363 lines
9 KiB
C
363 lines
9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Page Deallocation Table (PDT) support
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*
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* The Page Deallocation Table (PDT) is maintained by firmware and holds a
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* list of memory addresses in which memory errors were detected.
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* The list contains both single-bit (correctable) and double-bit
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* (uncorrectable) errors.
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*
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* Copyright 2017 by Helge Deller <deller@gmx.de>
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*
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* possible future enhancements:
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* - add userspace interface via procfs or sysfs to clear PDT
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*/
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#include <linux/memblock.h>
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#include <linux/seq_file.h>
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#include <linux/kthread.h>
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#include <linux/initrd.h>
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#include <asm/pdc.h>
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#include <asm/pdcpat.h>
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#include <asm/sections.h>
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#include <asm/pgtable.h>
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enum pdt_access_type {
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PDT_NONE,
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PDT_PDC,
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PDT_PAT_NEW,
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PDT_PAT_CELL
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};
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static enum pdt_access_type pdt_type;
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/* PDT poll interval: 1 minute if errors, 5 minutes if everything OK. */
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#define PDT_POLL_INTERVAL_DEFAULT (5*60*HZ)
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#define PDT_POLL_INTERVAL_SHORT (1*60*HZ)
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static unsigned long pdt_poll_interval = PDT_POLL_INTERVAL_DEFAULT;
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/* global PDT status information */
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static struct pdc_mem_retinfo pdt_status;
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#define MAX_PDT_TABLE_SIZE PAGE_SIZE
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#define MAX_PDT_ENTRIES (MAX_PDT_TABLE_SIZE / sizeof(unsigned long))
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static unsigned long pdt_entry[MAX_PDT_ENTRIES] __page_aligned_bss;
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/*
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* Constants for the pdt_entry format:
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* A pdt_entry holds the physical address in bits 0-57, bits 58-61 are
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* reserved, bit 62 is the perm bit and bit 63 is the error_type bit.
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* The perm bit indicates whether the error have been verified as a permanent
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* error (value of 1) or has not been verified, and may be transient (value
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* of 0). The error_type bit indicates whether the error is a single bit error
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* (value of 1) or a multiple bit error.
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* On non-PAT machines phys_addr is encoded in bits 0-59 and error_type in bit
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* 63. Those machines don't provide the perm bit.
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*/
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#define PDT_ADDR_PHYS_MASK (pdt_type != PDT_PDC ? ~0x3f : ~0x0f)
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#define PDT_ADDR_PERM_ERR (pdt_type != PDT_PDC ? 2UL : 0UL)
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#define PDT_ADDR_SINGLE_ERR 1UL
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/* report PDT entries via /proc/meminfo */
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void arch_report_meminfo(struct seq_file *m)
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{
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if (pdt_type == PDT_NONE)
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return;
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seq_printf(m, "PDT_max_entries: %7lu\n",
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pdt_status.pdt_size);
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seq_printf(m, "PDT_cur_entries: %7lu\n",
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pdt_status.pdt_entries);
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}
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static int get_info_pat_new(void)
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{
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struct pdc_pat_mem_retinfo pat_rinfo;
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int ret;
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/* newer PAT machines like C8000 report info for all cells */
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if (is_pdc_pat())
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ret = pdc_pat_mem_pdt_info(&pat_rinfo);
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else
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return PDC_BAD_PROC;
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pdt_status.pdt_size = pat_rinfo.max_pdt_entries;
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pdt_status.pdt_entries = pat_rinfo.current_pdt_entries;
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pdt_status.pdt_status = 0;
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pdt_status.first_dbe_loc = pat_rinfo.first_dbe_loc;
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pdt_status.good_mem = pat_rinfo.good_mem;
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return ret;
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}
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static int get_info_pat_cell(void)
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{
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struct pdc_pat_mem_cell_pdt_retinfo cell_rinfo;
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int ret;
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/* older PAT machines like rp5470 report cell info only */
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if (is_pdc_pat())
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ret = pdc_pat_mem_pdt_cell_info(&cell_rinfo, parisc_cell_num);
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else
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return PDC_BAD_PROC;
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pdt_status.pdt_size = cell_rinfo.max_pdt_entries;
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pdt_status.pdt_entries = cell_rinfo.current_pdt_entries;
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pdt_status.pdt_status = 0;
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pdt_status.first_dbe_loc = cell_rinfo.first_dbe_loc;
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pdt_status.good_mem = cell_rinfo.good_mem;
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return ret;
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}
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static void report_mem_err(unsigned long pde)
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{
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struct pdc_pat_mem_phys_mem_location loc;
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unsigned long addr;
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char dimm_txt[32];
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addr = pde & PDT_ADDR_PHYS_MASK;
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/* show DIMM slot description on PAT machines */
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if (is_pdc_pat()) {
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pdc_pat_mem_get_dimm_phys_location(&loc, addr);
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sprintf(dimm_txt, "DIMM slot %02x, ", loc.dimm_slot);
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} else
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dimm_txt[0] = 0;
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pr_warn("PDT: BAD MEMORY at 0x%08lx, %s%s%s-bit error.\n",
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addr, dimm_txt,
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pde & PDT_ADDR_PERM_ERR ? "permanent ":"",
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pde & PDT_ADDR_SINGLE_ERR ? "single":"multi");
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}
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/*
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* pdc_pdt_init()
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*
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* Initialize kernel PDT structures, read initial PDT table from firmware,
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* report all current PDT entries and mark bad memory with memblock_reserve()
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* to avoid that the kernel will use broken memory areas.
