Hi,
Few questions, see below.
On Wed, Feb 02, 2011 at 03:43:29PM +0100, Per Fransson wrote:
> When restarting using the kernel kexec functionality the MMU
> needs to be turned off. Any code which does this needs to use
> identity mapped addresses to get reliable results. In the ARM
> kexec case this identity mapping is done:
[...]
> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
> index 0c1172b..762bb43 100644
> --- a/arch/arm/mm/proc-v7.S
> +++ b/arch/arm/mm/proc-v7.S
> @@ -61,6 +61,10 @@ ENDPROC(cpu_v7_proc_fin)
> */
> .align 5
> ENTRY(cpu_v7_reset)
> + sub pc, pc, #PAGE_OFFSET+4 @ go to physical addresses
How the above is going to work if PHYS_OFFSET is something else than zero? Also
does this work with Thumb-2 kernels?
> + mrc p15, 0, ip, c1, c0, 0 @ ctrl register
> + bic ip, ip, #0x0001 @ ...............m
> + mcr p15, 0, ip, c1, c0, 0 @ ctrl register
> mov pc, r0
> ENDPROC(cpu_v7_reset)
>
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index 03e8e8d..6a1345b 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -106,7 +106,11 @@ struct kimage {
> #endif
> };
>
> -
> +struct kexec_mmu_ent {
> + pgd_t *ptr;
> + pgd_t store;
> +};
> +extern struct kexec_mmu_ent kexec_mmu_ents[4];
>
> /* kexec interface functions */
> extern void machine_kexec(struct kimage *image);
Is it good idea to place these in a generic header as they are only used in ARM?
Thanks,
MW
