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[linuxsh-dev] Re: [linux-sh:01233] Re: ROMable image
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From: Jesper S. <js...@re...> - 2000-08-25 09:03:31
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>>>>> "Jesper" == Jesper Skov <js...@re...> writes:
>>>>> "Manoj" == Manoj Kumar <man...@so...> writes:
Manoj> Hello all, I want to build a ROMable kernel image.I am using
Manoj> NIIBE's sh-linux 2.4.0. I am not using a CE device. Does
Manoj> anyone know about a patch for doing the same?
Manoj> I found a patch in Ludovic's site,but it is for linux2.3.23.
Jesper> I have some XIP patches. I need to clean them up and submit
Jesper> them. Hopefully today, but I need to check that they are OK to
Jesper> publicize - so no guarantees.
I have now uploaded the simple patch below to the patch manager at
sourceforge.
The only real problem with the patch as far as I'm concerned is that
it uses a hack to separate arguments from the empty_zero_page. I had
to do this because (a) I'm using some scripts to write boot parameters
into the start of the boot image and (b) empty_zero_page has to be in
the data section so it will end up in RAM.
I don't know if the patch is worth integrating the public tree before
that issue has been fixed. But even so, there are a few generic fixes
in there as well: Documentation fix + lose module exit functions.
For debugging with the XIP configuration, I configure something like
this (I have 8MB RAM @ 0x0c000000):
CONFIG_SH_XIP=y
CONFIG_XIP_ROM_START=0C100000
CONFIG_MEMORY_START=0C300000
CONFIG_MEMORY_SIZE=00500000
Thus leaving 2MB @ 0x0c100000 for the boot image (kernel text +
initrd). On startup the data section is copied to MEMORY_START and the
5MB @ 0x0c300000 is mapped as if it was the only RAM in the
system. Then I'm free to still use breakpoints/single-step the kernel
text.
For production I put CONFIG_XIP_ROM_START=00100000, and have the full
8MB of RAM for the system. (the 1MB missing are for the boot monitor).
Cheers,
Jesper
2000-08-25 Jesper Skov <js...@re...>
* arch/sh/Makefile: Select linker script based on XIP config.
* arch/sh/config.in: Added XIP related and memory default size
options.
* arch/sh/vmlinux.lds.S: Added _sdata label. Discard .exitcalls
from modules.
* arch/sh/vmlinux.lds.xip.S: [Added] Linker script for XIP
configuration.
* arch/sh/kernel/head.S: Copy data to RAM in XIP config. Crufty
hack to keep arguments at front of image while empty_zero_page ends
up in RAM.
* arch/sh/kernel/setup.c (parse_cmdline): Use configurable default
memory size. empty_zero_page/argument_page XIP hack.
* arch/sh/mm/init.c (mem_init): Use _sdata instead of _etext for
size calculation.
* Documentation/Configure.help: Added descriptions for new
options. Fixed CPU selection description.
Index: Documentation/Configure.help
===================================================================
RCS file: /cvsroot/linuxsh/kernel/Documentation/Configure.help,v
retrieving revision 1.21
diff -u -5 -r1.21 Configure.help
--- Documentation/Configure.help 2000/08/10 01:19:39 1.21
+++ Documentation/Configure.help 2000/08/25 08:48:00
@@ -14818,14 +14818,15 @@
# The following options are for Linux when running on the Hitachi
# SuperH family of RISC microprocessors.
CPU Selection
-CONFIG_CPU_SUBTYPE_SH7708
+CONFIG_CPU_SUBTYPE_SH7707
This is the type of your Hitachi SuperH processor. This information is
used for optimizing and configuration purposes.
+ - "SH7707" for SH7707
- "SH7708" for SH7708, SH7708S, SH7708R
- "SH7709" for SH7707, SH7709, SH7709A, and SH7729.
- "SH7750" for SH7750, and possibly SH7751
Physical memory start address
@@ -14837,10 +14838,40 @@
You should set this value to the address of the lowest
RAM location.
A value of 0c000000 will work for most boards.
+
+Execute-in-place kernel
+CONFIG_SH_XIP
+ Selecting this option (eXecute-In-Place) will allow the kernel text
+ and rodata segments to remain in flash/ROM memory, saving on RAM usage.
