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

Message ID 1473252644-4078-2-git-send-email-julien.grall@arm.com
State Superseded
Headers show

Commit Message

Julien Grall Sept. 7, 2016, 12:50 p.m. UTC
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@oracle.com>
Signed-off-by: Julien Grall <julien.grall@arm.com>

---
    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.

    [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(-)

Comments

Julien Grall Sept. 7, 2016, 2:26 p.m. UTC | #1
Hi Konrad,

On 07/09/2016 15:13, Konrad Rzeszutek Wilk wrote:
> On Wed, Sep 07, 2016 at 01:50:43PM +0100, Julien Grall wrote:
>> 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?)

Good point, I used 1U whilst moving the code in patch #2 but forgot here.

I will update the patch and resend it.

Regards,
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Patch

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,
                       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;
     }