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SubjectRe: [PATCH RFC 07/19] perf tools: Workaround missing maps for x86_64 KPTI entry trampolines
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On 10/05/18 23:47, Arnaldo Carvalho de Melo wrote:
> Em Thu, May 10, 2018 at 05:19:22PM -0300, Arnaldo Carvalho de Melo escreveu:
>> Em Thu, May 10, 2018 at 05:15:42PM -0300, Arnaldo Carvalho de Melo escreveu:
>>> Em Thu, May 10, 2018 at 07:08:37PM +0000, Hunter, Adrian escreveu:
>>>> Let me know if you want me to post the workaround patches separately,
>>>> otherwise I will wait a bit before sending the patches again.
>
>>> I'll see if I went thru all of the patches already...
>
>> So I looked at the patches posted and one comment is about the terse
>> commit logs for some of the kcore_copy patches, for instance:
>
>> --------------------
>> In preparation to add more program headers, get rid of kernel_map and
>> modules_map.
>> --------------------
>
>> Can't this be made a bit more verbose? Lemme re-read the patch...
>
> So you had just one pointers to the kernel map and a module_maps, and
> then this is replaced by kcore_copy__map() that instead of populating
> those fields that are being removed:
>
> - struct phdr_data kernel_map;
> - struct phdr_data modules_map;
>
> Will allocate and add "struct phdr_data" instances to the
> kcore_copy_info->phdrs list, so I propose, to follow convention used
> elsewhere in tools/perf/ that you rename kcore_copy__map() to
>
> kcore_copy_info__addnew(kci, fields)
>
> I would do it as:
>
> struct phdr_data *phdr_data__new(fields)
> {
> return zalloc() + init fields;
> }
>
> struct phdr_data *kcore_copy_info__addnew(kci, fields)
> {
> struct phdr_data *pd = phdr_data__new(fields);
>
> if (pd)
> list_add(&pd->list, &kci->phdrs)
> }
>
> Also please rename pd->list to pd->node, to clarify that it is a node in
> some list, not a list.
>
> The commit log list then could reflect that somehow, with something
> around:
>
> ----------------------
>
> Move ->kernel_map and ->modules_map to newly allocated entries in the
> ->phdrs list.
>
> ----------------------
>
> wdyt?

I have done the changes but still have kcore_copy__map() calling
kcore_copy_info__addnew(). The changes have been pushed to the same branch.

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