This is mostly a copy of arm926ejs relocation and known to _not_ work
correctly a.t.m!

Signed-off-by: Andreas Bießmann <andreas.de...@googlemail.com>
---
changes since v1:
 - adopted linker script as in patch series v3 "arm926ejs: fix linker file for 
newer ld support"
  * move rel.dyn and dynsym after bss
  * overlay bss with rel.dyn
 - double checked fixup loop in start.S
  -> there is still an error in relocation fixup loop breaks the boot,
     the board hangs after "relocation Offset is: 00f80000"

 Dear Albert Aribaud,
 can you please have a look for that?

changes since v2:
 - add missed parts in "branch board_init_r"

 Dear Albert Aribaud,
 still not working, do you have any advice?

 arch/arm/cpu/arm920t/start.S    |  129 ++++++++++++++++++++-------------------
 arch/arm/cpu/arm920t/u-boot.lds |   37 +++++++----
 2 files changed, 89 insertions(+), 77 deletions(-)

diff --git a/arch/arm/cpu/arm920t/start.S b/arch/arm/cpu/arm920t/start.S
index d4edde7..c547181 100644
--- a/arch/arm/cpu/arm920t/start.S
+++ b/arch/arm/cpu/arm920t/start.S
@@ -77,14 +77,17 @@ _TEXT_BASE:
 
 /*
  * 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 _bss_end - _start
 
 #ifdef CONFIG_USE_IRQ
 /* IRQ stack memory (calculated at run-time) */
@@ -103,30 +106,6 @@ FIQ_STACK_START:
 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 start code
  */
@@ -164,7 +143,7 @@ copyex:
 #  define pWTCON       0x15300000
 #  define INTMSK       0x14400008      /* Interupt-Controller base addresses */
 #  define CLKDIVN      0x14800014      /* clock divisor register */
-#else
+# else
 #  define pWTCON       0x53000000
 #  define INTMSK       0x4A000008      /* Interupt-Controller base addresses */
 #  define INTSUBMSK    0x4A00001C
@@ -230,9 +209,8 @@ stack_setup:
 
        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
 
@@ -243,35 +221,53 @@ copy_loop:
        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 offset */
+       add     r10, r10, r0            /* r10 <- sym table in FLASH */
+       ldr     r2, _rel_dyn_start_ofs  /*  r2 <- rel dyn start offset */
+       add     r2, r2, r0              /*  r2 <- rel dyn start in FLASH */
+       ldr     r3, _rel_dyn_end_ofs    /*  r3 <- rel dyn end offset */
+       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, 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 (offste) 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 address */
+       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
        blo     fixloop
 #endif
 
 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                            */
 
@@ -289,24 +285,33 @@ clbss_l:str       r2, [r0]                /* clear 
loop...                    */
  * initialization, now running from RAM.
  */
 #ifdef CONFIG_NAND_SPL
-       ldr     pc, _nand_boot
+       ldr     r0, _nand_boot_ofs
+       mov     pc, r0
 
-_nand_boot: .word nand_boot
+_nand_boot_ofs:
+       .word nand_boot
 #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     lr, r0, r1
+       add     lr, lr, r9      /* position from board_init_r in RAM */
        /* 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
+
 /*
  *************************************************************************
  *
@@ -317,8 +322,6 @@ _board_init_r: .word board_init_r
  *
  *************************************************************************
  */
-
-
 #ifndef CONFIG_SKIP_LOWLEVEL_INIT
 cpu_init_crit:
        /*
diff --git a/arch/arm/cpu/arm920t/u-boot.lds b/arch/arm/cpu/arm920t/u-boot.lds
index 6985434..d647952 100644
--- a/arch/arm/cpu/arm920t/u-boot.lds
+++ b/arch/arm/cpu/arm920t/u-boot.lds
@@ -49,28 +49,37 @@ SECTIONS
        . = 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 = .;
        . = .;
        __u_boot_cmd_start = .;
        .u_boot_cmd : { *(.u_boot_cmd) }
        __u_boot_cmd_end = .;
 
        . = ALIGN(4);
-       __bss_start = .;
-       .bss (NOLOAD) : { *(.bss) . = ALIGN(4); }
-       _end = .;
+       .bss (NOLOAD) : {
+               __bss_start = .;
+               *(.bss)
+                . = ALIGN(4);
+               _bss_end = .;
+       }
+
+       .rel.dyn __bss_start (OVERLAY) : {
+               __rel_dyn_start = .;
+               *(.rel*)
+               __rel_dyn_end = .;
+       }
+
+       .dynsym : {
+               __dynsym_start = .;
+               *(.dynsym)
+       }
+
+       /DISCARD/ : { *(.dynstr*) }
+       /DISCARD/ : { *(.dynamic*) }
+       /DISCARD/ : { *(.plt*) }
+       /DISCARD/ : { *(.interp*) }
+       /DISCARD/ : { *(.gnu*) }
 }
-- 
1.7.3.2

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