[U-Boot] [PATCH 03/12] x86: doc: Mention qemu-x86_64 support
Bin Meng
bmeng.cn at gmail.com
Sat Oct 13 15:06:45 UTC 2018
Currently only 32-bit U-Boot for QEMU x86 is documented. Mention
the 64-bit support.
Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
---
Changes in this version:
- add more information about 64-bit support
doc/README.x86 | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/doc/README.x86 b/doc/README.x86
index 8cc4672..64da4ac 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
+
+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 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
--
2.7.4
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