endif
endif
-ifndef CONFIG_SYS_ARM_WITHOUT_RELOC
-# needed for relocation
-PLATFORM_RELFLAGS += -fPIC
-endif
-
ifdef CONFIG_SYS_ARM_WITHOUT_RELOC
PLATFORM_CPPFLAGS += -DCONFIG_SYS_ARM_WITHOUT_RELOC
endif
endif
endif
LDSCRIPT := $(SRCTREE)/$(CPUDIR)/u-boot.lds
+
+ifndef CONFIG_SYS_ARM_WITHOUT_RELOC
+# needed for relocation
+PLATFORM_LDFLAGS += -pie
+endif
* Copyright (c) 2002 Gary Jennejohn <garyj@denx.de>
* Copyright (c) 2003 Richard Woodruff <r-woodruff2@ti.com>
* Copyright (c) 2003 Kshitij <kshitij@ti.com>
+ * Copyright (c) 2010 Albert Aribaud <albert.aribaud@free.fr>
*
* See file CREDITS for list of people who contributed to this
* project.
_TEXT_BASE:
.word TEXT_BASE
-#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
-.globl _armboot_start
-_armboot_start:
- .word _start
-#endif
-
/*
* These are defined in the board-specific linker script.
+ * Subtracting _start from them lets the linker put their
+ * relative position in the executable instead of leaving
+ * them null.
*/
-.globl _bss_start
-_bss_start:
- .word __bss_start
+.globl _bss_start_ofs
+_bss_start_ofs:
+ .word __bss_start - _start
-.globl _bss_end
-_bss_end:
- .word _end
+.globl _bss_end_ofs
+_bss_end_ofs:
+ .word _end - _start
#ifdef CONFIG_USE_IRQ
/* IRQ stack memory (calculated at run-time) */
IRQ_STACK_START_IN:
.word 0x0badc0de
-.globl _datarel_start
-_datarel_start:
- .word __datarel_start
-
-.globl _datarelrolocal_start
-_datarelrolocal_start:
- .word __datarelrolocal_start
-
-.globl _datarellocal_start
-_datarellocal_start:
- .word __datarellocal_start
-
-.globl _datarelro_start
-_datarelro_start:
- .word __datarelro_start
-
-.globl _got_start
-_got_start:
- .word __got_start
-
-.globl _got_end
-_got_end:
- .word __got_end
-
/*
* the actual reset code
*/
adr r0, _start
ldr r2, _TEXT_BASE
- ldr r3, _bss_start
- sub r2, r3, r2 /* r2 <- size of armboot */
- add r2, r0, r2 /* r2 <- source end address */
+ ldr r3, _bss_start_ofs
+ add r2, r0, r3 /* r2 <- source end address */
cmp r0, r6
beq clear_bss
blo copy_loop
#ifndef CONFIG_PRELOADER
- /* fix got entries */
- ldr r1, _TEXT_BASE /* Text base */
- mov r0, r7 /* reloc addr */
- ldr r2, _got_start /* addr in Flash */
- ldr r3, _got_end /* addr in Flash */
- sub r3, r3, r1
- add r3, r3, r0
- sub r2, r2, r1
- add r2, r2, r0
-
+ /*
+ * fix .rel.dyn relocations
+ */
+ ldr r0, _TEXT_BASE /* r0 <- Text base */
+ sub r9, r7, r0 /* r9 <- relocation offset */
+ ldr r10, _dynsym_start_ofs /* r10 <- sym table ofs */
+ add r10, r10, r0 /* r10 <- sym table in FLASH */
+ ldr r2, _rel_dyn_start_ofs /* r2 <- rel dyn start ofs */
+ add r2, r2, r0 /* r2 <- rel dyn start in FLASH */
+ ldr r3, _rel_dyn_end_ofs /* r3 <- rel dyn end ofs */
+ add r3, r3, r0 /* r3 <- rel dyn end in FLASH */
fixloop:
- ldr r4, [r2]
- sub r4, r4, r1
- add r4, r4, r0
- str r4, [r2]
- add r2, r2, #4
+ ldr r0, [r2] /* r0 <- location to fix up, IN FLASH! */
+ add r0, r9 /* r0 <- location to fix up in RAM */
+ ldr r1, [r2, #4]
+ and r8, r1, #0xff
+ cmp r8, #23 /* relative fixup? */
+ beq fixrel
+ cmp r8, #2 /* absolute fixup? */
+ beq fixabs
+ /* ignore unknown type of fixup */
+ b fixnext
+fixabs:
+ /* absolute fix: set location to (offset) symbol value */
+ mov r1, r1, LSR #4 /* r1 <- symbol index in .dynsym */
+ add r1, r10, r1 /* r1 <- address of symbol in table */
+ ldr r1, [r1, #4] /* r1 <- symbol value */
+ add r1, r9 /* r1 <- relocated sym addr */
+ b fixnext
+fixrel:
+ /* relative fix: increase location by offset */
+ ldr r1, [r0]
+ add r1, r1, r9
+fixnext:
+ str r1, [r0]
+ add r2, r2, #8 /* each rel.dyn entry is 8 bytes */
cmp r2, r3
- bne fixloop
+ blo fixloop
#endif
#endif /* #ifndef CONFIG_SKIP_RELOCATE_UBOOT */
clear_bss:
#ifndef CONFIG_PRELOADER
- ldr r0, _bss_start
- ldr r1, _bss_end
+ ldr r0, _bss_start_ofs
+ ldr r1, _bss_end_ofs
ldr r3, _TEXT_BASE /* Text base */
mov r4, r7 /* reloc addr */
- sub r0, r0, r3
add r0, r0, r4
- sub r1, r1, r3
add r1, r1, r4
mov r2, #0x00000000 /* clear */
* initialization, now running from RAM.
