linux-stable/include/asm-generic/export.h
Quentin Perret 54effa6532 asm-generic: export: Stub EXPORT_SYMBOL with __DISABLE_EXPORTS
It is currently possible to stub EXPORT_SYMBOL() macros in C code using
__DISABLE_EXPORTS, which is necessary to run in constrained environments
such as the EFI stub or the decompressor. But this currently doesn't
apply to exports from assembly, which can lead to somewhat confusing
situations.

Consolidate the __DISABLE_EXPORTS infrastructure by checking it from
asm-generic/export.h as well.

Signed-off-by: Quentin Perret <qperret@google.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210203141931.615898-2-qperret@google.com
2021-02-03 16:42:57 +00:00

94 lines
2.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef __ASM_GENERIC_EXPORT_H
#define __ASM_GENERIC_EXPORT_H
#ifndef KSYM_FUNC
#define KSYM_FUNC(x) x
#endif
#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
#define KSYM_ALIGN 4
#elif defined(CONFIG_64BIT)
#define KSYM_ALIGN 8
#else
#define KSYM_ALIGN 4
#endif
#ifndef KCRC_ALIGN
#define KCRC_ALIGN 4
#endif
.macro __put, val, name
#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
.long \val - ., \name - ., 0
#elif defined(CONFIG_64BIT)
.quad \val, \name, 0
#else
.long \val, \name, 0
#endif
.endm
/*
* note on .section use: we specify progbits since usage of the "M" (SHF_MERGE)
* section flag requires it. Use '%progbits' instead of '@progbits' since the
* former apparently works on all arches according to the binutils source.
*/
.macro ___EXPORT_SYMBOL name,val,sec
#if defined(CONFIG_MODULES) && !defined(__DISABLE_EXPORTS)
.section ___ksymtab\sec+\name,"a"
.balign KSYM_ALIGN
__ksymtab_\name:
__put \val, __kstrtab_\name
.previous
.section __ksymtab_strings,"aMS",%progbits,1
__kstrtab_\name:
.asciz "\name"
.previous
#ifdef CONFIG_MODVERSIONS
.section ___kcrctab\sec+\name,"a"
.balign KCRC_ALIGN
#if defined(CONFIG_MODULE_REL_CRCS)
.long __crc_\name - .
#else
.long __crc_\name
#endif
.weak __crc_\name
.previous
#endif
#endif
.endm
#if defined(CONFIG_TRIM_UNUSED_KSYMS)
#include <linux/kconfig.h>
#include <generated/autoksyms.h>
.macro __ksym_marker sym
.section ".discard.ksym","a"
__ksym_marker_\sym:
.previous
.endm
#define __EXPORT_SYMBOL(sym, val, sec) \
__ksym_marker sym; \
__cond_export_sym(sym, val, sec, __is_defined(__KSYM_##sym))
#define __cond_export_sym(sym, val, sec, conf) \
___cond_export_sym(sym, val, sec, conf)
#define ___cond_export_sym(sym, val, sec, enabled) \
__cond_export_sym_##enabled(sym, val, sec)
#define __cond_export_sym_1(sym, val, sec) ___EXPORT_SYMBOL sym, val, sec
#define __cond_export_sym_0(sym, val, sec) /* nothing */
#else
#define __EXPORT_SYMBOL(sym, val, sec) ___EXPORT_SYMBOL sym, val, sec
#endif
#define EXPORT_SYMBOL(name) \
__EXPORT_SYMBOL(name, KSYM_FUNC(name),)
#define EXPORT_SYMBOL_GPL(name) \
__EXPORT_SYMBOL(name, KSYM_FUNC(name), _gpl)
#define EXPORT_DATA_SYMBOL(name) \
__EXPORT_SYMBOL(name, name,)
#define EXPORT_DATA_SYMBOL_GPL(name) \
__EXPORT_SYMBOL(name, name,_gpl)
#endif