1 /*
2  * Copyright (c) 2014 Google, Inc
3  * Copyright (C) 2000 Ronald G. Minnich
4  *
5  * Microcode update for Intel PIII and later CPUs
6  *
7  * SPDX-License-Identifier:	GPL-2.0
8  */
9 
10 #include <common.h>
11 #include <errno.h>
12 #include <fdtdec.h>
13 #include <linux/libfdt.h>
14 #include <asm/cpu.h>
15 #include <asm/microcode.h>
16 #include <asm/msr.h>
17 #include <asm/msr-index.h>
18 #include <asm/processor.h>
19 
20 DECLARE_GLOBAL_DATA_PTR;
21 
22 /**
23  * struct microcode_update - standard microcode header from Intel
24  *
25  * We read this information out of the device tree and use it to determine
26  * whether the update is applicable or not. We also use the same structure
27  * to read information from the CPU.
28  */
29 struct microcode_update {
30 	uint header_version;
31 	uint update_revision;
32 	uint date_code;
33 	uint processor_signature;
34 	uint checksum;
35 	uint loader_revision;
36 	uint processor_flags;
37 	const void *data;
38 	int size;
39 };
40 
41 static int microcode_decode_node(const void *blob, int node,
42 				 struct microcode_update *update)
43 {
44 	update->data = fdt_getprop(blob, node, "data", &update->size);
45 	if (!update->data)
46 		return -ENOENT;
47 	update->data += UCODE_HEADER_LEN;
48 	update->size -= UCODE_HEADER_LEN;
49 
50 	update->header_version = fdtdec_get_int(blob, node,
51 						"intel,header-version", 0);
52 	update->update_revision = fdtdec_get_int(blob, node,
53 						 "intel,update-revision", 0);
54 	update->date_code = fdtdec_get_int(blob, node,
55 					   "intel,date-code", 0);
56 	update->processor_signature = fdtdec_get_int(blob, node,
57 					"intel,processor-signature", 0);
58 	update->checksum = fdtdec_get_int(blob, node, "intel,checksum", 0);
59 	update->loader_revision = fdtdec_get_int(blob, node,
60 						 "intel,loader-revision", 0);
61 	update->processor_flags = fdtdec_get_int(blob, node,
62 						 "intel,processor-flags", 0);
63 
64 	return 0;
65 }
66 
67 int microcode_read_rev(void)
68 {
69 	/* Quark does not have microcode MSRs */
70 #ifdef CONFIG_INTEL_QUARK
71 	return 0;
72 #else
73 	/*
74 	 * Some Intel CPUs can be very finicky about the CPUID sequence used.
75 	 * So this is implemented in assembly so that it works reliably.
76 	 */
77 	uint32_t low, high;
78 
79 	asm volatile (
80 		"xorl %%eax, %%eax\n"
81 		"xorl %%edx, %%edx\n"
82 		"movl %2, %%ecx\n"
83 		"wrmsr\n"
84 		"movl $0x01, %%eax\n"
85 		"cpuid\n"
86 		"movl %2, %%ecx\n"
87 		"rdmsr\n"
88 		: /* outputs */
89 		"=a" (low), "=d" (high)
90 		: /* inputs */
91 		"i" (MSR_IA32_UCODE_REV)
92 		: /* clobbers */
93 		 "ebx", "ecx"
94 	);
95 
96 	return high;
97 #endif
98 }
99 
100 static void microcode_read_cpu(struct microcode_update *cpu)
101 {
102 	/* CPUID sets MSR 0x8B iff a microcode update has been loaded. */
103 	unsigned int x86_model, x86_family;
104 	struct cpuid_result result;
105 	uint32_t low, high;
106 
107 	wrmsr(MSR_IA32_UCODE_REV, 0, 0);
108 	result = cpuid(1);
109 	rdmsr(MSR_IA32_UCODE_REV, low, cpu->update_revision);
110 	x86_model = (result.eax >> 4) & 0x0f;
111 	x86_family = (result.eax >> 8) & 0x0f;
112 	cpu->processor_signature = result.eax;
113 
114 	cpu->processor_flags = 0;
115 	if ((x86_model >= 5) || (x86_family > 6)) {
116 		rdmsr(0x17, low, high);
117 		cpu->processor_flags = 1 << ((high >> 18) & 7);
118 	}
119 	debug("microcode: sig=%#x pf=%#x revision=%#x\n",
120 	      cpu->processor_signature, cpu->processor_flags,
121 	      cpu->update_revision);
122 }
123 
124 /* Get a microcode update from the device tree and apply it */
125 int microcode_update_intel(void)
126 {
127 	struct microcode_update cpu, update;
128 	const void *blob = gd->fdt_blob;
129 	int skipped;
130 	int count;
131 	int node;
132 	int ret;
133 	int rev;
134 
135 	microcode_read_cpu(&cpu);
136 	node = 0;
137 	count = 0;
138 	skipped = 0;
139 	do {
140 		node = fdtdec_next_compatible(blob, node,
141 					      COMPAT_INTEL_MICROCODE);
142 		if (node < 0) {
143 			debug("%s: Found %d updates\n", __func__, count);
144 			return count ? 0 : skipped ? -EEXIST : -ENOENT;
145 		}
146 
147 		ret = microcode_decode_node(blob, node, &update);
148 		if (ret == -ENOENT && ucode_base) {
149 			/*
150 			 * The microcode has been removed from the device tree
151 			 * in the build system. In that case it will have
152 			 * already been updated in car_init().
153 			 */
154 			debug("%s: Microcode data not available\n", __func__);
155 			skipped++;
156 			continue;
157 		}
158 		if (ret) {
159 			debug("%s: Unable to decode update: %d\n", __func__,
160 			      ret);
161 			return ret;
162 		}
163 		if (!(update.processor_signature == cpu.processor_signature &&
164 		      (update.processor_flags & cpu.processor_flags))) {
165 			debug("%s: Skipping non-matching update, sig=%x, pf=%x\n",
166 			      __func__, update.processor_signature,
167 			      update.processor_flags);
168 			skipped++;
169 			continue;
170 		}
171 		wrmsr(MSR_IA32_UCODE_WRITE, (ulong)update.data, 0);
172 		rev = microcode_read_rev();
173 		debug("microcode: updated to revision 0x%x date=%04x-%02x-%02x\n",
174 		      rev, update.date_code & 0xffff,
175 		      (update.date_code >> 24) & 0xff,
176 		      (update.date_code >> 16) & 0xff);
177 		if (update.update_revision != rev) {
178 			printf("Microcode update failed\n");
179 			return -EFAULT;
180 		}
181 		count++;
182 	} while (1);
183 }
184