*/
#ifdef CONFIG_NAND_SPL
- ldr pc, _nand_boot
-
-_nand_boot: .word nand_boot
+ ldr r0, _nand_boot_ofs
+ adr r1, _start
+ add pc, r0, r1
+_nand_boot_ofs
+ : .word nand_boot - _start
#else
- ldr r0, _TEXT_BASE
- ldr r2, _board_init_r
- sub r2, r2, r0
- add r2, r2, r7 /* position from board_init_r in RAM */
+ ldr r0, _board_init_r_ofs
+ adr r1, _start
+ add r0, r0, r1
+ add lr, r0, r9
/* setup parameters for board_init_r */
mov r0, r5 /* gd_t */
mov r1, r7 /* dest_addr */
/* jump to it ... */
- mov lr, r2
mov pc, lr
-_board_init_r: .word board_init_r
+_board_init_r_ofs:
+ .word board_init_r - _start
#endif
+_rel_dyn_start_ofs:
+ .word __rel_dyn_start - _start
+_rel_dyn_end_ofs:
+ .word __rel_dyn_end - _start
+_dynsym_start_ofs:
+ .word __dynsym_start - _start
+
#else /* #if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC) */
/*
* the actual reset code
ldr r1, _TEXT_BASE /* test if we run from flash or RAM */
cmp r0, r1 /* don't reloc during debug */
beq stack_setup
- ldr r2, _armboot_start
- ldr r3, _bss_start
- sub r2, r3, r2 /* r2 <- size of armboot */
- add r2, r0, r2 /* r2 <- source end address */
+ ldr r3, _bss_start_ofs /* r3 <- _bss_start - _start */
+ add r2, r0, r3 /* r2 <- source end address */
copy_loop:
ldmia r0!, {r3-r10} /* copy from source address [r0] */
bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
clear_bss:
- ldr r0, _bss_start /* find start of bss segment */
- ldr r1, _bss_end /* stop here */
+ adr r2, _start
+ ldr r0, _bss_start_ofs /* find start of bss segment */
+ add r0, r0, r2
+ ldr r1, _bss_end_ofs /* stop here */
+ add r1, r1, r2
mov r2, #0x00000000 /* clear */
#ifndef CONFIG_PRELOADER
bl red_LED_on
#endif /* CONFIG_PRELOADER */
- ldr pc, _start_armboot
+ ldr r0, _start_armboot_ofs
+ adr r1, _start
+ add r0, r0, r1
+ ldr pc, r0
-_start_armboot:
+_start_armboot_ofs:
#ifdef CONFIG_NAND_SPL
- .word nand_boot
+ .word nand_boot - _start
#else
- .word start_armboot
+ .word start_armboot - _start
#endif /* CONFIG_NAND_SPL */
#endif /* #if !defined(CONFIG_SYS_ARM_WITHOUT_RELOC) */
sub sp, sp, #S_FRAME_SIZE
stmia sp, {r0 - r12} @ Save user registers (now in svc mode) r0-r12
#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
- ldr r2, _armboot_start
+ adr r2, _start
sub r2, r2, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
sub r2, r2, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ set base 2 words into abort stack
#else
.macro get_bad_stack
#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
- ldr r13, _armboot_start @ setup our mode stack
+ adr r13, _start @ setup our mode stack
sub r13, r13, #(CONFIG_STACKSIZE+CONFIG_SYS_MALLOC_LEN)
sub r13, r13, #(CONFIG_SYS_GBL_DATA_SIZE+8) @ reserved a couple spots in abort stack
#else
. = ALIGN(4);
.data : {
*(.data)
- __datarel_start = .;
- *(.data.rel)
- __datarelrolocal_start = .;
- *(.data.rel.ro.local)
- __datarellocal_start = .;
