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Subject[PATCH 5/6] x86/KASLR: Clean up unused code from old "run_size"
Date
From: Yinghai Lu <yinghai@kernel.org>

Since run_size is now calculated in misc.c, the old script and associated
argument passing is no longer needed. This patch removes them, and renames
"run_size" to the more descriptive "kernel_total_size".

Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Junjie Mao <eternal.n08@gmail.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Baoquan He <bhe@redhat.com>
[kees: rewrote changelog, rename run_size to kernel_total_size]
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/x86/boot/compressed/Makefile | 4 +---
arch/x86/boot/compressed/head_32.S | 3 +--
arch/x86/boot/compressed/head_64.S | 3 ---
arch/x86/boot/compressed/misc.c | 11 ++++------
arch/x86/boot/compressed/mkpiggy.c | 10 ++-------
arch/x86/tools/calc_run_size.sh | 42 --------------------------------------
6 files changed, 8 insertions(+), 65 deletions(-)
delete mode 100644 arch/x86/tools/calc_run_size.sh

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 45997805adad..adef26d22224 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -121,10 +121,8 @@ suffix-$(CONFIG_KERNEL_XZ) := xz
suffix-$(CONFIG_KERNEL_LZO) := lzo
suffix-$(CONFIG_KERNEL_LZ4) := lz4

-RUN_SIZE = $(shell $(OBJDUMP) -h vmlinux | \
- $(CONFIG_SHELL) $(srctree)/arch/x86/tools/calc_run_size.sh)
quiet_cmd_mkpiggy = MKPIGGY $@
- cmd_mkpiggy = $(obj)/mkpiggy $< $(RUN_SIZE) > $@ || ( rm -f $@ ; false )
+ cmd_mkpiggy = $(obj)/mkpiggy $< > $@ || ( rm -f $@ ; false )

targets += piggy.S
$(obj)/piggy.S: $(obj)/vmlinux.bin.$(suffix-y) $(obj)/mkpiggy FORCE
diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index 8a95e2f845aa..1038524270e7 100644
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -238,7 +238,6 @@ relocated:
* Do the extraction, and jump to the new kernel..
*/
/* push arguments for extract_kernel: */
- pushl $z_run_size /* size of kernel with .bss and .brk */
pushl $z_output_len /* decompressed length, end of relocs */

movl BP_init_size(%esi), %eax
@@ -254,7 +253,7 @@ relocated:
pushl %eax /* heap area */
pushl %esi /* real mode pointer */
call extract_kernel /* returns kernel location in %eax */
- addl $28, %esp
+ addl $24, %esp

/*
* Jump to the extracted kernel.
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 09cdc0c3ee7e..7c047002950c 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -415,8 +415,6 @@ relocated:
* Do the extraction, and jump to the new kernel..
*/
pushq %rsi /* Save the real mode argument */
- movq $z_run_size, %r9 /* size of kernel with .bss and .brk */
- pushq %r9
movq %rsi, %rdi /* real mode address */
leaq boot_heap(%rip), %rsi /* malloc area for uncompression */
leaq input_data(%rip), %rdx /* input_data */
@@ -424,7 +422,6 @@ relocated:
movq %rbp, %r8 /* output target address */
movq $z_output_len, %r9 /* decompressed length, end of relocs */
call extract_kernel /* returns kernel location in %rax */
- popq %r9
popq %rsi

/*
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index cda93d16ad4d..bee6238e7cfc 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -340,9 +340,9 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
unsigned char *input_data,
unsigned long input_len,
unsigned char *output,
- unsigned long output_len,
- unsigned long run_size)
+ unsigned long output_len)
{
+ const unsigned long kernel_total_size = VO__end - VO__text;
unsigned char *output_orig = output;

/* Retain x86 boot parameters pointer passed from startup_32/64. */
@@ -364,8 +364,6 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
lines = boot_params->screen_info.orig_video_lines;
cols = boot_params->screen_info.orig_video_cols;

- run_size = VO__end - VO__text;
-
console_init();
debug_putstr("early console in extract_kernel\n");

