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-rw-r--r--mm/memtest.c113
1 files changed, 113 insertions, 0 deletions
diff --git a/mm/memtest.c b/mm/memtest.c
new file mode 100644
index 000000000..f53ace709
--- /dev/null
+++ b/mm/memtest.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/memblock.h>
+
+static u64 patterns[] __initdata = {
+ /* The first entry has to be 0 to leave memtest with zeroed memory */
+ 0,
+ 0xffffffffffffffffULL,
+ 0x5555555555555555ULL,
+ 0xaaaaaaaaaaaaaaaaULL,
+ 0x1111111111111111ULL,
+ 0x2222222222222222ULL,
+ 0x4444444444444444ULL,
+ 0x8888888888888888ULL,
+ 0x3333333333333333ULL,
+ 0x6666666666666666ULL,
+ 0x9999999999999999ULL,
+ 0xccccccccccccccccULL,
+ 0x7777777777777777ULL,
+ 0xbbbbbbbbbbbbbbbbULL,
+ 0xddddddddddddddddULL,
+ 0xeeeeeeeeeeeeeeeeULL,
+ 0x7a6c7258554e494cULL, /* yeah ;-) */
+};
+
+static void __init reserve_bad_mem(u64 pattern, phys_addr_t start_bad, phys_addr_t end_bad)
+{
+ pr_info(" %016llx bad mem addr %pa - %pa reserved\n",
+ cpu_to_be64(pattern), &start_bad, &end_bad);
+ memblock_reserve(start_bad, end_bad - start_bad);
+}
+
+static void __init memtest(u64 pattern, phys_addr_t start_phys, phys_addr_t size)
+{
+ u64 *p, *start, *end;
+ phys_addr_t start_bad, last_bad;
+ phys_addr_t start_phys_aligned;
+ const size_t incr = sizeof(pattern);
+
+ start_phys_aligned = ALIGN(start_phys, incr);
+ start = __va(start_phys_aligned);
+ end = start + (size - (start_phys_aligned - start_phys)) / incr;
+ start_bad = 0;
+ last_bad = 0;
+
+ for (p = start; p < end; p++)
+ *p = pattern;
+
+ for (p = start; p < end; p++, start_phys_aligned += incr) {
+ if (*p == pattern)
+ continue;
+ if (start_phys_aligned == last_bad + incr) {
+ last_bad += incr;
+ continue;
+ }
+ if (start_bad)
+ reserve_bad_mem(pattern, start_bad, last_bad + incr);
+ start_bad = last_bad = start_phys_aligned;
+ }
+ if (start_bad)
+ reserve_bad_mem(pattern, start_bad, last_bad + incr);
+}
+
+static void __init do_one_pass(u64 pattern, phys_addr_t start, phys_addr_t end)
+{
+ u64 i;
+ phys_addr_t this_start, this_end;
+
+ for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &this_start,
+ &this_end, NULL) {
+ this_start = clamp(this_start, start, end);
+ this_end = clamp(this_end, start, end);
+ if (this_start < this_end) {
+ pr_info(" %pa - %pa pattern %016llx\n",
+ &this_start, &this_end, cpu_to_be64(pattern));
+ memtest(pattern, this_start, this_end - this_start);
+ }
+ }
+}
+
+/* default is disabled */
+static unsigned int memtest_pattern __initdata;
+
+static int __init parse_memtest(char *arg)
+{
+ int ret = 0;
+
+ if (arg)
+ ret = kstrtouint(arg, 0, &memtest_pattern);
+ else
+ memtest_pattern = ARRAY_SIZE(patterns);
+
+ return ret;
+}
+
+early_param("memtest", parse_memtest);
+
+void __init early_memtest(phys_addr_t start, phys_addr_t end)
+{
+ unsigned int i;
+ unsigned int idx = 0;
+
+ if (!memtest_pattern)
+ return;
+
+ pr_info("early_memtest: # of tests: %u\n", memtest_pattern);
+ for (i = memtest_pattern-1; i < UINT_MAX; --i) {
+ idx = i % ARRAY_SIZE(patterns);
+ do_one_pass(patterns[idx], start, end);
+ }
+}