skey.c

 1// SPDX-License-Identifier: GPL-2.0
 2
 3#include <asm/rwonce.h>
 4#include <asm/page.h>
 5#include <asm/skey.h>
 6
 7int skey_regions_initialized;
 8
 9static inline unsigned long load_real_address(unsigned long address)
10{
11	unsigned long real;
12
13	asm volatile(
14		"	lra	%[real],0(%[address])"
15		: [real] "=d" (real)
16		: [address] "a" (address)
17		: "cc");
18	return real;
19}
20
21/*
22 * Initialize storage keys of registered memory regions with the
23 * default key. This is useful for code which is executed with a
24 * non-default access key.
25 */
26void __skey_regions_initialize(void)
27{
28	unsigned long address, real;
29	struct skey_region *r, *end;
30
31	r = __skey_region_start;
32	end = __skey_region_end;
33	while (r < end) {
34		address = r->start & PAGE_MASK;
35		do {
36			real = load_real_address(address);
37			page_set_storage_key(real, PAGE_DEFAULT_KEY, 1);
38			address += PAGE_SIZE;
39		} while (address < r->end);
40		r++;
41	}
42	/*
43	 * Make sure storage keys are initialized before
44	 * skey_regions_initialized is changed.
45	 */
46	barrier();
47	WRITE_ONCE(skey_regions_initialized, 1);
48}