Hi Kumar,
I have been working on the CONFIG_RELOCATABLE support for PPC44x, trying to
process
the relocations generated by the compiler. Since the TLB size is 256M, we cannot
enforce a page aligned kernel load address.
I came across some issues with the __va() / __pa() translations, while the
kernel
load address is not page aligned.
We have the following definition :
#define __va(x) ((void *)(unsigned long)((phys_addr_t)(x) -
PHYSICAL_START + KERNELBASE)
where,
PHYSICAL_START is #define'd to kernstart_addr variable, updated at boot
time.
I would like to know the exact meaning of the value in kerstart_addr.
For e.g:
When we have :
PAGE_OFFSET = KERNELBASE = 0xc0000000,
and
kernel loaded at 64M (0x4000000)
and
we map Physical address 0 to Virtual address 0xc0000000.
What should be the value of kernstart_addr ? Should it be
0 ? Or should it be 0x4000000 ?
If we choose, 0x4000000, we get the translations wrong :
__va(0x1) = 0x1 - 0x4000000 + 0xc0000000
= 0xbc000001
If we select 0, we have problems at other places where we assume,
PHYSICAL_START to be the va() of _stext.
Thanks
Suzuki
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