2012-05-17 07:13:20

by Anton Vorontsov

Subject: [PATCH v3 0/3] Merge ramoops and persistent_ram, generic pstore RAM backend

Hi all,

Here comes v3:

- Rebased on current staging-next tree, so only 3 patches left;
- Fixed ram_console dependency in Kconfig (issue noticed by Greg KH).


And the boilerplate, background for the series:

There are currently two competing debug facilities to store kernel
messages in a persistent storage: a generic pstore and Google's
persistent_ram. Not so long ago (https://lkml.org/lkml/2012/3/8/252),
it was decided that we should fix this situation.

Recently ramoops has switched to pstore, which basically means that
it became a RAM backend for the pstore framework.

persistent_ram+ram_console and ramoops+pstore have almost the same
features, except:

1. Ramoops doesn't support ECC. Having ECC is useful when a hardware
reset was used to bring the machine back to life (i.e. a watchdog
triggered). In such cases, RAM may be somewhat corrupt, but
usually it is restorable.

2. Pstore doesn't support logging kernel messages in run-time, it only
dumps dmesg when kernel oopses/panics. This makes pstore useless for
debugging hangs caused by HW issues or improper use of HW (e.g.
weird device inserted -> driver tried to write a reserved bits ->
SoC hanged. In that case we don't get any messages in the pstore.

These patches solve the first issue, plus move things to their
proper places.

---
Documentation/ramoops.txt | 6 +
drivers/staging/android/Kconfig | 10 +-
drivers/staging/android/Makefile | 1 -
drivers/staging/android/persistent_ram.c | 532 ------------------------------
drivers/staging/android/persistent_ram.h | 82 -----
drivers/staging/android/ram_console.c | 2 +-
fs/pstore/Kconfig | 7 +-
fs/pstore/Makefile | 2 +-
fs/pstore/ram.c | 119 ++++---
fs/pstore/ram_core.c | 532 ++++++++++++++++++++++++++++++
include/linux/pstore_ram.h | 81 +++++
11 files changed, 697 insertions(+), 677 deletions(-)

--
Anton Vorontsov
Email: [email protected]

2012-05-17 07:16:41

by Anton Vorontsov

Subject: [PATCH 1/3] persistent_ram: Move to fs/pstore/ram_core.c

This is a first step for adding ECC support for pstore RAM backend: we
will use the persistent_ram routines, kindly provided by Google.

Basically, persistent_ram is a set of helper routines to deal with the
[optionally] ECC-protected persistent ram regions.

A bit of Makefile, Kconfig and header files adjustments were needed
because of the move.

Signed-off-by: Anton Vorontsov <[email protected]>
Acked-by: Kees Cook <[email protected]>
---
drivers/staging/android/Kconfig | 10 +-
drivers/staging/android/Makefile | 1 -
drivers/staging/android/persistent_ram.c | 532 ------------------------------
drivers/staging/android/persistent_ram.h | 82 -----
drivers/staging/android/ram_console.c | 2 +-
fs/pstore/Kconfig | 7 +-
fs/pstore/Makefile | 2 +-
fs/pstore/ram_core.c | 532 ++++++++++++++++++++++++++++++
include/linux/pstore_ram.h | 80 +++++
9 files changed, 620 insertions(+), 628 deletions(-)
delete mode 100644 drivers/staging/android/persistent_ram.c
delete mode 100644 drivers/staging/android/persistent_ram.h
create mode 100644 fs/pstore/ram_core.c

diff --git a/drivers/staging/android/Kconfig b/drivers/staging/android/Kconfig
index 775229d..63f9822 100644
--- a/drivers/staging/android/Kconfig
+++ b/drivers/staging/android/Kconfig
@@ -25,17 +25,9 @@ config ANDROID_LOGGER
tristate "Android log driver"
default n

-config ANDROID_PERSISTENT_RAM
- bool
- depends on HAVE_MEMBLOCK
- select REED_SOLOMON
- select REED_SOLOMON_ENC8
- select REED_SOLOMON_DEC8
-
config ANDROID_RAM_CONSOLE
bool "Android RAM buffer console"
- depends on !S390 && !UML && HAVE_MEMBLOCK
- select ANDROID_PERSISTENT_RAM
+ depends on !S390 && !UML && HAVE_MEMBLOCK && PSTORE_RAM=y
default n

