From ed253c8fd80573b2182aa5fd27033750cff48c0b Mon Sep 17 00:00:00 2001 From: Aaron Durbin Date: Wed, 7 Oct 2015 17:22:42 -0500 Subject: 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 Reviewed-on: http://review.coreboot.org/11823 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi --- src/lib/cbfs.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'src/lib/cbfs.c') 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); -- cgit v1.2.3