1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright IBM Corp. 2019
5 #include <asm/mem_detect.h>
6 #include <asm/pgtable.h>
10 #include "compressed/decompressor.h"
13 #define PRNG_MODE_TDES 1
14 #define PRNG_MODE_SHA512 2
15 #define PRNG_MODE_TRNG 3
31 static int check_prng(void)
33 if (!cpacf_query_func(CPACF_KMC, CPACF_KMC_PRNG)) {
34 sclp_early_printk("KASLR disabled: CPU has no PRNG\n");
37 if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_TRNG))
38 return PRNG_MODE_TRNG;
39 if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_SHA512_DRNG_GEN))
40 return PRNG_MODE_SHA512;
42 return PRNG_MODE_TDES;
45 static unsigned long get_random(unsigned long limit)
47 struct prng_parm prng = {
48 /* initial parameter block for tdes mode, copied from libica */
50 0x0F, 0x2B, 0x8E, 0x63, 0x8C, 0x8E, 0xD2, 0x52,
51 0x64, 0xB7, 0xA0, 0x7B, 0x75, 0x28, 0xB8, 0xF4,
52 0x75, 0x5F, 0xD2, 0xA6, 0x8D, 0x97, 0x11, 0xFF,
53 0x49, 0xD8, 0x23, 0xF3, 0x7E, 0x21, 0xEC, 0xA0
56 unsigned long seed, random;
57 struct prno_parm prno;
62 seed = get_tod_clock_fast();
65 cpacf_trng(NULL, 0, (u8 *) &random, sizeof(random));
67 case PRNG_MODE_SHA512:
68 cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED, &prno, NULL, 0,
69 (u8 *) &seed, sizeof(seed));
70 cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, &prno, (u8 *) &random,
71 sizeof(random), NULL, 0);
75 *(unsigned long *) prng.parm_block ^= seed;
76 for (i = 0; i < 16; i++) {
77 cpacf_kmc(CPACF_KMC_PRNG, prng.parm_block,
78 (u8 *) entropy, (u8 *) entropy,
80 memcpy(prng.parm_block, entropy, sizeof(entropy));
83 cpacf_kmc(CPACF_KMC_PRNG, prng.parm_block, (u8 *) &random,
84 (u8 *) &random, sizeof(random));
89 return random % limit;
92 unsigned long get_random_base(unsigned long safe_addr)
94 unsigned long memory_limit = memory_end_set ? memory_end : 0;
95 unsigned long base, start, end, kernel_size;
96 unsigned long block_sum, offset;
97 unsigned long kasan_needs;
100 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && INITRD_START && INITRD_SIZE) {
101 if (safe_addr < INITRD_START + INITRD_SIZE)
102 safe_addr = INITRD_START + INITRD_SIZE;
104 safe_addr = ALIGN(safe_addr, THREAD_SIZE);
106 if ((IS_ENABLED(CONFIG_KASAN))) {
108 * Estimate kasan memory requirements, which it will reserve
109 * at the very end of available physical memory. To estimate
110 * that, we take into account that kasan would require
111 * 1/8 of available physical memory (for shadow memory) +
112 * creating page tables for the whole memory + shadow memory
113 * region (1 + 1/8). To keep page tables estimates simple take
114 * the double of combined ptes size.
116 memory_limit = get_mem_detect_end();
117 if (memory_end_set && memory_limit > memory_end)
118 memory_limit = memory_end;
120 /* for shadow memory */
121 kasan_needs = memory_limit / 8;
122 /* for paging structures */
123 kasan_needs += (memory_limit + kasan_needs) / PAGE_SIZE /
124 _PAGE_ENTRIES * _PAGE_TABLE_SIZE * 2;
125 memory_limit -= kasan_needs;
128 kernel_size = vmlinux.image_size + vmlinux.bss_size;
130 for_each_mem_detect_block(i, &start, &end) {
132 if (start >= memory_limit)
134 if (end > memory_limit)
137 if (end - start < kernel_size)
139 block_sum += end - start - kernel_size;
142 sclp_early_printk("KASLR disabled: not enough memory\n");
146 base = get_random(block_sum);
149 if (base < safe_addr)
151 block_sum = offset = 0;
152 for_each_mem_detect_block(i, &start, &end) {
154 if (start >= memory_limit)
156 if (end > memory_limit)
159 if (end - start < kernel_size)
161 block_sum += end - start - kernel_size;
162 if (base <= block_sum) {
163 base = start + base - offset;
164 base = ALIGN_DOWN(base, THREAD_SIZE);