config ANDROID_TIMED_OUTPUT
diff --git a/drivers/staging/android/Makefile b/drivers/staging/android/Makefile
index b4be69f..4677e7b 100644
--- a/drivers/staging/android/Makefile
+++ b/drivers/staging/android/Makefile
@@ -1,7 +1,6 @@
obj-$(CONFIG_ANDROID_BINDER_IPC) += binder.o
obj-$(CONFIG_ASHMEM) += ashmem.o
obj-$(CONFIG_ANDROID_LOGGER) += logger.o
-obj-$(CONFIG_ANDROID_PERSISTENT_RAM) += persistent_ram.o
obj-$(CONFIG_ANDROID_RAM_CONSOLE) += ram_console.o
obj-$(CONFIG_ANDROID_TIMED_OUTPUT) += timed_output.o
obj-$(CONFIG_ANDROID_TIMED_GPIO) += timed_gpio.o
diff --git a/drivers/staging/android/persistent_ram.c b/drivers/staging/android/persistent_ram.c
deleted file mode 100644
index 4b46eaa..0000000
--- a/drivers/staging/android/persistent_ram.c
+++ /dev/null
@@ -1,532 +0,0 @@
-/*
- * Copyright (C) 2012 Google, Inc.
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- */
-
-#include <linux/device.h>
-#include <linux/err.h>
-#include <linux/errno.h>
-#include <linux/kernel.h>
-#include <linux/init.h>
-#include <linux/io.h>
-#include <linux/list.h>
-#include <linux/memblock.h>
-#include <linux/rslib.h>
-#include <linux/slab.h>
-#include <linux/vmalloc.h>
-#include <asm/page.h>
-#include "persistent_ram.h"
-
-struct persistent_ram_buffer {
- uint32_t sig;
- atomic_t start;
- atomic_t size;
- uint8_t data[0];
-};
-
-#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
-
-static __initdata LIST_HEAD(persistent_ram_list);
-
-static inline size_t buffer_size(struct persistent_ram_zone *prz)
-{
- return atomic_read(&prz->buffer->size);
-}
-
-static inline size_t buffer_start(struct persistent_ram_zone *prz)
-{
- return atomic_read(&prz->buffer->start);
-}
-
-/* increase and wrap the start pointer, returning the old value */
-static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
-{
- int old;
- int new;
-
- do {
- old = atomic_read(&prz->buffer->start);
- new = old + a;
- while (unlikely(new > prz->buffer_size))
- new -= prz->buffer_size;
- } while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
-
- return old;
-}
-
-/* increase the size counter until it hits the max size */
-static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
-{
- size_t old;
- size_t new;
-
- if (atomic_read(&prz->buffer->size) == prz->buffer_size)
- return;
-
- do {
- old = atomic_read(&prz->buffer->size);
- new = old + a;
- if (new > prz->buffer_size)
- new = prz->buffer_size;
- } while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
-}
-
-static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
- uint8_t *data, size_t len, uint8_t *ecc)
-{
- int i;
- uint16_t par[prz->ecc_size];
-
- /* Initialize the parity buffer */
- memset(par, 0, sizeof(par));
- encode_rs8(prz->rs_decoder, data, len, par, 0);
- for (i = 0; i < prz->ecc_size; i++)
- ecc[i] = par[i];
-}
-
-static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
- void *data, size_t len, uint8_t *ecc)
-{
- int i;
- uint16_t par[prz->ecc_size];
-
- for (i = 0; i < prz->ecc_size; i++)
- par[i] = ecc[i];
- return decode_rs8(prz->rs_decoder, data, par, len,
- NULL, 0, NULL, 0, NULL);
-}
-
-static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
- unsigned int start, unsigned int count)
-{
- struct persistent_ram_buffer *buffer = prz->buffer;
- uint8_t *buffer_end = buffer->data + prz->buffer_size;
- uint8_t *block;
- uint8_t *par;
- int ecc_block_size = prz->ecc_block_size;
- int ecc_size = prz->ecc_size;
- int size = prz->ecc_block_size;
-
- if (!prz->ecc)
- return;
-
- block = buffer->data + (start & ~(ecc_block_size - 1));
- par = prz->par_buffer + (start / ecc_block_size) * prz->ecc_size;
-
- do {
- if (block + ecc_block_size > buffer_end)
- size = buffer_end - block;
- persistent_ram_encode_rs8(prz, block, size, par);
- block += ecc_block_size;
- par += ecc_size;
- } while (block < buffer->data + start + count);
-}
-
-static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
-{
- struct persistent_ram_buffer *buffer = prz->buffer;
-
- if (!prz->ecc)
- return;
-
- persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
- prz->par_header);
-}
-
-static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
-{
- struct persistent_ram_buffer *buffer = prz->buffer;
- uint8_t *block;
- uint8_t *par;
-
- if (!prz->ecc)
- return;
-
- block = buffer->data;
- par = prz->par_buffer;
- while (block < buffer->data + buffer_size(prz)) {
- int numerr;
- int size = prz->ecc_block_size;
- if (block + size > buffer->data + prz->buffer_size)
- size = buffer->data + prz->buffer_size - block;
- numerr = persistent_ram_decode_rs8(prz, block, size, par);
- if (numerr > 0) {
- pr_devel("persistent_ram: error in block %p, %d\n",
- block, numerr);
- prz->corrected_bytes += numerr;
- } else if (numerr < 0) {
- pr_devel("persistent_ram: uncorrectable error in block %p\n",
- block);
- prz->bad_blocks++;
- }
- block += prz->ecc_block_size;
- par += prz->ecc_size;
- }
-}
-
-static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
- size_t buffer_size)
-{
- int numerr;
- struct persistent_ram_buffer *buffer = prz->buffer;
- int ecc_blocks;
-
- if (!prz->ecc)
- return 0;
-
- prz->ecc_block_size = 128;
- prz->ecc_size = 16;
- prz->ecc_symsize = 8;
- prz->ecc_poly = 0x11d;
-
- ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
- prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size;
-
- if (prz->buffer_size > buffer_size) {
- pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n",
- buffer_size, prz->buffer_size);
- return -EINVAL;
- }
-
- prz->par_buffer = buffer->data + prz->buffer_size;
- prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size;
-
- /*
- * first consecutive root is 0
- * primitive element to generate roots = 1
- */
- prz->rs_decoder = init_rs(prz->ecc_symsize, prz->ecc_poly, 0, 1,
- prz->ecc_size);
- if (prz->rs_decoder == NULL) {
- pr_info("persistent_ram: init_rs failed\n");
- return -EINVAL;
- }
-
- prz->corrected_bytes = 0;
- prz->bad_blocks = 0;
-
- numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
- prz->par_header);
- if (numerr > 0) {
- pr_info("persistent_ram: error in header, %d\n", numerr);
- prz->corrected_bytes += numerr;
- } else if (numerr < 0) {
- pr_info("persistent_ram: uncorrectable error in header\n");
- prz->bad_blocks++;
- }
-
- return 0;
-}
-
-ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
- char *str, size_t len)
-{
- ssize_t ret;
-
- if (prz->corrected_bytes || prz->bad_blocks)
- ret = snprintf(str, len, ""
- "\n%d Corrected bytes, %d unrecoverable blocks\n",
- prz->corrected_bytes, prz->bad_blocks);
- else
- ret = snprintf(str, len, "\nNo errors detected\n");
-
- return ret;
-}
-
-static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
- const void *s, unsigned int start, unsigned int count)
-{
- struct persistent_ram_buffer *buffer = prz->buffer;
- memcpy(buffer->data + start, s, count);
- persistent_ram_update_ecc(prz, start, count);
-}
-
-static void __init
-persistent_ram_save_old(struct persistent_ram_zone *prz)
-{
- struct persistent_ram_buffer *buffer = prz->buffer;
- size_t size = buffer_size(prz);
- size_t start = buffer_start(prz);
- char *dest;
-
- persistent_ram_ecc_old(prz);
-
- dest = kmalloc(size, GFP_KERNEL);
- if (dest == NULL) {
- pr_err("persistent_ram: failed to allocate buffer\n");
- return;
- }
-
- prz->old_log = dest;
- prz->old_log_size = size;
- memcpy(prz->old_log, &buffer->data[start], size - start);
- memcpy(prz->old_log + size - start, &buffer->data[0], start);
-}
-
-int notrace persistent_ram_write(struct persistent_ram_zone *prz,
- const void *s, unsigned int count)
-{
- int rem;
- int c = count;
- size_t start;
-
- if (unlikely(c > prz->buffer_size)) {
- s += c - prz->buffer_size;
- c = prz->buffer_size;
- }
-
- buffer_size_add(prz, c);
-
- start = buffer_start_add(prz, c);
-
- rem = prz->buffer_size - start;
- if (unlikely(rem < c)) {
- persistent_ram_update(prz, s, start, rem);
- s += rem;
- c -= rem;
- start = 0;
- }
- persistent_ram_update(prz, s, start, c);
