CPU: Introduce ARCH_HAS_CPU_AUTOPROBE and X86 parts

This patch is based on Andi Kleen's work:
Implement autoprobing/loading of modules serving CPU
specific features (x86cpu autoloading).

And Kay Siever's work to get rid of sysdev cpu structures
and making use of struct device instead.

Before, the cpuid driver had to be loaded to get the x86cpu
autoloading feature. With this patch autoloading works through
the /sys/devices/system/cpu object

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Acked-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 44 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c
index 7acc961..940e2d4 100644
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -2,6 +2,7 @@
 #include <asm/processor.h>
 #include <linux/cpu.h>
 #include <linux/module.h>
+#include <linux/slab.h>
 
 /**
  * x86_match_cpu - match current CPU again an array of x86_cpu_ids
@@ -46,3 +47,46 @@ 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 -= 2;
+	for (i = 0; i < NCAPINTS*32; i++) {
+		if (boot_cpu_has(i)) {
+			n = snprintf(buf, size, ",%04X", i);
+			if (n < 0) {
+				WARN(1, "x86 features overflow page\n");
+				break;
+			}
+			size -= n;
+			buf += n;
+		}
+	}
+	*buf++ = ',';
+	*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;
+}