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-rw-r--r--arch/parisc/kernel/pdt.c143
1 files changed, 143 insertions, 0 deletions
diff --git a/arch/parisc/kernel/pdt.c b/arch/parisc/kernel/pdt.c
new file mode 100644
index 000000000000..f3a797e670b0
--- /dev/null
+++ b/arch/parisc/kernel/pdt.c
@@ -0,0 +1,143 @@
+/*
+ * Page Deallocation Table (PDT) support
+ *
+ * The Page Deallocation Table (PDT) holds a table with pointers to bad
+ * memory (broken RAM modules) which is maintained by firmware.
+ *
+ * Copyright 2017 by Helge Deller <deller@gmx.de>
+ *
+ * TODO:
+ * - check regularily for new bad memory
+ * - add userspace interface with procfs or sysfs
+ * - increase number of PDT entries dynamically
+ */
+
+#include <linux/memblock.h>
+#include <linux/seq_file.h>
+
+#include <asm/pdc.h>
+#include <asm/pdcpat.h>
+#include <asm/sections.h>
+#include <asm/pgtable.h>
+
+enum pdt_access_type {
+ PDT_NONE,
+ PDT_PDC,
+ PDT_PAT_NEW,
+ PDT_PAT_OLD
+};
+
+static enum pdt_access_type pdt_type;
+
+/* global PDT status information */
+static struct pdc_mem_retinfo pdt_status;
+
+#define MAX_PDT_TABLE_SIZE PAGE_SIZE
+#define MAX_PDT_ENTRIES (MAX_PDT_TABLE_SIZE / sizeof(unsigned long))
+static unsigned long pdt_entry[MAX_PDT_ENTRIES] __page_aligned_bss;
+
+
+/* report PDT entries via /proc/meminfo */
+void arch_report_meminfo(struct seq_file *m)
+{
+ if (pdt_type == PDT_NONE)
+ return;
+
+ seq_printf(m, "PDT_max_entries: %7lu\n",
+ pdt_status.pdt_size);
+ seq_printf(m, "PDT_cur_entries: %7lu\n",
+ pdt_status.pdt_entries);
+}
+
+/*
+ * pdc_pdt_init()
+ *
+ * Initialize kernel PDT structures, read initial PDT table from firmware,
+ * report all current PDT entries and mark bad memory with memblock_reserve()
+ * to avoid that the kernel will use broken memory areas.
+ *
+ */
+void __init pdc_pdt_init(void)
+{
+ int ret, i;
+ unsigned long entries;
+ struct pdc_mem_read_pdt pdt_read_ret;
+
+ if (is_pdc_pat()) {
+ struct pdc_pat_mem_retinfo pat_rinfo;
+
+ pdt_type = PDT_PAT_NEW;
+ ret = pdc_pat_mem_pdt_info(&pat_rinfo);
+ pdt_status.pdt_size = pat_rinfo.max_pdt_entries;
+ pdt_status.pdt_entries = pat_rinfo.current_pdt_entries;
+ pdt_status.pdt_status = 0;
+ pdt_status.first_dbe_loc = pat_rinfo.first_dbe_loc;
+ pdt_status.good_mem = pat_rinfo.good_mem;
+ } else {
+ pdt_type = PDT_PDC;
+ ret = pdc_mem_pdt_info(&pdt_status);
+ }
+
+ if (ret != PDC_OK) {
+ pdt_type = PDT_NONE;
+ pr_info("PDT: Firmware does not provide any page deallocation"
+ " information.\n");
+ return;
+ }
+
+ entries = pdt_status.pdt_entries;
+ WARN_ON(entries > MAX_PDT_ENTRIES);
+
+ pr_info("PDT: size %lu, entries %lu, status %lu, dbe_loc 0x%lx,"
+ " good_mem %lu\n",
+ pdt_status.pdt_size, pdt_status.pdt_entries,
+ pdt_status.pdt_status, pdt_status.first_dbe_loc,
+ pdt_status.good_mem);
+
+ if (entries == 0) {
+ pr_info("PDT: Firmware reports all memory OK.\n");
+ return;
+ }
+
+ if (pdt_status.first_dbe_loc &&
+ pdt_status.first_dbe_loc <= __pa((unsigned long)&_end))
+ pr_crit("CRITICAL: Bad memory inside kernel image memory area!\n");
+
+ pr_warn("PDT: Firmware reports %lu entries of faulty memory:\n",
+ entries);
+
+ if (pdt_type == PDT_PDC)
+ ret = pdc_mem_pdt_read_entries(&pdt_read_ret, pdt_entry);
+ else {
+#ifdef CONFIG_64BIT
+ struct pdc_pat_mem_read_pd_retinfo pat_pret;
+
+ ret = pdc_pat_mem_read_cell_pdt(&pat_pret, pdt_entry,
+ MAX_PDT_ENTRIES);
+ if (ret != PDC_OK) {
+ pdt_type = PDT_PAT_OLD;
+ ret = pdc_pat_mem_read_pd_pdt(&pat_pret, pdt_entry,
+ MAX_PDT_TABLE_SIZE, 0);
+ }
+#else
+ ret = PDC_BAD_PROC;
+#endif
+ }
+
+ if (ret != PDC_OK) {
+ pdt_type = PDT_NONE;
+ pr_debug("PDT type %d, retval = %d\n", pdt_type, ret);
+ return;
+ }
+
+ for (i = 0; i < pdt_status.pdt_entries; i++) {
+ if (i < 20)
+ pr_warn("PDT: BAD PAGE #%d at 0x%08lx (error_type = %lu)\n",
+ i,
+ pdt_entry[i] & PAGE_MASK,
+ pdt_entry[i] & 1);
+
+ /* mark memory page bad */
+ memblock_reserve(pdt_entry[i] & PAGE_MASK, PAGE_SIZE);
+ }
+}