-
- persistent_ram_update_header_ecc(prz);
-
- return count;
-}
-
-size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
-{
- return prz->old_log_size;
-}
-
-void *persistent_ram_old(struct persistent_ram_zone *prz)
-{
- return prz->old_log;
-}
-
-void persistent_ram_free_old(struct persistent_ram_zone *prz)
-{
- kfree(prz->old_log);
- prz->old_log = NULL;
- prz->old_log_size = 0;
-}
-
-static void *persistent_ram_vmap(phys_addr_t start, size_t size)
-{
- struct page **pages;
- phys_addr_t page_start;
- unsigned int page_count;
- pgprot_t prot;
- unsigned int i;
- void *vaddr;
-
- page_start = start - offset_in_page(start);
- page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
-
- prot = pgprot_noncached(PAGE_KERNEL);
-
- pages = kmalloc(sizeof(struct page *) * page_count, GFP_KERNEL);
- if (!pages) {
- pr_err("%s: Failed to allocate array for %u pages\n", __func__,
- page_count);
- return NULL;
- }
-
- for (i = 0; i < page_count; i++) {
- phys_addr_t addr = page_start + i * PAGE_SIZE;
- pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
- }
- vaddr = vmap(pages, page_count, VM_MAP, prot);
- kfree(pages);
-
- return vaddr;
-}
-
-static void *persistent_ram_iomap(phys_addr_t start, size_t size)
-{
- if (!request_mem_region(start, size, "persistent_ram")) {
- pr_err("request mem region (0x%llx@0x%llx) failed\n",
- (unsigned long long)size, (unsigned long long)start);
- return NULL;
- }
-
- return ioremap(start, size);
-}
-
-static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
- struct persistent_ram_zone *prz)
-{
- prz->paddr = start;
- prz->size = size;
-
- if (pfn_valid(start >> PAGE_SHIFT))
- prz->vaddr = persistent_ram_vmap(start, size);
- else
- prz->vaddr = persistent_ram_iomap(start, size);
-
- if (!prz->vaddr) {
- pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
- (unsigned long long)size, (unsigned long long)start);
- return -ENOMEM;
- }
-
- prz->buffer = prz->vaddr + offset_in_page(start);
- prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
-
- return 0;
-}
-
-static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool ecc)
-{
- int ret;
-
- prz->ecc = ecc;
-
- ret = persistent_ram_init_ecc(prz, prz->buffer_size);
- if (ret)
- return ret;
-
- if (prz->buffer->sig == PERSISTENT_RAM_SIG) {
- if (buffer_size(prz) > prz->buffer_size ||
- buffer_start(prz) > buffer_size(prz))
- pr_info("persistent_ram: found existing invalid buffer,"
- " size %zu, start %zu\n",
- buffer_size(prz), buffer_start(prz));
- else {
- pr_info("persistent_ram: found existing buffer,"
- " size %zu, start %zu\n",
- buffer_size(prz), buffer_start(prz));
- persistent_ram_save_old(prz);
- }
- } else {
- pr_info("persistent_ram: no valid data in buffer"
- " (sig = 0x%08x)\n", prz->buffer->sig);
- }
-
- prz->buffer->sig = PERSISTENT_RAM_SIG;
- atomic_set(&prz->buffer->start, 0);
- atomic_set(&prz->buffer->size, 0);
-
- return 0;
-}
-
-void persistent_ram_free(struct persistent_ram_zone *prz)
-{
- if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
- vunmap(prz->vaddr);
- } else {
- iounmap(prz->vaddr);
- release_mem_region(prz->paddr, prz->size);
- }
- persistent_ram_free_old(prz);
- kfree(prz);
-}
-
-struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
- size_t size,
- bool ecc)
-{
- struct persistent_ram_zone *prz;
- int ret = -ENOMEM;
-
- prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
- if (!prz) {
- pr_err("persistent_ram: failed to allocate persistent ram zone\n");
- goto err;
- }
-
- ret = persistent_ram_buffer_map(start, size, prz);
- if (ret)
- goto err;
-
- persistent_ram_post_init(prz, ecc);
- persistent_ram_update_header_ecc(prz);
-
- return prz;
-err:
- kfree(prz);
- return ERR_PTR(ret);
-}
-
-#ifndef MODULE
-static int __init persistent_ram_buffer_init(const char *name,
- struct persistent_ram_zone *prz)
-{
- int i;
- struct persistent_ram *ram;
- struct persistent_ram_descriptor *desc;
- phys_addr_t start;
-
- list_for_each_entry(ram, &persistent_ram_list, node) {
- start = ram->start;
- for (i = 0; i < ram->num_descs; i++) {
- desc = &ram->descs[i];
- if (!strcmp(desc->name, name))
- return persistent_ram_buffer_map(start,
- desc->size, prz);
- start += desc->size;
- }
- }
-
- return -EINVAL;
-}
-
-static __init
-struct persistent_ram_zone *__persistent_ram_init(struct device *dev, bool ecc)
-{
- struct persistent_ram_zone *prz;
- int ret = -ENOMEM;
-
- prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
- if (!prz) {
- pr_err("persistent_ram: failed to allocate persistent ram zone\n");
- goto err;
- }
-
- ret = persistent_ram_buffer_init(dev_name(dev), prz);
- if (ret) {
- pr_err("persistent_ram: failed to initialize buffer\n");
- goto err;
- }
-
- persistent_ram_post_init(prz, ecc);
-
- return prz;
-err:
- kfree(prz);
- return ERR_PTR(ret);
-}
-
-struct persistent_ram_zone * __init
-persistent_ram_init_ringbuffer(struct device *dev, bool ecc)
-{
- return __persistent_ram_init(dev, ecc);
-}
-
-int __init persistent_ram_early_init(struct persistent_ram *ram)
-{
- int ret;
-
- ret = memblock_reserve(ram->start, ram->size);
- if (ret) {
- pr_err("Failed to reserve persistent memory from %08lx-%08lx\n",
- (long)ram->start, (long)(ram->start + ram->size - 1));
- return ret;
- }
-
- list_add_tail(&ram->node, &persistent_ram_list);
-
- pr_info("Initialized persistent memory from %08lx-%08lx\n",
- (long)ram->start, (long)(ram->start + ram->size - 1));
-
- return 0;
-}
-#endif
diff --git a/drivers/staging/android/persistent_ram.h b/drivers/staging/android/persistent_ram.h
deleted file mode 100644
index d23850c..0000000
--- a/drivers/staging/android/persistent_ram.h
+++ /dev/null
@@ -1,82 +0,0 @@
-/*
- * Copyright (C) 2011 Google, Inc.
- *
- * This software is licensed under the terms of the GNU General Public
- * License version 2, as published by the Free Software Foundation, and
- * may be copied, distributed, and modified under those terms.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- */
-
-#ifndef __LINUX_PERSISTENT_RAM_H__
-#define __LINUX_PERSISTENT_RAM_H__
-
-#include <linux/device.h>
-#include <linux/kernel.h>
-#include <linux/list.h>
-#include <linux/types.h>
-#include <linux/init.h>
-
-struct persistent_ram_buffer;
-
-struct persistent_ram_descriptor {
- const char *name;
- phys_addr_t size;
-};
-
-struct persistent_ram {
- phys_addr_t start;
- phys_addr_t size;
-
- int num_descs;
- struct persistent_ram_descriptor *descs;
-
- struct list_head node;
-};
-
-struct persistent_ram_zone {
- phys_addr_t paddr;
- size_t size;
- void *vaddr;
- struct persistent_ram_buffer *buffer;
- size_t buffer_size;
-
- /* ECC correction */
- bool ecc;
- char *par_buffer;
- char *par_header;
- struct rs_control *rs_decoder;
- int corrected_bytes;
- int bad_blocks;
- int ecc_block_size;
- int ecc_size;
- int ecc_symsize;
- int ecc_poly;
-
- char *old_log;
- size_t old_log_size;
-};
-
-int persistent_ram_early_init(struct persistent_ram *ram);
-
-struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
- size_t size,
- bool ecc);
-void persistent_ram_free(struct persistent_ram_zone *prz);
-struct persistent_ram_zone *persistent_ram_init_ringbuffer(struct device *dev,
- bool ecc);
-
-int persistent_ram_write(struct persistent_ram_zone *prz, const void *s,
- unsigned int count);
-
-size_t persistent_ram_old_size(struct persistent_ram_zone *prz);
-void *persistent_ram_old(struct persistent_ram_zone *prz);
-void persistent_ram_free_old(struct persistent_ram_zone *prz);
-ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
- char *str, size_t len);
-
-#endif
diff --git a/drivers/staging/android/ram_console.c b/drivers/staging/android/ram_console.c
index ce140ff..82323bb 100644
--- a/drivers/staging/android/ram_console.c
+++ b/drivers/staging/android/ram_console.c
@@ -21,7 +21,7 @@
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/io.h>
-#include "persistent_ram.h"
+#include <linux/pstore_ram.h>
#include "ram_console.h"

