On Wed, 27 Jan 2016 20:39:23 +0100 Ard Biesheuvel <[email protected]> wrote:
> On 27 January 2016 at 20:35, Andrew Morton <[email protected]> wrote: > > On Wed, 27 Jan 2016 11:55:23 +0100 Ard Biesheuvel > > <[email protected]> wrote: > > > >> Instead of using absolute addresses for both the exception location > >> and the fixup, use offsets relative to the exception table entry values. > >> Not only does this cut the size of the exception table in half, it is > >> also a prerequisite for KASLR, since absolute exception table entries > >> are subject to dynamic relocation, which is incompatible with the sorting > >> of the exception table that occurs at build time. > >> > >> This patch also introduces the _ASM_EXTABLE preprocessor macro (which > >> exists on x86 as well) and its _asm_extable assembly counterpart, as > >> shorthands to emit exception table entries. > > > > checkpatch speaketh truth: > > > > ERROR: #define of 'ARCH_HAS_RELATIVE_EXTABLE' is wrong - use Kconfig > > variables or standard guards instead > > #113: FILE: arch/arm64/include/asm/uaccess.h:56: > > That may be true, but it extends an established pattern of #defines in > the various uaccess.h versions, i.e., ARCH_HAS_SORT_EXTABLE, and > ARCH_HAS_SEARCH_EXTABLE True. But now we have two things to fix, not one ;) Whatever. Later.
