// 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/proc_fs.h>
#include <linux/initrd.h>
#include <linux/pgtable.h>
#include <linux/mm.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_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
#ifdef CONFIG_PROC_FS
/* 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);
}
#endif
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(addr >> PAGE_SHIFT);
}
}
/*
* 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_run(pdt_mainloop, NULL, "kpdtd");
return PTR_ERR_OR_ZERO(kpdtd_task);
}
late_initcall(pdt_initcall);