- *(.data.rel.local)
- __datarelro_start = .;
- *(.data.rel.ro)
}
- __got_start = .;
. = ALIGN(4);
- .got : { *(.got) }
- __got_end = .;
+ __rel_dyn_start = .;
+ .rel.dyn : { *(.rel.dyn) }
+ __rel_dyn_end = .;
+
+ __dynsym_start = .;
+ .dynsym : { *(.dynsym) }
+
+ . = ALIGN(4);
+
. = .;
__u_boot_cmd_start = .;
.u_boot_cmd : { *(.u_boot_cmd) }
__bss_start = .;
.bss (NOLOAD) : { *(.bss) . = ALIGN(4); }
_end = .;
+
+ /DISCARD/ : { *(.dynstr*) }
+ /DISCARD/ : { *(.dynamic*) }
+ /DISCARD/ : { *(.plt*) }
+ /DISCARD/ : { *(.interp*) }
+ /DISCARD/ : { *(.gnu*) }
}
#ifndef _ASM_CONFIG_H_
#define _ASM_CONFIG_H_
-#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
/* Relocation to SDRAM works on all ARM boards */
#define CONFIG_RELOC_FIXUP_WORKS
#endif
-#endif
#define _U_BOOT_ARM_H_ 1
/* for the following variables, see start.S */
-extern ulong _bss_start; /* code + data end == BSS start */
-extern ulong _bss_end; /* BSS end */
+extern ulong _bss_start_ofs; /* BSS start relative to _start */
+extern ulong _bss_end_ofs; /* BSS end relative to _start */
extern ulong IRQ_STACK_START; /* top of IRQ stack */
extern ulong FIQ_STACK_START; /* top of FIQ stack */
#if defined(CONFIG_SYS_ARM_WITHOUT_RELOC)
-extern ulong _armboot_start; /* code start */
+extern ulong _armboot_start_ofs; /* code start */
#else
extern ulong _TEXT_BASE; /* code start */
-extern ulong _datarel_start;
-extern ulong _datarelrolocal_start;
-extern ulong _datarellocal_start;
-extern ulong _datarelro_start;
+extern ulong _datarel_start_ofs;
+extern ulong _datarelrolocal_start_ofs;
+extern ulong _datarellocal_start_ofs;
+extern ulong _datarelro_start_ofs;
extern ulong IRQ_STACK_START_IN; /* 8 bytes in IRQ stack */
#endif
#else
_armboot_start,
#endif
- _bss_start, _bss_end);
+ _bss_start_ofs+_TEXT_BASE, _bss_end_ofs+_TEXT_BASE);
#ifdef CONFIG_MODEM_SUPPORT
debug ("Modem Support enabled\n");
#endif
memset ((void*)gd, 0, sizeof (gd_t));
- gd->mon_len = _bss_end - _TEXT_BASE;
+ gd->mon_len = _bss_end_ofs;
for (init_fnc_ptr = init_sequence; *init_fnc_ptr; ++init_fnc_ptr) {
if ((*init_fnc_ptr)() != 0) {
*
************************************************************************
*/
+
void board_init_r (gd_t *id, ulong dest_addr)
{
char *s;
gd->flags |= GD_FLG_RELOC; /* tell others: relocation done */
- monitor_flash_len = _bss_start - _TEXT_BASE;
+ monitor_flash_len = _bss_start_ofs;
debug ("monitor flash len: %08lX\n", monitor_flash_len);
board_init(); /* Setup chipselects */
/* NOTREACHED - no way out of command loop except booting */
}
+
#endif /* defined(CONFIG_SYS_ARM_WITHOUT_RELOC) */
void hang (void)
To make relocation on arm working, the following changes are done:
-Add new compilerflag:
+At arch level: add linker flag -pie
--fPIC
+ This causes the linker to generate fixup tables .rel.dyn and .dynsym,
+ which must be applied to the relocated image before transferring
+ control to it.
