scottwood at freescale.com
Thu Feb 17 06:24:03 EST 2011
On Wed, 16 Feb 2011 12:00:25 -0600
Meador Inge <meador_inge at mentor.com> wrote:
> Hi Kumar,
> Quick question about the support for booting at a non-zero base address
> (as committed here:
> Is booting from a non-zero address as simple as changing
> "CONFIG_PHYSICAL_START" (assuming it meets the alignment constraints, of
Another option is to turn on CONFIG_RELOCATABLE. Note that you'll still
have the same alignment constraints; it doesn't generate a truly relocatable
binary (the effective addresses are fixed). But you don't have to specify
the physical address at compile-time. This allows you to use the same
kernel image for multiple AMP partitions.
> For example, I want to boot from a non-zero address on the P1022DS. I
> should just be able to change "CONFIG_PHYSICAL_START" to, say,
> 0x08000000, and it should work, right? Any other bits that need to be
> done (i.e. U-Boot or device tree magic)?
You'll want the memory node adjusted for your restricted address range
(I'm assuming that this is why you want to start at non-zero, and that
you're not trying to have the kernel be located in the middle of its
There are some special u-boot variables (bootm_low/bootm_size) that govern
placement of the kernel, fdt, etc.
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