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*
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*/
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void __init pdc_pdt_init(void)
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{
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int ret, i;
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unsigned long entries;
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struct pdc_mem_read_pdt pdt_read_ret;
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pdt_type = PDT_PAT_NEW;
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ret = get_info_pat_new();
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if (ret != PDC_OK) {
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pdt_type = PDT_PAT_CELL;
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ret = get_info_pat_cell();
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}
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if (ret != PDC_OK) {
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pdt_type = PDT_PDC;
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/* non-PAT machines provide the standard PDC call */
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ret = pdc_mem_pdt_info(&pdt_status);
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}
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if (ret != PDC_OK) {
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pdt_type = PDT_NONE;
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pr_info("PDT: Firmware does not provide any page deallocation"
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" information.\n");
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return;
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}
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entries = pdt_status.pdt_entries;
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if (WARN_ON(entries > MAX_PDT_ENTRIES))
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entries = pdt_status.pdt_entries = MAX_PDT_ENTRIES;
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pr_info("PDT: type %s, size %lu, entries %lu, status %lu, dbe_loc 0x%lx,"
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" good_mem %lu MB\n",
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pdt_type == PDT_PDC ? __stringify(PDT_PDC) :
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pdt_type == PDT_PAT_CELL ? __stringify(PDT_PAT_CELL)
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: __stringify(PDT_PAT_NEW),
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pdt_status.pdt_size, pdt_status.pdt_entries,
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pdt_status.pdt_status, pdt_status.first_dbe_loc,
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pdt_status.good_mem / 1024 / 1024);
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if (entries == 0) {
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pr_info("PDT: Firmware reports all memory OK.\n");
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return;
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}
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if (pdt_status.first_dbe_loc &&
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pdt_status.first_dbe_loc <= __pa((unsigned long)&_end))
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pr_crit("CRITICAL: Bad memory inside kernel image memory area!\n");
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pr_warn("PDT: Firmware reports %lu entries of faulty memory:\n",
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entries);
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if (pdt_type == PDT_PDC)
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ret = pdc_mem_pdt_read_entries(&pdt_read_ret, pdt_entry);
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else {
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#ifdef CONFIG_64BIT
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struct pdc_pat_mem_read_pd_retinfo pat_pret;
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if (pdt_type == PDT_PAT_CELL)
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ret = pdc_pat_mem_read_cell_pdt(&pat_pret, pdt_entry,
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MAX_PDT_ENTRIES);
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else
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ret = pdc_pat_mem_read_pd_pdt(&pat_pret, pdt_entry,
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MAX_PDT_TABLE_SIZE, 0);
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#else
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ret = PDC_BAD_PROC;
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#endif
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}
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if (ret != PDC_OK) {
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pdt_type = PDT_NONE;
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pr_warn("PDT: Get PDT entries failed with %d\n", ret);
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return;
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}
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for (i = 0; i < pdt_status.pdt_entries; i++) {
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unsigned long addr;
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report_mem_err(pdt_entry[i]);
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addr = pdt_entry[i] & PDT_ADDR_PHYS_MASK;
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if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) &&
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addr >= initrd_start && addr < initrd_end)
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pr_crit("CRITICAL: initrd possibly broken "
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"due to bad memory!\n");
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/* mark memory page bad */
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memblock_reserve(pdt_entry[i] & PAGE_MASK, PAGE_SIZE);
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}
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}
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/*
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* This is the PDT kernel thread main loop.
