[PATCH v6 01/11] x86/microcode/intel: Expose collect_cpu_info_early() for IFS

Tony Luck
2022-05-06T01:40:54Z

From: Jithu Joseph <jithu.joseph@intel.com>

IFS is a CPU feature that allows a binary blob, similar to microcode,
to be loaded and consumed to perform low level validation of CPU
circuitry. In fact, it carries the same Processor Signature
(family/model/stepping) details that are contained in Intel microcode
blobs.

In support of an IFS driver to trigger loading, validation, and running
of these tests blobs, make the functionality of cpu_signatures_match()
and collect_cpu_info_early() available outside of the microcode driver.

Add an "intel_" prefix and drop the "_early" suffix from
collect_cpu_info_early() and EXPORT_SYMBOL_GPL() it. Add
declaration to x86 <asm/cpu.h>

Make cpu_signatures_match() an inline function in x86 <asm/cpu.h>,
and also give it an "intel_" prefix.

No functional change intended.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
Co-developed-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov <bp@suse.de>
Reviewed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpu.h | 18 ++++++++
arch/x86/kernel/cpu/intel.c | 32 +++++++++++++++
arch/x86/kernel/cpu/microcode/intel.c | 59 ++++-----------------------
3 files changed, 57 insertions(+), 52 deletions(-)

diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index 86e5e4e26fcb..990167357c34 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -76,4 +76,22 @@ static inline void init_ia32_feat_ctl(struct cpuinfo_x86 *c) {}

extern __noendbr void cet_disable(void);

+struct ucode_cpu_info;
+
+int intel_cpu_collect_info(struct ucode_cpu_info *uci);
+
+static inline bool intel_cpu_signatures_match(unsigned int s1, unsigned int p1,
+ unsigned int s2, unsigned int p2)
+{
+ if (s1 != s2)
+ return false;
+
+ /* Processor flags are either both 0 ... */
+ if (!p1 && !p2)
+ return true;
+
+ /* ... or they intersect. */
+ return p1 & p2;
+}
+
#endif /* _ASM_X86_CPU_H */
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index f7a5370a9b3b..94779146275d 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -181,6 +181,38 @@ static bool bad_spectre_microcode(struct cpuinfo_x86 *c)
return false;
}

+int intel_cpu_collect_info(struct ucode_cpu_info *uci)
+{
+ unsigned int val[2];
+ unsigned int family, model;
+ struct cpu_signature csig = { 0 };
+ unsigned int eax, ebx, ecx, edx;
+
+ memset(uci, 0, sizeof(*uci));
+
+ eax = 0x00000001;
+ ecx = 0;
+ native_cpuid(&eax, &ebx, &ecx, &edx);
+ csig.sig = eax;
+
+ family = x86_family(eax);
+ model = x86_model(eax);
+
+ if (model >= 5 || family > 6) {
+ /* get processor flags from MSR 0x17 */
+ native_rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
+ csig.pf = 1 << ((val[1] >> 18) & 7);
+ }
+
+ csig.rev = intel_get_microcode_revision();
+
+ uci->cpu_sig = csig;
+ uci->valid = 1;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(intel_cpu_collect_info);
+
static void early_init_intel(struct cpuinfo_x86 *c)
{
u64 misc_enable;
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index d28a9f8f3fec..025c8f0cd948 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -45,20 +45,6 @@ static struct microcode_intel *intel_ucode_patch;
/* last level cache size per core */
static int llc_size_per_core;

-static inline bool cpu_signatures_match(unsigned int s1, unsigned int p1,
- unsigned int s2, unsigned int p2)
-{
- if (s1 != s2)
- return false;
-
- /* Processor flags are either both 0 ... */
- if (!p1 && !p2)
- return true;
-
- /* ... or they intersect. */
- return p1 & p2;
-}
-
/*
* Returns 1 if update has been found, 0 otherwise.
*/
@@ -69,7 +55,7 @@ static int find_matching_signature(void *mc, unsigned int csig, int cpf)
struct extended_signature *ext_sig;
int i;

- if (cpu_signatures_match(csig, cpf, mc_hdr->sig, mc_hdr->pf))
+ if (intel_cpu_signatures_match(csig, cpf, mc_hdr->sig, mc_hdr->pf))
return 1;

/* Look for ext. headers: */
@@ -80,7 +66,7 @@ static int find_matching_signature(void *mc, unsigned int csig, int cpf)
ext_sig = (void *)ext_hdr + EXT_HEADER_SIZE;

for (i = 0; i < ext_hdr->count; i++) {
- if (cpu_signatures_match(csig, cpf, ext_sig->sig, ext_sig->pf))
+ if (intel_cpu_signatures_match(csig, cpf, ext_sig->sig, ext_sig->pf))
return 1;
ext_sig++;
}
@@ -342,37 +328,6 @@ scan_microcode(void *data, size_t size, struct ucode_cpu_info *uci, bool save)
return patch;
}

-static int collect_cpu_info_early(struct ucode_cpu_info *uci)
-{
- unsigned int val[2];
- unsigned int family, model;
- struct cpu_signature csig = { 0 };
- unsigned int eax, ebx, ecx, edx;
-
- memset(uci, 0, sizeof(*uci));
-
- eax = 0x00000001;
- ecx = 0;
- native_cpuid(&eax, &ebx, &ecx, &edx);
- csig.sig = eax;
-
- family = x86_family(eax);
- model = x86_model(eax);
-
- if ((model >= 5) || (family > 6)) {
- /* get processor flags from MSR 0x17 */
- native_rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
- csig.pf = 1 << ((val[1] >> 18) & 7);
- }
-
- csig.rev = intel_get_microcode_revision();
-
- uci->cpu_sig = csig;
- uci->valid = 1;
-
- return 0;
-}
-
static void show_saved_mc(void)
{
#ifdef DEBUG
@@ -386,7 +341,7 @@ static void show_saved_mc(void)
return;
}

- collect_cpu_info_early(&uci);
+ intel_cpu_collect_info(&uci);

sig = uci.cpu_sig.sig;
pf = uci.cpu_sig.pf;
@@ -502,7 +457,7 @@ void show_ucode_info_early(void)
struct ucode_cpu_info uci;

if (delay_ucode_info) {
- collect_cpu_info_early(&uci);
+ intel_cpu_collect_info(&uci);
print_ucode_info(&uci, current_mc_date);
delay_ucode_info = 0;
}
@@ -604,7 +559,7 @@ int __init save_microcode_in_initrd_intel(void)
if (!(cp.data && cp.size))
return 0;

- collect_cpu_info_early(&uci);
+ intel_cpu_collect_info(&uci);

scan_microcode(cp.data, cp.size, &uci, true);

@@ -637,7 +592,7 @@ static struct microcode_intel *__load_ucode_intel(struct ucode_cpu_info *uci)
if (!(cp.data && cp.size))
return NULL;

- collect_cpu_info_early(uci);
+ intel_cpu_collect_info(uci);

return scan_microcode(cp.data, cp.size, uci, false);
}
@@ -712,7 +667,7 @@ void reload_ucode_intel(void)
struct microcode_intel *p;
struct ucode_cpu_info uci;

- collect_cpu_info_early(&uci);
+ intel_cpu_collect_info(&uci);

p = find_patch(&uci);
if (!p)
--
2.35.1