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elog: Correct behavior when FMAP section doesn't exist on ChromeOS 

The elog driver has a really stupid bug that checks a result which is
stored in an unsigned variable for < 0. Surprisingly GCC does not catch
this nonsense right now, and I spent an hour trying out different
warning options without finding one that doesn't also bring a load of
stupid and unavoidable false positives (the biggest offender being
-Wtype-limits, which does exactly what we'd want except for flagging
things like if ((u8)var >= CONFIG_VAR_MIN) where the VAR_MIN Kconfig may
or may not be 0).

So, the only thing we can do is fix this one and wait for the next time
something like that blows up. -.- Also change some more code to make the
behavior more explicit (the old code already intended to work this way
since flash_base is statically initialized to 0, never assigned in the
error path and checked later in elog_init()... but there was an error
message that incorrectly claimed a different fallback behavior, and
explicitly assigning the values makes this easier to see). Finally, add
another state to the elog_initialized variable to avoid trying to
reinitialize a broken eventlog on every event (if it doesn't work the
first time, chances are that it won't work later on during the same boot
either).

BRANCH=None
BUG=chrome-os-partner:35940
TEST=Flashed Jerry with RO 6588.4 and RW 6588.23, observed how it now
cleanly enters recovery mode without blowing its bootblock away with
stray eventlog entries.

Change-Id: I0e5348ba961ce4835c30f7108a2453522095f2ee
Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Original-Commit-Id: f9798dbf0c2b2e337062ecd84d0f45434343c0d9
Original-Change-Id: I4d93f48d2d01d75a04550d419e023aa42ca95a7a
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/243671
Original-Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/9557
Tested-by: build bot (Jenkins)
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
This commit is contained in:
Julius Werner 2015-01-27 15:40:47 -08:00 committed by Patrick Georgi
parent b9d961550c
commit 5d686229e8
1 changed files with 21 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
src/drivers/elog/elog.c
View File

@ -75,9 +75,13 @@ static elog_event_buffer_state event_buffer_state;
static u16 next_event_offset; static u16 next_event_offset;
static u16 event_count; static u16 event_count;
static int elog_initialized;
static struct spi_flash *elog_spi; static struct spi_flash *elog_spi;
static enum {
ELOG_UNINITIALIZED = 0,
ELOG_INITIALIZED,
ELOG_BROKEN,
} elog_initialized = ELOG_UNINITIALIZED;
static inline u32 get_rom_size(void) static inline u32 get_rom_size(void)
{ {
@ -522,25 +526,18 @@ int elog_clear(void)
static void elog_find_flash(void) static void elog_find_flash(void)
{ {
#if CONFIG_CHROMEOS
u8 *flash_base_ptr;
#endif
elog_debug("elog_find_flash()\n"); elog_debug("elog_find_flash()\n");
#if CONFIG_CHROMEOS #if CONFIG_CHROMEOS
/* Find the ELOG base and size in FMAP */ /* Find the ELOG base and size in FMAP */
total_size = find_fmap_entry("RW_ELOG", (void **)&flash_base_ptr); u8 *flash_base_ptr;
if (total_size < 0) { int fmap_size = find_fmap_entry("RW_ELOG", (void **)&flash_base_ptr);
printk(BIOS_WARNING, "ELOG: Unable to find RW_ELOG in FMAP, " if (fmap_size < 0) {
"using CONFIG_ELOG_FLASH_BASE instead\n"); printk(BIOS_WARNING, "ELOG: Unable to find RW_ELOG in FMAP\n");
total_size = CONFIG_ELOG_AREA_SIZE; flash_base = total_size = 0;
} else { } else {
flash_base = elog_flash_address_to_offset(flash_base_ptr); flash_base = elog_flash_address_to_offset(flash_base_ptr);
total_size = MIN(fmap_size, CONFIG_ELOG_AREA_SIZE);
/* Use configured size if smaller than FMAP size */
if (total_size > CONFIG_ELOG_AREA_SIZE)
total_size = CONFIG_ELOG_AREA_SIZE;
} }
#else #else
flash_base = CONFIG_ELOG_FLASH_BASE; flash_base = CONFIG_ELOG_FLASH_BASE;
@ -554,8 +551,15 @@ static void elog_find_flash(void)
*/ */
int elog_init(void) int elog_init(void)
{ {
if (elog_initialized) switch (elog_initialized) {
case ELOG_UNINITIALIZED:
break;
case ELOG_INITIALIZED:
return 0; return 0;
case ELOG_BROKEN:
return -1;
}
elog_initialized = ELOG_BROKEN;
elog_debug("elog_init()\n"); elog_debug("elog_init()\n");
@ -600,8 +604,6 @@ int elog_init(void)
return -1; return -1;
} }
elog_initialized = 1;
printk(BIOS_INFO, "ELOG: FLASH @0x%p [SPI 0x%08x]\n", printk(BIOS_INFO, "ELOG: FLASH @0x%p [SPI 0x%08x]\n",
elog_area, flash_base); elog_area, flash_base);
@ -637,6 +639,8 @@ int elog_init(void)
#endif #endif
#endif #endif
elog_initialized = ELOG_INITIALIZED;
return 0; return 0;
} }