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authorH. Peter Anvin <hpa@zytor.com>2009-05-08 17:42:16 -0700
committerH. Peter Anvin <hpa@zytor.com>2009-05-08 17:46:34 -0700
commit02a884c0fe7ec8459d00d34b7d4101af21fc4a86 (patch)
tree164783f84130482e52290af03d96ff8e887f8605
parent36d3793c947f1ef7ba3d24eeeddc1be41adc5ab4 (diff)
x86, boot: determine compressed code offset at compile time
Determine the compressed code offset (from the kernel runtime address) at compile time. This allows some minor optimizations in arch/x86/boot/compressed/head_*.S, but more importantly it makes this value available to the build process, which will enable a future patch to export the necessary linear memory footprint into the bzImage header. [ Impact: cleanup, future patch enabling ] Signed-off-by: H. Peter Anvin <hpa@zytor.com>
-rw-r--r--arch/x86/boot/compressed/Makefile11
-rw-r--r--arch/x86/boot/compressed/head_32.S24
-rw-r--r--arch/x86/boot/compressed/head_64.S41
-rw-r--r--arch/x86/boot/compressed/mkpiggy.c97
-rw-r--r--arch/x86/boot/compressed/vmlinux.scr10
5 files changed, 123 insertions, 60 deletions
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 7f24fdb584e..49c8a4c37d7 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -19,6 +19,8 @@ KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__
LDFLAGS := -m elf_$(UTS_MACHINE)
LDFLAGS_vmlinux := -T
+hostprogs-y := mkpiggy
+
$(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/head_$(BITS).o $(obj)/misc.o $(obj)/piggy.o FORCE
$(call if_changed,ld)
@:
@@ -50,6 +52,9 @@ suffix-$(CONFIG_KERNEL_GZIP) := gz
suffix-$(CONFIG_KERNEL_BZIP2) := bz2
suffix-$(CONFIG_KERNEL_LZMA) := lzma
-LDFLAGS_piggy.o := -r --format binary --oformat $(CONFIG_OUTPUT_FORMAT) -T
-$(obj)/piggy.o: $(obj)/vmlinux.scr $(obj)/vmlinux.bin.$(suffix-y) FORCE
- $(call if_changed,ld)
+quiet_cmd_mkpiggy = MKPIGGY $@
+ cmd_mkpiggy = $(obj)/mkpiggy $< > $@ || ( rm -f $@ ; false )
+
+targets += piggy.S
+$(obj)/piggy.S: $(obj)/vmlinux.bin.$(suffix-y) $(obj)/mkpiggy FORCE
+ $(call if_changed,mkpiggy)
diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index 6710dc78ac5..470474bafc4 100644
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -75,18 +75,8 @@ ENTRY(startup_32)
movl $LOAD_PHYSICAL_ADDR, %ebx
#endif
- /* Replace the compressed data size with the uncompressed size */
- subl input_len(%ebp), %ebx
- movl output_len(%ebp), %eax
- addl %eax, %ebx
- /* Add 8 bytes for every 32K input block */
- shrl $12, %eax
- addl %eax, %ebx
- /* Add 32K + 18 bytes of extra slack */
- addl $(32768 + 18), %ebx
- /* Align on a 4K boundary */
- addl $4095, %ebx
- andl $~4095, %ebx
+ /* Target address to relocate to for decompression */
+ addl $z_extract_offset, %ebx
/* Set up the stack */
leal boot_stack_end(%ebx), %esp
@@ -142,12 +132,10 @@ relocated:
/*
* Do the decompression, and jump to the new kernel..
*/
- movl output_len(%ebx), %eax
- pushl %eax
+ leal z_extract_offset_negative(%ebx), %ebp
/* push arguments for decompress_kernel: */
pushl %ebp /* output address */
- movl input_len(%ebx), %eax
- pushl %eax /* input_len */
+ pushl $z_input_len /* input_len */
leal input_data(%ebx), %eax
pushl %eax /* input_data */
leal boot_heap(%ebx), %eax
@@ -155,14 +143,12 @@ relocated:
pushl %esi /* real mode pointer */
call decompress_kernel
addl $20, %esp
- popl %ecx
#if CONFIG_RELOCATABLE
/*
* Find the address of the relocations.
*/
- movl %ebp, %edi
- addl %ecx, %edi
+ leal z_output_len(%ebp), %edi
/*
* Calculate the delta between where vmlinux was compiled to run
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 723c72dfd7b..2b9f2510507 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -90,16 +90,8 @@ ENTRY(startup_32)
movl $CONFIG_PHYSICAL_START, %ebx
#endif
- /* Replace the compressed data size with the uncompressed size */
- subl input_len(%ebp), %ebx
- movl output_len(%ebp), %eax
- addl %eax, %ebx
- /* Add 8 bytes for every 32K input block */
- shrl $12, %eax
- addl %eax, %ebx
- /* Add 32K + 18 bytes of extra slack and align on a 4K boundary */
- addl $(32768 + 18 + 4095), %ebx
- andl $~4095, %ebx
+ /* Target address to relocate to for decompression */
+ addl $z_extract_offset, %ebx
/*
* Prepare for entering 64 bit mode
@@ -224,6 +216,9 @@ ENTRY(startup_64)
* If it is a relocatable kernel then decompress and run the kernel
* from load address aligned to 2MB addr, otherwise decompress and
* run the kernel from CONFIG_PHYSICAL_START
+ *
+ * We cannot rely on the calculation done in 32-bit mode, since we
+ * may have been invoked via the 64-bit entry point.
