[PATCH v2 2/2] x86: align x86 arch with generic CPU modalias handling

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

The x86 CPU feature modalias handling existed before it was reimplemented
generically. This patch aligns the x86 handling so that it
(a) reuses some more code that is now generic;
(b) uses the generic format for the modalias module metadata entry, i.e., it
    now uses 'cpu:type:x86,venVVVVfamFFFFmodMMMM:feature:,XXXX,YYYY' instead of
    the 'x86cpu:vendor:VVVV:family:FFFF:model:MMMM:feature:,XXXX,YYYY' that was
    used before.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/Kconfig                  |  4 +---
 arch/x86/include/asm/cpufeature.h |  7 +++++++
 arch/x86/kernel/cpu/match.c       | 42 ---------------------------------------
 drivers/base/Kconfig              |  5 -----
 drivers/base/cpu.c                | 10 +++-------
 include/linux/cpu.h               |  7 -------
 scripts/mod/file2alias.c          | 10 +++++-----
 7 files changed, 16 insertions(+), 69 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 940e50e..7d3b790 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -127,6 +127,7 @@ config X86
 	select HAVE_DEBUG_STACKOVERFLOW
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
 	select HAVE_CC_STACKPROTECTOR
+	select GENERIC_CPU_AUTOPROBE
 
 config INSTRUCTION_DECODER
 	def_bool y
@@ -195,9 +196,6 @@ config ARCH_HAS_CPU_RELAX
 config ARCH_HAS_CACHE_LINE_SIZE
 	def_bool y
 
-config ARCH_HAS_CPU_AUTOPROBE
-	def_bool y
-
 config HAVE_SETUP_PER_CPU_AREA
 	def_bool y
 
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index e099f95..d86dc3d 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -541,6 +541,13 @@ static __always_inline __pure bool _static_cpu_has_safe(u16 bit)
 #define static_cpu_has_bug(bit)	static_cpu_has((bit))
 #define boot_cpu_has_bug(bit)	cpu_has_bug(&boot_cpu_data, (bit))
 
+#define MAX_CPU_FEATURES	(NCAPINTS * 32)
+#define cpu_have_feature	boot_cpu_has
+
+#define CPU_FEATURE_TYPEFMT	"x86,ven%04Xfam%04Xmod%04X"
+#define CPU_FEATURE_TYPEVAL	boot_cpu_data.x86_vendor, boot_cpu_data.x86, \
+				boot_cpu_data.x86_model
+
 #endif /* defined(__KERNEL__) && !defined(__ASSEMBLY__) */
 
 #endif /* _ASM_X86_CPUFEATURE_H */
diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c
index 3656537..afa9f0d 100644
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -47,45 +47,3 @@ const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match)
 	return NULL;
 }
 EXPORT_SYMBOL(x86_match_cpu);
-
-ssize_t arch_print_cpu_modalias(struct device *dev,
-				struct device_attribute *attr,
-				char *bufptr)
-{
-	int size = PAGE_SIZE;
-	int i, n;
-	char *buf = bufptr;
-
-	n = snprintf(buf, size, "x86cpu:vendor:%04X:family:%04X:"
-		     "model:%04X:feature:",
-		boot_cpu_data.x86_vendor,
-		boot_cpu_data.x86,
-		boot_cpu_data.x86_model);
-	size -= n;
-	buf += n;
-	size -= 1;
-	for (i = 0; i < NCAPINTS*32; i++) {
-		if (boot_cpu_has(i)) {
-			n = snprintf(buf, size, ",%04X", i);
-			if (n >= size) {
-				WARN(1, "x86 features overflow page\n");
-				break;
-			}
-			size -= n;
-			buf += n;
-		}
-	}
-	*buf++ = '\n';
-	return buf - bufptr;
-}
-
-int arch_cpu_uevent(struct device *dev, struct kobj_uevent_env *env)
-{
-	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
-	if (buf) {
-		arch_print_cpu_modalias(NULL, NULL, buf);
-		add_uevent_var(env, "MODALIAS=%s", buf);
-		kfree(buf);
-	}
-	return 0;
-}
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 3f0d373..8fa8dea 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -185,13 +185,8 @@ config GENERIC_CPU_DEVICES
 	bool
 	default n
 