static struct persistent_ram_zone *ram_console_zone;
diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index b75ee51..23ade26 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -14,9 +14,12 @@ config PSTORE

config PSTORE_RAM
tristate "Log panic/oops to a RAM buffer"
- depends on HAS_IOMEM
depends on PSTORE
- default n
+ depends on HAS_IOMEM
+ depends on HAVE_MEMBLOCK
+ select REED_SOLOMON
+ select REED_SOLOMON_ENC8
+ select REED_SOLOMON_DEC8
help
This enables panic and oops messages to be logged to a circular
buffer in RAM where it can be read back at some later point.
diff --git a/fs/pstore/Makefile b/fs/pstore/Makefile
index 2ab3d0d..278a44e 100644
--- a/fs/pstore/Makefile
+++ b/fs/pstore/Makefile
@@ -6,5 +6,5 @@ obj-y += pstore.o

pstore-objs += inode.o platform.o

-ramoops-objs += ram.o
+ramoops-objs += ram.o ram_core.o
obj-$(CONFIG_PSTORE_RAM) += ramoops.o
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
new file mode 100644
index 0000000..31f8d18
--- /dev/null
+++ b/fs/pstore/ram_core.c
@@ -0,0 +1,532 @@
+/*
+ * Copyright (C) 2012 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/list.h>
+#include <linux/memblock.h>
+#include <linux/rslib.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/pstore_ram.h>
+#include <asm/page.h>
+
+struct persistent_ram_buffer {
+ uint32_t sig;
+ atomic_t start;
+ atomic_t size;
+ uint8_t data[0];
+};
+
+#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
+
+static __initdata LIST_HEAD(persistent_ram_list);
+
+static inline size_t buffer_size(struct persistent_ram_zone *prz)
+{
+ return atomic_read(&prz->buffer->size);
+}
+
+static inline size_t buffer_start(struct persistent_ram_zone *prz)
+{
+ return atomic_read(&prz->buffer->start);
+}
+
+/* increase and wrap the start pointer, returning the old value */
+static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
+{
+ int old;
+ int new;
+
+ do {
+ old = atomic_read(&prz->buffer->start);
+ new = old + a;
+ while (unlikely(new > prz->buffer_size))
+ new -= prz->buffer_size;
+ } while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
+
+ return old;
+}
+
+/* increase the size counter until it hits the max size */
+static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
+{
+ size_t old;
+ size_t new;
+
+ if (atomic_read(&prz->buffer->size) == prz->buffer_size)
+ return;
+
+ do {
+ old = atomic_read(&prz->buffer->size);
+ new = old + a;
+ if (new > prz->buffer_size)
+ new = prz->buffer_size;
+ } while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
+}
+
+static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
+ uint8_t *data, size_t len, uint8_t *ecc)
+{
+ int i;
+ uint16_t par[prz->ecc_size];
+
+ /* Initialize the parity buffer */
+ memset(par, 0, sizeof(par));
+ encode_rs8(prz->rs_decoder, data, len, par, 0);
+ for (i = 0; i < prz->ecc_size; i++)
+ ecc[i] = par[i];
+}
+
+static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
+ void *data, size_t len, uint8_t *ecc)
+{
+ int i;
+ uint16_t par[prz->ecc_size];
+
+ for (i = 0; i < prz->ecc_size; i++)
+ par[i] = ecc[i];
+ return decode_rs8(prz->rs_decoder, data, par, len,
+ NULL, 0, NULL, 0, NULL);
+}
+
+static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
+ unsigned int start, unsigned int count)
+{
+ struct persistent_ram_buffer *buffer = prz->buffer;
+ uint8_t *buffer_end = buffer->data + prz->buffer_size;
+ uint8_t *block;
+ uint8_t *par;
+ int ecc_block_size = prz->ecc_block_size;
+ int ecc_size = prz->ecc_size;
+ int size = prz->ecc_block_size;
+
+ if (!prz->ecc)
+ return;
+
+ block = buffer->data + (start & ~(ecc_block_size - 1));
+ par = prz->par_buffer + (start / ecc_block_size) * prz->ecc_size;
+
+ do {
+ if (block + ecc_block_size > buffer_end)
+ size = buffer_end - block;
+ persistent_ram_encode_rs8(prz, block, size, par);
+ block += ecc_block_size;
+ par += ecc_size;
+ } while (block < buffer->data + start + count);
+}
+
+static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
+{
+ struct persistent_ram_buffer *buffer = prz->buffer;
+
+ if (!prz->ecc)
+ return;
+
+ persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
+ prz->par_header);
+}
+
+static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
+{
+ struct persistent_ram_buffer *buffer = prz->buffer;
+ uint8_t *block;
+ uint8_t *par;
+
+ if (!prz->ecc)
+ return;
+
+ block = buffer->data;
+ par = prz->par_buffer;
+ while (block < buffer->data + buffer_size(prz)) {
+ int numerr;
+ int size = prz->ecc_block_size;
+ if (block + size > buffer->data + prz->buffer_size)
+ size = buffer->data + prz->buffer_size - block;
+ numerr = persistent_ram_decode_rs8(prz, block, size, par);
+ if (numerr > 0) {
+ pr_devel("persistent_ram: error in block %p, %d\n",
+ block, numerr);
+ prz->corrected_bytes += numerr;
+ } else if (numerr < 0) {
+ pr_devel("persistent_ram: uncorrectable error in block %p\n",
+ block);
+ prz->bad_blocks++;
+ }
+ block += prz->ecc_block_size;
+ par += prz->ecc_size;
+ }
+}
+
+static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
+ size_t buffer_size)
+{
+ int numerr;
+ struct persistent_ram_buffer *buffer = prz->buffer;
+ int ecc_blocks;
+
+ if (!prz->ecc)
+ return 0;
+
+ prz->ecc_block_size = 128;
+ prz->ecc_size = 16;
+ prz->ecc_symsize = 8;
+ prz->ecc_poly = 0x11d;
+
+ ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
+ prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size;
+
+ if (prz->buffer_size > buffer_size) {
+ pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n",
+ buffer_size, prz->buffer_size);
+ return -EINVAL;
+ }
+
+ prz->par_buffer = buffer->data + prz->buffer_size;
+ prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size;
+
+ /*
+ * first consecutive root is 0
+ * primitive element to generate roots = 1
+ */
+ prz->rs_decoder = init_rs(prz->ecc_symsize, prz->ecc_poly, 0, 1,
+ prz->ecc_size);
+ if (prz->rs_decoder == NULL) {
+ pr_info("persistent_ram: init_rs failed\n");
+ return -EINVAL;
+ }
+
+ prz->corrected_bytes = 0;
+ prz->bad_blocks = 0;
+
+ numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
+ prz->par_header);
+ if (numerr > 0) {
+ pr_info("persistent_ram: error in header, %d\n", numerr);
+ prz->corrected_bytes += numerr;
+ } else if (numerr < 0) {
+ pr_info("persistent_ram: uncorrectable error in header\n");
+ prz->bad_blocks++;
+ }
+
+ return 0;
+}
+
+ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
+ char *str, size_t len)
+{
+ ssize_t ret;
+
+ if (prz->corrected_bytes || prz->bad_blocks)
+ ret = snprintf(str, len, ""
+ "\n%d Corrected bytes, %d unrecoverable blocks\n",
+ prz->corrected_bytes, prz->bad_blocks);
+ else
+ ret = snprintf(str, len, "\nNo errors detected\n");
+
+ return ret;
+}
+
+static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
+ const void *s, unsigned int start, unsigned int count)
+{
+ struct persistent_ram_buffer *buffer = prz->buffer;
+ memcpy(buffer->data + start, s, count);
+ persistent_ram_update_ecc(prz, start, count);
+}