+
+ There might be a small performance degradation due to the flash/ROM
+ being slower than DRAM, but since the kernel only uses a fraction of
+ the total CPU time, this should not be a problem. The RAM freed up
+ by running the kernel out of flash/ROM will probably more than
+ counter this slowdown.
+
+XIP text segment start address
+CONFIG_XIP_ROM_START
+ When the XIP option is selected, this option controls where the
+ kernel text segment starts. SuperH processors always have flash/ROM
+ at address zero, but there may be reasons to put the kernel
+ elsewhere:
+
+ Higher up in the flash/ROM, leaving the start of the flash/ROM to a
+ boot monitor which can start Linux.
+
+ In RAM, allowing for debugging. In this case you should adjust the
+ CONFIG_MEMORY_START option as well, leaving a gap for the kernel in
+ RAM.
+
+Memory size
+CONFIG_MEMORY_SIZE
+ The amount of RAM used by Linux can be controlled with a kernel
+ parameter, but this option allows for a configurable default.
Directly Connected Compact Flash support
CONFIG_CF_ENABLER
If your board has "Directly Connected" Compact Flash at area 6,
you may want to enable this option. Then, you can use CF as
Index: arch/sh/Makefile
===================================================================
RCS file: /cvsroot/linuxsh/kernel/arch/sh/Makefile,v
retrieving revision 1.9
diff -u -5 -r1.9 Makefile
--- arch/sh/Makefile 2000/07/31 12:35:55 1.9
+++ arch/sh/Makefile 2000/08/25 08:48:01
@@ -80,14 +80,20 @@
SUBDIRS += arch/sh/overdrive
CORE_FILES += arch/sh/overdrive/overdrive.o
endif
endif
+ifdef CONFIG_SH_XIP
+LINKSCRIPT_SRC = arch/sh/vmlinux.lds.xip.S
+else
+LINKSCRIPT_SRC = arch/sh/vmlinux.lds.S
+endif
+
vmlinux: arch/sh/vmlinux.lds
-arch/sh/vmlinux.lds: arch/sh/vmlinux.lds.S FORCE
- $(CPP) -C -P -I$(HPATH) -Ush arch/sh/vmlinux.lds.S >arch/sh/vmlinux.lds
+arch/sh/vmlinux.lds: $(LINKSCRIPT_SRC) FORCE
+ $(CPP) -C -P -I$(HPATH) -Ush $(LINKSCRIPT_SRC) >arch/sh/vmlinux.lds
FORCE: ;
zImage: vmlinux
@$(MAKEBOOT) zImage
Index: arch/sh/config.in
===================================================================
RCS file: /cvsroot/linuxsh/kernel/arch/sh/config.in,v
retrieving revision 1.19
diff -u -5 -r1.19 config.in
--- arch/sh/config.in 2000/08/05 07:04:45 1.19
+++ arch/sh/config.in 2000/08/25 08:48:02
@@ -52,16 +52,21 @@
if [ "$CONFIG_CPU_SUBTYPE_SH7750" = "y" ]; then
define_bool CONFIG_CPU_SH3 n
define_bool CONFIG_CPU_SH4 y
fi
bool 'Little Endian' CONFIG_CPU_LITTLE_ENDIAN
+bool 'Kernel XIP' CONFIG_SH_XIP
+if [ "$CONFIG_SH_XIP" = "y" ]; then
+ hex 'ROM physical start address' CONFIG_XIP_ROM_START 08100000
+fi
if [ "$CONFIG_SH_SOLUTION_ENGINE" = "y" -o "$CONFIG_SH_HP600" = "y" -o \
"$CONFIG_SH_OVERDRIVE" = "y" ]; then
define_hex CONFIG_MEMORY_START 0c000000
else
hex 'Physical memory start address' CONFIG_MEMORY_START 08000000
fi
+hex 'Memory size' CONFIG_MEMORY_SIZE 00400000
endmenu
mainmenu_option next_comment
comment 'General setup'
Index: arch/sh/vmlinux.lds.S
===================================================================
RCS file: /cvsroot/linuxsh/kernel/arch/sh/vmlinux.lds.S,v
retrieving revision 1.6
diff -u -5 -r1.6 vmlinux.lds.S
--- arch/sh/vmlinux.lds.S 2000/08/05 06:25:22 1.6
+++ arch/sh/vmlinux.lds.S 2000/08/25 08:48:02
@@ -35,10 +35,11 @@
__start___ksymtab = .; /* Kernel symbol table */
__ksymtab : { *(__ksymtab) }
__stop___ksymtab = .;
_etext = .; /* End of text section */
+ _sdata = .; /* Start of data section */
.data : { /* Data */
*(.data)
CONSTRUCTORS
}
@@ -87,10 +88,11 @@
* it's a module.
