Re: [Xen-devel] [PATCH v4 14/16] livepatch, arm[32|64]: Share arch_livepatch_revert_jmp

[Julien Grall <julien.grall@xxxxxxx>]

Hi Konrad,

On 16/09/2016 18:38, Konrad Rzeszutek Wilk wrote:
> It is exactly the same in both platforms.
>
> No functional change.
>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
With the small change request below:

Acked-by: Julien Grall <julien.grall@xxxxxxx>

> ---
> Cc: Julien Grall <julien.grall@xxxxxxx>
> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
>
> v3: New submission.
> v4: s/arch_livepatch_insn_len/livepatch_insn_len/
>     s/PATCH_INSN_SIZE/ARCH_PATCH_INSN_SIZE/
> ---
>  xen/arch/arm/arm32/livepatch.c | 19 +------------------
>  xen/arch/arm/arm64/livepatch.c | 19 +------------------
>  xen/arch/arm/livepatch.c       | 19 +++++++++++++++++++
>  3 files changed, 21 insertions(+), 36 deletions(-)
>
> diff --git a/xen/arch/arm/arm32/livepatch.c b/xen/arch/arm/arm32/livepatch.c
> index 6ad0ce5..606a00c 100644
> --- a/xen/arch/arm/arm32/livepatch.c
> +++ b/xen/arch/arm/arm32/livepatch.c
[...]

> +/* arch_livepatch_revert_jmp shared with ARM 64. */
You use ARM 64 here but ...

>  int arch_livepatch_verify_elf(const struct livepatch_elf *elf)
>  {
> diff --git a/xen/arch/arm/arm64/livepatch.c b/xen/arch/arm/arm64/livepatch.c
> index d53fe59..89d061e 100644
> --- a/xen/arch/arm/arm64/livepatch.c
> +++ b/xen/arch/arm/arm64/livepatch.c
[...]

> +/* arch_livepatch_revert_jmp shared with ARM32. */
... ARM32 here. Please use either ARM 32/ARM 64 or ARM32/ARM64.

>  int arch_livepatch_verify_elf(const struct livepatch_elf *elf)
>  {
> diff --git a/xen/arch/arm/livepatch.c b/xen/arch/arm/livepatch.c
> index 9c198e9..c77030e 100644
> --- a/xen/arch/arm/livepatch.c
> +++ b/xen/arch/arm/livepatch.c
> @@ -69,6 +69,25 @@ int arch_livepatch_verify_func(const struct livepatch_func 
> *func)
>      return 0;
>  }
>
> +void arch_livepatch_revert_jmp(const struct livepatch_func *func)
> +{
> +    uint32_t *new_ptr;
> +    unsigned int i, len;
> +
> +    new_ptr = func->old_addr - (void *)_start + vmap_of_xen_text;
> +    len = livepatch_insn_len(func) / sizeof(uint32_t);
> +    for ( i = 0; i < len; i++ )
> +    {
> +        uint32_t insn;
> +
> +        memcpy(&insn, func->opaque + (i * sizeof(uint32_t)), 
> ARCH_PATCH_INSN_SIZE);
> +        /* PATCH! */
> +        *(new_ptr + i) = insn;
> +    }
> +
> +    clean_and_invalidate_dcache_va_range(new_ptr, sizeof(*new_ptr) * len);
> +}
> +
>  void arch_livepatch_post_action(void)
>  {
>      /* arch_livepatch_revive has nuked the instruction cache. */
Regards,

--
Julien Grall

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