RAS: Convert mce-inject module to debugfs

[Joe Perches]

On Tue, 2012-10-16 at 16:52 +0200, Borislav Petkov wrote:
> From: Borislav Petkov <borislav.petkov@amd.com>
[]
> diff --git a/arch/x86/ras/amd/mce-inject.c b/arch/x86/ras/amd/mce-inject.c
[]
> +#define MCE_INJECT_GET(reg)						\
> +static int inj_##reg##_get(void *data, u64 *val)			\
>  {									\
> -	return sprintf(buf, "0x%016llx\n", i_mce.reg);			\
> +	struct mce *m = (struct mce *)data;				\

trivia: doesn't need a cast

Re: [PATCH -v2 3/6] x86, RAS: Convert mce-inject module to debugfs

[Borislav Petkov]

On Tue, Oct 16, 2012 at 08:41:17AM -0700, Joe Perches wrote:
> On Tue, 2012-10-16 at 16:52 +0200, Borislav Petkov wrote:
> > From: Borislav Petkov <borislav.petkov@amd.com>
> []
> > diff --git a/arch/x86/ras/amd/mce-inject.c b/arch/x86/ras/amd/mce-inject.c
> []
> > +#define MCE_INJECT_GET(reg)						\
> > +static int inj_##reg##_get(void *data, u64 *val)			\
> >  {									\
> > -	return sprintf(buf, "0x%016llx\n", i_mce.reg);			\
> > +	struct mce *m = (struct mce *)data;				\
> 
> trivia: doesn't need a cast

Corrected, thanks.

-- 
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
Einsteinring 24, 85609 Dornach
GM: Alberto Bozzo
Reg: Dornach, Landkreis Muenchen
HRB Nr. 43632 WEEE Registernr: 129 19551

Re: [PATCH -v2 4/6] x86, RAS: Add function enabling direct writes to MCE MSRs

[Joe Perches]

On Tue, 2012-10-16 at 16:52 +0200, Borislav Petkov wrote:
> From: Borislav Petkov <borislav.petkov@amd.com>
> 
> Normally, writing to MCE MSRs causes a #GP. Add a function to enable
> direct accesses to those MSRs.
[]
> diff --git a/arch/x86/ras/amd/mce-inject.c b/arch/x86/ras/amd/mce-inject.c

> @@ -55,6 +55,30 @@ DEFINE_SIMPLE_ATTRIBUTE(misc_fops, inj_misc_get, inj_misc_set, "%llx\n");
[]
> +static int toggle_hw_mce_inject(unsigned int cpu, bool enable)
[]
> +	enable ? (l |= BIT(18)) : (l &= ~BIT(18));

This is very unusual style.
I found just one like it in the kernel tree.
(unnecessary parens here too btw)

This style is much more common:
	if (enable)
		l |= BIT(18);
	else
		l &= ~BIT(18);

Re: [PATCH -v2 3/6] x86, RAS: Convert mce-inject module to debugfs

[Andi Kleen]

Borislav Petkov <bp@amd64.org> writes:

> From: Borislav Petkov <borislav.petkov@amd.com>
>
> This is a module which is used for debugging MCE decoding paths so its
> userspace interface should go to debugfs, where it belongs conceptually.
>
> While at it, add a warning to the Kconfig text that this interface is
> unstable and no userspace scripts should rely all too much on it.

Nack. You broke mce-test/mce-inject, aka existing userland which is not 
allowed in Linux.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only

Re: [PATCH -v2 3/6] x86, RAS: Convert mce-inject module to debugfs

[Borislav Petkov]

On Wed, Oct 17, 2012 at 12:06:35PM -0700, Andi Kleen wrote:
> Borislav Petkov <bp@amd64.org> writes:
> 
> > From: Borislav Petkov <borislav.petkov@amd.com>
> >
> > This is a module which is used for debugging MCE decoding paths so its
> > userspace interface should go to debugfs, where it belongs conceptually.
> >
> > While at it, add a warning to the Kconfig text that this interface is
> > unstable and no userspace scripts should rely all too much on it.
> 
> Nack. You broke mce-test/mce-inject, aka existing userland which is not 
> allowed in Linux.

WTF? Have you actually even looked at the patch?

-- 
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
Einsteinring 24, 85609 Dornach
GM: Alberto Bozzo
Reg: Dornach, Landkreis Muenchen
HRB Nr. 43632 WEEE Registernr: 129 19551