*/
/DISCARD/ : {
*(.text.exit)
*(.data.exit)
+ *(.exitcall.*)
}
/* Stabs debugging sections. */
.stab 0 : { *(.stab) }
.stabstr 0 : { *(.stabstr) }
Index: arch/sh/vmlinux.lds.xip.S
===================================================================
RCS file: vmlinux.lds.xip.S
diff -N vmlinux.lds.xip.S
--- arch/sh/vmlinux.lds.xip.S Tue May 5 13:32:27 1998
+++ arch/sh/vmlinux.lds.xip.S Fri Aug 25 01:48:03 2000
@@ -0,0 +1,155 @@
+/* $Id: vmlinux.lds.xip.S,v 1.3 2000/08/21 14:12:02 jskov Exp $
+ * ld script to make SuperH Linux kernel
+ * Written by Niibe Yutaka
+ */
+
+#include <linux/config.h>
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+OUTPUT_FORMAT("elf32-shl", "elf32-shl", "elf32-shl")
+#else
+OUTPUT_FORMAT("elf32-sh", "elf32-sh", "elf32-sh")
+#endif
+OUTPUT_ARCH(sh)
+ENTRY(_start)
+
+#define ALIGN_LMA 4
+#define ALIGNED_GAP(_section_, _align_) (((ADDR(_section_)+SIZEOF(_section_)+(_align_)-1) & ~((_align_)-1))-ADDR(_section_))
+#define FOLLOWING(_section_, _align_) AT (LOADADDR (_section_) + ALIGNED_GAP(_section_, _align_))
+
+SECTIONS
+{
+ . = 0x80000000 + CONFIG_XIP_ROM_START + 0x1000;
+ _text = .; /* Text and read-only data */
+ text = .; /* Text and read-only data */
+ .argument_page : {
+ *(.argument_page)
+ } = 0
+ .text : {
+ *(.text)
+ *(.fixup)
+ *(.gnu.warning)
+ *(.text.init)
+ } = 0x0009
+ .text.lock : { *(.text.lock) } /* out-of-line lock text */
+ .rodata : { *(.rodata) }
+ .kstrtab : { *(.kstrtab) }
+
+ . = ALIGN(16); /* Exception table */
+ __start___ex_table = .;
+ __ex_table : { *(__ex_table) }
+ __stop___ex_table = .;
+
+ __start___ksymtab = .; /* Kernel symbol table */
+ __ksymtab : { *(__ksymtab) }
+ __stop___ksymtab = .;
+
+ _etext = .; /* End of text section */
+
+ _xip_load = .; /* Load address of data for RAM */
+ . = 0x80000000 + CONFIG_MEMORY_START;
+ _xip_sdata = .; /* Start of data section */
+ _sdata = .; /* Start of data section */
+ .empty_zero_page : FOLLOWING(__ksymtab, 1) {
+ *(.empty_zero_page)
+ } = 0
+ . = ALIGN(4096);
+ .data : FOLLOWING(.empty_zero_page, 4096) {/* Data */
+ *(.data)
+#if 0
+ CONSTRUCTORS
+#endif
+ }
+
+ _edata = .; /* End of data section */
+
+ . = ALIGN(8192); /* init_task */
+ .data.init_task : FOLLOWING(.data, 8192) { *(.data.init_task) }
+ /* stack */
+ .stack : { stack = .; _stack = .; }
+
+ . = ALIGN(4096); /* Init code and data */
+ __init_begin = .;
+ .data.init : FOLLOWING(.data.init_task, 4096) { *(.data.init) }
+ . = ALIGN(16);
+ __setup_start = .;
+ .setup.init : FOLLOWING(.data.init, 16) { *(.setup.init) }
+ __setup_end = .;
+ __initcall_start = .;
+ .initcall.init : FOLLOWING(.setup.init, 1) { *(.initcall.init) }
+ __initcall_end = .;
+ __machvec_start = .;
+ .machvec.init : FOLLOWING(.initcall.init, 1) { *(.machvec.init) }
+ __machvec_end = .;
+ . = ALIGN(4096);
+ __init_end = .;
+
+#if 0
+ . = ALIGN(4096);
+ .data.page_aligned : FOLLOWING(.setup.init, 4096) { *(.data.idt) }
+#endif
+
+#if 0
+ . = ALIGN(32);
+ .data.cacheline_aligned : FOLLOWING(.data.page_aligned, 32) { *(.data.cacheline_aligned) }
+#else
+ . = ALIGN(4096);
+ .data.cacheline_aligned : FOLLOWING(.initcall.init, 4096) { *(.data.cacheline_aligned) }
+#endif
+
+ . = ALIGN(4);
+
+ _xip_edata = .; /* End of data that needs to be copied */
+
+ __bss_start = .; /* BSS */
+ .bss : {
+ *(.bss)
+ }
+ . = ALIGN(4);
+ _end = . ;
+
+ /* When something in the kernel is NOT compiled as a module, the
+ * module cleanup code and data are put into these segments. Both
+ * can then be thrown away, as cleanup code is never called unless
+ * it's a module.
