Re: [Xen-devel] [PATCH v2 1/2] xen/arm: alternative: Clean-up __apply_alternatives

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Wed, Sep 07, 2016 at 01:50:43PM +0100, Julien Grall wrote:
> This patch contains only renaming and comment update. There are no
> functional changes:
>     - Don't mix _start and _stext, they both point to the same address
>     but the former makes more sense (we are mapping the Xen binary, not
>     only the text section).
>     - s/text_mfn/xen_mfn/ and s/text_order/xen_order/ to make clear that
>     we map the Xen binary.
>     - Mention about inittext as alternative may patch this section.
> 
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> 
> ---
>     Konrad, I added your signed-off by because I squashed your patch [1]
>     in it. Let me know if there is any issue for that.

No issues. Albeit it may be odd for me to review my own patch :-)

See below

> 
>     [1] https://lists.xen.org/archives/html/xen-devel/2016-08/msg02890.html
> 
>     Changes in v2:
>         - Patch added
> ---
>  xen/arch/arm/alternative.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/xen/arch/arm/alternative.c b/xen/arch/arm/alternative.c
> index 8ee5a11..0ca97b9 100644
> --- a/xen/arch/arm/alternative.c
> +++ b/xen/arch/arm/alternative.c
> @@ -99,21 +99,21 @@ static int __apply_alternatives(const struct alt_region 
> *region)
>      const struct alt_instr *alt;
>      const u32 *origptr, *replptr;
>      u32 *writeptr, *writemap;
> -    mfn_t text_mfn = _mfn(virt_to_mfn(_stext));
> -    unsigned int text_order = get_order_from_bytes(_end - _start);
> +    mfn_t xen_mfn = _mfn(virt_to_mfn(_start));
> +    unsigned int xen_order = get_order_from_bytes(_end - _start);
>  
>      printk(XENLOG_INFO "alternatives: Patching kernel code\n");
>  
>      /*
> -     * The text section is read-only. So re-map Xen to be able to patch
> -     * the code.
> +     * The text and inittext section are read-only. So re-map Xen to be
> +     * able to patch the code.
>       */
> -    writemap = __vmap(&text_mfn, 1 << text_order, 1, 1, PAGE_HYPERVISOR,
> +    writemap = __vmap(&xen_mfn, 1 << xen_order, 1, 1, PAGE_HYPERVISOR,

Do you want to make it 1U? (You pointed that out in my patchset so perhaps you
want it here?)

>                        VMAP_DEFAULT);
>      if ( !writemap )
>      {
>          printk(XENLOG_ERR "alternatives: Unable to map the text section 
> (size %u)\n",
> -               1 << text_order);
> +               1 << xen_order);
>          return -ENOMEM;
>      }
>  
> -- 
> 1.9.1
> 

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