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-rw-r--r--include/asm-generic/export.h94
-rw-r--r--include/asm-generic/vmlinux.lds.h57
-rw-r--r--include/linux/compiler.h23
-rw-r--r--include/linux/export.h30
-rw-r--r--include/linux/init.h38
5 files changed, 179 insertions, 63 deletions
diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
new file mode 100644
index 000000000000..43199a049da5
--- /dev/null
+++ b/include/asm-generic/export.h
@@ -0,0 +1,94 @@
+#ifndef __ASM_GENERIC_EXPORT_H
+#define __ASM_GENERIC_EXPORT_H
+
+#ifndef KSYM_FUNC
+#define KSYM_FUNC(x) x
+#endif
+#ifdef CONFIG_64BIT
+#define __put .quad
+#ifndef KSYM_ALIGN
+#define KSYM_ALIGN 8
+#endif
+#ifndef KCRC_ALIGN
+#define KCRC_ALIGN 8
+#endif
+#else
+#define __put .long
+#ifndef KSYM_ALIGN
+#define KSYM_ALIGN 4
+#endif
+#ifndef KCRC_ALIGN
+#define KCRC_ALIGN 4
+#endif
+#endif
+
+#ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
+#define KSYM(name) _##name
+#else
+#define KSYM(name) name
+#endif
+
+/*
+ * note on .section use: @progbits vs %progbits nastiness doesn't matter,
+ * since we immediately emit into those sections anyway.
+ */
+.macro ___EXPORT_SYMBOL name,val,sec
+#ifdef CONFIG_MODULES
+ .globl KSYM(__ksymtab_\name)
+ .section ___ksymtab\sec+\name,"a"
+ .balign KSYM_ALIGN
+KSYM(__ksymtab_\name):
+ __put \val, KSYM(__kstrtab_\name)
+ .previous
+ .section __ksymtab_strings,"a"
+KSYM(__kstrtab_\name):
+#ifdef CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX
+ .asciz "_\name"
+#else
+ .asciz "\name"
+#endif
+ .previous
+#ifdef CONFIG_MODVERSIONS
+ .section ___kcrctab\sec+\name,"a"
+ .balign KCRC_ALIGN
+KSYM(__kcrctab_\name):
+ __put KSYM(__crc_\name)
+ .weak KSYM(__crc_\name)
+ .previous
+#endif
+#endif
+.endm
+#undef __put
+
+#if defined(__KSYM_DEPS__)
+
+#define __EXPORT_SYMBOL(sym, val, sec) === __KSYM_##sym ===
+
+#elif defined(CONFIG_TRIM_UNUSED_KSYMS)
+
+#include <linux/kconfig.h>
+#include <generated/autoksyms.h>
+
+#define __EXPORT_SYMBOL(sym, val, sec) \
+ __cond_export_sym(sym, val, sec, config_enabled(__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(KSYM(name)),)
+#define EXPORT_SYMBOL_GPL(name) \
+ __EXPORT_SYMBOL(name, KSYM_FUNC(KSYM(name)), _gpl)
+#define EXPORT_DATA_SYMBOL(name) \
+ __EXPORT_SYMBOL(name, KSYM(name),)
+#define EXPORT_DATA_SYMBOL_GPL(name) \
+ __EXPORT_SYMBOL(name, KSYM(name),_gpl)
+
+#endif
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 3e42bcdd014b..30747960bc54 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -196,9 +196,14 @@
*(.dtb.init.rodata) \
VMLINUX_SYMBOL(__dtb_end) = .;
-/* .data section */
+/*
+ * .data section
+ * LD_DEAD_CODE_DATA_ELIMINATION option enables -fdata-sections generates
+ * .data.identifier which needs to be pulled in with .data, but don't want to
+ * pull in .data..stuff which has its own requirements. Same for bss.
