144 lines
3.5 KiB
C
144 lines
3.5 KiB
C
/*
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* Page Deallocation Table (PDT) support
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*
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* The Page Deallocation Table (PDT) holds a table with pointers to bad
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* memory (broken RAM modules) which is maintained by firmware.
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*
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* Copyright 2017 by Helge Deller <deller@gmx.de>
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*
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* TODO:
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* - check regularily for new bad memory
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* - add userspace interface with procfs or sysfs
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* - increase number of PDT entries dynamically
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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 <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_OLD
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};
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static enum pdt_access_type pdt_type;
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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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/* 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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/*
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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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if (is_pdc_pat()) {
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struct pdc_pat_mem_retinfo pat_rinfo;
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pdt_type = PDT_PAT_NEW;
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ret = pdc_pat_mem_pdt_info(&pat_rinfo);
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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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} else {
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pdt_type = PDT_PDC;
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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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WARN_ON(entries > MAX_PDT_ENTRIES);
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pr_info("PDT: size %lu, entries %lu, status %lu, dbe_loc 0x%lx,"
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" good_mem %lu\n",
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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);
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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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ret = pdc_pat_mem_read_cell_pdt(&pat_pret, pdt_entry,
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MAX_PDT_ENTRIES);
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if (ret != PDC_OK) {
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pdt_type = PDT_PAT_OLD;
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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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}
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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_debug("PDT type %d, retval = %d\n", pdt_type, 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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if (i < 20)
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pr_warn("PDT: BAD PAGE #%d at 0x%08lx (error_type = %lu)\n",
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i,
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pdt_entry[i] & PAGE_MASK,
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pdt_entry[i] & 1);
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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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