This attribute can make init data to be into .initbss section,
this will make the data to be NO_BITS in vmlinux, can shrink the
Image file size, and speed up the boot up time.
Signed-off-by: yalin wang <yalin.wang2...@gmail.com>
---
arch/arm/kernel/vmlinux.lds.S | 2 +-
arch/arm/mm/init.c | 1 +
include/asm-generic/sections.h | 1 +
include/asm-generic/vmlinux.lds.h | 11 ++++++++++-
include/linux/init.h | 1 +
include/linux/mm.h | 4 +++-
6 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index 8b60fde..ad6d740 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -330,7 +330,7 @@ SECTIONS
}
#endif
- BSS_SECTION(0, 0, 0)
+ BSS_SECTION(0, 0, 0, 0)
_end = .;
STABS_DEBUG
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 8a63b4c..50b881e 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -722,6 +722,7 @@ void free_initmem(void)
free_tcmmem();
poison_init_mem(__init_begin, __init_end - __init_begin);
+ poison_init_mem(__initbss_start, __initbss_start - __initbss_end);
if (!machine_is_integrator() && !machine_is_cintegrator())
free_initmem_default(-1);
}
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index b58fd66..a63ebe9 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -29,6 +29,7 @@ extern char _text[], _stext[], _etext[];
extern char _data[], _sdata[], _edata[];
extern char __bss_start[], __bss_stop[];
extern char __init_begin[], __init_end[];
+extern char __initbss_start[], __initbss_end[];
extern char _sinittext[], _einittext[];
extern char _end[];
extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[];
diff --git a/include/asm-generic/vmlinux.lds.h
b/include/asm-generic/vmlinux.lds.h
index c4bd0e2..b3db62d 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -574,6 +574,14 @@
*(COMMON) \
}
+#define INITBSS(initbss_align) \
+ . = ALIGN(initbss_align); \
+ .initbss : AT(ADDR(.initbss) - LOAD_OFFSET) { \
+ VMLINUX_SYMBOL(__initbss_start) = .; \
+ *(.bss.init.data) \
+ VMLINUX_SYMBOL(__initbss_end) = .; \
+ }
+
/*
* DWARF debug sections.
* Symbols in the DWARF debugging sections are relative to
@@ -831,10 +839,11 @@
INIT_RAM_FS \
}
-#define BSS_SECTION(sbss_align, bss_align, stop_align) \
+#define BSS_SECTION(sbss_align, bss_align, initbss_align, stop_align)
\
. = ALIGN(sbss_align); \
VMLINUX_SYMBOL(__bss_start) = .; \
SBSS(sbss_align) \
BSS(bss_align) \
+ INITBSS(initbss_align) \
. = ALIGN(stop_align); \
VMLINUX_SYMBOL(__bss_stop) = .;
diff --git a/include/linux/init.h b/include/linux/init.h
index b449f37..f2960b2 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -41,6 +41,7 @@
discard it in modules) */
#define __init __section(.init.text) __cold notrace
#define __initdata __section(.init.data)
+#define __initbss __section(.bss.init.data)
#define __initconst __constsection(.init.rodata)
#define __exitdata __section(.exit.data)
#define __exit_call __used __section(.exitcall.exit)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d30eea3..1f266f7 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -21,6 +21,7 @@
#include <linux/resource.h>
#include <linux/page_ext.h>
#include <linux/err.h>
+#include <asm/sections.h>
struct mempolicy;
struct anon_vma;
@@ -1722,10 +1723,11 @@ static inline void mark_page_reserved(struct page *page)
*/
static inline unsigned long free_initmem_default(int poison)
{
- extern char __init_begin[], __init_end[];
return free_reserved_area(&__init_begin, &__init_end,
poison, "unused kernel");
+ return free_reserved_area(&__initbss_start, &__initbss_end,
+ poison, "unused kernel");
}
static inline unsigned long get_num_physpages(void)
--
1.9.1
--
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