+
+static void __init
+persistent_ram_save_old(struct persistent_ram_zone *prz)
+{
+ struct persistent_ram_buffer *buffer = prz->buffer;
+ size_t size = buffer_size(prz);
+ size_t start = buffer_start(prz);
+ char *dest;
+
+ persistent_ram_ecc_old(prz);
+
+ dest = kmalloc(size, GFP_KERNEL);
+ if (dest == NULL) {
+ pr_err("persistent_ram: failed to allocate buffer\n");
+ return;
+ }
+
+ prz->old_log = dest;
+ prz->old_log_size = size;
+ memcpy(prz->old_log, &buffer->data[start], size - start);
+ memcpy(prz->old_log + size - start, &buffer->data[0], start);
+}
+
+int notrace persistent_ram_write(struct persistent_ram_zone *prz,
+ const void *s, unsigned int count)
+{
+ int rem;
+ int c = count;
+ size_t start;
+
+ if (unlikely(c > prz->buffer_size)) {
+ s += c - prz->buffer_size;
+ c = prz->buffer_size;
+ }
+
+ buffer_size_add(prz, c);
+
+ start = buffer_start_add(prz, c);
+
+ rem = prz->buffer_size - start;
+ if (unlikely(rem < c)) {
+ persistent_ram_update(prz, s, start, rem);
+ s += rem;
+ c -= rem;
+ start = 0;
+ }
+ persistent_ram_update(prz, s, start, c);
+
+ persistent_ram_update_header_ecc(prz);
+
+ return count;
+}
+
+size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
+{
+ return prz->old_log_size;
+}
+
+void *persistent_ram_old(struct persistent_ram_zone *prz)
+{
+ return prz->old_log;
+}
+
+void persistent_ram_free_old(struct persistent_ram_zone *prz)
+{
+ kfree(prz->old_log);
+ prz->old_log = NULL;
+ prz->old_log_size = 0;
+}
+
+static void *persistent_ram_vmap(phys_addr_t start, size_t size)
+{
+ struct page **pages;
+ phys_addr_t page_start;
+ unsigned int page_count;
+ pgprot_t prot;
+ unsigned int i;
+ void *vaddr;
+
+ page_start = start - offset_in_page(start);
+ page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
+
+ prot = pgprot_noncached(PAGE_KERNEL);
+
+ pages = kmalloc(sizeof(struct page *) * page_count, GFP_KERNEL);
+ if (!pages) {
+ pr_err("%s: Failed to allocate array for %u pages\n", __func__,
+ page_count);
+ return NULL;
+ }
+
+ for (i = 0; i < page_count; i++) {
+ phys_addr_t addr = page_start + i * PAGE_SIZE;
+ pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
+ }
+ vaddr = vmap(pages, page_count, VM_MAP, prot);
+ kfree(pages);
+
+ return vaddr;
+}
+
+static void *persistent_ram_iomap(phys_addr_t start, size_t size)
+{
+ if (!request_mem_region(start, size, "persistent_ram")) {
+ pr_err("request mem region (0x%llx@0x%llx) failed\n",
+ (unsigned long long)size, (unsigned long long)start);
+ return NULL;
+ }
+
+ return ioremap(start, size);
+}
+
+static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
+ struct persistent_ram_zone *prz)
+{
+ prz->paddr = start;
+ prz->size = size;
+
+ if (pfn_valid(start >> PAGE_SHIFT))
+ prz->vaddr = persistent_ram_vmap(start, size);
+ else
+ prz->vaddr = persistent_ram_iomap(start, size);
+
+ if (!prz->vaddr) {
+ pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
+ (unsigned long long)size, (unsigned long long)start);
+ return -ENOMEM;
+ }
+
+ prz->buffer = prz->vaddr + offset_in_page(start);
+ prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
+
+ return 0;
+}
+
+static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool ecc)
+{
+ int ret;
+
+ prz->ecc = ecc;
+
+ ret = persistent_ram_init_ecc(prz, prz->buffer_size);
+ if (ret)
+ return ret;
+
+ if (prz->buffer->sig == PERSISTENT_RAM_SIG) {
+ if (buffer_size(prz) > prz->buffer_size ||
+ buffer_start(prz) > buffer_size(prz))
+ pr_info("persistent_ram: found existing invalid buffer,"
+ " size %zu, start %zu\n",
+ buffer_size(prz), buffer_start(prz));
+ else {
+ pr_info("persistent_ram: found existing buffer,"
+ " size %zu, start %zu\n",
+ buffer_size(prz), buffer_start(prz));
+ persistent_ram_save_old(prz);
+ }
+ } else {
+ pr_info("persistent_ram: no valid data in buffer"
+ " (sig = 0x%08x)\n", prz->buffer->sig);
+ }
+
+ prz->buffer->sig = PERSISTENT_RAM_SIG;
+ atomic_set(&prz->buffer->start, 0);
+ atomic_set(&prz->buffer->size, 0);
+
+ return 0;
+}
+
+void persistent_ram_free(struct persistent_ram_zone *prz)
+{
+ if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
+ vunmap(prz->vaddr);
+ } else {
+ iounmap(prz->vaddr);
+ release_mem_region(prz->paddr, prz->size);
+ }
+ persistent_ram_free_old(prz);
+ kfree(prz);
+}
+
+struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
+ size_t size,
+ bool ecc)
+{
+ struct persistent_ram_zone *prz;
+ int ret = -ENOMEM;
+
+ prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
+ if (!prz) {
+ pr_err("persistent_ram: failed to allocate persistent ram zone\n");
+ goto err;
+ }
+
+ ret = persistent_ram_buffer_map(start, size, prz);
+ if (ret)
+ goto err;
+
+ persistent_ram_post_init(prz, ecc);
+ persistent_ram_update_header_ecc(prz);
+
+ return prz;
+err:
+ kfree(prz);
+ return ERR_PTR(ret);
+}
+
+#ifndef MODULE
+static int __init persistent_ram_buffer_init(const char *name,
+ struct persistent_ram_zone *prz)
+{
+ int i;
+ struct persistent_ram *ram;
+ struct persistent_ram_descriptor *desc;
+ phys_addr_t start;
+
+ list_for_each_entry(ram, &persistent_ram_list, node) {
+ start = ram->start;
+ for (i = 0; i < ram->num_descs; i++) {
+ desc = &ram->descs[i];
+ if (!strcmp(desc->name, name))
+ return persistent_ram_buffer_map(start,
+ desc->size, prz);
+ start += desc->size;
+ }
+ }
+
+ return -EINVAL;
+}
+
+static __init
+struct persistent_ram_zone *__persistent_ram_init(struct device *dev, bool ecc)
+{
+ struct persistent_ram_zone *prz;
+ int ret = -ENOMEM;
+
+ prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
+ if (!prz) {
+ pr_err("persistent_ram: failed to allocate persistent ram zone\n");
+ goto err;
+ }
+
+ ret = persistent_ram_buffer_init(dev_name(dev), prz);
+ if (ret) {
+ pr_err("persistent_ram: failed to initialize buffer\n");
+ goto err;
+ }
+
+ persistent_ram_post_init(prz, ecc);
+
+ return prz;
+err:
+ kfree(prz);
+ return ERR_PTR(ret);
+}
+
+struct persistent_ram_zone * __init
+persistent_ram_init_ringbuffer(struct device *dev, bool ecc)
+{
+ return __persistent_ram_init(dev, ecc);
+}
+
+int __init persistent_ram_early_init(struct persistent_ram *ram)
+{
+ int ret;
+
+ ret = memblock_reserve(ram->start, ram->size);
+ if (ret) {
+ pr_err("Failed to reserve persistent memory from %08lx-%08lx\n",
+ (long)ram->start, (long)(ram->start + ram->size - 1));
+ return ret;
+ }
+
+ list_add_tail(&ram->node, &persistent_ram_list);
+
+ pr_info("Initialized persistent memory from %08lx-%08lx\n",
+ (long)ram->start, (long)(ram->start + ram->size - 1));
+
+ return 0;
+}
+#endif
diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h
index fa4cb02..ffe24a5 100644
--- a/include/linux/pstore_ram.h
+++ b/include/linux/pstore_ram.h
@@ -1,6 +1,86 @@
+/*
+ * Copyright (C) 2010 Marco Stornelli <[email protected]>
+ * Copyright (C) 2011 Kees Cook <[email protected]>
+ * Copyright (C) 2011 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
#ifndef __LINUX_PSTORE_RAM_H__
#define __LINUX_PSTORE_RAM_H__

