| From | Kees Cook <> | Date | Wed, 18 Apr 2018 17:11:39 -0700 | Subject | Re: [PATCH 11/11] x86/pti: leave kernel text global for !PCID |
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On Fri, Apr 6, 2018 at 1:55 PM, Dave Hansen <dave.hansen@linux.intel.com> wrote: > +/* > + * For some configurations, map all of kernel text into the user page > + * tables. This reduces TLB misses, especially on non-PCID systems. > + */ > +void pti_clone_kernel_text(void) > +{ > + unsigned long start = PFN_ALIGN(_text); > + unsigned long end = ALIGN((unsigned long)_end, PMD_PAGE_SIZE);
I think this is too much set global: _end is after data, bss, and brk, and all kinds of other stuff that could hold secrets. I think this should match what mark_rodata_ro() is doing and use __end_rodata_hpage_align. (And on i386, this should be maybe _etext.)
-Kees
-- Kees Cook Pixel Security
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