Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * Copyright IBM Corp. 2019
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5) #include <linux/pgtable.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6) #include <asm/mem_detect.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) #include <asm/cpacf.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) #include <asm/timex.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <asm/sclp.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include "compressed/decompressor.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include "boot.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #define PRNG_MODE_TDES	 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #define PRNG_MODE_SHA512 2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #define PRNG_MODE_TRNG	 3
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) struct prno_parm {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) 	u32 res;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) 	u32 reseed_counter;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) 	u64 stream_bytes;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) 	u8  V[112];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) 	u8  C[112];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) struct prng_parm {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) 	u8  parm_block[32];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 	u32 reseed_counter;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 	u64 byte_counter;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) static int check_prng(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 	if (!cpacf_query_func(CPACF_KMC, CPACF_KMC_PRNG)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 		sclp_early_printk("KASLR disabled: CPU has no PRNG\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 	if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_TRNG))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 		return PRNG_MODE_TRNG;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 	if (cpacf_query_func(CPACF_PRNO, CPACF_PRNO_SHA512_DRNG_GEN))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 		return PRNG_MODE_SHA512;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 		return PRNG_MODE_TDES;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) static int get_random(unsigned long limit, unsigned long *value)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 	struct prng_parm prng = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 		/* initial parameter block for tdes mode, copied from libica */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 		.parm_block = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 			0x0F, 0x2B, 0x8E, 0x63, 0x8C, 0x8E, 0xD2, 0x52,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 			0x64, 0xB7, 0xA0, 0x7B, 0x75, 0x28, 0xB8, 0xF4,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 			0x75, 0x5F, 0xD2, 0xA6, 0x8D, 0x97, 0x11, 0xFF,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 			0x49, 0xD8, 0x23, 0xF3, 0x7E, 0x21, 0xEC, 0xA0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 		},
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	};
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	unsigned long seed, random;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	struct prno_parm prno;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 	__u64 entropy[4];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 	int mode, i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 	mode = check_prng();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 	seed = get_tod_clock_fast();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 	switch (mode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	case PRNG_MODE_TRNG:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 		cpacf_trng(NULL, 0, (u8 *) &random, sizeof(random));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 	case PRNG_MODE_SHA512:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 		cpacf_prno(CPACF_PRNO_SHA512_DRNG_SEED, &prno, NULL, 0,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 			   (u8 *) &seed, sizeof(seed));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 		cpacf_prno(CPACF_PRNO_SHA512_DRNG_GEN, &prno, (u8 *) &random,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 			   sizeof(random), NULL, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 	case PRNG_MODE_TDES:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 		/* add entropy */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 		*(unsigned long *) prng.parm_block ^= seed;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 		for (i = 0; i < 16; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 			cpacf_kmc(CPACF_KMC_PRNG, prng.parm_block,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 				  (u8 *) entropy, (u8 *) entropy,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 				  sizeof(entropy));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 			memcpy(prng.parm_block, entropy, sizeof(entropy));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 		random = seed;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 		cpacf_kmc(CPACF_KMC_PRNG, prng.parm_block, (u8 *) &random,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 			  (u8 *) &random, sizeof(random));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 	default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 		return -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	*value = random % limit;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94)  * To randomize kernel base address we have to consider several facts:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95)  * 1. physical online memory might not be continuous and have holes. mem_detect
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96)  *    info contains list of online memory ranges we should consider.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97)  * 2. we have several memory regions which are occupied and we should not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98)  *    overlap and destroy them. Currently safe_addr tells us the border below
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99)  *    which all those occupied regions are. We are safe to use anything above
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100)  *    safe_addr.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)  * 3. the upper limit might apply as well, even if memory above that limit is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102)  *    online. Currently those limitations are:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)  *    3.1. Limit set by "mem=" kernel command line option
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104)  *    3.2. memory reserved at the end for kasan initialization.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105)  * 4. kernel base address must be aligned to THREAD_SIZE (kernel stack size).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106)  *    Which is required for CONFIG_CHECK_STACK. Currently THREAD_SIZE is 4 pages
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107)  *    (16 pages when the kernel is built with kasan enabled)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108)  * Assumptions:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109)  * 1. kernel size (including .bss size) and upper memory limit are page aligned.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110)  * 2. mem_detect memory region start is THREAD_SIZE aligned / end is PAGE_SIZE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111)  *    aligned (in practice memory configurations granularity on z/VM and LPAR
