[PATCH 08/16] x86/microcode: Decrease CPUID use

From: Borislav Petkov
Date: Fri Jan 20 2017 - 15:31:22 EST

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From: Borislav Petkov <bp@xxxxxxx>

Get CPUID(1).EAX value once per CPU and propagate value into the callers
instead of conveniently calling it every time.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/microcode/amd.c | 52 +++++++++++++++++-------------------
arch/x86/kernel/cpu/microcode/core.c | 38 ++++++++++----------------
2 files changed, 38 insertions(+), 52 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 9d5f4f3626f7..9fb398e64b0a 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -47,6 +47,7 @@ static struct equiv_cpu_entry *equiv_cpu_table;
*/
static struct cont_desc {
struct microcode_amd *mc;
+ u32 cpuid_1_eax;
u32 psize;
u16 eq_id;
u8 *data;
@@ -86,7 +87,6 @@ static ssize_t parse_container(u8 *ucode, ssize_t size, struct cont_desc *desc)
struct equiv_cpu_entry *eq;
ssize_t orig_size = size;
u32 *hdr = (u32 *)ucode;
- u32 eax, ebx, ecx, edx;
u16 eq_id;
u8 *buf;

@@ -102,12 +102,8 @@ static ssize_t parse_container(u8 *ucode, ssize_t size, struct cont_desc *desc)

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

- eax = 1;
- ecx = 0;
- native_cpuid(&eax, &ebx, &ecx, &edx);
-
/* Find the equivalence ID of our CPU in this table: */
- eq_id = find_equiv_id(eq, eax);
+ eq_id = find_equiv_id(eq, desc->cpuid_1_eax);

buf += hdr[2] + CONTAINER_HDR_SZ;
size -= hdr[2] + CONTAINER_HDR_SZ;
@@ -205,8 +201,9 @@ static int __apply_microcode_amd(struct microcode_amd *mc)
*
* 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 *ret_desc)
+static bool
+apply_microcode_early_amd(u32 cpuid_1_eax, void *ucode, size_t size,
+ bool save_patch, struct cont_desc *ret_desc)
{
struct cont_desc desc = { 0 };
u8 (*patch)[PATCH_MAX_SIZE];
@@ -225,6 +222,8 @@ static bool apply_microcode_early_amd(void *ucode, size_t size, bool save_patch,
if (check_current_patch_level(&rev, true))
return false;

+ desc.cpuid_1_eax = cpuid_1_eax;
+
scan_containers(ucode, size, &desc);
if (!desc.eq_id)
return ret;
@@ -267,10 +266,9 @@ static bool get_builtin_microcode(struct cpio_data *cp, unsigned int family)
#endif
}

-void __init load_ucode_amd_bsp(unsigned int family)
+void __init load_ucode_amd_bsp(unsigned int cpuid_1_eax)
{
struct ucode_cpu_info *uci;
- u32 eax, ebx, ecx, edx;
struct cpio_data cp;
const char *path;
bool use_pa;
@@ -285,19 +283,16 @@ void __init load_ucode_amd_bsp(unsigned int family)
use_pa = false;
}

- if (!get_builtin_microcode(&cp, family))
+ if (!get_builtin_microcode(&cp, x86_family(cpuid_1_eax)))
cp = find_microcode_in_initrd(path, use_pa);

if (!(cp.data && cp.size))
return;

- /* Get BSP's CPUID.EAX(1), needed in load_microcode_amd() */
- eax = 1;
- ecx = 0;
- native_cpuid(&eax, &ebx, &ecx, &edx);
- uci->cpu_sig.sig = eax;
+ /* Needed in load_microcode_amd() */
+ uci->cpu_sig.sig = cpuid_1_eax;

- apply_microcode_early_amd(cp.data, cp.size, true, NULL);
+ apply_microcode_early_amd(cpuid_1_eax, cp.data, cp.size, true, NULL);
}

