[PATCHv4 3/7] arm64: Move cpu_resume into the text section

[Ard Biesheuvel]

On 27 October 2014 21:12, Laura Abbott <lauraa at codeaurora.org> wrote:
> The function cpu_resume currently lives in the .data
> section. There's no reason for it to be there since
> we can use relative instructions without a problem.
> Move it to the text section where it belongs.
>
> Reviewed-by: Kees Cook <keescook at chromium.org>
> Signed-off-by: Laura Abbott <lauraa at codeaurora.org>
> ---
>  arch/arm64/kernel/sleep.S | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
>

Hi Laura,

Apologies for waiting until v4 to bring this up, but I have some minor comments.

> diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
> index a564b44..5762b16 100644
> --- a/arch/arm64/kernel/sleep.S
> +++ b/arch/arm64/kernel/sleep.S
> @@ -147,12 +147,12 @@ cpu_resume_after_mmu:
>         ret
>  ENDPROC(cpu_resume_after_mmu)
>
> -       .data
>  ENTRY(cpu_resume)
>         bl      el2_setup               // if in EL2 drop to EL1 cleanly
>  #ifdef CONFIG_SMP
>         mrs     x1, mpidr_el1
> -       adr     x4, mpidr_hash_ptr
> +       adrp    x4, mpidr_hash_ptr
> +       add     x4, x4, #:lo12:mpidr_hash_ptr

Instead of this change, you could put mpidr_hash_ptr itself in .text as well.

>         ldr     x5, [x4]
>         add     x8, x4, x5              // x8 = struct mpidr_hash phys address
>          /* retrieve mpidr_hash members to compute the hash */
> @@ -164,14 +164,15 @@ ENTRY(cpu_resume)
>  #else
>         mov     x7, xzr
>  #endif
> -       adr     x0, sleep_save_sp
> +       adrp    x0, sleep_save_sp
> +       add     x0, x0, #:lo12:sleep_save_sp
>         ldr     x0, [x0, #SLEEP_SAVE_SP_PHYS]

Nit:
ldr x0, [x0, #:lo12:sleep_save_sp + SLEEP_SAVE_SP_PHYS]

>         ldr     x0, [x0, x7, lsl #3]
>         /* load sp from context */
>         ldr     x2, [x0, #CPU_CTX_SP]
> -       adr     x1, sleep_idmap_phys
> +       adrp    x1, sleep_idmap_phys
>         /* load physical address of identity map page table in x1 */
> -       ldr     x1, [x1]
> +       ldr     x1, [x1, #:lo12:sleep_idmap_phys]
>         mov     sp, x2
>         /*
>          * cpu_do_resume expects x0 to contain context physical address
> @@ -181,6 +182,7 @@ ENTRY(cpu_resume)
>         b       cpu_resume_mmu          // Resume MMU, never returns
>  ENDPROC(cpu_resume)
>
> +       .data
>         .align 3
>  mpidr_hash_ptr:
>         /*

Acked-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>