Re: [Xen-devel] [PATCH v5 15/16] livepatch, arm[32|64]: Share arch_livepatch_revert

[Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>]

On 09/21/2016 06:32 PM, Konrad Rzeszutek Wilk wrote:
> It is exactly the same in both platforms.
>
> No functional change.
>
> Acked-by: Julien Grall <julien.grall@xxxxxxx>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> ---
> 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/
> v5: Added Julien's Acked-by.
>     Fixed comments.
>   - Rebase on top "livepatch: Drop _jmp from arch_livepatch_[apply,revert]_jmp"
>   - s/_jmp//
> ---
>  xen/arch/arm/arm32/livepatch.c | 17 +----------------
>  xen/arch/arm/arm64/livepatch.c | 17 +----------------
>  xen/arch/arm/livepatch.c       | 17 +++++++++++++++++
>  3 files changed, 19 insertions(+), 32 deletions(-)
>
> diff --git a/xen/arch/arm/arm32/livepatch.c b/xen/arch/arm/arm32/livepatch.c
> index 3f47326..7e600f2 100644
> --- a/xen/arch/arm/arm32/livepatch.c
> +++ b/xen/arch/arm/arm32/livepatch.c
> @@ -74,22 +74,7 @@ void arch_livepatch_apply(struct livepatch_func *func)
>          clean_and_invalidate_dcache_va_range(func->new_addr, func->new_size);
>  }
>
> -void arch_livepatch_revert(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;
> -    }
> -}
> +/* arch_livepatch_revert shared with ARM 32/ARM 64. */
>
>  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 ea8044d..a7a292f 100644
> --- a/xen/arch/arm/arm64/livepatch.c
> +++ b/xen/arch/arm/arm64/livepatch.c
> @@ -61,22 +61,7 @@ void arch_livepatch_apply(struct livepatch_func *func)
>          clean_and_invalidate_dcache_va_range(func->new_addr, func->new_size);
>  }
>
> -void arch_livepatch_revert(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;
> -    }
> -}
> +/* arch_livepatch_revert shared with ARM 32/ARM 64. */
>
>  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 6ee7081..2d62a24 100644
> --- a/xen/arch/arm/livepatch.c
> +++ b/xen/arch/arm/livepatch.c
> @@ -69,6 +69,23 @@ int arch_livepatch_verify_func(const struct livepatch_func 
> *func)
>      return 0;
>  }
>
> +void arch_livepatch_revert(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;
> +    }
> +}
> +
Same as previously, can this not be done with a simple memcpy?

--
Ross Lagerwall

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