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git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git
synced 2026-10-29 13:23:23 +01:00
Paolo Bonzini
5335e318ad
Linus points out that dumping undefsyms_base.c form the Makefile is rather ugly, and that a much better course of action would be to have this file as a first-class citizen in the git tree. This allows some extra cleanup in the Makefile, and the removal of the .gitignore file in kernel/trace. Cc: Marc Zyngier <[email protected]> Cc: Arnd Bergmann <[email protected]> Link: https://lore.kernel.org/r/CAHk-=wieqGd_XKpu8UxDoyADZx8TDe8CF3RmkUXt5N_9t5Pf_w@mail.gmail.com Link: https://lore.kernel.org/all/[email protected]/ Link: https://patch.msgid.link/[email protected] Reported-by: Linus Torvalds <[email protected]> Reviewed-by: Nathan Chancellor <[email protected]> Tested-by: Nathan Chancellor <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]> Signed-off-by: Steven Rostedt <[email protected]>
29 lines
757 B
C
29 lines
757 B
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* simple_ring_buffer is used by the pKVM hypervisor which does not have access
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* to all kernel symbols. Whatever is undefined when compiling this file is
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* compiler and tooling-generated symbols that can safely be ignored for
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* simple_ring_buffer.
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*/
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#include <linux/atomic.h>
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#include <linux/string.h>
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#include <asm/page.h>
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void undefsyms_base(void *p, int n);
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static char page[PAGE_SIZE] __aligned(PAGE_SIZE);
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void undefsyms_base(void *p, int n)
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{
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char buffer[256] = { 0 };
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u32 u = 0;
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memset((char * volatile)page, 8, PAGE_SIZE);
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memset((char * volatile)buffer, 8, sizeof(buffer));
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memcpy((void * volatile)p, buffer, sizeof(buffer));
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cmpxchg((u32 * volatile)&u, 0, 8);
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WARN_ON(n == 0xdeadbeef);
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}
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