Hi,
* Wu Zhangjin <wuzhangjin@gmail.com> [2010-06-01 18:29:03+0800]:
>
> We have calculated VMLINUZ_LOAD_ADDRESS in shell, which is awful. This patch
> rewrites it in C.
>
I really feel that going down the C route is even worse....what's more
this implementation is broken as it always returns with zero, even when
sscanf() fails....and 'return -1' is just plain wrong too (look at
sysexits.h for wisdom[1]).
What is so 'awful' about the shell code version?
The shell lump is shorter in implementation size and I am personally not
convinced any reasons hinting towards 'clarity' even apply as the shell
code is well documented plus it is trivial to step through on any POSIX
shell implementation; which cannot be said for the C code. I am also
not too confident 'unsigned long long' is a great idea...maybe 'u64' or
'uint64_t' if you are relying on C99[1]?
Wise man says, do not use cannonball to kill mosquito :)
Cheers
[1] http://www.gnu.org/software/libc/manual/html_node/Exit-Status.html
[2] http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html
> Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
> ---
> arch/mips/boot/.gitignore | 1 +
> arch/mips/boot/compressed/Makefile | 22 ++++-----
> arch/mips/boot/compressed/calc_vmlinuz_load_addr.c | 52
> ++++++++++++++++++++
> 3 files changed, 63 insertions(+), 12 deletions(-)
> create mode 100644 arch/mips/boot/compressed/calc_vmlinuz_load_addr.c
>
> diff --git a/arch/mips/boot/.gitignore b/arch/mips/boot/.gitignore
> index 4667a5f..f210b09 100644
> --- a/arch/mips/boot/.gitignore
> +++ b/arch/mips/boot/.gitignore
> @@ -3,3 +3,4 @@ elf2ecoff
> vmlinux.*
> zImage
> zImage.tmp
> +calc_vmlinuz_load_addr
> diff --git a/arch/mips/boot/compressed/Makefile
> b/arch/mips/boot/compressed/Makefile
> index 7204dfc..cd9ee04 100644
> --- a/arch/mips/boot/compressed/Makefile
> +++ b/arch/mips/boot/compressed/Makefile
> @@ -12,14 +12,6 @@
> # Author: Wu Zhangjin <wuzhangjin@gmail.com>
> #
>
> -# compressed kernel load addr: VMLINUZ_LOAD_ADDRESS > VMLINUX_LOAD_ADDRESS +
> VMLINUX_SIZE
> -VMLINUX_SIZE := $(shell wc -c $(objtree)/$(KBUILD_IMAGE) 2>/dev/null | cut
> -d' ' -f1)
> -VMLINUX_SIZE := $(shell [ -n "$(VMLINUX_SIZE)" ] && echo -n
> $$(($(VMLINUX_SIZE) + (65536 - $(VMLINUX_SIZE) % 65536))))
> -# VMLINUZ_LOAD_ADDRESS = concat "high32 of VMLINUX_LOAD_ADDRESS" and "(low32
> of VMLINUX_LOAD_ADDRESS) + VMLINUX_SIZE"
> -HIGH32 := $(shell A=$(VMLINUX_LOAD_ADDRESS); [ $${\#A} -gt 10 ] && expr
> substr "$(VMLINUX_LOAD_ADDRESS)" 3 $$(($${\#A} - 10)))
> -LOW32 := $(shell [ -n "$(HIGH32)" ] && A=11 || A=3; expr substr
> "$(VMLINUX_LOAD_ADDRESS)" $${A} 8)
> -VMLINUZ_LOAD_ADDRESS := 0x$(shell [ -n "$(VMLINUX_SIZE)" -a -n "$(LOW32)" ]
> && printf "$(HIGH32)%08x" $$(($(VMLINUX_SIZE) + 0x$(LOW32))))
> -
> # set the default size of the mallocing area for decompressing
> BOOT_HEAP_SIZE := 0x400000
>
> @@ -63,9 +55,15 @@ OBJCOPYFLAGS_piggy.o :=
> --add-section=.image=$(obj)/vmlinux.z \
> $(obj)/piggy.o: $(obj)/dummy.o $(obj)/vmlinux.z FORCE
> $(call if_changed,objcopy)
>
> -LDFLAGS_vmlinuz := $(LDFLAGS) -Ttext $(VMLINUZ_LOAD_ADDRESS) -T
> -vmlinuz: $(src)/ld.script $(vmlinuzobjs-y) $(obj)/piggy.o
> - $(call cmd,ld)
> +# Calculate the load address of the compressed kernel
> +hostprogs-y := calc_vmlinuz_load_addr
> +
> +vmlinuzobjs-y += $(obj)/piggy.o
> +
> +quiet_cmd_zld = LD $@
> + cmd_zld = $(LD) $(LDFLAGS) -Ttext $(shell
> $(obj)/calc_vmlinuz_load_addr $(objtree)/$(KBUILD_IMAGE)
> $(VMLINUX_LOAD_ADDRESS)) -T $< $(vmlinuzobjs-y) -o $@
> +vmlinuz: $(src)/ld.script $(vmlinuzobjs-y) $(obj)/calc_vmlinuz_load_addr
> + $(call cmd,zld)
> $(Q)$(OBJCOPY) $(OBJCOPYFLAGS) $@
>
> #
> @@ -76,7 +74,7 @@ ifdef CONFIG_MACH_DECSTATION
> endif
>
> # elf2ecoff can only handle 32bit image
> -hostprogs-y := ../elf2ecoff
> +hostprogs-y += ../elf2ecoff
>
> ifdef CONFIG_32BIT
> VMLINUZ = vmlinuz
> diff --git a/arch/mips/boot/compressed/calc_vmlinuz_load_addr.c
> b/arch/mips/boot/compressed/calc_vmlinuz_load_addr.c
> new file mode 100644
> index 0000000..1787dce
> --- /dev/null
> +++ b/arch/mips/boot/compressed/calc_vmlinuz_load_addr.c
> @@ -0,0 +1,52 @@
> +/*
> + * Copyright (C) 2010 "Wu Zhangjin" <wuzhangjin@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2 of the License, or (at your
> + * option) any later version.
> + */
> +
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <errno.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +
> +int main(int argc, char *argv[])
> +{
> + int n;
> + struct stat sb;
> + unsigned long long vmlinux_size, vmlinux_load_addr, vmlinuz_load_addr;
> +
> + if (argc != 3) {
> + fprintf(stderr, "Usage: %s <pathname> <vmlinux_load_addr>\n",
> + argv[0]);
> + return -1;
> + }
> +
> + if (stat(argv[1], &sb) == -1) {
> + perror("stat");
> + return -1;
> + }
> +
> + /* Convert hex characters to dec number */
> + errno = 0;
> + n = sscanf(argv[2], "%llx", &vmlinux_load_addr);
> + if (n != 1) {
> + if (errno != 0)
> + perror("sscanf");
> + else
> + fprintf(stderr, "No matching characters\n");
> + }
> +
> + vmlinux_size = (unsigned long long)sb.st_size;
> + vmlinuz_load_addr = vmlinux_load_addr + vmlinux_size;
> +
> + /* Align with 65536 */
> + vmlinuz_load_addr += (65536 - vmlinux_size % 65536);
> +
> + printf("0x%llx\n", vmlinuz_load_addr);
> +
> + return 0;
> +}
> --
> 1.6.5
>
--
Alexander Clouter
.sigmonster says: To teach is to learn twice.
-- Joseph Joubert
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