From patchwork Sun Apr 26 15:13:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Simon Glass X-Patchwork-Id: 238497 List-Id: U-Boot discussion From: sjg at chromium.org (Simon Glass) Date: Sun, 26 Apr 2020 09:13:00 -0600 Subject: [PATCH v4 8/9] x86: Use the existing stack when chain-loading In-Reply-To: <20200426151302.93418-1-sjg@chromium.org> References: <20200426151302.93418-1-sjg@chromium.org> Message-ID: <20200426151302.93418-8-sjg@chromium.org> With chromebook_coral we normally run TPL->SPL->U-Boot. This is the 'bare metal' case. When running from coreboot we put u-boot.bin in the RW_LEGACY portion of the image, e.g. with: cbfstool image-coral.serial.bin add-flat-binary -r RW_LEGACY \ -f /tmp/b/chromebook_coral/u-boot.bin -n altfw/u-boot \ -c lzma -l 0x1110000 -e 0x1110000 In this case U-Boot is run from coreboot (actually Depthcharge, its payload) so we cannot access CAR. Use the existing stack instead. Signed-off-by: Simon Glass Reviewed-by: Bin Meng --- Changes in v4: - Update to use locate_coreboot_table() Changes in v3: None Changes in v2: None arch/x86/cpu/start_from_spl.S | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/arch/x86/cpu/start_from_spl.S b/arch/x86/cpu/start_from_spl.S index 22cab2dd6c..905c825cdc 100644 --- a/arch/x86/cpu/start_from_spl.S +++ b/arch/x86/cpu/start_from_spl.S @@ -14,18 +14,30 @@ .globl _start .type _start, @function _start: - /* Set up memory using the existing stack */ + /* + * If running from coreboot, CAR is no-longer available. Use the + * existing stack, which is large enough. + */ + call locate_coreboot_table + cmp $0, %eax + jge use_existing_stack + movl $(CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE - 4), %eax #ifdef CONFIG_DCACHE_RAM_MRC_VAR_SIZE subl $CONFIG_DCACHE_RAM_MRC_VAR_SIZE, %eax #endif + jmp 2f /* - * We don't subject CONFIG_DCACHE_RAM_MRC_VAR_SIZE since memory is + * We don't subtract CONFIG_DCACHE_RAM_MRC_VAR_SIZE since memory is * already set up. This has the happy side-effect of putting gd in a * new place separate from SPL, so the memset() in * board_init_f_init_reserve() does not cause any problems (otherwise * it would zero out the gd and crash) */ + /* Set up memory using the existing stack */ +use_existing_stack: + mov %esp, %eax +2: call board_init_f_alloc_reserve mov %eax, %esp