+ */
#define DATA_DATA \
- *(.data) \
+ *(.data .data.[0-9a-zA-Z_]*) \
*(.ref.data) \
*(.data..shared_aligned) /* percpu related */ \
MEM_KEEP(init.data) \
@@ -320,76 +325,76 @@
/* Kernel symbol table: Normal symbols */ \
__ksymtab : AT(ADDR(__ksymtab) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___ksymtab) = .; \
- *(SORT(___ksymtab+*)) \
+ KEEP(*(SORT(___ksymtab+*))) \
VMLINUX_SYMBOL(__stop___ksymtab) = .; \
} \
\
/* Kernel symbol table: GPL-only symbols */ \
__ksymtab_gpl : AT(ADDR(__ksymtab_gpl) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___ksymtab_gpl) = .; \
- *(SORT(___ksymtab_gpl+*)) \
+ KEEP(*(SORT(___ksymtab_gpl+*))) \
VMLINUX_SYMBOL(__stop___ksymtab_gpl) = .; \
} \
\
/* Kernel symbol table: Normal unused symbols */ \
__ksymtab_unused : AT(ADDR(__ksymtab_unused) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___ksymtab_unused) = .; \
- *(SORT(___ksymtab_unused+*)) \
+ KEEP(*(SORT(___ksymtab_unused+*))) \
VMLINUX_SYMBOL(__stop___ksymtab_unused) = .; \
} \
\
/* Kernel symbol table: GPL-only unused symbols */ \
__ksymtab_unused_gpl : AT(ADDR(__ksymtab_unused_gpl) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___ksymtab_unused_gpl) = .; \
- *(SORT(___ksymtab_unused_gpl+*)) \
+ KEEP(*(SORT(___ksymtab_unused_gpl+*))) \
VMLINUX_SYMBOL(__stop___ksymtab_unused_gpl) = .; \
} \
\
/* Kernel symbol table: GPL-future-only symbols */ \
__ksymtab_gpl_future : AT(ADDR(__ksymtab_gpl_future) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___ksymtab_gpl_future) = .; \
- *(SORT(___ksymtab_gpl_future+*)) \
+ KEEP(*(SORT(___ksymtab_gpl_future+*))) \
VMLINUX_SYMBOL(__stop___ksymtab_gpl_future) = .; \
} \
\
/* Kernel symbol table: Normal symbols */ \
__kcrctab : AT(ADDR(__kcrctab) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab) = .; \
- *(SORT(___kcrctab+*)) \
+ KEEP(*(SORT(___kcrctab+*))) \
VMLINUX_SYMBOL(__stop___kcrctab) = .; \
} \
\
/* Kernel symbol table: GPL-only symbols */ \
__kcrctab_gpl : AT(ADDR(__kcrctab_gpl) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab_gpl) = .; \
- *(SORT(___kcrctab_gpl+*)) \
+ KEEP(*(SORT(___kcrctab_gpl+*))) \
VMLINUX_SYMBOL(__stop___kcrctab_gpl) = .; \
} \
\
/* Kernel symbol table: Normal unused symbols */ \
__kcrctab_unused : AT(ADDR(__kcrctab_unused) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab_unused) = .; \
- *(SORT(___kcrctab_unused+*)) \
+ KEEP(*(SORT(___kcrctab_unused+*))) \
VMLINUX_SYMBOL(__stop___kcrctab_unused) = .; \
} \
\
/* Kernel symbol table: GPL-only unused symbols */ \
__kcrctab_unused_gpl : AT(ADDR(__kcrctab_unused_gpl) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab_unused_gpl) = .; \
- *(SORT(___kcrctab_unused_gpl+*)) \
+ KEEP(*(SORT(___kcrctab_unused_gpl+*))) \
VMLINUX_SYMBOL(__stop___kcrctab_unused_gpl) = .; \
} \
\
/* Kernel symbol table: GPL-future-only symbols */ \
__kcrctab_gpl_future : AT(ADDR(__kcrctab_gpl_future) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__start___kcrctab_gpl_future) = .; \
- *(SORT(___kcrctab_gpl_future+*)) \
+ KEEP(*(SORT(___kcrctab_gpl_future+*))) \
VMLINUX_SYMBOL(__stop___kcrctab_gpl_future) = .; \
} \
\
/* Kernel symbol table: strings */ \
__ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) { \
- *(__ksymtab_strings) \
+ KEEP(*(__ksymtab_strings)) \
} \
\
/* __*init sections */ \
@@ -424,12 +429,17 @@
#define SECURITY_INIT \
.security_initcall.init : AT(ADDR(.security_initcall.init) - LOAD_OFFSET) { \
VMLINUX_SYMBOL(__security_initcall_start) = .; \
- *(.security_initcall.init) \
+ KEEP(*(.security_initcall.init)) \
VMLINUX_SYMBOL(__security_initcall_end) = .; \
}
/* .text section. Map to function alignment to avoid address changes
- * during second ld run in second ld pass when generating System.map */
+ * during second ld run in second ld pass when generating System.map
+ * LD_DEAD_CODE_DATA_ELIMINATION option enables -ffunction-sections generates
+ * .text.identifier which needs to be pulled in with .text , but some
+ * architectures define .text.foo which is not intended to be pulled in here.