+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/types.h>
+#include <linux/init.h>
+
+struct persistent_ram_buffer;
+
+struct persistent_ram_descriptor {
+ const char *name;
+ phys_addr_t size;
+};
+
+struct persistent_ram {
+ phys_addr_t start;
+ phys_addr_t size;
+
+ int num_descs;
+ struct persistent_ram_descriptor *descs;
+
+ struct list_head node;
+};
+
+struct persistent_ram_zone {
+ phys_addr_t paddr;
+ size_t size;
+ void *vaddr;
+ struct persistent_ram_buffer *buffer;
+ size_t buffer_size;
+
+ /* ECC correction */
+ bool ecc;
+ char *par_buffer;
+ char *par_header;
+ struct rs_control *rs_decoder;
+ int corrected_bytes;
+ int bad_blocks;
+ int ecc_block_size;
+ int ecc_size;
+ int ecc_symsize;
+ int ecc_poly;
+
+ char *old_log;
+ size_t old_log_size;
+};
+
+int persistent_ram_early_init(struct persistent_ram *ram);
+
+struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
+ size_t size,
+ bool ecc);
+void persistent_ram_free(struct persistent_ram_zone *prz);
+struct persistent_ram_zone *persistent_ram_init_ringbuffer(struct device *dev,
+ bool ecc);
+
+int persistent_ram_write(struct persistent_ram_zone *prz, const void *s,
+ unsigned int count);
+
+size_t persistent_ram_old_size(struct persistent_ram_zone *prz);
+void *persistent_ram_old(struct persistent_ram_zone *prz);
+void persistent_ram_free_old(struct persistent_ram_zone *prz);
+ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
+ char *str, size_t len);
+
/*
* Ramoops platform data
* @mem_size memory size for ramoops
--
1.7.9.2

2012-05-17 07:16:52

by Anton Vorontsov

Subject: [PATCH 2/3] pstore/ram: Switch to persistent_ram routines

The patch switches pstore RAM backend to use persistent_ram routines,
one step closer to the ECC support.

Signed-off-by: Anton Vorontsov <[email protected]>
Acked-by: Marco Stornelli <[email protected]>
---
fs/pstore/ram.c | 106 +++++++++++++++++++++++++++++++------------------------
1 file changed, 59 insertions(+), 47 deletions(-)

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index e443c9c..62b13ed 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -57,7 +57,7 @@ MODULE_PARM_DESC(dump_oops,
"set to 1 to dump oopses, 0 to only dump panics (default 1)");

struct ramoops_context {
- void *virt_addr;
+ struct persistent_ram_zone **przs;
phys_addr_t phys_addr;
unsigned long size;
size_t record_size;
@@ -85,39 +85,56 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
struct pstore_info *psi)
{
ssize_t size;
- char *rambuf;
struct ramoops_context *cxt = psi->data;
+ struct persistent_ram_zone *prz;

if (cxt->read_count >= cxt->max_count)
return -EINVAL;
+
*id = cxt->read_count++;
+ prz = cxt->przs[*id];
+
/* Only supports dmesg output so far. */
*type = PSTORE_TYPE_DMESG;
/* TODO(kees): Bogus time for the moment. */
time->tv_sec = 0;
time->tv_nsec = 0;

- rambuf = cxt->virt_addr + (*id * cxt->record_size);
- size = strnlen(rambuf, cxt->record_size);
+ size = persistent_ram_old_size(prz);
*buf = kmalloc(size, GFP_KERNEL);
if (*buf == NULL)
return -ENOMEM;
- memcpy(*buf, rambuf, size);
+ memcpy(*buf, persistent_ram_old(prz), size);

return size;
}

+static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
+{
+ char *hdr;
+ struct timeval timestamp;
+ size_t len;
+
+ do_gettimeofday(&timestamp);
+ hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
+ (long)timestamp.tv_sec, (long)timestamp.tv_usec);
+ WARN_ON_ONCE(!hdr);
+ len = hdr ? strlen(hdr) : 0;
+ persistent_ram_write(prz, hdr, len);
+ kfree(hdr);
+
+ return len;
+}
+
static int ramoops_pstore_write(enum pstore_type_id type,
enum kmsg_dump_reason reason,
u64 *id,
unsigned int part,
size_t size, struct pstore_info *psi)
{
- char *buf;
- size_t res;
- struct timeval timestamp;
struct ramoops_context *cxt = psi->data;
- size_t available = cxt->record_size;
+ struct persistent_ram_zone *prz = cxt->przs[cxt->count];
+ size_t hlen;

/* Currently ramoops is designed to only store dmesg dumps. */
if (type != PSTORE_TYPE_DMESG)
@@ -142,22 +159,10 @@ static int ramoops_pstore_write(enum pstore_type_id type,
if (part != 1)
return -ENOSPC;

- buf = cxt->virt_addr + (cxt->count * cxt->record_size);
-
- res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
- buf += res;
- available -= res;
-
- do_gettimeofday(&timestamp);
- res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
- buf += res;
- available -= res;
-
- if (size > available)
- size = available;
-
- memcpy(buf, cxt->pstore.buf, size);
- memset(buf + size, '\0', available - size);
+ hlen = ramoops_write_kmsg_hdr(prz);
+ if (size + hlen > prz->buffer_size)
+ size = prz->buffer_size - hlen;
+ persistent_ram_write(prz, cxt->pstore.buf, size);

cxt->count = (cxt->count + 1) % cxt->max_count;

@@ -167,14 +172,12 @@ static int ramoops_pstore_write(enum pstore_type_id type,
static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,
struct pstore_info *psi)
{
- char *buf;
struct ramoops_context *cxt = psi->data;

if (id >= cxt->max_count)
return -EINVAL;

- buf = cxt->virt_addr + (id * cxt->record_size);
- memset(buf, '\0', cxt->record_size);
+ persistent_ram_free_old(cxt->przs[id]);

return 0;
}
@@ -192,9 +195,11 @@ static struct ramoops_context oops_cxt = {

static int __init ramoops_probe(struct platform_device *pdev)
{
+ struct device *dev = &pdev->dev;
struct ramoops_platform_data *pdata = pdev->dev.platform_data;
struct ramoops_context *cxt = &oops_cxt;
int err = -EINVAL;
+ int i;

/* Only a single ramoops area allowed at a time, so fail extra
* probes.
@@ -232,8 +237,28 @@ static int __init ramoops_probe(struct platform_device *pdev)
cxt->record_size = pdata->record_size;
cxt->dump_oops = pdata->dump_oops;

+ cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_count, GFP_KERNEL);
+ if (!cxt->przs) {
+ err = -ENOMEM;
+ dev_err(dev, "failed to initialize a prz array\n");
+ goto fail_out;
+ }
+
+ for (i = 0; i < cxt->max_count; i++) {
+ size_t sz = cxt->record_size;
+ phys_addr_t start = cxt->phys_addr + sz * i;
+
+ cxt->przs[i] = persistent_ram_new(start, sz, 0);
+ if (IS_ERR(cxt->przs[i])) {
+ err = PTR_ERR(cxt->przs[i]);
+ dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
+ sz, (unsigned long long)start, err);
+ goto fail_przs;
+ }
+ }
+
cxt->pstore.data = cxt;
- cxt->pstore.bufsize = cxt->record_size;
+ cxt->pstore.bufsize = cxt->przs[0]->buffer_size;
cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);
spin_lock_init(&cxt->pstore.buf_lock);
if (!cxt->pstore.buf) {
@@ -241,23 +266,10 @@ static int __init ramoops_probe(struct platform_device *pdev)
goto fail_clear;
}

- if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
- pr_err("request mem region (0x%lx@0x%llx) failed\n",
- cxt->size, (unsigned long long)cxt->phys_addr);
- err = -EINVAL;
- goto fail_buf;
- }
-
- cxt->virt_addr = ioremap(cxt->phys_addr, cxt->size);
- if (!cxt->virt_addr) {
- pr_err("ioremap failed\n");
- goto fail_mem_region;
- }
-
err = pstore_register(&cxt->pstore);
if (err) {
pr_err("registering with pstore failed\n");
- goto fail_iounmap;
+ goto fail_buf;
}

/*
@@ -275,15 +287,15 @@ static int __init ramoops_probe(struct platform_device *pdev)

return 0;

-fail_iounmap:
- iounmap(cxt->virt_addr);
-fail_mem_region:
- release_mem_region(cxt->phys_addr, cxt->size);
fail_buf:
kfree(cxt->pstore.buf);
fail_clear:
cxt->pstore.bufsize = 0;
cxt->max_count = 0;
+fail_przs:
+ for (i = 0; cxt->przs[i]; i++)
+ persistent_ram_free(cxt->przs[i]);
+ kfree(cxt->przs);
fail_out:
return err;
}
--
1.7.9.2

2012-05-17 07:17:08

by Anton Vorontsov

Subject: [PATCH 3/3] pstore/ram: Add ECC support

This is now straightforward: just introduce a module parameter and pass
the needed value to persistent_ram_new().

Signed-off-by: Anton Vorontsov <[email protected]>
Acked-by: Marco Stornelli <[email protected]>
Acked-by: Kees Cook <[email protected]>
---
Documentation/ramoops.txt | 6 ++++++
fs/pstore/ram.c | 15 ++++++++++++---
include/linux/pstore_ram.h | 1 +
3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/Documentation/ramoops.txt b/Documentation/ramoops.txt
index 470d2c4..4ba7db2 100644
--- a/Documentation/ramoops.txt
+++ b/Documentation/ramoops.txt
@@ -30,6 +30,11 @@ variable while setting 0 in that variable dumps only the panics.
The module uses a counter to record multiple dumps but the counter gets reset
on restart (i.e. new dumps after the restart will overwrite old ones).

+Ramoops also supports software ECC protection of persistent memory regions.
+This might be useful when a hardware reset was used to bring the machine back
+to life (i.e. a watchdog triggered). In such cases, RAM may be somewhat
+corrupt, but usually it is restorable.
+
2. Setting the parameters

Setting the ramoops parameters can be done in 2 different manners:
@@ -46,6 +51,7 @@ static struct ramoops_platform_data ramoops_data = {
.mem_address = <...>,
.record_size = <...>,
.dump_oops = <...>,
+ .ecc = <...>,
};

static struct platform_device ramoops_dev = {
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 62b13ed..9123cce 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -56,12 +56,18 @@ module_param(dump_oops, int, 0600);
MODULE_PARM_DESC(dump_oops,
"set to 1 to dump oopses, 0 to only dump panics (default 1)");

+static int ramoops_ecc;
+module_param_named(ecc, ramoops_ecc, int, 0600);
+MODULE_PARM_DESC(ramoops_ecc,
+ "set to 1 to enable ECC support");
+
struct ramoops_context {
struct persistent_ram_zone **przs;
phys_addr_t phys_addr;
unsigned long size;
size_t record_size;
int dump_oops;
+ bool ecc;
unsigned int count;
unsigned int max_count;
unsigned int read_count;
@@ -236,6 +242,7 @@ static int __init ramoops_probe(struct platform_device *pdev)
cxt->phys_addr = pdata->mem_address;
cxt->record_size = pdata->record_size;
cxt->dump_oops = pdata->dump_oops;
+ cxt->ecc = pdata->ecc;

cxt->przs = kzalloc(sizeof(*cxt->przs) * cxt->max_count, GFP_KERNEL);
if (!cxt->przs) {
@@ -248,7 +255,7 @@ static int __init ramoops_probe(struct platform_device *pdev)
size_t sz = cxt->record_size;
phys_addr_t start = cxt->phys_addr + sz * i;

- cxt->przs[i] = persistent_ram_new(start, sz, 0);
+ cxt->przs[i] = persistent_ram_new(start, sz, cxt->ecc);
if (IS_ERR(cxt->przs[i])) {
err = PTR_ERR(cxt->przs[i]);
dev_err(dev, "failed to request mem region (0x%zx@0x%llx): %d\n",
@@ -281,9 +288,10 @@ static int __init ramoops_probe(struct platform_device *pdev)
record_size = pdata->record_size;
dump_oops = pdata->dump_oops;

- pr_info("attached 0x%lx@0x%llx (%ux0x%zx)\n",
+ pr_info("attached 0x%lx@0x%llx (%ux0x%zx), ecc: %s\n",
cxt->size, (unsigned long long)cxt->phys_addr,
- cxt->max_count, cxt->record_size);
+ cxt->max_count, cxt->record_size,
+ ramoops_ecc ? "on" : "off");

return 0;

@@ -347,6 +355,7 @@ static int __init ramoops_init(void)
dummy_data->mem_address = mem_address;
dummy_data->record_size = record_size;
dummy_data->dump_oops = dump_oops;
+ dummy_data->ecc = ramoops_ecc;
dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
NULL, 0, dummy_data,
sizeof(struct ramoops_platform_data));
diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h
index ffe24a5..7ed7fd4 100644
--- a/include/linux/pstore_ram.h
+++ b/include/linux/pstore_ram.h
@@ -92,6 +92,7 @@ struct ramoops_platform_data {
unsigned long mem_address;
unsigned long record_size;
int dump_oops;
+ bool ecc;
};

#endif
--
1.7.9.2

2012-05-17 15:52:49

by Greg Kroah-Hartman

Subject: Re: [PATCH v3 0/3] Merge ramoops and persistent_ram, generic pstore RAM backend

On Thu, May 17, 2012 at 12:11:48AM -0700, Anton Vorontsov wrote:
> Hi all,
>
> Here comes v3:
>
> - Rebased on current staging-next tree, so only 3 patches left;
> - Fixed ram_console dependency in Kconfig (issue noticed by Greg KH).

