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authorAaron Durbin <adurbin@chromium.org>2015-10-07 17:22:42 -0500
committerAaron Durbin <adurbin@gmail.com>2015-10-11 23:56:46 +0000
commited253c8fd80573b2182aa5fd27033750cff48c0b (patch)
tree00cb4f59ce9bf9fe07fb3655677fe5348195ba09
parentfb9e378f2d239df8f3bd582f4f9d862f31748cbb (diff)
cbfs: don't load x86 programs over the top of read-only media
On x86 the early stages are currently execute-in-place which means they live in the memory-mapped spi flash. However, when loading romstage from verstage the romstage is execute-in-place so it's unnecessary to write over a read-only media -- not to mention writing to read-only memory is wrong to begin with. BUG=chrome-os-partner:44827 BRANCH=None TEST=Built and booted glados. Noted reduction of 20ms when loading romstage. Change-Id: I7cd399302a3925a05fbce82600b4c50ea66a0fcb Signed-off-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: http://review.coreboot.org/11823 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi <pgeorgi@google.com>
-rw-r--r--src/lib/cbfs.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/src/lib/cbfs.c b/src/lib/cbfs.c
index 05b939cdfe..9cdc365963 100644
--- a/src/lib/cbfs.c
+++ b/src/lib/cbfs.c
@@ -220,6 +220,16 @@ int cbfs_prog_stage_load(struct prog *pstage)
load = (void *)(uintptr_t)stage.load;
entry = (void *)(uintptr_t)stage.entry;
+ /* Hacky way to not load programs over read only media. The stages
+ * that would hit this path initialize themselves. */
+ if (ENV_VERSTAGE && IS_ENABLED(CONFIG_ARCH_X86) &&
+ IS_ENABLED(CONFIG_SPI_FLASH_MEMORY_MAPPED)) {
+ void *mapping = rdev_mmap(fh, foffset, fsize);
+ rdev_munmap(fh, mapping);
+ if (mapping == load)
+ goto out;
+ }
+
if (stage.compression == CBFS_COMPRESS_NONE) {
if (rdev_readat(fh, load, foffset, fsize) != fsize)
return -1;
@@ -242,6 +252,8 @@ int cbfs_prog_stage_load(struct prog *pstage)
memset(&load[fsize], 0, stage.memlen - fsize);
arch_segment_loaded((uintptr_t)load, stage.memlen, SEG_FINAL);
+
+out:
prog_set_area(pstage, load, stage.memlen);
prog_set_entry(pstage, entry, NULL);