#ifdef CONFIG_X86_32
@@ -308,7 +303,7 @@ void __init load_ucode_amd_bsp(unsigned int family)
* In save_microcode_in_initrd_amd() BSP's patch is copied to amd_ucode_patch,
* which is used upon resume from suspend.
*/
-void load_ucode_amd_ap(unsigned int family)
+void load_ucode_amd_ap(unsigned int cpuid_1_eax)
{
struct microcode_amd *mc;
struct cpio_data cp;
@@ -319,7 +314,7 @@ void load_ucode_amd_ap(unsigned int family)
return;
}

- if (!get_builtin_microcode(&cp, family))
+ if (!get_builtin_microcode(&cp, x86_family(cpuid_1_eax)))
cp = find_microcode_in_initrd((const char *)__pa_nodebug(ucode_path), true);

if (!(cp.data && cp.size))
@@ -329,14 +324,14 @@ void load_ucode_amd_ap(unsigned int family)
* This would set amd_ucode_patch above so that the following APs can
* use it directly instead of going down this path again.
*/
- apply_microcode_early_amd(cp.data, cp.size, true, NULL);
+ apply_microcode_early_amd(cpuid_1_eax, cp.data, cp.size, true, NULL);
}
#else
-void load_ucode_amd_ap(unsigned int family)
+void load_ucode_amd_ap(unsigned int cpuid_1_eax)
{
struct equiv_cpu_entry *eq;
struct microcode_amd *mc;
- u32 rev, eax;
+ u32 rev;
u16 eq_id;

/* 64-bit runs with paging enabled, thus early==false. */
@@ -351,7 +346,7 @@ void load_ucode_amd_ap(unsigned int family)
return;

reget:
- if (!get_builtin_microcode(&cp, family)) {
+ if (!get_builtin_microcode(&cp, x86_family(cpuid_1_eax))) {
#ifdef CONFIG_BLK_DEV_INITRD
cp = find_cpio_data(ucode_path, (void *)initrd_start,
initrd_end - initrd_start, NULL);
@@ -367,17 +362,16 @@ void load_ucode_amd_ap(unsigned int family)
}
}

- if (!apply_microcode_early_amd(cp.data, cp.size, false, &cont)) {
+ if (!apply_microcode_early_amd(cpuid_1_eax, cp.data, cp.size, false, &cont)) {
cont.data = NULL;
cont.size = -1;
return;
}
}

- eax = cpuid_eax(0x00000001);
eq = (struct equiv_cpu_entry *)(cont.data + CONTAINER_HDR_SZ);

- eq_id = find_equiv_id(eq, eax);
+ eq_id = find_equiv_id(eq, cpuid_1_eax);
if (!eq_id)
return;

@@ -403,7 +397,7 @@ void load_ucode_amd_ap(unsigned int family)
static enum ucode_state
load_microcode_amd(int cpu, u8 family, const u8 *data, size_t size);

-int __init save_microcode_in_initrd_amd(unsigned int fam)
+int __init save_microcode_in_initrd_amd(unsigned int cpuid_1_eax)
{
enum ucode_state ret;
int retval = 0;
@@ -422,6 +416,8 @@ int __init save_microcode_in_initrd_amd(unsigned int fam)
return -EINVAL;
}

+ cont.cpuid_1_eax = cpuid_1_eax;
+
scan_containers(cp.data, cp.size, &cont);
if (!cont.eq_id) {
cont.size = -1;
@@ -432,7 +428,7 @@ int __init save_microcode_in_initrd_amd(unsigned int fam)
return -EINVAL;
}

- ret = load_microcode_amd(smp_processor_id(), fam, cont.data, cont.size);
+ ret = load_microcode_amd(smp_processor_id(), x86_family(cpuid_1_eax), cont.data, cont.size);
if (ret != UCODE_OK)
retval = -EINVAL;

diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index 2af69d27da62..437996c9be67 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -64,10 +64,6 @@ static DEFINE_MUTEX(microcode_mutex);

struct ucode_cpu_info ucode_cpu_info[NR_CPUS];