-config HAVE_CPU_AUTOPROBE
-	def_bool ARCH_HAS_CPU_AUTOPROBE
-
 config GENERIC_CPU_AUTOPROBE
 	bool
-	depends on !ARCH_HAS_CPU_AUTOPROBE
-	select HAVE_CPU_AUTOPROBE
 
 config SOC_BUS
 	bool
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index 8a38bf8..006b1bc 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -287,7 +287,6 @@ static void cpu_device_release(struct device *dev)
 	 */
 }
 
-#ifdef CONFIG_HAVE_CPU_AUTOPROBE
 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
 static ssize_t print_cpu_modalias(struct device *dev,
 				  struct device_attribute *attr,
@@ -310,9 +309,6 @@ static ssize_t print_cpu_modalias(struct device *dev,
 	buf[n++] = '\n';
 	return n;
 }
-#else
-#define print_cpu_modalias	arch_print_cpu_modalias
-#endif
 
 static int cpu_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
@@ -346,7 +342,7 @@ int register_cpu(struct cpu *cpu, int num)
 	cpu->dev.offline_disabled = !cpu->hotpluggable;
 	cpu->dev.offline = !cpu_online(num);
 	cpu->dev.of_node = of_get_cpu_node(num, NULL);
-#ifdef CONFIG_HAVE_CPU_AUTOPROBE
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
 	cpu->dev.bus->uevent = cpu_uevent;
 #endif
 	cpu->dev.groups = common_cpu_attr_groups;
@@ -370,7 +366,7 @@ struct device *get_cpu_device(unsigned cpu)
 }
 EXPORT_SYMBOL_GPL(get_cpu_device);
 
-#ifdef CONFIG_HAVE_CPU_AUTOPROBE
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
 static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
 #endif
 
@@ -384,7 +380,7 @@ static struct attribute *cpu_root_attrs[] = {
 	&cpu_attrs[2].attr.attr,
 	&dev_attr_kernel_max.attr,
 	&dev_attr_offline.attr,
-#ifdef CONFIG_HAVE_CPU_AUTOPROBE
+#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
 	&dev_attr_modalias.attr,
 #endif
 	NULL
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 03e235ad..03e962e 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -46,13 +46,6 @@ extern ssize_t arch_cpu_release(const char *, size_t);
 #endif
 struct notifier_block;
 
-#ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
-extern int arch_cpu_uevent(struct device *dev, struct kobj_uevent_env *env);
-extern ssize_t arch_print_cpu_modalias(struct device *dev,
-				       struct device_attribute *attr,
-				       char *bufptr);
-#endif
-
 /*
  * CPU notifier priorities.
  */
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 8a69005..5fdad83 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -1110,7 +1110,7 @@ static int do_amba_entry(const char *filename,
 }
 ADD_TO_DEVTABLE("amba", amba_id, do_amba_entry);
 
-/* LOOKS like x86cpu:vendor:VVVV:family:FFFF:model:MMMM:feature:*,FEAT,*
+/* LOOKS like cpu:type:x86,venVVVVfamFFFFmodMMMM:feature:*,FEAT,*
  * All fields are numbers. It would be nicer to use strings for vendor
  * and feature, but getting those out of the build system here is too
  * complicated.
@@ -1124,10 +1124,10 @@ static int do_x86cpu_entry(const char *filename, void *symval,
 	DEF_FIELD(symval, x86_cpu_id, model);
 	DEF_FIELD(symval, x86_cpu_id, vendor);
 
-	strcpy(alias, "x86cpu:");
-	ADD(alias, "vendor:",  vendor != X86_VENDOR_ANY, vendor);
-	ADD(alias, ":family:", family != X86_FAMILY_ANY, family);
-	ADD(alias, ":model:",  model  != X86_MODEL_ANY,  model);
+	strcpy(alias, "cpu:type:x86,");
+	ADD(alias, "ven", vendor != X86_VENDOR_ANY, vendor);
+	ADD(alias, "fam", family != X86_FAMILY_ANY, family);
+	ADD(alias, "mod", model  != X86_MODEL_ANY,  model);
 	strcat(alias, ":feature:*");
 	if (feature != X86_FEATURE_ANY)
 		sprintf(alias + strlen(alias), "%04X*", feature);
-- 
1.8.3.2