- -> compiler generates position independent code
+ These fixups are described in the ARM ELF documentation as type 23
+ (program-base-relative) and 2 (symbol-relative)
-changes in board code:
+At cpu level: modify linker file and add a relocation and fixup loop
-- dram_init:
- - bd pointer is now at this point not accessible, so only
- detect the real dramsize, and store it in gd->ram_size.
- best detected with get_ram_size();
- ToDo: move there also the dram initialization on boards where
- it is possible.
- - setup the bd_t dram bank info in the new function
- dram_init_banksize().
+ the linker file must be modified to include the .rel.dyn and .dynsym
+ tables in the binary image, and to provide symbols for the relocation
+ code to access these tables
-- board.c code is adapted from ppc code
+ The relocation and fixup loop must be executed after executing
+ board_init_f at initial location and before executing board_init_r
+ at final location.
-- undef CONFIG_RELOC_FIXUP_WORKS
+At board level:
- -> cmdtabl, and subcommand table must be handled from "hand"
- collected in section "__datarellocal_start".
+ dram_init(): bd pointer is now at this point not accessible, so only
+ detect the real dramsize, and store it in gd->ram_size. Bst detected
+ with get_ram_size().
- - How To fixup the sections:
+TODO: move also dram initialization there on boards where it is possible.
- __datarel_start, __datarelrolocal_start, __datarellocal_start and
- __datarelro_start
+ Setup of the the bd_t dram bank info is done in the new function
+ dram_init_banksize() called after bd is accessible.
- automatically? Then it should be possible to define again
- CONFIG_RELOC_FIXUP_WORKS
+At lib level:
-- irq stack setup is now not longer on a fix position, instead it is
- calculated in board_init_f, and stored in gd->irq_sp
+ Board.c code is adapted from ppc code
--------------------------------------------------------------------------------------
+At config level:
-To compile a board without relocation, define CONFIG_SYS_ARM_WITHOUT_RELOC
-This possibility will removed!! So please fix your board to compile without
-CONFIG_SYS_ARM_WITHOUT_RELOC defined!!!
+ Define CONFIG_RELOC_FIXUP_WORKS.
+ Undefine CONFIG_SYS_ARM_WITHOUT_RELOC
--------------------------------------------------------------------------------------
+* WARNING ** WARNING ** WARNING ** WARNING ** WARNING ** WARNING ** WARNING *
+
+Boards which are not fixed to support relocation will be REMOVED!
+
+Eventually, CONFIG_SYS_ARM_WITHOUT_RELOC and CONFIG_RELOC_FIXUP_WORKS will
+disappear and boards which have to migrated to relocation will disappear too.
+
+-----------------------------------------------------------------------------
-For boards which boot from nand_spl, it is possible to save a copy
+For boards which boot from nand_spl, it is possible to save one copy
if TEXT_BASE == relocation address! This prevents that uboot code
is copied again in relocate_code().
If TEXT_BASE == relocation address, the copying of u-boot
in f) could be saved.
--------------------------------------------------------------------------------------
+-----------------------------------------------------------------------------
-ToDo:
+TODO
- fill in bd_t infos (check)
- adapt all boards
- new function dram_init_banksize() is actual board specific. Maybe
we make a weak default function in arch/arm/lib/board.c ?
--------------------------------------------------------------------------------------
+-----------------------------------------------------------------------------
Relocation with NAND_SPL (example for the tx25):
from the nand_spl code), no need to copy, just go on with bss clear
and jump to board_init_r.
--------------------------------------------------------------------------------------
-
-Relocation:
-How to translate flash addresses in GOT to ram addresses.
