Commit 16a58307 authored by Kees Cook's avatar Kees Cook
Browse files

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: default avatarKees Cook <keescook@chromium.org>
parent df9bf19d

fs/pstore/ftrace.c

+54 −0
Original line number Diff line number Diff line
@@ -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);

fs/pstore/internal.h

+9 −0
Original line number Diff line number Diff line
@@ -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

fs/pstore/ram.c

+3 −54
Original line number Diff line number Diff line
@@ -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);

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