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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright IBM Corp. 2019
*/
#include <linux/pgtable.h>
#include <asm/physmem_info.h>
#include <asm/cpacf.h>
#include <asm/timex.h>
#include <asm/sclp.h>
#include <asm/kasan.h>
#include "decompressor.h"
#include "boot.h"
#define PRNG_MODE_TDES 1
#define PRNG_MODE_SHA512 2
#define PRNG_MODE_TRNG 3
struct prno_parm {
u32 res;
u32 reseed_counter;
u64 stream_bytes;
u8 V[112];
u8 C[112];
};
struct prng_parm {
u8 parm_block[32];
u32 reseed_counter;
u64 byte_counter;
};
static int check_prng(void)
{
if (!cpacf_query_func(CPACF_KMC, CPACF_KMC_PRNG)) {
sclp_early_printk("KASLR disabled: CPU has no PRNG\n");
return 0;
}
if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_TRNG))
return PRNG_MODE_TRNG;
if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_SHA512_DRNG_GEN))
return PRNG_MODE_SHA512;
else
return PRNG_MODE_TDES;
}
static int get_random(unsigned long limit, unsigned long *value)
{
struct prng_parm prng = {
/* initial parameter block for tdes mode, copied from libica */
.parm_block = {
0x0F, 0x2B, 0x8E, 0x63, 0x8C, 0x8E, 0xD2, 0x52,
0x64, 0xB7, 0xA0, 0x7B, 0x75, 0x28, 0xB8, 0xF4,
0x75, 0x5F, 0xD2, 0xA6, 0x8D, 0x97, 0x11, 0xFF,
0x49, 0xD8, 0x23, 0xF3, 0x7E, 0x21, 0xEC, 0xA0
},
};
unsigned long seed, random;
struct prno_parm prno;
__u64 entropy[4];
int mode, i;
mode = check_prng();
seed = get_tod_clock_fast();
switch (mode) {
case PRNG_MODE_TRNG:
cpacf_trng(NULL, 0, (u8 *) &random, sizeof(random));
break;
case PRNG_MODE_SHA512:
cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED, &prno, NULL, 0,
(u8 *) &seed, sizeof(seed));
cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, &prno, (u8 *) &random,
sizeof(random), NULL, 0);
break;
case PRNG_MODE_TDES:
/* add entropy */
*(unsigned long *) prng.parm_block ^= seed;
for (i = 0; i < 16; i++) {
cpacf_kmc(CPACF_KMC_PRNG, prng.parm_block,
(u8 *) entropy, (u8 *) entropy,
sizeof(entropy));
memcpy(prng.parm_block, entropy, sizeof(entropy));
}
random = seed;
cpacf_kmc(CPACF_KMC_PRNG, prng.parm_block, (u8 *) &random,
(u8 *) &random, sizeof(random));
break;
default:
return -1;
}
*value = random % limit;
return 0;
}
unsigned long get_random_base(void)
{
unsigned long vmlinux_size = vmlinux.image_size + vmlinux.bss_size;
unsigned long minimal_pos = vmlinux.default_lma + vmlinux_size;
unsigned long random;
/* [vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size : physmem_info.usable] */
if (get_random(physmem_info.usable - minimal_pos, &random))
return 0;
return physmem_alloc_range(RR_VMLINUX, vmlinux_size, THREAD_SIZE,
vmlinux.default_lma, minimal_pos + random, false);
}
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