+ * Those enabling LD_DEAD_CODE_DATA_ELIMINATION must ensure they don't have
+ * conflicting section names, and must pull in .text.[0-9a-zA-Z_]* */
#define TEXT_TEXT \
ALIGN_FUNCTION(); \
*(.text.hot .text .text.fixup .text.unlikely) \
@@ -533,6 +543,7 @@
/* init and exit section handling */
#define INIT_DATA \
+ KEEP(*(SORT(___kentry+*))) \
*(.init.data) \
MEM_DISCARD(init.data) \
KERNEL_CTORS() \
@@ -599,7 +610,7 @@
BSS_FIRST_SECTIONS \
*(.bss..page_aligned) \
*(.dynbss) \
- *(.bss) \
+ *(.bss .bss.[0-9a-zA-Z_]*) \
*(COMMON) \
}
@@ -682,12 +693,12 @@
#define INIT_CALLS_LEVEL(level) \
VMLINUX_SYMBOL(__initcall##level##_start) = .; \
- *(.initcall##level##.init) \
- *(.initcall##level##s.init) \
+ KEEP(*(.initcall##level##.init)) \
+ KEEP(*(.initcall##level##s.init)) \
#define INIT_CALLS \
VMLINUX_SYMBOL(__initcall_start) = .; \
- *(.initcallearly.init) \
+ KEEP(*(.initcallearly.init)) \
INIT_CALLS_LEVEL(0) \
INIT_CALLS_LEVEL(1) \
INIT_CALLS_LEVEL(2) \
@@ -701,21 +712,21 @@
#define CON_INITCALL \
VMLINUX_SYMBOL(__con_initcall_start) = .; \
- *(.con_initcall.init) \
+ KEEP(*(.con_initcall.init)) \
VMLINUX_SYMBOL(__con_initcall_end) = .;
#define SECURITY_INITCALL \
VMLINUX_SYMBOL(__security_initcall_start) = .; \
- *(.security_initcall.init) \
+ KEEP(*(.security_initcall.init)) \
VMLINUX_SYMBOL(__security_initcall_end) = .;
#ifdef CONFIG_BLK_DEV_INITRD
#define INIT_RAM_FS \
. = ALIGN(4); \
VMLINUX_SYMBOL(__initramfs_start) = .; \
- *(.init.ramfs) \
+ KEEP(*(.init.ramfs)) \
. = ALIGN(8); \
- *(.init.ramfs.info)
+ KEEP(*(.init.ramfs.info))
#else
#define INIT_RAM_FS
#endif
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 668569844d37..f1bfa15b6f9b 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -182,6 +182,29 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
# define unreachable() do { } while (1)
#endif
+/*
+ * KENTRY - kernel entry point
+ * This can be used to annotate symbols (functions or data) that are used
+ * without their linker symbol being referenced explicitly. For example,
+ * interrupt vector handlers, or functions in the kernel image that are found
+ * programatically.
+ *
+ * Not required for symbols exported with EXPORT_SYMBOL, or initcalls. Those
+ * are handled in their own way (with KEEP() in linker scripts).
+ *
+ * KENTRY can be avoided if the symbols in question are marked as KEEP() in the
+ * linker script. For example an architecture could KEEP() its entire
+ * boot/exception vector code rather than annotate each function and data.