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*/
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static int pdt_mainloop(void *unused)
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{
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struct pdc_mem_read_pdt pdt_read_ret;
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struct pdc_pat_mem_read_pd_retinfo pat_pret __maybe_unused;
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unsigned long old_num_entries;
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unsigned long *bad_mem_ptr;
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int num, ret;
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for (;;) {
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set_current_state(TASK_INTERRUPTIBLE);
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old_num_entries = pdt_status.pdt_entries;
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schedule_timeout(pdt_poll_interval);
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if (kthread_should_stop())
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break;
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/* Do we have new PDT entries? */
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switch (pdt_type) {
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case PDT_PAT_NEW:
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ret = get_info_pat_new();
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break;
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case PDT_PAT_CELL:
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ret = get_info_pat_cell();
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break;
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default:
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ret = pdc_mem_pdt_info(&pdt_status);
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break;
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}
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if (ret != PDC_OK) {
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pr_warn("PDT: unexpected failure %d\n", ret);
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return -EINVAL;
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}
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/* if no new PDT entries, just wait again */
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num = pdt_status.pdt_entries - old_num_entries;
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if (num <= 0)
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continue;
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/* decrease poll interval in case we found memory errors */
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if (pdt_status.pdt_entries &&
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pdt_poll_interval == PDT_POLL_INTERVAL_DEFAULT)
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pdt_poll_interval = PDT_POLL_INTERVAL_SHORT;
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/* limit entries to get */
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if (num > MAX_PDT_ENTRIES) {
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num = MAX_PDT_ENTRIES;
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pdt_status.pdt_entries = old_num_entries + num;
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}
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/* get new entries */
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switch (pdt_type) {
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#ifdef CONFIG_64BIT
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case PDT_PAT_CELL:
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if (pdt_status.pdt_entries > MAX_PDT_ENTRIES) {
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pr_crit("PDT: too many entries.\n");
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return -ENOMEM;
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}
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ret = pdc_pat_mem_read_cell_pdt(&pat_pret, pdt_entry,
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MAX_PDT_ENTRIES);
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bad_mem_ptr = &pdt_entry[old_num_entries];
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break;
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case PDT_PAT_NEW:
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ret = pdc_pat_mem_read_pd_pdt(&pat_pret,
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pdt_entry,
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num * sizeof(unsigned long),
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old_num_entries * sizeof(unsigned long));
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bad_mem_ptr = &pdt_entry[0];
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break;
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#endif
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default:
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ret = pdc_mem_pdt_read_entries(&pdt_read_ret,
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pdt_entry);
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bad_mem_ptr = &pdt_entry[old_num_entries];
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break;
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}
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/* report and mark memory broken */
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while (num--) {
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unsigned long pde = *bad_mem_ptr++;
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report_mem_err(pde);
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#ifdef CONFIG_MEMORY_FAILURE
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if ((pde & PDT_ADDR_PERM_ERR) ||
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((pde & PDT_ADDR_SINGLE_ERR) == 0))
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memory_failure(pde >> PAGE_SHIFT, 0);
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else
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soft_offline_page(
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pfn_to_page(pde >> PAGE_SHIFT), 0);
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#else
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pr_crit("PDT: memory error at 0x%lx ignored.\n"
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"Rebuild kernel with CONFIG_MEMORY_FAILURE=y "
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"for real handling.\n",
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pde & PDT_ADDR_PHYS_MASK);
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#endif
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}
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}
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return 0;
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}
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static int __init pdt_initcall(void)
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{
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struct task_struct *kpdtd_task;
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if (pdt_type == PDT_NONE)
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return -ENODEV;
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kpdtd_task = kthread_create(pdt_mainloop, NULL, "kpdtd");
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if (IS_ERR(kpdtd_task))
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return PTR_ERR(kpdtd_task);
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wake_up_process(kpdtd_task);
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return 0;
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}
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late_initcall(pdt_initcall);
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