1 files changed, 364 insertions, 0 deletions
diff --git a/arch/parisc/kernel/pdt.c b/arch/parisc/kernel/pdt.c
new file mode 100644
index 000000000..fcc761b0e
--- /dev/null
+++ b/arch/parisc/kernel/pdt.c
@@ -0,0 +1,364 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *    Page Deallocation Table (PDT) support
+ *
+ *    The Page Deallocation Table (PDT) is maintained by firmware and holds a
+ *    list of memory addresses in which memory errors were detected.
+ *    The list contains both single-bit (correctable) and double-bit
+ *    (uncorrectable) errors.
+ *
+ *    Copyright 2017 by Helge Deller <deller@gmx.de>
+ *
+ *    possible future enhancements:
+ *    - add userspace interface via procfs or sysfs to clear PDT
+ */
+
+#include <linux/memblock.h>
+#include <linux/seq_file.h>
+#include <linux/kthread.h>
+#include <linux/initrd.h>
+#include <linux/pgtable.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+
+#include <asm/pdc.h>
+#include <asm/pdcpat.h>
+#include <asm/sections.h>
+
+enum pdt_access_type {
+	PDT_NONE,
+	PDT_PDC,
+	PDT_PAT_NEW,
+	PDT_PAT_CELL
+};
+
+static enum pdt_access_type pdt_type;
+
+/* PDT poll interval: 1 minute if errors, 5 minutes if everything OK. */
+#define PDT_POLL_INTERVAL_DEFAULT	(5*60*HZ)
+#define PDT_POLL_INTERVAL_SHORT		(1*60*HZ)
+static unsigned long pdt_poll_interval = PDT_POLL_INTERVAL_DEFAULT;
+
+/* 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;
+
+/*
+ * Constants for the pdt_entry format:
+ * A pdt_entry holds the physical address in bits 0-57, bits 58-61 are
+ * reserved, bit 62 is the perm bit and bit 63 is the error_type bit.
+ * The perm bit indicates whether the error have been verified as a permanent
+ * error (value of 1) or has not been verified, and may be transient (value
+ * of 0). The error_type bit indicates whether the error is a single bit error
+ * (value of 1) or a multiple bit error.
+ * On non-PAT machines phys_addr is encoded in bits 0-59 and error_type in bit
+ * 63. Those machines don't provide the perm bit.
+ */
+
+#define PDT_ADDR_PHYS_MASK	(pdt_type != PDT_PDC ? ~0x3f : ~0x0f)
+#define PDT_ADDR_PERM_ERR	(pdt_type != PDT_PDC ? 2UL : 0UL)
+#define PDT_ADDR_SINGLE_ERR	1UL
+
+/* 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);
+}
+
+static int get_info_pat_new(void)
+{
+	struct pdc_pat_mem_retinfo pat_rinfo;
+	int ret;
+
+	/* newer PAT machines like C8000 report info for all cells */
+	if (is_pdc_pat())
+		ret = pdc_pat_mem_pdt_info(&pat_rinfo);
+	else
+		return PDC_BAD_PROC;
+
+	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;
+
+	return ret;
+}
+
+static int get_info_pat_cell(void)
+{
+	struct pdc_pat_mem_cell_pdt_retinfo cell_rinfo;
+	int ret;
+
+	/* older PAT machines like rp5470 report cell info only */
+	if (is_pdc_pat())
+		ret = pdc_pat_mem_pdt_cell_info(&cell_rinfo, parisc_cell_num);
+	else
+		return PDC_BAD_PROC;
+
+	pdt_status.pdt_size = cell_rinfo.max_pdt_entries;
+	pdt_status.pdt_entries = cell_rinfo.current_pdt_entries;
+	pdt_status.pdt_status = 0;
+	pdt_status.first_dbe_loc = cell_rinfo.first_dbe_loc;
+	pdt_status.good_mem = cell_rinfo.good_mem;
+
+	return ret;
+}
+
+static void report_mem_err(unsigned long pde)
+{
+	struct pdc_pat_mem_phys_mem_location loc;
+	unsigned long addr;
+	char dimm_txt[32];
+
+	addr = pde & PDT_ADDR_PHYS_MASK;
+
+	/* show DIMM slot description on PAT machines */
+	if (is_pdc_pat()) {
+		pdc_pat_mem_get_dimm_phys_location(&loc, addr);
+		sprintf(dimm_txt, "DIMM slot %02x, ", loc.dimm_slot);
+	} else
+		dimm_txt[0] = 0;
+
+	pr_warn("PDT: BAD MEMORY at 0x%08lx, %s%s%s-bit error.\n",
+		addr, dimm_txt,
+		pde & PDT_ADDR_PERM_ERR ? "permanent ":"",
+		pde & PDT_ADDR_SINGLE_ERR ? "single":"multi");
+}
+
+
+/*
+ * 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;
+
+	pdt_type = PDT_PAT_NEW;
+	ret = get_info_pat_new();
+
+	if (ret != PDC_OK) {
+		pdt_type = PDT_PAT_CELL;
+		ret = get_info_pat_cell();
+	}
+
+	if (ret != PDC_OK) {
+		pdt_type = PDT_PDC;
+		/* non-PAT machines provide the standard PDC call */
+		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;
+	if (WARN_ON(entries > MAX_PDT_ENTRIES))
+		entries = pdt_status.pdt_entries = MAX_PDT_ENTRIES;
+
+	pr_info("PDT: type %s, size %lu, entries %lu, status %lu, dbe_loc 0x%lx,"
+		" good_mem %lu MB\n",
+			pdt_type == PDT_PDC ? __stringify(PDT_PDC) :
+			pdt_type == PDT_PAT_CELL ? __stringify(PDT_PAT_CELL)
+						 : __stringify(PDT_PAT_NEW),
+			pdt_status.pdt_size, pdt_status.pdt_entries,
+			pdt_status.pdt_status, pdt_status.first_dbe_loc,
+			pdt_status.good_mem / 1024 / 1024);
+
+	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;
+
+		if (pdt_type == PDT_PAT_CELL)
+			ret = pdc_pat_mem_read_cell_pdt(&pat_pret, pdt_entry,
+				MAX_PDT_ENTRIES);
+		else
+			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_warn("PDT: Get PDT entries failed with %d\n", ret);
+		return;
+	}
+
+	for (i = 0; i < pdt_status.pdt_entries; i++) {
+		unsigned long addr;
+
+		report_mem_err(pdt_entry[i]);
+
+		addr = pdt_entry[i] & PDT_ADDR_PHYS_MASK;
+		if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) &&
+			addr >= initrd_start && addr < initrd_end)
+			pr_crit("CRITICAL: initrd possibly broken "
+				"due to bad memory!\n");
+
+		/* mark memory page bad */
+		memblock_reserve(pdt_entry[i] & PAGE_MASK, PAGE_SIZE);
+		num_poisoned_pages_inc();
+	}
+}
+
+
+/*
+ * This is the PDT kernel thread main loop.
