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| author | Nicolas Pitre <nicolas.pitre@linaro.org> | 2011-02-21 03:57:38 (GMT) |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2011-02-26 13:39:51 (GMT) |
| commit | d239b1dc093d551046a909920b5310c1d1e308c1 (patch) | |
| tree | eacba86f9a13fe7fd512219ef88755988dc09a20 /arch/arm/boot/compressed | |
| parent | 6d7d0ae51574943bf571d269da3243257a2d15db (diff) | |
| download | linux-d239b1dc093d551046a909920b5310c1d1e308c1.tar.xz | |
ARM: 6746/1: remove the 4x expansion presumption while decompressing the kernel
We currently presume a 4x expansion to guess the decompressed kernel size
in order to determine if the decompressed kernel is in conflict with
the location where zImage is loaded. This guess may cause many issues
by overestimating the final kernel image size:
- This may force a needless relocation if the location of zImage was
fine, wasting some precious microseconds of boot time.
- The relocation may be located way too far, possibly overwriting the
initrd image in RAM.
- If the kernel image includes a large already-compressed initramfs image
then the problem is even more exacerbated.
And if by some strange means the 4x guess is too low then we may overwrite
ourselves with the decompressed image.
So let's use the exact decompressed kernel image size instead. For that
we need to rely on the stat command, but this is hardly a new build
dependency as the kernel already depends on many external commands
to be built provided by the coreutils package where stat is found.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/boot/compressed')
| -rw-r--r-- | arch/arm/boot/compressed/Makefile | 4 | ||||
| -rw-r--r-- | arch/arm/boot/compressed/vmlinux.lds.in | 3 |
2 files changed, 3 insertions, 4 deletions
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile index 0a8f748..9d328be 100644 --- a/arch/arm/boot/compressed/Makefile +++ b/arch/arm/boot/compressed/Makefile @@ -83,9 +83,11 @@ endif EXTRA_CFLAGS := -fpic -fno-builtin EXTRA_AFLAGS := -Wa,-march=all +# Provide size of uncompressed kernel to the decompressor via a linker symbol. +LDFLAGS_vmlinux := --defsym _image_size=$(shell stat -c "%s" $(obj)/../Image) # Supply ZRELADDR to the decompressor via a linker symbol. ifneq ($(CONFIG_AUTO_ZRELADDR),y) -LDFLAGS_vmlinux := --defsym zreladdr=$(ZRELADDR) +LDFLAGS_vmlinux += --defsym zreladdr=$(ZRELADDR) endif ifeq ($(CONFIG_CPU_ENDIAN_BE8),y) LDFLAGS_vmlinux += --be8 diff --git a/arch/arm/boot/compressed/vmlinux.lds.in b/arch/arm/boot/compressed/vmlinux.lds.in index 366a924..5309909 100644 --- a/arch/arm/boot/compressed/vmlinux.lds.in +++ b/arch/arm/boot/compressed/vmlinux.lds.in @@ -43,9 +43,6 @@ SECTIONS _etext = .; - /* Assume size of decompressed image is 4x the compressed image */ - _image_size = (_etext - _text) * 4; - _got_start = .; .got : { *(.got) } _got_end = .; |