Messages in this thread | | | Date | Mon, 9 May 2016 15:27:21 -0700 | Subject | Re: [PATCH v7 1/9] x86/KASLR: Initialize mapping_info every time | From | Yinghai Lu <> |
| |
On Mon, May 9, 2016 at 3:23 PM, Yinghai Lu <yinghai@kernel.org> wrote: > On Mon, May 9, 2016 at 3:01 PM, Yinghai Lu <yinghai@kernel.org> wrote:
>> Still should be assigned once, and should be done in >> prepare_level4(). --- by may need different name for that ? >> >> The exact reason to have assigning in functions. >> >> pgt_data address could be changed during kernel relocation. >> so can not assigned during compiling time. > > Something like: > > -/* > - * Mapping information structure passed to kernel_ident_mapping_init(). > - * Since this never changes, there's no reason to repeatedly fill it > - * in on the stack when calling add_identity_map(). > - */ > -static struct x86_mapping_info mapping_info = { > - .alloc_pgt_page = alloc_pgt_page, > - .context = &pgt_data, > - .pmd_flag = __PAGE_KERNEL_LARGE_EXEC, > -}; > +static struct x86_mapping_info mapping_info; > > /* > * Adds the specified range to what will become the new identity mappings. > @@ -110,8 +101,14 @@ void add_identity_map(unsigned long start, > unsigned long size) > unsigned long end = start + size; > > /* Make sure we have a top level page table ready to use. */ > - if (!level4p) > + if (!level4p) { > + /* need to set once during run time */ > + mapping_info.alloc_pgt_page = alloc_pgt_page; > + mapping_info.context = &pgt_data; > + mapping_info.pmd_flag = __PAGE_KERNEL_LARGE_EXEC; > + > prepare_level4(); > + } > > /* Align boundary to 2M. */ > start = round_down(start, PMD_SIZE);
It would be better if Ingo could fold the change to
https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/patch/?id=3a94707d7a7bb1eb82acae5fbc035247dd1ba8a5 x86/KASLR: Build identity mappings on demand
As it happens to the last commit in tip/x86/boot.
Thanks
Yinghai
| |