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https://github.com/torvalds/linux
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bd23024b97
Currently the memtest results were only presented in dmesg. When running a large fleet of devices without ECC RAM it's currently not easy to do bulk monitoring for memory corruption. You have to parse dmesg, but that's a ring buffer so the error might disappear after some time. In general I do not consider dmesg to be a great API to query RAM status. In several companies I've seen such errors remain undetected and cause issues for way too long. So I think it makes sense to provide a monitoring API, so that we can safely detect and act upon them. This adds /proc/meminfo entry which can be easily used by scripts. Link: https://lkml.kernel.org/r/20230321103430.7130-1-tomas.mudrunka@gmail.com Signed-off-by: Tomas Mudrunka <tomas.mudrunka@gmail.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
119 lines
2.9 KiB
C
119 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/init.h>
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#include <linux/memblock.h>
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bool early_memtest_done;
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phys_addr_t early_memtest_bad_size;
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static u64 patterns[] __initdata = {
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/* The first entry has to be 0 to leave memtest with zeroed memory */
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0,
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0xffffffffffffffffULL,
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0x5555555555555555ULL,
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0xaaaaaaaaaaaaaaaaULL,
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0x1111111111111111ULL,
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0x2222222222222222ULL,
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0x4444444444444444ULL,
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0x8888888888888888ULL,
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0x3333333333333333ULL,
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0x6666666666666666ULL,
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0x9999999999999999ULL,
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0xccccccccccccccccULL,
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0x7777777777777777ULL,
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0xbbbbbbbbbbbbbbbbULL,
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0xddddddddddddddddULL,
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0xeeeeeeeeeeeeeeeeULL,
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0x7a6c7258554e494cULL, /* yeah ;-) */
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};
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static void __init reserve_bad_mem(u64 pattern, phys_addr_t start_bad, phys_addr_t end_bad)
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{
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pr_info(" %016llx bad mem addr %pa - %pa reserved\n",
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cpu_to_be64(pattern), &start_bad, &end_bad);
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memblock_reserve(start_bad, end_bad - start_bad);
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early_memtest_bad_size += (end_bad - start_bad);
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}
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static void __init memtest(u64 pattern, phys_addr_t start_phys, phys_addr_t size)
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{
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u64 *p, *start, *end;
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phys_addr_t start_bad, last_bad;
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phys_addr_t start_phys_aligned;
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const size_t incr = sizeof(pattern);
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start_phys_aligned = ALIGN(start_phys, incr);
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start = __va(start_phys_aligned);
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end = start + (size - (start_phys_aligned - start_phys)) / incr;
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start_bad = 0;
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last_bad = 0;
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for (p = start; p < end; p++)
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*p = pattern;
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for (p = start; p < end; p++, start_phys_aligned += incr) {
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if (*p == pattern)
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continue;
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if (start_phys_aligned == last_bad + incr) {
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last_bad += incr;
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continue;
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}
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if (start_bad)
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reserve_bad_mem(pattern, start_bad, last_bad + incr);
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start_bad = last_bad = start_phys_aligned;
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}
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if (start_bad)
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reserve_bad_mem(pattern, start_bad, last_bad + incr);
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early_memtest_done = true;
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}
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static void __init do_one_pass(u64 pattern, phys_addr_t start, phys_addr_t end)
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{
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u64 i;
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phys_addr_t this_start, this_end;
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for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &this_start,
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&this_end, NULL) {
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this_start = clamp(this_start, start, end);
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this_end = clamp(this_end, start, end);
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if (this_start < this_end) {
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pr_info(" %pa - %pa pattern %016llx\n",
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&this_start, &this_end, cpu_to_be64(pattern));
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memtest(pattern, this_start, this_end - this_start);
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}
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}
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}
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/* default is disabled */
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static unsigned int memtest_pattern __initdata;
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static int __init parse_memtest(char *arg)
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{
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int ret = 0;
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if (arg)
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ret = kstrtouint(arg, 0, &memtest_pattern);
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else
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memtest_pattern = ARRAY_SIZE(patterns);
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return ret;
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}
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early_param("memtest", parse_memtest);
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void __init early_memtest(phys_addr_t start, phys_addr_t end)
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{
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unsigned int i;
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unsigned int idx = 0;
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if (!memtest_pattern)
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return;
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pr_info("early_memtest: # of tests: %u\n", memtest_pattern);
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for (i = memtest_pattern-1; i < UINT_MAX; --i) {
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idx = i % ARRAY_SIZE(patterns);
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do_one_pass(patterns[idx], start, end);
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}
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}
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