-/*
- * Operations that are run on a target cpu:
- */
-
struct cpu_info_ctx {
struct cpu_signature *cpu_sig;
int err;
@@ -76,7 +72,6 @@ struct cpu_info_ctx {
static bool __init check_loader_disabled_bsp(void)
{
static const char *__dis_opt_str = "dis_ucode_ldr";
- u32 a, b, c, d;

#ifdef CONFIG_X86_32
const char *cmdline = (const char *)__pa_nodebug(boot_command_line);
@@ -92,16 +87,12 @@ static bool __init check_loader_disabled_bsp(void)
if (!have_cpuid_p())
return *res;

- a = 1;
- c = 0;
- native_cpuid(&a, &b, &c, &d);
-
/*
* CPUID(1).ECX[31]: reserved for hypervisor use. This is still not
* completely accurate as xen pv guests don't see that CPUID bit set but
* that's good enough as they don't land on the BSP path anyway.
*/
- if (c & BIT(31))
+ if (native_cpuid_ecx(1) & BIT(31))
return *res;

if (cmdline_find_option_bool(cmdline, option) <= 0)
@@ -131,23 +122,22 @@ bool get_builtin_firmware(struct cpio_data *cd, const char *name)

void __init load_ucode_bsp(void)
{
- int vendor;
- unsigned int family;
+ unsigned int vendor, cpuid_1_eax;

if (check_loader_disabled_bsp())
return;

- vendor = x86_cpuid_vendor();
- family = x86_cpuid_family();
+ vendor = x86_cpuid_vendor();
+ cpuid_1_eax = native_cpuid_eax(1);

switch (vendor) {
case X86_VENDOR_INTEL:
- if (family >= 6)
+ if (x86_family(cpuid_1_eax) >= 6)
load_ucode_intel_bsp();
break;
case X86_VENDOR_AMD:
- if (family >= 0x10)
- load_ucode_amd_bsp(family);
+ if (x86_family(cpuid_1_eax) >= 0x10)
+ load_ucode_amd_bsp(cpuid_1_eax);
break;
default:
break;
@@ -165,22 +155,22 @@ static bool check_loader_disabled_ap(void)

void load_ucode_ap(void)
{
- int vendor, family;
+ unsigned int vendor, cpuid_1_eax;

if (check_loader_disabled_ap())
return;

- vendor = x86_cpuid_vendor();
- family = x86_cpuid_family();
+ vendor = x86_cpuid_vendor();
+ cpuid_1_eax = native_cpuid_eax(1);

switch (vendor) {
case X86_VENDOR_INTEL:
- if (family >= 6)
+ if (x86_family(cpuid_1_eax) >= 6)
load_ucode_intel_ap();
break;
case X86_VENDOR_AMD:
- if (family >= 0x10)
- load_ucode_amd_ap(family);
+ if (x86_family(cpuid_1_eax) >= 0x10)
+ load_ucode_amd_ap(cpuid_1_eax);
break;
default:
break;
@@ -198,7 +188,7 @@ static int __init save_microcode_in_initrd(void)
break;
case X86_VENDOR_AMD:
if (c->x86 >= 0x10)
- return save_microcode_in_initrd_amd(c->x86);
+ return save_microcode_in_initrd_amd(cpuid_eax(1));
break;
default:
break;
--
2.11.0

Next message: Borislav Petkov: "[PATCH 16/16] x86/microcode/AMD: Remove struct cont_desc.eq_id"
Previous message: Maxime Ripard: "Re: [PATCH v3 1/6] dt-bindings: add device tree binding for Allwinner V3s pinctrl"
In reply to: Borislav Petkov: "[PATCH 00/16 v2] x86/microcode: 4.11 queue"
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