+ */
+ /DISCARD/ : {
+ *(.text.exit)
+ *(.data.exit)
+ *(.exitcall.*)
+ }
+
+ /* Stabs debugging sections. */
+ .stab 0 : { *(.stab) }
+ .stabstr 0 : { *(.stabstr) }
+ .stab.excl 0 : { *(.stab.excl) }
+ .stab.exclstr 0 : { *(.stab.exclstr) }
+ .stab.index 0 : { *(.stab.index) }
+ .stab.indexstr 0 : { *(.stab.indexstr) }
+ .comment 0 : { *(.comment) }
+ /* DWARF debug sections.
+ Symbols in the DWARF debugging section are relative to the beginning
+ of the section so we begin .debug at 0. */
+ /* DWARF 1 */
+ .debug 0 : { *(.debug) }
+ .line 0 : { *(.line) }
+ /* GNU DWARF 1 extensions */
+ .debug_srcinfo 0 : { *(.debug_srcinfo) }
+ .debug_sfnames 0 : { *(.debug_sfnames) }
+ /* DWARF 1.1 and DWARF 2 */
+ .debug_aranges 0 : { *(.debug_aranges) }
+ .debug_pubnames 0 : { *(.debug_pubnames) }
+ /* DWARF 2 */
+ .debug_info 0 : { *(.debug_info) }
+ .debug_abbrev 0 : { *(.debug_abbrev) }
+ .debug_line 0 : { *(.debug_line) }
+ .debug_frame 0 : { *(.debug_frame) }
+ .debug_str 0 : { *(.debug_str) }
+ .debug_loc 0 : { *(.debug_loc) }
+ .debug_macinfo 0 : { *(.debug_macinfo) }
+ /* SGI/MIPS DWARF 2 extensions */
+ .debug_weaknames 0 : { *(.debug_weaknames) }
+ .debug_funcnames 0 : { *(.debug_funcnames) }
+ .debug_typenames 0 : { *(.debug_typenames) }
+ .debug_varnames 0 : { *(.debug_varnames) }
+ /* These must appear regardless of . */
+}
Index: arch/sh/kernel/head.S
===================================================================
RCS file: /cvsroot/linuxsh/kernel/arch/sh/kernel/head.S,v
retrieving revision 1.7
diff -u -5 -r1.7 head.S
--- arch/sh/kernel/head.S 2000/07/04 06:24:39 1.7
+++ arch/sh/kernel/head.S 2000/08/25 08:48:03
@@ -10,12 +10,21 @@
*
* Head.S contains the SH exception handlers and startup code.
