Commit 8801b3fc authored by Borislav Petkov's avatar Borislav Petkov Committed by Thomas Gleixner
Browse files

x86/microcode/AMD: Rework container parsing 



It was pretty clumsy before and the whole work of parsing the microcode
containers was spread around the functions wrongly.

Clean it up so that there's a main scan_containers() function which
iterates over the microcode blob and picks apart the containers glued
together. For each container, it calls a parse_container() helper which
concentrates on one container only: sanity-checking, parsing, counting
microcode patches in there, etc.

It makes much more sense now and it is actually very readable. Oh, and
we luvz a diffstat removing more crap than adding.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-8-bp@alien8.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent f454177f

arch/x86/kernel/cpu/microcode/amd.c

+105 −133
Original line number Diff line number Diff line
@@ -64,43 +64,6 @@ static u16 this_equiv_id; 
static const char

ucode_path[] __maybe_unused = "kernel/x86/microcode/AuthenticAMD.bin";



static size_t compute_container_size(u8 *data, u32 total_size)

{

	size_t size = 0;

	u32 *header = (u32 *)data;



	if (header[0] != UCODE_MAGIC ||

	    header[1] != UCODE_EQUIV_CPU_TABLE_TYPE || /* type */

	    header[2] == 0)                            /* size */

		return size;



	size = header[2] + CONTAINER_HDR_SZ;

	total_size -= size;

	data += size;



	while (total_size) {

		u16 patch_size;



		header = (u32 *)data;



		if (header[0] != UCODE_UCODE_TYPE)

			break;



		/*

		 * Sanity-check patch size.

		 */

		patch_size = header[1];

		if (patch_size > PATCH_MAX_SIZE)

			break;



		size	   += patch_size + SECTION_HDR_SIZE;

		data	   += patch_size + SECTION_HDR_SIZE;

		total_size -= patch_size + SECTION_HDR_SIZE;

	}



	return size;

}



static u16 find_equiv_id(struct equiv_cpu_entry *equiv_table, u32 sig)

{

	for (; equiv_table && equiv_table->installed_cpu; equiv_table++) {
@@ -115,80 +78,106 @@ static u16 find_equiv_id(struct equiv_cpu_entry *equiv_table, u32 sig) 
 * This scans the ucode blob for the proper container as we can have multiple

 * containers glued together. Returns the equivalence ID from the equivalence

 * table or 0 if none found.

 * Returns the amount of bytes consumed while scanning. @desc contains all the

 * data we're going to use in later stages of the application.

 */

static u16

find_proper_container(u8 *ucode, size_t size, struct cont_desc *desc)

static ssize_t parse_container(u8 *ucode, ssize_t size, struct cont_desc *desc)

{

	struct cont_desc ret = { 0 };

	u32 eax, ebx, ecx, edx;

	struct equiv_cpu_entry *eq;

	int offset, left;

	u16 eq_id = 0;

	u32 *header;

	u8 *data;

	ssize_t orig_size = size;

	u32 *hdr = (u32 *)ucode;

	u32 eax, ebx, ecx, edx;

	u16 eq_id;

	u8 *buf;



	data   = ucode;

	left   = size;

	header = (u32 *)data;

	/* Am I looking at an equivalence table header? */

	if (hdr[0] != UCODE_MAGIC ||

	    hdr[1] != UCODE_EQUIV_CPU_TABLE_TYPE ||

	    hdr[2] == 0) {

		desc->eq_id = 0;

		return CONTAINER_HDR_SZ;

	}



	buf = ucode;



	/* find equiv cpu table */

	if (header[0] != UCODE_MAGIC ||

	    header[1] != UCODE_EQUIV_CPU_TABLE_TYPE || /* type */

	    header[2] == 0)                            /* size */

		return eq_id;

	eq = (struct equiv_cpu_entry *)(buf + CONTAINER_HDR_SZ);



	eax = 0x00000001;

	eax = 1;

	ecx = 0;

	native_cpuid(&eax, &ebx, &ecx, &edx);



	while (left > 0) {

		eq = (struct equiv_cpu_entry *)(data + CONTAINER_HDR_SZ);



		ret.data = data;



		/* Advance past the container header */

		offset = header[2] + CONTAINER_HDR_SZ;

		data  += offset;

		left  -= offset;



	/* Find the equivalence ID of our CPU in this table: */

	eq_id = find_equiv_id(eq, eax);

		if (eq_id) {

			ret.size = compute_container_size(ret.data, left + offset);



	buf  += hdr[2] + CONTAINER_HDR_SZ;

	size -= hdr[2] + CONTAINER_HDR_SZ;



	/*

			 * truncate how much we need to iterate over in the

			 * ucode update loop below

	 * Scan through the rest of the container to find where it ends. We do

	 * some basic sanity-checking too.

	 */

			left = ret.size - offset;

	while (size > 0) {

		struct microcode_amd *mc;

		u32 patch_size;



		hdr = (u32 *)buf;



		if (hdr[0] != UCODE_UCODE_TYPE)

			break;



		/* Sanity-check patch size. */

		patch_size = hdr[1];

		if (patch_size > PATCH_MAX_SIZE)

			break;



			*desc = ret;

			return eq_id;

		/* Skip patch section header: */

		buf  += SECTION_HDR_SIZE;

		size -= SECTION_HDR_SIZE;



		mc = (struct microcode_amd *)buf;

		if (eq_id == mc->hdr.processor_rev_id) {

			desc->psize = patch_size;

			desc->mc = mc;

		}



		buf  += patch_size;

		size -= patch_size;

	}



	/*

		 * support multiple container files appended together. if this

		 * one does not have a matching equivalent cpu entry, we fast

		 * forward to the next container file.

