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pstore/ftrace: Provide ftrace log merging routine

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Move the ftrace log merging logic out of pstore/ram into pstore/ftrace
so other backends can use it, like pstore/zone.

Link: https://lore.kernel.org/lkml/20200510202436.63222-7-keescook@chromium.org/
Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Kees Cook 2020-05-08 08:42:12 -07:00
parent df9bf19d88
commit 16a583079e
3 changed files with 66 additions and 54 deletions
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54
fs/pstore/ftrace.c
View File

@ -16,6 +16,7 @@
#include <linux/debugfs.h>
#include <linux/err.h>
#include <linux/cache.h>
#include <linux/slab.h>
#include <asm/barrier.h>
#include "internal.h"
@ -132,3 +133,56 @@ void pstore_unregister_ftrace(void)
debugfs_remove_recursive(pstore_ftrace_dir);
}
ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size,
const char *src_log, size_t src_log_size)
{
size_t dest_size, src_size, total, dest_off, src_off;
size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
void *merged_buf;
struct pstore_ftrace_record *drec, *srec, *mrec;
size_t record_size = sizeof(struct pstore_ftrace_record);
dest_off = *dest_log_size % record_size;
dest_size = *dest_log_size - dest_off;
src_off = src_log_size % record_size;
src_size = src_log_size - src_off;
total = dest_size + src_size;
merged_buf = kmalloc(total, GFP_KERNEL);
if (!merged_buf)
return -ENOMEM;
drec = (struct pstore_ftrace_record *)(*dest_log + dest_off);
srec = (struct pstore_ftrace_record *)(src_log + src_off);
mrec = (struct pstore_ftrace_record *)(merged_buf);
while (dest_size > 0 && src_size > 0) {
if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
pstore_ftrace_read_timestamp(&srec[src_idx])) {
mrec[merged_idx++] = drec[dest_idx++];
dest_size -= record_size;
} else {
mrec[merged_idx++] = srec[src_idx++];
src_size -= record_size;
}
}
while (dest_size > 0) {
mrec[merged_idx++] = drec[dest_idx++];
dest_size -= record_size;
}
while (src_size > 0) {
mrec[merged_idx++] = srec[src_idx++];
src_size -= record_size;
}
kfree(*dest_log);
*dest_log = merged_buf;
*dest_log_size = total;
return 0;
}
EXPORT_SYMBOL_GPL(pstore_ftrace_combine_log);

9
fs/pstore/internal.h
View File

@ -12,9 +12,18 @@ extern unsigned long kmsg_bytes;
#ifdef CONFIG_PSTORE_FTRACE
extern void pstore_register_ftrace(void);
extern void pstore_unregister_ftrace(void);
ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size,
const char *src_log, size_t src_log_size);
#else
static inline void pstore_register_ftrace(void) {}
static inline void pstore_unregister_ftrace(void) {}
static inline ssize_t
pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size,
const char *src_log, size_t src_log_size)
{
*dest_log_size = 0;
return 0;
}
#endif
#ifdef CONFIG_PSTORE_PMSG

57
fs/pstore/ram.c
View File

@ -21,6 +21,7 @@
#include <linux/pstore_ram.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include "internal.h"
#define RAMOOPS_KERNMSG_HDR "===="
#define MIN_MEM_SIZE 4096UL
@ -168,59 +169,6 @@ static bool prz_ok(struct persistent_ram_zone *prz)
persistent_ram_ecc_string(prz, NULL, 0));
}
static
ssize_t ftrace_log_combine(char **dest_log, size_t *dest_log_size,
const char *src_log, size_t src_log_size)
{
size_t dest_size, src_size, total, dest_off, src_off;
size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
void *merged_buf;
struct pstore_ftrace_record *drec, *srec, *mrec;
size_t record_size = sizeof(struct pstore_ftrace_record);
dest_off = *dest_log_size % record_size;
dest_size = *dest_log_size - dest_off;
src_off = src_log_size % record_size;
src_size = src_log_size - src_off;
total = dest_size + src_size;
merged_buf = kmalloc(total, GFP_KERNEL);
if (!merged_buf)
return -ENOMEM;
drec = (struct pstore_ftrace_record *)(*dest_log + dest_off);
srec = (struct pstore_ftrace_record *)(src_log + src_off);
mrec = (struct pstore_ftrace_record *)(merged_buf);
while (dest_size > 0 && src_size > 0) {
if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
pstore_ftrace_read_timestamp(&srec[src_idx])) {
mrec[merged_idx++] = drec[dest_idx++];
dest_size -= record_size;
} else {
mrec[merged_idx++] = srec[src_idx++];
src_size -= record_size;
}
}
while (dest_size > 0) {
mrec[merged_idx++] = drec[dest_idx++];
dest_size -= record_size;
}
while (src_size > 0) {
mrec[merged_idx++] = srec[src_idx++];
src_size -= record_size;
}
kfree(*dest_log);
*dest_log = merged_buf;
*dest_log_size = total;
return 0;
}
static ssize_t ramoops_pstore_read(struct pstore_record *record)
{
ssize_t size = 0;
@ -293,7 +241,8 @@ static ssize_t ramoops_pstore_read(struct pstore_record *record)
prz_next->corrected_bytes;
tmp_prz->bad_blocks += prz_next->bad_blocks;
size = ftrace_log_combine(&tmp_prz->old_log,
size = pstore_ftrace_combine_log(
&tmp_prz->old_log,
&tmp_prz->old_log_size,
prz_next->old_log,
prz_next->old_log_size);