*/
#include <linux/linkage.h>
+#ifdef CONFIG_SH_XIP
.section .empty_zero_page, "aw"
ENTRY(empty_zero_page)
+ .long 0
+
+ .section .argument_page, "aw"
+ENTRY(argument_page)
+#else
+ .section .empty_zero_page, "aw"
+ENTRY(empty_zero_page)
+#endif
.long 1 /* MOUNT_ROOT_RDONLY */
.long 0 /* RAMDISK_FLAGS */
.long 0x0200 /* ORIG_ROOT_DEV */
.long 1 /* LOADER_TYPE */
.long 0x00360000 /* INITRD_START */
@@ -58,10 +67,21 @@
#endif
! Enable cache
mov.l 6f, $r0
jsr @$r0
nop
+#ifdef CONFIG_SH_XIP
+ ! Copy data to RAM
+ mov.l 10f,$r0
+ mov.l 11f,$r1
+ mov.l 12f,$r2
+9: mov.l @$r0+,$r3 ! get word from ROM
+ mov.l $r3,@$r1 ! store in RAM
+ add #4,$r1
+ cmp/eq $r1,$r2 ! compare
+ bf 9b ! loop if not yet done
+#endif
! Clear BSS area
mov.l 3f, $r1
add #4, $r1
mov.l 4f, $r2
mov #0, $r0
@@ -80,6 +100,11 @@
4: .long SYMBOL_NAME(_end)
5: .long SYMBOL_NAME(start_kernel)
6: .long SYMBOL_NAME(cache_init)
#if defined(__SH4__)
7: .long SYMBOL_NAME(fpu_init)
+#endif
+#ifdef CONFIG_SH_XIP
+10: .long SYMBOL_NAME(_xip_load)
+11: .long SYMBOL_NAME(_xip_sdata)
+12: .long SYMBOL_NAME(_xip_edata)
#endif
Index: arch/sh/kernel/setup.c
===================================================================
RCS file: /cvsroot/linuxsh/kernel/arch/sh/kernel/setup.c,v
retrieving revision 1.11
diff -u -5 -r1.11 setup.c
--- arch/sh/kernel/setup.c 2000/08/05 06:25:23 1.11
+++ arch/sh/kernel/setup.c 2000/08/25 08:48:04
@@ -69,11 +69,16 @@
static struct sh_machine_vector* __init get_mv_byname(const char* name);
/*
* This is set up by the setup-routine at boot-time
*/
+#ifndef CONFIG_SH_XIP
#define PARAM ((unsigned char *)empty_zero_page)
+#else
+extern unsigned char argument_page;
+#define PARAM ((unsigned char *)&argument_page)
+#endif
#define MOUNT_ROOT_RDONLY (*(unsigned long *) (PARAM+0x000))
#define RAMDISK_FLAGS (*(unsigned long *) (PARAM+0x004))
#define ORIG_ROOT_DEV (*(unsigned long *) (PARAM+0x008))
#define LOADER_TYPE (*(unsigned long *) (PARAM+0x00c))
@@ -202,12 +207,12 @@
/* Save unparsed command line copy for /proc/cmdline */
memcpy(saved_command_line, COMMAND_LINE, COMMAND_LINE_SIZE);
saved_command_line[COMMAND_LINE_SIZE-1] = '\0';
memory_start = (unsigned long)PAGE_OFFSET+__MEMORY_START;
- /* Default is 4Mbyte. */
- memory_end = (unsigned long)PAGE_OFFSET+0x00400000+__MEMORY_START;
+ /* Default is specified by the configuration */
+ memory_end = (unsigned long)PAGE_OFFSET+CONFIG_MEMORY_SIZE+__MEMORY_START;
for (;;) {
/*
* "mem=XXX[kKmM]" defines a size of memory.
*/
Index: arch/sh/mm/init.c
===================================================================
RCS file: /cvsroot/linuxsh/kernel/arch/sh/mm/init.c,v
retrieving revision 1.6
diff -u -5 -r1.6 init.c
--- arch/sh/mm/init.c 2000/08/16 08:34:04 1.6
+++ arch/sh/mm/init.c 2000/08/25 08:48:04
@@ -176,11 +176,11 @@
show_buffers();
}
/* References to section boundaries */
-extern char _text, _etext, _edata, __bss_start, _end;
+extern char _text, _etext, _sdata, _edata, __bss_start, _end;
extern char __init_begin, __init_end;
pgd_t swapper_pg_dir[1024];
/* It'd be good if these lines were in the standard header file. */
@@ -251,11 +251,11 @@
* Only count reserved RAM pages
*/
if (PageReserved(mem_map+tmp))
reservedpages++;
codesize = (unsigned long) &_etext - (unsigned long) &_text;
- datasize = (unsigned long) &_edata - (unsigned long) &_etext;
+ datasize = (unsigned long) &_edata - (unsigned long) &_sdata;
initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;
printk("Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init)\n",
(unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
max_mapnr << (PAGE_SHIFT-10),
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