Message-Id: <20170117173734.14251-8-bp@alien8.de>
Date:   Tue, 17 Jan 2017 18:37:28 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     X86 ML <x86@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 07/13] x86/microcode: Decrease CPUID use

From: Borislav Petkov <bp@...e.de>

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@...e.de>
---
 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 1893f41c2d29..35c01243dec6 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;
  */
 struct cont_desc {
 	struct microcode_amd *mc;
+	u32 cpuid_1_eax;
 	u32 psize;
 	u16 eq_id;
 	u8 *data;
@@ -92,7 +93,6 @@ 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;
 
@@ -108,12 +108,8 @@ 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;
@@ -214,8 +210,9 @@ 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];
@@ -234,6 +231,8 @@ static bool apply_microcode_early_amd(void *ucode, size_t size, bool save_patch,
 	if (check_current_patch_level(&rev, true))
 		return ret;
 
+	desc.cpuid_1_eax = cpuid_1_eax;
+
 	scan_containers(ucode, size, &desc);
 	if (!desc.eq_id)
 		return ret;
@@ -276,10 +275,9 @@ 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;
@@ -294,19 +292,16 @@ 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
@@ -317,7 +312,7 @@ 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;
@@ -328,7 +323,7 @@ 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))
@@ -338,14 +333,14 @@ 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. */
@@ -360,7 +355,7 @@ 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);
@@ -376,17 +371,16 @@ 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;
 
@@ -412,7 +406,7 @@ 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;
@@ -431,6 +425,8 @@ 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;
@@ -441,7 +437,7 @@ 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

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