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112)  *    is 1mb).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114)  * To guarantee uniform distribution of kernel base address among all suitable
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115)  * addresses we generate random value just once. For that we need to build a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116)  * continuous range in which every value would be suitable. We can build this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117)  * range by simply counting all suitable addresses (let's call them positions)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118)  * which would be valid as kernel base address. To count positions we iterate
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119)  * over online memory ranges. For each range which is big enough for the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120)  * kernel image we count all suitable addresses we can put the kernel image at
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121)  * that is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122)  * (end - start - kernel_size) / THREAD_SIZE + 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123)  * Two functions count_valid_kernel_positions and position_to_address help
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124)  * to count positions in memory range given and then convert position back
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125)  * to address.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) static unsigned long count_valid_kernel_positions(unsigned long kernel_size,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 						  unsigned long _min,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 						  unsigned long _max)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 	unsigned long start, end, pos = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 	int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	for_each_mem_detect_block(i, &start, &end) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 		if (_min >= end)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 		if (start >= _max)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 		start = max(_min, start);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 		end = min(_max, end);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 		if (end - start < kernel_size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 		pos += (end - start - kernel_size) / THREAD_SIZE + 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	return pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) static unsigned long position_to_address(unsigned long pos, unsigned long kernel_size,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 				 unsigned long _min, unsigned long _max)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 	unsigned long start, end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 	int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	for_each_mem_detect_block(i, &start, &end) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 		if (_min >= end)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 		if (start >= _max)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 		start = max(_min, start);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 		end = min(_max, end);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 		if (end - start < kernel_size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 			continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 		if ((end - start - kernel_size) / THREAD_SIZE + 1 >= pos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 			return start + (pos - 1) * THREAD_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 		pos -= (end - start - kernel_size) / THREAD_SIZE + 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) unsigned long get_random_base(unsigned long safe_addr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	unsigned long memory_limit = get_mem_detect_end();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	unsigned long base_pos, max_pos, kernel_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	unsigned long kasan_needs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	if (memory_end_set)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 		memory_limit = min(memory_limit, memory_end);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && INITRD_START && INITRD_SIZE) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 		if (safe_addr < INITRD_START + INITRD_SIZE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 			safe_addr = INITRD_START + INITRD_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 	safe_addr = ALIGN(safe_addr, THREAD_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	if ((IS_ENABLED(CONFIG_KASAN))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 		 * Estimate kasan memory requirements, which it will reserve
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 		 * at the very end of available physical memory. To estimate
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 		 * that, we take into account that kasan would require
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 		 * 1/8 of available physical memory (for shadow memory) +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 		 * creating page tables for the whole memory + shadow memory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 		 * region (1 + 1/8). To keep page tables estimates simple take
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 		 * the double of combined ptes size.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 		memory_limit = get_mem_detect_end();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 		if (memory_end_set && memory_limit > memory_end)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 			memory_limit = memory_end;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 		/* for shadow memory */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 		kasan_needs = memory_limit / 8;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 		/* for paging structures */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 		kasan_needs += (memory_limit + kasan_needs) / PAGE_SIZE /
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 			       _PAGE_ENTRIES * _PAGE_TABLE_SIZE * 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 		memory_limit -= kasan_needs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 	kernel_size = vmlinux.image_size + vmlinux.bss_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 	if (safe_addr + kernel_size > memory_limit)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 	max_pos = count_valid_kernel_positions(kernel_size, safe_addr, memory_limit);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 	if (!max_pos) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 		sclp_early_printk("KASLR disabled: not enough memory\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 	/* we need a value in the range [1, base_pos] inclusive */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 	if (get_random(max_pos, &base_pos))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) 	return position_to_address(base_pos + 1, kernel_size, safe_addr, memory_limit);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) }