Currently only 32-bit U-Boot for QEMU x86 is documented. Mention the 64-bit support.
Signed-off-by: Bin Meng bmeng.cn@gmail.com Reviewed-by: Heinrich Schuchardt xypron.glpk@gmx.de
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Changes in v2: - some rewording in the doc per Heinrich's review comments
doc/README.x86 | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/doc/README.x86 b/doc/README.x86 index 8cc4672..22bfbab 100644 --- a/doc/README.x86 +++ b/doc/README.x86 @@ -32,7 +32,7 @@ are supported: - Link (Chromebook Pixel) - Minnowboard MAX - Samus (Chromebook Pixel 2015) - - QEMU x86 + - QEMU x86 (32-bit & 64-bit)
As for loading an OS, U-Boot supports directly booting a 32-bit or 64-bit Linux kernel as part of a FIT image. It also supports a compressed zImage. @@ -376,7 +376,9 @@ QEMU x86 target instructions for bare mode:
To build u-boot.rom for QEMU x86 targets, just simply run
-$ make qemu-x86_defconfig +$ make qemu-x86_defconfig (for 32-bit) +or +$ make qemu-x86_64_defconfig (for 64-bit) $ make all
Note this default configuration will build a U-Boot for the QEMU x86 i440FX @@ -479,6 +481,19 @@ Here the kernel (bzImage) is loaded to 01000000 and initrd is to 04000000. Then,
=> zboot 01000000 - 04000000 1b1ab50
+To run 64-bit U-Boot, qemu-system-x86_64 should be used instead, e.g.: +$ qemu-system-x86_64 -nographic -bios path/to/u-boot.rom + +A specific CPU can be specified via the '-cpu' parameter but please make +sure the specified CPU supports 64-bit like '-cpu core2duo'. Conversely +'-cpu pentium' won't work for obvious reasons that the processor only +supports 32-bit. + +Note 64-bit support is very preliminary at this point. Lots of features +are missing in the 64-bit world. One notable feature is the VGA console +support which is currently missing, so that you must specify '-nographic' +to get 64-bit U-Boot up and running. + Updating U-Boot on Edison ------------------------- By default Intel Edison boards are shipped with preinstalled heavily