[U-Boot] [RFC] [PATCH V2] arm: arm926ejs: use ELF relocations
Heiko Schocher
hs at denx.de
Tue Oct 5 14:52:16 CEST 2010
Hello Albert,
Albert Aribaud wrote:
> HISTORY:
>
> V1 Initial patch
> V2 Rebased on latest mainline master
>
> This patch is *not* a submission for master!
Following patch works on the beagle (ARMv7) board, with
booting from mmc.
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
index f411c0f..b011d7b 100644
--- a/arch/arm/cpu/armv7/start.S
+++ b/arch/arm/cpu/armv7/start.S
@@ -78,13 +78,13 @@ _armboot_start:
/*
* These are defined in the board-specific linker script.
*/
-.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) */
@@ -104,29 +104,29 @@ FIQ_STACK_START:
IRQ_STACK_START_IN:
.word 0x0badc0de
-.globl _datarel_start
-_datarel_start:
- .word __datarel_start
+.globl _datarel_start_ofs
+_datarel_start_ofs:
+ .word __datarel_start - _start
-.globl _datarelrolocal_start
-_datarelrolocal_start:
- .word __datarelrolocal_start
+.globl _datarelrolocal_start_ofs
+_datarelrolocal_start_ofs:
+ .word __datarelrolocal_start - _start
-.globl _datarellocal_start
-_datarellocal_start:
- .word __datarellocal_start
+.globl _datarellocal_start_ofs
+_datarellocal_start_ofs:
+ .word __datarellocal_start - _start
-.globl _datarelro_start
-_datarelro_start:
- .word __datarelro_start
+.globl _datarelro_start_ofs
+_datarelro_start_ofs:
+ .word __datarelro_start - _start
-.globl _got_start
-_got_start:
- .word __got_start
+.globl _got_start_ofs
+_got_start_ofs:
+ .word __got_start - _start
-.globl _got_end
-_got_end:
- .word __got_end
+.globl _got_end_Ofs
+_got_end_ofs:
+ .word __got_end - _start
/*
* the actual reset code
@@ -198,9 +198,8 @@ stack_setup:
#ifndef CONFIG_SKIP_RELOCATE_UBOOT
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
#ifndef CONFIG_PRELOADER
beq jump_2_ram
@@ -213,33 +212,51 @@ copy_loop:
ble copy_loop
#ifndef CONFIG_PRELOADER
- /* fix got entries */
- ldr r1, _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
clear_bss:
- 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 */
@@ -255,18 +272,26 @@ clbss_l:str r2, [r0] /* clear loop... */
* initialization, now running from RAM.
*/
jump_2_ram:
- 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
+
+_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
diff --git a/arch/arm/cpu/armv7/u-boot.lds b/arch/arm/cpu/armv7/u-boot.lds
index d4fd3fc..88a0fec 100644
--- a/arch/arm/cpu/armv7/u-boot.lds
+++ b/arch/arm/cpu/armv7/u-boot.lds
@@ -53,6 +53,13 @@ SECTIONS
__datarelro_start = .;
*(.data.rel.ro)
}
+ . = ALIGN(4);
+ __rel_dyn_start = .;
+ .rel.dyn : { *(.rel.dyn) }
+ __rel_dyn_end = .;
+
+ __dynsym_start = .;
+ .dynsym : { *(.dynsym) }
__got_start = .;
. = ALIGN(4);
diff --git a/include/configs/omap3_beagle.h b/include/configs/omap3_beagle.h
index 2463be4..5404d60 100644
--- a/include/configs/omap3_beagle.h
+++ b/include/configs/omap3_beagle.h
@@ -342,6 +342,7 @@ extern unsigned int boot_flash_type;
/* additions for new relocation code, must added to all boards */
#undef CONFIG_SYS_ARM_WITHOUT_RELOC /* This board is tested with relocation support */
+#define CONFIG_RELOC_FIXUP_WORKS
#define CONFIG_SYS_SDRAM_BASE PHYS_SDRAM_1
#define CONFIG_SYS_INIT_SP_ADDR (LOW_LEVEL_SRAM_STACK - CONFIG_SYS_GBL_DATA_SIZE)
--
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HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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