a7bf0bd5e6
Making a variable page-aligned by using
__attribute__((section(".data.page_aligned"))) is fragile because if
sizeof(variable) is not also a multiple of page size, it leaves
variables in the remainder of the section unaligned.
This patch introduces two new qualifiers, __page_aligned_data and
__page_aligned_bss to set the section *and* the alignment of
variables. This makes page-aligned variables more robust because the
linker will make sure they're aligned properly. Unfortunately it
requires *all* page-aligned data to use these macros...
Signed-off-by: Ingo Molnar <mingo@elte.hu>
96 lines
2 KiB
C
96 lines
2 KiB
C
#ifndef _LINUX_LINKAGE_H
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#define _LINUX_LINKAGE_H
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#include <linux/compiler.h>
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#include <asm/linkage.h>
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#ifdef __cplusplus
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#define CPP_ASMLINKAGE extern "C"
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#else
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#define CPP_ASMLINKAGE
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#endif
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#ifndef asmlinkage
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#define asmlinkage CPP_ASMLINKAGE
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#endif
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#ifndef asmregparm
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# define asmregparm
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#endif
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#define __page_aligned_data __section(.data.page_aligned) __aligned(PAGE_SIZE)
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#define __page_aligned_bss __section(.bss.page_aligned) __aligned(PAGE_SIZE)
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/*
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* This is used by architectures to keep arguments on the stack
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* untouched by the compiler by keeping them live until the end.
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* The argument stack may be owned by the assembly-language
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* caller, not the callee, and gcc doesn't always understand
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* that.
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*
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* We have the return value, and a maximum of six arguments.
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*
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* This should always be followed by a "return ret" for the
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* protection to work (ie no more work that the compiler might
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* end up needing stack temporaries for).
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*/
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/* Assembly files may be compiled with -traditional .. */
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#ifndef __ASSEMBLY__
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#ifndef asmlinkage_protect
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# define asmlinkage_protect(n, ret, args...) do { } while (0)
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#endif
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#endif
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#ifndef __ALIGN
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#define __ALIGN .align 4,0x90
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#define __ALIGN_STR ".align 4,0x90"
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#endif
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#ifdef __ASSEMBLY__
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#define ALIGN __ALIGN
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#define ALIGN_STR __ALIGN_STR
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#ifndef ENTRY
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#define ENTRY(name) \
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.globl name; \
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ALIGN; \
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name:
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#endif
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#ifndef WEAK
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#define WEAK(name) \
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.weak name; \
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name:
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#endif
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#define KPROBE_ENTRY(name) \
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.pushsection .kprobes.text, "ax"; \
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ENTRY(name)
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#define KPROBE_END(name) \
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END(name); \
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.popsection
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#ifndef END
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#define END(name) \
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.size name, .-name
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#endif
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/* If symbol 'name' is treated as a subroutine (gets called, and returns)
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* then please use ENDPROC to mark 'name' as STT_FUNC for the benefit of
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* static analysis tools such as stack depth analyzer.
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*/
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#ifndef ENDPROC
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#define ENDPROC(name) \
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.type name, @function; \
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END(name)
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#endif
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#endif
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#define NORET_TYPE /**/
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#define ATTRIB_NORET __attribute__((noreturn))
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#define NORET_AND noreturn,
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#endif
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