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Commit a3eb3b4d authored by Borislav Petkov's avatar Borislav Petkov Committed by H. Peter Anvin
Browse files

x86, microcode, AMD: Add a small, per-family patches cache 



This is a trivial cache which collects all ucode patches for the current
family of CPUs on the system. If a newer patch appears due to the
container file being updated in userspace, we replace our cached version
with the new one.

Signed-off-by: default avatarBorislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/1344361461-10076-12-git-send-email-bp@amd64.org


Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent c96d2c09

arch/x86/kernel/microcode_amd.c

+66 −1
Original line number Diff line number Diff line
@@ -78,12 +78,22 @@ static struct equiv_cpu_entry *equiv_cpu_table; 
/* page-sized ucode patch buffer */

void *patch;



struct ucode_patch {

	struct list_head plist;

	void *data;

	u32 patch_id;

	u16 equiv_cpu;

};



static LIST_HEAD(pcache);



static u16 find_equiv_id(unsigned int cpu)

{

	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

	int i = 0;



	BUG_ON(equiv_cpu_table == NULL);

	if (!equiv_cpu_table)

		return 0;



	while (equiv_cpu_table[i].installed_cpu != 0) {

		if (uci->cpu_sig.sig == equiv_cpu_table[i].installed_cpu)
@@ -108,6 +118,61 @@ static u32 find_cpu_family_by_equiv_cpu(u16 equiv_cpu) 
	return 0;

}



/*

 * a small, trivial cache of per-family ucode patches

 */

static struct ucode_patch *cache_find_patch(u16 equiv_cpu)

{

	struct ucode_patch *p;



	list_for_each_entry(p, &pcache, plist)

		if (p->equiv_cpu == equiv_cpu)

			return p;

	return NULL;

}



static void update_cache(struct ucode_patch *new_patch)

{

	struct ucode_patch *p;



	list_for_each_entry(p, &pcache, plist) {

		if (p->equiv_cpu == new_patch->equiv_cpu) {

			if (p->patch_id >= new_patch->patch_id)

				/* we already have the latest patch */

				return;



			list_replace(&p->plist, &new_patch->plist);

			kfree(p->data);

			kfree(p);

			return;

		}

	}

	/* no patch found, add it */

	list_add_tail(&new_patch->plist, &pcache);

}



static void free_cache(void)

{

	struct ucode_patch *p;



	list_for_each_entry_reverse(p, &pcache, plist) {

		__list_del(p->plist.prev, p->plist.next);

		kfree(p->data);

		kfree(p);

	}

}



static struct ucode_patch *find_patch(unsigned int cpu)

{

	u16 equiv_id;



	equiv_id = find_equiv_id(cpu);

	if (!equiv_id)

		return NULL;



	return cache_find_patch(equiv_id);

}



static int collect_cpu_info_amd(int cpu, struct cpu_signature *csig)

{

	struct cpuinfo_x86 *c = &cpu_data(cpu);