pstore/ftrace: Provide ftrace log merging routine

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>

diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c
index bfbfc26..5c04507 100644 (file)
--- a/fs/pstore/ftrace.c
+++ b/fs/pstore/ftrace.c
@@ -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);

diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h
index 8efd72d..7fb2190 100644 (file)
--- a/fs/pstore/internal.h
+++ b/fs/pstore/internal.h
@@ -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

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index dba9b4e..26a1f50 100644 (file)
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -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);