1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/kernel.h> 3 #include <linux/types.h> 4 #include <linux/init.h> 5 #include <linux/memblock.h> 6 #include <linux/seq_file.h> 7 8 static bool early_memtest_done; 9 static phys_addr_t early_memtest_bad_size; 10 11 static u64 patterns[] __initdata = { 12 /* The first entry has to be 0 to leave memtest with zeroed memory */ 13 0, 14 0xffffffffffffffffULL, 15 0x5555555555555555ULL, 16 0xaaaaaaaaaaaaaaaaULL, 17 0x1111111111111111ULL, 18 0x2222222222222222ULL, 19 0x4444444444444444ULL, 20 0x8888888888888888ULL, 21 0x3333333333333333ULL, 22 0x6666666666666666ULL, 23 0x9999999999999999ULL, 24 0xccccccccccccccccULL, 25 0x7777777777777777ULL, 26 0xbbbbbbbbbbbbbbbbULL, 27 0xddddddddddddddddULL, 28 0xeeeeeeeeeeeeeeeeULL, 29 0x7a6c7258554e494cULL, /* yeah ;-) */ 30 }; 31 32 static void __init reserve_bad_mem(u64 pattern, phys_addr_t start_bad, phys_addr_t end_bad) 33 { 34 pr_info(" %016llx bad mem addr %pa - %pa reserved\n", 35 cpu_to_be64(pattern), &start_bad, &end_bad); 36 memblock_reserve(start_bad, end_bad - start_bad); 37 early_memtest_bad_size += (end_bad - start_bad); 38 } 39 40 static void __init memtest(u64 pattern, phys_addr_t start_phys, phys_addr_t size) 41 { 42 u64 *p, *start, *end; 43 phys_addr_t start_bad, last_bad; 44 phys_addr_t start_phys_aligned; 45 const size_t incr = sizeof(pattern); 46 47 start_phys_aligned = ALIGN(start_phys, incr); 48 start = __va(start_phys_aligned); 49 end = start + (size - (start_phys_aligned - start_phys)) / incr; 50 start_bad = 0; 51 last_bad = 0; 52 53 VM_WARN_ON_ONCE(size < start_phys_aligned - start_phys); 54 55 for (p = start; p < end; p++) 56 WRITE_ONCE(*p, pattern); 57 58 for (p = start; p < end; p++, start_phys_aligned += incr) { 59 if (READ_ONCE(*p) == pattern) 60 continue; 61 if (start_phys_aligned == last_bad + incr) { 62 last_bad += incr; 63 continue; 64 } 65 if (start_bad) 66 reserve_bad_mem(pattern, start_bad, last_bad + incr); 67 start_bad = last_bad = start_phys_aligned; 68 } 69 if (start_bad) 70 reserve_bad_mem(pattern, start_bad, last_bad + incr); 71 72 early_memtest_done = true; 73 } 74 75 static void __init do_one_pass(u64 pattern, phys_addr_t start, phys_addr_t end) 76 { 77 u64 i; 78 phys_addr_t this_start, this_end; 79 80 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &this_start, 81 &this_end, NULL) { 82 this_start = clamp(this_start, start, end); 83 this_end = clamp(this_end, start, end); 84 if (this_start < this_end) { 85 pr_info(" %pa - %pa pattern %016llx\n", 86 &this_start, &this_end, cpu_to_be64(pattern)); 87 memtest(pattern, this_start, this_end - this_start); 88 } 89 } 90 } 91 92 /* default is disabled */ 93 static unsigned int memtest_pattern __initdata; 94 95 static int __init parse_memtest(char *arg) 96 { 97 int ret = 0; 98 99 if (arg) 100 ret = kstrtouint(arg, 0, &memtest_pattern); 101 else 102 memtest_pattern = ARRAY_SIZE(patterns); 103 104 return ret; 105 } 106 107 early_param("memtest", parse_memtest); 108 109 void __init early_memtest(phys_addr_t start, phys_addr_t end) 110 { 111 unsigned int i; 112 unsigned int idx = 0; 113 114 if (!memtest_pattern) 115 return; 116 117 pr_info("early_memtest: # of tests: %u\n", memtest_pattern); 118 for (i = memtest_pattern-1; i < UINT_MAX; --i) { 119 idx = i % ARRAY_SIZE(patterns); 120 do_one_pass(patterns[idx], start, end); 121 } 122 } 123 124 void memtest_report_meminfo(struct seq_file *m) 125 { 126 unsigned long early_memtest_bad_size_kb; 127 128 if (!IS_ENABLED(CONFIG_PROC_FS)) 129 return; 130 131 if (!early_memtest_done) 132 return; 133 134 early_memtest_bad_size_kb = early_memtest_bad_size >> 10; 135 if (early_memtest_bad_size && !early_memtest_bad_size_kb) 136 early_memtest_bad_size_kb = 1; 137 /* When 0 is reported, it means there actually was a successful test */ 138 seq_printf(m, "EarlyMemtestBad: %5lu kB\n", early_memtest_bad_size_kb); 139 } 140