+ */
+#ifndef KENTRY
+# define KENTRY(sym) \
+ extern typeof(sym) sym; \
+ static const unsigned long __kentry_##sym \
+ __used \
+ __attribute__((section("___kentry" "+" #sym ), used)) \
+ = (unsigned long)&sym;
+#endif
+
#ifndef RELOC_HIDE
# define RELOC_HIDE(ptr, off) \
({ unsigned long __ptr; \
diff --git a/include/linux/export.h b/include/linux/export.h
index d7df4922da1d..2a0f61fbc731 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -1,5 +1,6 @@
#ifndef _LINUX_EXPORT_H
#define _LINUX_EXPORT_H
+
/*
* Export symbols from the kernel to modules. Forked from module.h
* to reduce the amount of pointless cruft we feed to gcc when only
@@ -42,27 +43,26 @@ extern struct module __this_module;
#ifdef CONFIG_MODVERSIONS
/* Mark the CRC weak since genksyms apparently decides not to
* generate a checksums for some symbols */
-#define __CRC_SYMBOL(sym, sec) \
- extern __visible void *__crc_##sym __attribute__((weak)); \
- static const unsigned long __kcrctab_##sym \
- __used \
- __attribute__((section("___kcrctab" sec "+" #sym), unused)) \
+#define __CRC_SYMBOL(sym, sec) \
+ extern __visible void *__crc_##sym __attribute__((weak)); \
+ static const unsigned long __kcrctab_##sym \
+ __used \
+ __attribute__((section("___kcrctab" sec "+" #sym), used)) \
= (unsigned long) &__crc_##sym;
#else
#define __CRC_SYMBOL(sym, sec)
#endif
/* For every exported symbol, place a struct in the __ksymtab section */
-#define ___EXPORT_SYMBOL(sym, sec) \
- extern typeof(sym) sym; \
- __CRC_SYMBOL(sym, sec) \
- static const char __kstrtab_##sym[] \
- __attribute__((section("__ksymtab_strings"), aligned(1))) \
- = VMLINUX_SYMBOL_STR(sym); \
- extern const struct kernel_symbol __ksymtab_##sym; \
- __visible const struct kernel_symbol __ksymtab_##sym \
- __used \
- __attribute__((section("___ksymtab" sec "+" #sym), unused)) \
+#define ___EXPORT_SYMBOL(sym, sec) \
+ extern typeof(sym) sym; \
+ __CRC_SYMBOL(sym, sec) \
+ static const char __kstrtab_##sym[] \
+ __attribute__((section("__ksymtab_strings"), aligned(1))) \
+ = VMLINUX_SYMBOL_STR(sym); \
+ static const struct kernel_symbol __ksymtab_##sym \
+ __used \
+ __attribute__((section("___ksymtab" sec "+" #sym), used)) \
= { (unsigned long)&sym, __kstrtab_##sym }
#if defined(__KSYM_DEPS__)
diff --git a/include/linux/init.h b/include/linux/init.h
index 5a3321a7909b..024a0b5b3ed0 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -139,24 +139,8 @@ extern bool initcall_debug;
#ifndef __ASSEMBLY__
-#ifdef CONFIG_LTO
-/* Work around a LTO gcc problem: when there is no reference to a variable
- * in a module it will be moved to the end of the program. This causes
- * reordering of initcalls which the kernel does not like.
- * Add a dummy reference function to avoid this. The function is
- * deleted by the linker.
- */
-#define LTO_REFERENCE_INITCALL(x) \
- ; /* yes this is needed */ \
- static __used __exit void *reference_##x(void) \
- { \
- return &x; \
- }
-#else
-#define LTO_REFERENCE_INITCALL(x)
-#endif
-
-/* initcalls are now grouped by functionality into separate
+/*
+ * initcalls are now grouped by functionality into separate
* subsections. Ordering inside the subsections is determined
* by link order.
* For backwards compatibility, initcall() puts the call in
@@ -164,12 +148,16 @@ extern bool initcall_debug;
*
* The `id' arg to __define_initcall() is needed so that multiple initcalls
* can point at the same handler without causing duplicate-symbol build errors.
+ *
+ * Initcalls are run by placing pointers in initcall sections that the
+ * kernel iterates at runtime. The linker can do dead code / data elimination
+ * and remove that completely, so the initcall sections have to be marked
+ * as KEEP() in the linker script.
*/
#define __define_initcall(fn, id) \
static initcall_t __initcall_##fn##id __used \
- __attribute__((__section__(".initcall" #id ".init"))) = fn; \
- LTO_REFERENCE_INITCALL(__initcall_##fn##id)
+ __attribute__((__section__(".initcall" #id ".init"))) = fn;
/*
* Early initcalls run before initializing SMP.
@@ -205,15 +193,15 @@ extern bool initcall_debug;
#define __initcall(fn) device_initcall(fn)
-#define __exitcall(fn) \
+#define __exitcall(fn) \
static exitcall_t __exitcall_##fn __exit_call = fn
-#define console_initcall(fn) \
- static initcall_t __initcall_##fn \
+#define console_initcall(fn) \
+ static initcall_t __initcall_##fn \
__used __section(.con_initcall.init) = fn
-#define security_initcall(fn) \
- static initcall_t __initcall_##fn \
+#define security_initcall(fn) \
+ static initcall_t __initcall_##fn \
__used __section(.security_initcall.init) = fn
struct obs_kernel_param {
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-26 06:47:56 +0000