-This is automagically done from code, but this example
-shows, how this magic code works ;-)
-(example on the qong board)
-
-Find a variable:
-
-a) search it in System.map
-(for example flash_info)
-
-a005b4c0 B BootpID
-a005b4c4 B BootpTry
-a005b4c8 b slave
-a005b4cc B flash_info
-^^^^^^^^
-a005c908 b saved_sector.4002
-a005c910 b cfi_mtd_info
-a005c9c0 b cfi_mtd_names
-a005c9d0 B mtd_table
-
----------------------------------------
-
-b) create hexdump from u-boot code:
-
-hexdump -C u-boot > gnlmpfhex
-
----------------------------------------
-
-c) search the variables address in the hexdump
-
-
-*
-0005fc80 00 00 00 00 00 00 00 00 2c 06 01 a0 18 cd 05 a0 |........,.......|
-0005fc90 9c d4 05 a0 bc b4 05 a0 1c 7f 05 a0 f0 05 01 a0 |................|
-0005fca0 08 5a 04 a0 1c ab 05 a0 ec a4 05 a0 98 c3 01 a0 |.Z..............|
-0005fcb0 a0 d6 05 a0 04 71 05 a0 c0 f9 00 a0 3c cd 05 a0 |.....q......<...|
-0005fcc0 cc b4 05 a0 f0 fa 00 a0 f0 d6 05 a0 10 86 05 a0 |................|
- ^^^^^^^^^^^
-0005fcd0 a4 16 06 a0 dc 64 05 a0 18 86 05 a0 52 48 05 a0 |.....d......RH..|
-0005fce0 c0 86 05 a0 24 6e 02 a0 b4 6c 05 a0 b0 94 01 a0 |....$n...l......|
-0005fcf0 1c 86 05 a0 50 85 05 a0 d4 0c 06 a0 bc 0b 06 a0 |....P...........|
-
-
--> 0005fcc0
-
-----------------------------------------
-
-d) know we calculate this address in RAM
-
-
- 8ff08000 (new address of code in RAM *1)
-
-+ 0005fcc0
-
-- 00008000 (offset of text *2)
-
-----------
-
- 8ff5fcc0 -> Addr GOT in RAM
-
-*1:
-activate debug and look for the line:
-Now running in RAM - U-Boot at: 8ff08000
- ^^^^^^^^
- new address of u-boot code in RAM
-
-*2:
-Section Headers:
- [Nr] Name Type Addr Off Size ES Flg Lk Inf Al
- [ 0] NULL 00000000 000000 000000 00 0 0 0
- [ 1] .text PROGBITS a0000000 008000 04599c 00 AX 0 0 32
- ^^^^^^
- Offset of text
+-----------------------------------------------------------------------------
-----------------------------------------
+How ELF relocations 23 and 2 work.
-e) now we look in 8ff5fcc0 (RAM)
-
-
-QongEVB>md 0x8ff5fcc0
-8ff5fcc0 : a005b4cc a000faf0 a005d6f0 a0058610 ................
- ^^^^^^^^
- Bingo, here we have the old flash address (when relocation
- is working, here is the fixed ram address. see @ f, how
- it gets calculated)
-
-
-----------------------------------------
-
-f) now translate it in the new RAM address
-
- a005b4cc
-
-- a0000000 TextBase
-
-+ 8ff08000 new address of u-boot in ram
-----------
- 8ff634cc
-
-QongEVB>mm 0x8ff5fcc0 0x8ff634cc 1
-QongEVB>md 0x8ff5fcc0
-8ff5fcc0 : 8ff634cc a000faf0 a005d6f0 a0058610 .4..............
-8ff5fcd0 : a00616a4 a00564dc a0058618 a0054852 .....d......RH..
-
-As this must be done for all address in the GOT, the u-boot
-code did this automagically ... :-)
-
-----------------------------------------------
-
-g) check if the new address is really in the bss section:
-
-bss start:
-8ff6054c (8ff08000 + 0005854C monitorlen)
-
-bss end:
-8ff698ac (8ff08000 + 618AC)
-
-8ff634cc is in bss :-)
-
-----------------------------------------------
-
-h) u-boot prints:
-
-important addresses:
-
-U-Boot code: A0000000 -> A005854C BSS: -> A00618AC TextBase 0xa0000000
-Now running in RAM - U-Boot at: 8ff08000 relocBase 0x8ff08000
-
-
----------
-
-U-Boot 2010.06-rc2-00002-gf8fbb25-dirty (Jun 18 2010 - 17:07:19)
-
-U-Boot code: A0000000 -> A005854C BSS: -> A00618AC
-CPU: Freescale i.MX31 at 398 MHz
-Board: DAVE/DENX Qong
-mon: FFFFFFFF gd->monLen: 000618AC
-Top of RAM usable for U-Boot at: 90000000
-LCD panel info: 640 x 480, 16 bit/pix
-Reserving 600k for LCD Framebuffer at: 8ff6a000
-Reserving 390k for U-Boot at: 8ff08000
-Reserving 1280k for malloc() at: 8fdc8000
-Reserving 28 Bytes for Board Info at: 8fdc7fe4
-Reserving 48 Bytes for Global Data at: 8fdc7fb4
-New Stack Pointer is: 8fdc7fb0
-RAM Configuration:
-Bank #0: 80000000 256 MiB
-mon: 0005854C gd->monLen: 000618AC
-Now running in RAM - U-Boot at: 8ff08000
+TBC
-------------------------------------------------------------------------------------
projects / u-boot.git / commitdiff