1*5335e318SPaolo Bonzini // SPDX-License-Identifier: GPL-2.0
2*5335e318SPaolo Bonzini
3*5335e318SPaolo Bonzini /*
4*5335e318SPaolo Bonzini * simple_ring_buffer is used by the pKVM hypervisor which does not have access
5*5335e318SPaolo Bonzini * to all kernel symbols. Whatever is undefined when compiling this file is
6*5335e318SPaolo Bonzini * compiler and tooling-generated symbols that can safely be ignored for
7*5335e318SPaolo Bonzini * simple_ring_buffer.
8*5335e318SPaolo Bonzini */
9*5335e318SPaolo Bonzini
10*5335e318SPaolo Bonzini #include <linux/atomic.h>
11*5335e318SPaolo Bonzini #include <linux/string.h>
12*5335e318SPaolo Bonzini #include <asm/page.h>
13*5335e318SPaolo Bonzini
14*5335e318SPaolo Bonzini void undefsyms_base(void *p, int n);
15*5335e318SPaolo Bonzini
16*5335e318SPaolo Bonzini static char page[PAGE_SIZE] __aligned(PAGE_SIZE);
17*5335e318SPaolo Bonzini
undefsyms_base(void * p,int n)18*5335e318SPaolo Bonzini void undefsyms_base(void *p, int n)
19*5335e318SPaolo Bonzini {
20*5335e318SPaolo Bonzini char buffer[256] = { 0 };
21*5335e318SPaolo Bonzini
22*5335e318SPaolo Bonzini u32 u = 0;
23*5335e318SPaolo Bonzini memset((char * volatile)page, 8, PAGE_SIZE);
24*5335e318SPaolo Bonzini memset((char * volatile)buffer, 8, sizeof(buffer));
25*5335e318SPaolo Bonzini memcpy((void * volatile)p, buffer, sizeof(buffer));
26*5335e318SPaolo Bonzini cmpxchg((u32 * volatile)&u, 0, 8);
27*5335e318SPaolo Bonzini WARN_ON(n == 0xdeadbeef);
28*5335e318SPaolo Bonzini }
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