Commit 716f3802 authored by Jithu Joseph's avatar Jithu Joseph Committed by Borislav Petkov
Browse files

x86/microcode/intel: Reuse find_matching_signature() 



IFS uses test images provided by Intel that can be regarded as firmware.
An IFS test image carries microcode header with an extended signature
table.

Reuse find_matching_signature() for verifying if the test image header
or the extended signature table indicate whether that image is fit to
run on a system.

No functional changes.

Signed-off-by: default avatarJithu Joseph <jithu.joseph@intel.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarTony Luck <tony.luck@intel.com>
Reviewed-by: default avatarAshok Raj <ashok.raj@intel.com>
Reviewed-by: default avatarSohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20221117035935.4136738-6-jithu.joseph@intel.com
parent cb5eceee

arch/x86/include/asm/cpu.h

+1 −0
Original line number Diff line number Diff line
@@ -95,5 +95,6 @@ static inline bool intel_cpu_signatures_match(unsigned int s1, unsigned int p1, 
}



extern u64 x86_read_arch_cap_msr(void);

int intel_find_matching_signature(void *mc, unsigned int csig, int cpf);



#endif /* _ASM_X86_CPU_H */

arch/x86/kernel/cpu/intel.c

+29 −0
Original line number Diff line number Diff line
@@ -215,6 +215,35 @@ int intel_cpu_collect_info(struct ucode_cpu_info *uci) 
}

EXPORT_SYMBOL_GPL(intel_cpu_collect_info);



/*

 * Returns 1 if update has been found, 0 otherwise.

 */

int intel_find_matching_signature(void *mc, unsigned int csig, int cpf)

{

	struct microcode_header_intel *mc_hdr = mc;

	struct extended_sigtable *ext_hdr;

	struct extended_signature *ext_sig;

	int i;



	if (intel_cpu_signatures_match(csig, cpf, mc_hdr->sig, mc_hdr->pf))

		return 1;



	/* Look for ext. headers: */

	if (get_totalsize(mc_hdr) <= get_datasize(mc_hdr) + MC_HEADER_SIZE)

		return 0;



	ext_hdr = mc + get_datasize(mc_hdr) + MC_HEADER_SIZE;

	ext_sig = (void *)ext_hdr + EXT_HEADER_SIZE;



	for (i = 0; i < ext_hdr->count; i++) {

		if (intel_cpu_signatures_match(csig, cpf, ext_sig->sig, ext_sig->pf))

			return 1;

		ext_sig++;

	}

	return 0;

}

EXPORT_SYMBOL_GPL(intel_find_matching_signature);



static void early_init_intel(struct cpuinfo_x86 *c)

{

	u64 misc_enable;

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

+8 −36
Original line number Diff line number Diff line
@@ -45,34 +45,6 @@ static struct microcode_intel *intel_ucode_patch; 
/* last level cache size per core */

static int llc_size_per_core;



/*

 * Returns 1 if update has been found, 0 otherwise.

 */

static int find_matching_signature(void *mc, unsigned int csig, int cpf)

{

	struct microcode_header_intel *mc_hdr = mc;

	struct extended_sigtable *ext_hdr;

	struct extended_signature *ext_sig;

	int i;



	if (intel_cpu_signatures_match(csig, cpf, mc_hdr->sig, mc_hdr->pf))

		return 1;



	/* Look for ext. headers: */

	if (get_totalsize(mc_hdr) <= get_datasize(mc_hdr) + MC_HEADER_SIZE)

		return 0;



	ext_hdr = mc + get_datasize(mc_hdr) + MC_HEADER_SIZE;

	ext_sig = (void *)ext_hdr + EXT_HEADER_SIZE;



	for (i = 0; i < ext_hdr->count; i++) {

		if (intel_cpu_signatures_match(csig, cpf, ext_sig->sig, ext_sig->pf))

			return 1;

		ext_sig++;

	}

	return 0;

}



/*

 * Returns 1 if update has been found, 0 otherwise.

 */
@@ -83,7 +55,7 @@ static int has_newer_microcode(void *mc, unsigned int csig, int cpf, int new_rev 
	if (mc_hdr->rev <= new_rev)

		return 0;



	return find_matching_signature(mc, csig, cpf);

	return intel_find_matching_signature(mc, csig, cpf);

}



static struct ucode_patch *memdup_patch(void *data, unsigned int size)
@@ -117,7 +89,7 @@ static void save_microcode_patch(struct ucode_cpu_info *uci, void *data, unsigne 
		sig	     = mc_saved_hdr->sig;

		pf	     = mc_saved_hdr->pf;



		if (find_matching_signature(data, sig, pf)) {

		if (intel_find_matching_signature(data, sig, pf)) {

			prev_found = true;



			if (mc_hdr->rev <= mc_saved_hdr->rev)
@@ -149,7 +121,7 @@ static void save_microcode_patch(struct ucode_cpu_info *uci, void *data, unsigne 
	if (!p)

		return;



	if (!find_matching_signature(p->data, uci->cpu_sig.sig, uci->cpu_sig.pf))

	if (!intel_find_matching_signature(p->data, uci->cpu_sig.sig, uci->cpu_sig.pf))

		return;



	/*
@@ -286,7 +258,7 @@ scan_microcode(void *data, size_t size, struct ucode_cpu_info *uci, bool save) 


		size -= mc_size;



		if (!find_matching_signature(data, uci->cpu_sig.sig,

		if (!intel_find_matching_signature(data, uci->cpu_sig.sig,

						   uci->cpu_sig.pf)) {

			data += mc_size;

			continue;
@@ -652,7 +624,7 @@ static struct microcode_intel *find_patch(struct ucode_cpu_info *uci) 
		if (phdr->rev <= uci->cpu_sig.rev)

			continue;



		if (!find_matching_signature(phdr,

		if (!intel_find_matching_signature(phdr,

						   uci->cpu_sig.sig,

						   uci->cpu_sig.pf))

			continue;