	 * If we have found a patch (desc->mc), it means we're looking at the

	 * container which has a patch for this CPU so return 0 to mean, @ucode

	 * already points to the proper container. Otherwise, we return the size

	 * we scanned so that we can advance to the next container in the

	 * buffer.

	 */

		while (left > 0) {

			header = (u32 *)data;



			if (header[0] == UCODE_MAGIC &&

			    header[1] == UCODE_EQUIV_CPU_TABLE_TYPE)

				break;

	if (desc->mc) {

		desc->eq_id = eq_id;

		desc->data  = ucode;

		desc->size  = orig_size - size;



			offset = header[1] + SECTION_HDR_SIZE;

			data  += offset;

			left  -= offset;

		return 0;

	}



		/* mark where the next microcode container file starts */

		offset    = data - (u8 *)ucode;

		ucode     = data;

	return orig_size - size;

}



	return eq_id;

/*

 * Scan the ucode blob for the proper container as we can have multiple

 * containers glued together.

 */

static void scan_containers(u8 *ucode, size_t size, struct cont_desc *desc)

{

	ssize_t rem = size;



	while (rem >= 0) {

		ssize_t s = parse_container(ucode, rem, desc);

		if (!s)

			return;



		ucode += s;

		rem   -= s;

	}

}



static int __apply_microcode_amd(struct microcode_amd *mc)
@@ -214,17 +203,16 @@ static int __apply_microcode_amd(struct microcode_amd *mc) 
 * load_microcode_amd() to save equivalent cpu table and microcode patches in

 * kernel heap memory.

 *

 * Returns true if container found (sets @ret_cont), false otherwise.

 * Returns true if container found (sets @desc), false otherwise.

 */

static bool apply_microcode_early_amd(void *ucode, size_t size, bool save_patch,

				      struct cont_desc *desc)

				      struct cont_desc *ret_desc)

{

	struct cont_desc desc = { 0 };

	u8 (*patch)[PATCH_MAX_SIZE];

	u32 rev, *header, *new_rev;

	struct cont_desc ret;

	int offset, left;

	u16 eq_id = 0;

	u8  *data;

	struct microcode_amd *mc;

	u32 rev, *new_rev;

	bool ret = false;



#ifdef CONFIG_X86_32

	new_rev = (u32 *)__pa_nodebug(&ucode_new_rev);
@@ -237,47 +225,31 @@ static bool apply_microcode_early_amd(void *ucode, size_t size, bool save_patch, 
	if (check_current_patch_level(&rev, true))

		return false;



	eq_id = find_proper_container(ucode, size, &ret);

	if (!eq_id)

		return false;



	this_equiv_id = eq_id;

	header = (u32 *)ret.data;



	/* We're pointing to an equiv table, skip over it. */

	data = ret.data +  header[2] + CONTAINER_HDR_SZ;

	left = ret.size - (header[2] + CONTAINER_HDR_SZ);



	while (left > 0) {

		struct microcode_amd *mc;

	scan_containers(ucode, size, &desc);

	if (!desc.eq_id)

		return ret;



		header = (u32 *)data;

		if (header[0] != UCODE_UCODE_TYPE || /* type */

		    header[1] == 0)                  /* size */

			break;

	this_equiv_id = desc.eq_id;



		mc = (struct microcode_amd *)(data + SECTION_HDR_SIZE);

	mc = desc.mc;

	if (!mc)

		return ret;



		if (eq_id == mc->hdr.processor_rev_id && rev < mc->hdr.patch_id) {

	if (rev >= mc->hdr.patch_id)

		return ret;



	if (!__apply_microcode_amd(mc)) {

				rev = mc->hdr.patch_id;

				*new_rev = rev;

		*new_rev = mc->hdr.patch_id;

		ret      = true;



		if (save_patch)

					memcpy(patch, mc, min_t(u32, header[1], PATCH_MAX_SIZE));

			}

		}



		offset  = header[1] + SECTION_HDR_SIZE;

		data   += offset;

		left   -= offset;

			memcpy(patch, mc, min_t(u32, desc.psize, PATCH_MAX_SIZE));

	}



	if (desc)

		*desc = ret;

	if (ret_desc)

		*ret_desc = desc;



	return true;

	return ret;

}



static bool get_builtin_microcode(struct cpio_data *cp, unsigned int family)
@@ -396,6 +368,7 @@ reget: 
		}



		if (!apply_microcode_early_amd(cp.data, cp.size, false, &cont)) {

			cont.data = NULL;

			cont.size = -1;

			return;

		}
@@ -434,7 +407,6 @@ int __init save_microcode_in_initrd_amd(unsigned int fam) 
{

	enum ucode_state ret;

	int retval = 0;

	u16 eq_id;



	if (!cont.data) {

		if (IS_ENABLED(CONFIG_X86_32) && (cont.size != -1)) {
@@ -450,8 +422,8 @@ int __init save_microcode_in_initrd_amd(unsigned int fam) 
				return -EINVAL;

			}



			eq_id = find_proper_container(cp.data, cp.size, &cont);

			if (!eq_id) {

			scan_containers(cp.data, cp.size, &cont);

			if (!cont.eq_id) {

				cont.size = -1;

				return -EINVAL;

			}

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