@@ -377,7 +375,7 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
debug_putaddr(input_len);
debug_putaddr(output);
debug_putaddr(output_len);
- debug_putaddr(run_size);
+ debug_putaddr(kernel_total_size);

/*
* The memory hole needed for the kernel is the larger of either
@@ -385,8 +383,7 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
* entire decompressed kernel plus .bss and .brk sections.
*/
output = choose_random_location(input_data, input_len, output,
- output_len > run_size ? output_len
- : run_size);
+ max(output_len, kernel_total_size));

/* Validate memory location choices. */
if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
diff --git a/arch/x86/boot/compressed/mkpiggy.c b/arch/x86/boot/compressed/mkpiggy.c
index f095ed9e7d3c..72bad2c8debe 100644
--- a/arch/x86/boot/compressed/mkpiggy.c
+++ b/arch/x86/boot/compressed/mkpiggy.c
@@ -34,13 +34,11 @@ int main(int argc, char *argv[])
{
uint32_t olen;
long ilen;
- unsigned long run_size;
FILE *f = NULL;
int retval = 1;

- if (argc < 3) {
- fprintf(stderr, "Usage: %s compressed_file run_size\n",
- argv[0]);
+ if (argc < 2) {
+ fprintf(stderr, "Usage: %s compressed_file\n", argv[0]);
goto bail;
}

@@ -65,15 +63,11 @@ int main(int argc, char *argv[])
ilen = ftell(f);
olen = get_unaligned_le32(&olen);

- run_size = atoi(argv[2]);
-
printf(".section \".rodata..compressed\",\"a\",@progbits\n");
printf(".globl z_input_len\n");
printf("z_input_len = %lu\n", ilen);
printf(".globl z_output_len\n");
printf("z_output_len = %lu\n", (unsigned long)olen);
- printf(".globl z_run_size\n");
- printf("z_run_size = %lu\n", run_size);

printf(".globl input_data, input_data_end\n");
printf("input_data:\n");
diff --git a/arch/x86/tools/calc_run_size.sh b/arch/x86/tools/calc_run_size.sh
deleted file mode 100644
index 1a4c17bb3910..000000000000
--- a/arch/x86/tools/calc_run_size.sh
+++ /dev/null
@@ -1,42 +0,0 @@
-#!/bin/sh
-#
-# Calculate the amount of space needed to run the kernel, including room for
-# the .bss and .brk sections.
-#
-# Usage:
-# objdump -h a.out | sh calc_run_size.sh
-
-NUM='\([0-9a-fA-F]*[ \t]*\)'
-OUT=$(sed -n 's/^[ \t0-9]*.b[sr][sk][ \t]*'"$NUM$NUM$NUM$NUM"'.*/\1\4/p')
-if [ -z "$OUT" ] ; then
- echo "Never found .bss or .brk file offset" >&2
- exit 1
-fi
-
-OUT=$(echo ${OUT# })
-sizeA=$(printf "%d" 0x${OUT%% *})
-OUT=${OUT#* }
-offsetA=$(printf "%d" 0x${OUT%% *})
-OUT=${OUT#* }
-sizeB=$(printf "%d" 0x${OUT%% *})
-OUT=${OUT#* }
-offsetB=$(printf "%d" 0x${OUT%% *})
-
-run_size=$(( $offsetA + $sizeA + $sizeB ))
-
-# BFD linker shows the same file offset in ELF.
-if [ "$offsetA" -ne "$offsetB" ] ; then
- # Gold linker shows them as consecutive.
- endB=$(( $offsetB + $sizeB ))
- if [ "$endB" != "$run_size" ] ; then
- printf "sizeA: 0x%x\n" $sizeA >&2
- printf "offsetA: 0x%x\n" $offsetA >&2
- printf "sizeB: 0x%x\n" $sizeB >&2
- printf "offsetB: 0x%x\n" $offsetB >&2
- echo ".bss and .brk are non-contiguous" >&2
- exit 1
- fi
-fi
-
-printf "%d\n" $run_size
-exit 0
--
2.6.3
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