Commit d9344522 authored Jun 04, 2019 by Andrey Konovalov Committed by Linus Torvalds Jun 07, 2019

uaccess: add noop untagged_addr definition



Architectures that support memory tagging have a need to perform untagging
(stripping the tag) in various parts of the kernel. This patch adds an
untagged_addr() macro, which is defined as noop for architectures that do
not support memory tagging. The oncoming patch series will define it at
least for sparc64 and arm64.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent d18c7e9d

include/linux/mm.h

+11 −0

Original line number	Diff line number	Diff line
		@@ -99,6 +99,17 @@ extern int mmap_rnd_compat_bits __read_mostly;
		#include <asm/pgtable.h>
		#include <asm/processor.h>

		/*
		* Architectures that support memory tagging (assigning tags to memory regions,
		* embedding these tags into addresses that point to these memory regions, and
		* checking that the memory and the pointer tags match on memory accesses)
		* redefine this macro to strip tags from pointers.
		* It's defined as noop for arcitectures that don't support memory tagging.
		*/
		#ifndef untagged_addr
		#define untagged_addr(addr) (addr)
		#endif

		#ifndef __pa_symbol
		#define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x), 0))
		#endif