cfi_flash: fix bug with flash banks with different sector numbers

The function find_sector() does not take into account if the flash bank has changed since the last call. This could lead to illegal accesses inside and beyond the flash_info_t info strcture. For example if the current flash bank has less sectors than the last used flash bank.

This patch adds two cheks. One that insures, that the current sector does not exceed the allowed maximum (which is always a good idea). And one that checks if the current access is to the same flash bank as the last access. If not, the search loop will start with sector 0.

Signed-off-by Martin Krause <[email protected]>

---
 drivers/mtd/cfi_flash.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

drivers/mtd/cfi_flash.c +5 -0

index dd394a8..0909fe7 100644
@@ -744,8 +744,12 @@ static void flash_add_byte (flash_info_t * info, cfiword_t * cword, uchar c)
 static flash_sect_t find_sector (flash_info_t * info, ulong addr)
 {
 	static flash_sect_t saved_sector = 0; /* previously found sector */
+	static flash_info_t *saved_info = 0; /* previously used flash bank */
 	flash_sect_t sector = saved_sector;
 
+	if ((info != saved_info) || (sector >= info->sector_count))
+		sector = 0;
+
 	while ((info->start[sector] < addr)
 			&& (sector < info->sector_count - 1))
 		sector++;

@@ -757,6 +761,7 @@ static flash_sect_t find_sector (flash_info_t * info, ulong addr)
 		sector--;
 
 	saved_sector = sector;
+	saved_info = info;
 	return sector;
 }

The function find_sector() does not take into account if the flash bank has changed since the last call. This could lead to illegal accesses inside and beyond the flash_info_t info strcture. For example if the current flash bank has less sectors than the last used flash bank.

This patch adds two cheks. One that insures, that the current sector does not exceed the allowed maximum (which is always a good idea). And one that checks if the current access is to the same flash bank as the last access. If not, the search loop will start with sector 0.

Signed-off-by Martin Krause <[email protected]>

Quoted 5 lines

The function find_sector() does not take into account if the flash bank has changed since the last call. This could lead to illegal accesses inside and beyond the flash_info_t info strcture. For example if the current flash bank has less sectors than the last used flash bank.

Quoted 6 lines

This patch adds two cheks. One that insures, that the current sector does not exceed the allowed maximum (which is always a good idea). And one that checks if the current access is to the same flash bank as the last access. If not, the search loop will start with sector 0.

Signed-off-by Martin Krause <[email protected]>

Can you please comment on Martins fix? Thanks!

Hi Detlev,

Quoted 12 lines · On Monday 28 March 2011 17:55:03 Detlev Zundel wrote:

Quoted 11 lines

The function find_sector() does not take into account if the flash bank has changed since the last call. This could lead to illegal accesses inside and beyond the flash_info_t info strcture. For example if the current flash bank has less sectors than the last used flash bank.

This patch adds two cheks. One that insures, that the current sector does not exceed the allowed maximum (which is always a good idea). And one that checks if the current access is to the same flash bank as the last access. If not, the search loop will start with sector 0.

Signed-off-by Martin Krause <[email protected]>

Quoted 1 line

Can you please comment on Martins fix? Thanks!

I already did and asked for a non line-wrapped patch version:

http://lists.denx.de/pipermail/u-boot/2011-March/088950.html

Still no answer though. Martin, how is your schedule here? Will you find the time to send an updated patch shortly?

Quoted 4 lines

Quoted 1 line

Can you please comment on Martins fix? Thanks!

I already did and asked for a non line-wrapped patch version:

Quoted 4 lines

http://lists.denx.de/pipermail/u-boot/2011-March/088950.html

Still no answer though. Martin, how is your schedule here? Will you find the time to send an updated patch shortly?

Well actually I followed up to a patch version that Martin sent out pretty much immediately and which I can apply without problems. Can you please try again if the patch works for you also?

The function find_sector() does not take into account if the flash bank has changed since the last call. This could lead to illegal accesses inside and beyond the flash_info_t info strcture. For example if the current flash bank has less sectors than the last used flash bank.

This patch adds two cheks. One that insures, that the current sector does not exceed the allowed maximum (which is always a good idea). And one that checks if the current access is to the same flash bank as the last access. If not, the search loop will start with sector 0.