Nice, thanks for reworking this, now applied.

greg k-h

2012-05-17 16:34:26

by Kees Cook

Subject: Re: [PATCH 2/3] pstore/ram: Switch to persistent_ram routines

On Thu, May 17, 2012 at 12:15 AM, Anton Vorontsov
<[email protected]> wrote:
> The patch switches pstore RAM backend to use persistent_ram routines,
> one step closer to the ECC support.
>
> Signed-off-by: Anton Vorontsov <[email protected]>
> Acked-by: Marco Stornelli <[email protected]>
> ---
> ?fs/pstore/ram.c | ?106 +++++++++++++++++++++++++++++++------------------------
> ?1 file changed, 59 insertions(+), 47 deletions(-)
>
> diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
> index e443c9c..62b13ed 100644
> --- a/fs/pstore/ram.c
> +++ b/fs/pstore/ram.c
> @@ -57,7 +57,7 @@ MODULE_PARM_DESC(dump_oops,
> ? ? ? ? ? ? ? ?"set to 1 to dump oopses, 0 to only dump panics (default 1)");
>
> ?struct ramoops_context {
> - ? ? ? void *virt_addr;
> + ? ? ? struct persistent_ram_zone **przs;
> ? ? ? ?phys_addr_t phys_addr;
> ? ? ? ?unsigned long size;
> ? ? ? ?size_t record_size;
> @@ -85,39 +85,56 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? struct pstore_info *psi)
> ?{
> ? ? ? ?ssize_t size;
> - ? ? ? char *rambuf;
> ? ? ? ?struct ramoops_context *cxt = psi->data;
> + ? ? ? struct persistent_ram_zone *prz;
>
> ? ? ? ?if (cxt->read_count >= cxt->max_count)
> ? ? ? ? ? ? ? ?return -EINVAL;
> +
> ? ? ? ?*id = cxt->read_count++;
> + ? ? ? prz = cxt->przs[*id];
> +
> ? ? ? ?/* Only supports dmesg output so far. */
> ? ? ? ?*type = PSTORE_TYPE_DMESG;
> ? ? ? ?/* TODO(kees): Bogus time for the moment. */
> ? ? ? ?time->tv_sec = 0;
> ? ? ? ?time->tv_nsec = 0;
>
> - ? ? ? rambuf = cxt->virt_addr + (*id * cxt->record_size);
> - ? ? ? size = strnlen(rambuf, cxt->record_size);
> + ? ? ? size = persistent_ram_old_size(prz);
> ? ? ? ?*buf = kmalloc(size, GFP_KERNEL);
> ? ? ? ?if (*buf == NULL)
> ? ? ? ? ? ? ? ?return -ENOMEM;
> - ? ? ? memcpy(*buf, rambuf, size);
> + ? ? ? memcpy(*buf, persistent_ram_old(prz), size);
>
> ? ? ? ?return size;
> ?}
>
> +static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
> +{
> + ? ? ? char *hdr;
> + ? ? ? struct timeval timestamp;
> + ? ? ? size_t len;
> +
> + ? ? ? do_gettimeofday(&timestamp);
> + ? ? ? hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
> + ? ? ? ? ? ? ? (long)timestamp.tv_sec, (long)timestamp.tv_usec);
> + ? ? ? WARN_ON_ONCE(!hdr);
> + ? ? ? len = hdr ? strlen(hdr) : 0;
> + ? ? ? persistent_ram_write(prz, hdr, len);
> + ? ? ? kfree(hdr);
> +
> + ? ? ? return len;
> +}
> +
> ?static int ramoops_pstore_write(enum pstore_type_id type,
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?enum kmsg_dump_reason reason,
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?u64 *id,
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?unsigned int part,
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?size_t size, struct pstore_info *psi)
> ?{
> - ? ? ? char *buf;
> - ? ? ? size_t res;
> - ? ? ? struct timeval timestamp;
> ? ? ? ?struct ramoops_context *cxt = psi->data;
> - ? ? ? size_t available = cxt->record_size;
> + ? ? ? struct persistent_ram_zone *prz = cxt->przs[cxt->count];
> + ? ? ? size_t hlen;
>
> ? ? ? ?/* Currently ramoops is designed to only store dmesg dumps. */
> ? ? ? ?if (type != PSTORE_TYPE_DMESG)
> @@ -142,22 +159,10 @@ static int ramoops_pstore_write(enum pstore_type_id type,
> ? ? ? ?if (part != 1)
> ? ? ? ? ? ? ? ?return -ENOSPC;
>
> - ? ? ? buf = cxt->virt_addr + (cxt->count * cxt->record_size);
> -
> - ? ? ? res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
> - ? ? ? buf += res;
> - ? ? ? available -= res;
> -
> - ? ? ? do_gettimeofday(&timestamp);
> - ? ? ? res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
> - ? ? ? buf += res;
> - ? ? ? available -= res;
> -
> - ? ? ? if (size > available)
> - ? ? ? ? ? ? ? size = available;
> -
> - ? ? ? memcpy(buf, cxt->pstore.buf, size);
> - ? ? ? memset(buf + size, '\0', available - size);
> + ? ? ? hlen = ramoops_write_kmsg_hdr(prz);
> + ? ? ? if (size + hlen > prz->buffer_size)
> + ? ? ? ? ? ? ? size = prz->buffer_size - hlen;
> + ? ? ? persistent_ram_write(prz, cxt->pstore.buf, size);

This still needs to wipe out the remaining bytes in the buffer (the
second memset above).

> ? ? ? ?cxt->count = (cxt->count + 1) % cxt->max_count;
>
> @@ -167,14 +172,12 @@ static int ramoops_pstore_write(enum pstore_type_id type,
> ?static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?struct pstore_info *psi)
> ?{
> - ? ? ? char *buf;
> ? ? ? ?struct ramoops_context *cxt = psi->data;
>
> ? ? ? ?if (id >= cxt->max_count)
> ? ? ? ? ? ? ? ?return -EINVAL;
>
> - ? ? ? buf = cxt->virt_addr + (id * cxt->record_size);
> - ? ? ? memset(buf, '\0', cxt->record_size);
> + ? ? ? persistent_ram_free_old(cxt->przs[id]);

Same here -- erasing the buffer means wiping it with NULL bytes.

Otherwise, it looks good to me.

-Kees

--
Kees Cook
Chrome OS Security

2012-05-18 21:51:12

by Anton Vorontsov

Subject: Re: [PATCH 2/3] pstore/ram: Switch to persistent_ram routines

On Thu, May 17, 2012 at 09:34:19AM -0700, Kees Cook wrote:
[...]
> > -       memcpy(buf, cxt->pstore.buf, size);
> > -       memset(buf + size, '\0', available - size);
> > +       hlen = ramoops_write_kmsg_hdr(prz);
> > +       if (size + hlen > prz->buffer_size)
> > +               size = prz->buffer_size - hlen;
> > +       persistent_ram_write(prz, cxt->pstore.buf, size);
>
> This still needs to wipe out the remaining bytes in the buffer (the
> second memset above).
[...]
> > -       buf = cxt->virt_addr + (id * cxt->record_size);
> > -       memset(buf, '\0', cxt->record_size);
> > +       persistent_ram_free_old(cxt->przs[id]);
>
> Same here -- erasing the buffer means wiping it with NULL bytes.

Well, with persistent_ram we don't need to actually erase buffers
(with persistent_ram we might even hold binary data). But yes,
we'd better reset size pointer, otherwise the unlinked buffer
will show up on the next reboot. Thanks for noticing!

--
Anton Vorontsov
Email: [email protected]