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authorJulius Werner <jwerner@chromium.org>2015-01-27 15:40:47 -0800
committerPatrick Georgi <pgeorgi@google.com>2015-04-13 12:21:02 +0200
commit5d686229e8f808c65934c17da9313e758b4ef9e9 (patch)
treef5e19fe280e636ce9714e3c68df1ea32e8574fd0
parentb9d961550ce07951b472ae558281e288413ab445 (diff)
downloadcoreboot-5d686229e8f808c65934c17da9313e758b4ef9e9.tar.xz
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>
-rw-r--r--src/drivers/elog/elog.c38
1 files changed, 21 insertions, 17 deletions
diff --git a/src/drivers/elog/elog.c b/src/drivers/elog/elog.c
index f6b0006db8..76e8cf71b8 100644
--- a/src/drivers/elog/elog.c
+++ b/src/drivers/elog/elog.c
@@ -75,9 +75,13 @@ static elog_event_buffer_state event_buffer_state;
static u16 next_event_offset;
static u16 event_count;
-static int elog_initialized;
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)
{
@@ -522,25 +526,18 @@ int elog_clear(void)
static void elog_find_flash(void)
{
-#if CONFIG_CHROMEOS
- u8 *flash_base_ptr;
-#endif
-
elog_debug("elog_find_flash()\n");
#if CONFIG_CHROMEOS
/* Find the ELOG base and size in FMAP */
- total_size = find_fmap_entry("RW_ELOG", (void **)&flash_base_ptr);
- if (total_size < 0) {
- printk(BIOS_WARNING, "ELOG: Unable to find RW_ELOG in FMAP, "
- "using CONFIG_ELOG_FLASH_BASE instead\n");
- total_size = CONFIG_ELOG_AREA_SIZE;
+ u8 *flash_base_ptr;
+ int fmap_size = find_fmap_entry("RW_ELOG", (void **)&flash_base_ptr);
+ if (fmap_size < 0) {
+ printk(BIOS_WARNING, "ELOG: Unable to find RW_ELOG in FMAP\n");
+ flash_base = total_size = 0;
} else {
flash_base = elog_flash_address_to_offset(flash_base_ptr);
-
- /* Use configured size if smaller than FMAP size */
- if (total_size > CONFIG_ELOG_AREA_SIZE)
- total_size = CONFIG_ELOG_AREA_SIZE;
+ total_size = MIN(fmap_size, CONFIG_ELOG_AREA_SIZE);
}
#else
flash_base = CONFIG_ELOG_FLASH_BASE;
@@ -554,8 +551,15 @@ static void elog_find_flash(void)
*/
int elog_init(void)
{
- if (elog_initialized)
+ switch (elog_initialized) {
+ case ELOG_UNINITIALIZED:
+ break;
+ case ELOG_INITIALIZED:
return 0;
+ case ELOG_BROKEN:
+ return -1;
+ }
+ elog_initialized = ELOG_BROKEN;
elog_debug("elog_init()\n");
@@ -600,8 +604,6 @@ int elog_init(void)
return -1;
}
- elog_initialized = 1;
-
printk(BIOS_INFO, "ELOG: FLASH @0x%p [SPI 0x%08x]\n",
elog_area, flash_base);
@@ -637,6 +639,8 @@ int elog_init(void)
#endif
#endif
+ elog_initialized = ELOG_INITIALIZED;
+
return 0;
}