*/
/* Start with the delta to where the kernel will run at. */
@@ -237,17 +232,8 @@ ENTRY(startup_64)
movq %rbp, %rbx
#endif
- /* Replace the compressed data size with the uncompressed size */
- movl input_len(%rip), %eax
- subq %rax, %rbx
- movl output_len(%rip), %eax
- addq %rax, %rbx
- /* Add 8 bytes for every 32K input block */
- shrq $12, %rax
- addq %rax, %rbx
- /* Add 32K + 18 bytes of extra slack and align on a 4K boundary */
- addq $(32768 + 18 + 4095), %rbx
- andq $~4095, %rbx
+ /* Target address to relocate to for decompression */
+ leaq z_extract_offset(%rbp), %rbx
/* Set up the stack */
leaq boot_stack_end(%rbx), %rsp
@@ -292,13 +278,12 @@ relocated:
/*
* Do the decompression, and jump to the new kernel..
*/
- pushq %rsi # Save the real mode argument
- movq %rsi, %rdi # real mode address
- leaq boot_heap(%rip), %rsi # malloc area for uncompression
- leaq input_data(%rip), %rdx # input_data
- movl input_len(%rip), %eax
- movq %rax, %rcx # input_len
- movq %rbp, %r8 # output
+ pushq %rsi /* Save the real mode argument */
+ movq %rsi, %rdi /* real mode address */
+ leaq boot_heap(%rip), %rsi /* malloc area for uncompression */
+ leaq input_data(%rip), %rdx /* input_data */
+ movl $z_input_len, %ecx /* input_len */
+ movq %rbp, %r8 /* output target address */
call decompress_kernel
popq %rsi
diff --git a/arch/x86/boot/compressed/mkpiggy.c b/arch/x86/boot/compressed/mkpiggy.c
new file mode 100644
index 00000000000..bcbd36c4143
--- /dev/null
+++ b/arch/x86/boot/compressed/mkpiggy.c
@@ -0,0 +1,97 @@
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright (C) 2009 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * H. Peter Anvin <hpa@linux.intel.com>
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * Compute the desired load offset from a compressed program; outputs
+ * a small assembly wrapper with the appropriate symbols defined.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+
+static uint32_t getle32(const void *p)
+{
+ const uint8_t *cp = p;
+
+ return (uint32_t)cp[0] + ((uint32_t)cp[1] << 8) +
+ ((uint32_t)cp[2] << 16) + ((uint32_t)cp[3] << 24);
+}
+
+int main(int argc, char *argv[])
+{
+ uint32_t olen;
+ long ilen;
+ unsigned long offs;
+ FILE *f;
+
+ if (argc < 2) {
+ fprintf(stderr, "Usage: %s compressed_file\n", argv[0]);
+ return 1;
+ }
+
+ /* Get the information for the compressed kernel image first */
+
+ f = fopen(argv[1], "r");
+ if (!f) {
+ perror(argv[1]);
+ return 1;
+ }
+
+
+ if (fseek(f, -4L, SEEK_END)) {
+ perror(argv[1]);
+ }
+ fread(&olen, sizeof olen, 1, f);
+ ilen = ftell(f);
+ olen = getle32(&olen);
+ fclose(f);
+
+ /*
+ * Now we have the input (compressed) and output (uncompressed)
+ * sizes, compute the necessary decompression offset...
+ */
+
+ offs = (olen > ilen) ? olen - ilen : 0;
+ offs += olen >> 12; /* Add 8 bytes for each 32K block */
+ offs += 32*1024 + 18; /* Add 32K + 18 bytes slack */
+ offs = (offs+4095) & ~4095; /* Round to a 4K boundary */
+
+ 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_extract_offset\n");
+ printf("z_extract_offset = 0x%lx\n", offs);
+ /* z_extract_offset_negative allows simplification of head_32.S */
+ printf(".globl z_extract_offset_negative\n");
+ printf("z_extract_offset_negative = -0x%lx\n", offs);
+
+ printf(".globl input_data, input_data_end\n");
+ printf("input_data:\n");
+ printf(".incbin \"%s\"\n", argv[1]);
+ printf("input_data_end:\n");
+
+ return 0;
+}
diff --git a/arch/x86/boot/compressed/vmlinux.scr b/arch/x86/boot/compressed/vmlinux.scr
deleted file mode 100644
index f02382ae5c4..00000000000
--- a/arch/x86/boot/compressed/vmlinux.scr
+++ /dev/null
@@ -1,10 +0,0 @@
-SECTIONS
-{
- .rodata.compressed : {
- input_len = .;
- LONG(input_data_end - input_data) input_data = .;
- *(.data)
- output_len = . - 4;
- input_data_end = .;
- }
-}