+ */
+
+static int pdt_mainloop(void *unused)
+{
+	struct pdc_mem_read_pdt pdt_read_ret;
+	struct pdc_pat_mem_read_pd_retinfo pat_pret __maybe_unused;
+	unsigned long old_num_entries;
+	unsigned long *bad_mem_ptr;
+	int num, ret;
+
+	for (;;) {
+		set_current_state(TASK_INTERRUPTIBLE);
+
+		old_num_entries = pdt_status.pdt_entries;
+
+		schedule_timeout(pdt_poll_interval);
+		if (kthread_should_stop())
+			break;
+
+		/* Do we have new PDT entries? */
+		switch (pdt_type) {
+		case PDT_PAT_NEW:
+			ret = get_info_pat_new();
+			break;
+		case PDT_PAT_CELL:
+			ret = get_info_pat_cell();
+			break;
+		default:
+			ret = pdc_mem_pdt_info(&pdt_status);
+			break;
+		}
+
+		if (ret != PDC_OK) {
+			pr_warn("PDT: unexpected failure %d\n", ret);
+			return -EINVAL;
+		}
+
+		/* if no new PDT entries, just wait again */
+		num = pdt_status.pdt_entries - old_num_entries;
+		if (num <= 0)
+			continue;
+
+		/* decrease poll interval in case we found memory errors */
+		if (pdt_status.pdt_entries &&
+			pdt_poll_interval == PDT_POLL_INTERVAL_DEFAULT)
+			pdt_poll_interval = PDT_POLL_INTERVAL_SHORT;
+
+		/* limit entries to get */
+		if (num > MAX_PDT_ENTRIES) {
+			num = MAX_PDT_ENTRIES;
+			pdt_status.pdt_entries = old_num_entries + num;
+		}
+
+		/* get new entries */
+		switch (pdt_type) {
+#ifdef CONFIG_64BIT
+		case PDT_PAT_CELL:
+			if (pdt_status.pdt_entries > MAX_PDT_ENTRIES) {
+				pr_crit("PDT: too many entries.\n");
+				return -ENOMEM;
+			}
+			ret = pdc_pat_mem_read_cell_pdt(&pat_pret, pdt_entry,
+				MAX_PDT_ENTRIES);
+			bad_mem_ptr = &pdt_entry[old_num_entries];
+			break;
+		case PDT_PAT_NEW:
+			ret = pdc_pat_mem_read_pd_pdt(&pat_pret,
+				pdt_entry,
+				num * sizeof(unsigned long),
+				old_num_entries * sizeof(unsigned long));
+			bad_mem_ptr = &pdt_entry[0];
+			break;
+#endif
+		default:
+			ret = pdc_mem_pdt_read_entries(&pdt_read_ret,
+				pdt_entry);
+			bad_mem_ptr = &pdt_entry[old_num_entries];
+			break;
+		}
+
+		/* report and mark memory broken */
+		while (num--) {
+			unsigned long pde = *bad_mem_ptr++;
+
+			report_mem_err(pde);
+
+#ifdef CONFIG_MEMORY_FAILURE
+			if ((pde & PDT_ADDR_PERM_ERR) ||
+			    ((pde & PDT_ADDR_SINGLE_ERR) == 0))
+				memory_failure(pde >> PAGE_SHIFT, 0);
+			else
+				soft_offline_page(pde >> PAGE_SHIFT, 0);
+#else
+			pr_crit("PDT: memory error at 0x%lx ignored.\n"
+				"Rebuild kernel with CONFIG_MEMORY_FAILURE=y "
+				"for real handling.\n",
+				pde & PDT_ADDR_PHYS_MASK);
+#endif
+
+		}
+	}
+
+	return 0;
+}
+
+
+static int __init pdt_initcall(void)
+{
+	struct task_struct *kpdtd_task;
+
+	if (pdt_type == PDT_NONE)
+		return -ENODEV;
+
+	kpdtd_task = kthread_create(pdt_mainloop, NULL, "kpdtd");
+	if (IS_ERR(kpdtd_task))
+		return PTR_ERR(kpdtd_task);
+
+	wake_up_process(kpdtd_task);
+
+	return 0;
+}
+
+late_initcall(pdt_initcall);