Hi,
On Tue, 2010-01-19 at 09:55 +0000, Alexander Clouter wrote:
[...]
> >
> As a passing query, why do we have the high 32bit (0xffffffff....) spiel
> if later we can just make VMLINU[XZ]_LOAD_ADDRESS the low half? I see
> the output of 'nm' shows:
> ----
> alex@berk:/usr/src/wag54g/linux$ nm vmlinux | head -n1
> 941019e4 t .ex0
> alex@berk:/usr/src/wag54g/linux$ nm vmlinuz | head -n1
> 944abb50 B .heap
> ----
>
Mine:
$ mips64el-unknown-linux-gnu-nm vmlinux | head -n1
ffffffff80202304 t .ex0
$ mips64el-unknown-linux-gnu-nm vmlinuz | head -n1
ffffffff80b174e0 B .heap
and exactly, here is why we need to reserve the high 32bit:
$ cat arch/mips/Makefile | grep ^load | grep -v 0xffffffff
load-$(CONFIG_MIPS_SIM) += 0x80100000
load-$(CONFIG_SGI_IP27) += 0xc00000004001c000
load-$(CONFIG_SGI_IP27) += 0xa80000000001c000
load-$(CONFIG_SGI_IP28) += 0xa800000020004000
(Hi, Ralf, can we use the low 32bit directly?)
> However I am guessing it's some 64bit CPU requirement as my x86_64
> kernel seems to have 0xffffffff.... Which raises the question, why is
> AR7 not just using VMLINUX_LOAD_ADDRESS=0x94100000?
>
> > 1. Append "the high 32bit of VMLINUX_LOAD_ADDRESS" as the prefix if it
> > exists.
> >
> > 2. Get the sum of "the low 32bit of VMLINUX_LOAD_ADDRESS + VMLINUX_SIZE"
> > with printf "%08x" (08 herein is used to prefix the result with 0...)
> >
> > The corresponding shell script is:
> >
> > A=$VMLINUX_LOAD_ADDRESS;
> > # Append "the high 32bit of VMLINUX_LOAD_ADDRESS" as the prefix if it exists.
> > [ "${A:0:10}" != "${A}" ] && echo -n ${A:2:8};
> > # Get the sum of "the low 32bit of VMLINUX_LOAD_ADDRESS + VMLINUX_SIZE"
> > printf "%08x" $(($VMLINUX_SIZE + 0x${A:(-8)}))
> >
> Eugh, bash-ism's...
> ----
> alex@berk:/usr/src/wag54g/linux$ bash -c 'A=1234567890; echo ${A:0:5}'
> 12345
> alex@berk:/usr/src/wag54g/linux$ dash -c 'A=1234567890; echo ${A:0:5}'
> dash: Bad substitution
> ----
Ooh! really forget to test it with the dash, dash.... So, this revision
is also broken ;(
>
> Your 'punishment', use Plan9 for a period of no less than a week! :)
>
I have never played with Plan9, but ubuntu, archlinux, gentoo... and
created my user with "useradd -s /bin/bash ....", so, I only work with
bash ;)
> You have to use the pattern matching approach I used in my original
> patch, that's portable. Look at 'man 1 dash' and search for 'substr'
> for more details.
To consider "portable" and "good-looking", Perhaps it's better to use C
language here ;)
Thanks!
Regards,
Wu Zhangjin
