4 files changed, 118 insertions, 70 deletions

diff --git a/arch/powerpc/boot/crt0.S b/arch/powerpc/boot/crt0.S
index f1c4dfc635be..0f7428a37efb 100644
--- a/arch/powerpc/boot/crt0.S
+++ b/arch/powerpc/boot/crt0.S
@@ -6,16 +6,28 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  *
- * NOTE: this code runs in 32 bit mode and is packaged as ELF32.
+ * NOTE: this code runs in 32 bit mode, is position-independent,
+ * and is packaged as ELF32.
  */
 
 #include "ppc_asm.h"
 
         .text
-        /* a procedure descriptor used when booting this as a COFF file */
+        /* A procedure descriptor used when booting this as a COFF file.
+         * When making COFF, this comes first in the link and we're
+         * linked at 0x500000.
+         */
         .globl  _zimage_start_opd
 _zimage_start_opd:
-        .long   _zimage_start, 0, 0, 0
+        .long   0x500000, 0, 0, 0
+
+p_start:        .long   _start
+p_etext:        .long   _etext
+p_bss_start:    .long   __bss_start
+p_end:          .long   _end
+
+        .weak   _platform_stack_top
+p_pstack:       .long   _platform_stack_top
 
         .weak   _zimage_start
         .globl  _zimage_start
@@ -24,37 +36,65 @@ _zimage_start:
 _zimage_start_lib:
         /* Work out the offset between the address we were linked at
            and the address where we're running. */
-        bl      1f
-1:      mflr    r0
-        lis     r9,1b@ha
-        addi    r9,r9,1b@l
-        subf.   r0,r9,r0
-        beq     3f              /* if running at same address as linked */
+        bl      .+4
+p_base: mflr    r10             /* r10 now points to runtime addr of p_base */
+        /* grab the link address of the dynamic section in r11 */
+        addis   r11,r10,(_GLOBAL_OFFSET_TABLE_-p_base)@ha
+        lwz     r11,(_GLOBAL_OFFSET_TABLE_-p_base)@l(r11)
+        cmpwi   r11,0
+        beq     3f              /* if not linked -pie */
+        /* get the runtime address of the dynamic section in r12 */
+        .weak   __dynamic_start
+        addis   r12,r10,(__dynamic_start-p_base)@ha
+        addi    r12,r12,(__dynamic_start-p_base)@l
+        subf    r11,r11,r12     /* runtime - linktime offset */
+
+        /* The dynamic section contains a series of tagged entries.
+         * We need the RELA and RELACOUNT entries. */
+RELA = 7
+RELACOUNT = 0x6ffffff9
+        li      r9,0
+        li      r0,0
+9:      lwz     r8,0(r12)       /* get tag */
+        cmpwi   r8,0
+        beq     10f             /* end of list */
+        cmpwi   r8,RELA
+        bne     11f
+        lwz     r9,4(r12)       /* get RELA pointer in r9 */
+        b       12f
+11:     addis   r8,r8,(-RELACOUNT)@ha
+        cmpwi   r8,RELACOUNT@l
+        bne     12f
+        lwz     r0,4(r12)       /* get RELACOUNT value in r0 */
+12:     addi    r12,r12,8
+        b       9b
 
-        /* The .got2 section contains a list of addresses, so add
-           the address offset onto each entry. */
-        lis     r9,__got2_start@ha
-        addi    r9,r9,__got2_start@l
-        lis     r8,__got2_end@ha
-        addi    r8,r8,__got2_end@l
-        subf.   r8,r9,r8
+        /* The relocation section contains a list of relocations.
+         * We now do the R_PPC_RELATIVE ones, which point to words
+         * which need to be initialized with addend + offset.
+         * The R_PPC_RELATIVE ones come first and there are RELACOUNT
+         * of them. */
+10:     /* skip relocation if we don't have both */
+        cmpwi   r0,0
         beq     3f
-        srwi.   r8,r8,2
-        mtctr   r8
-        add     r9,r0,r9
-2:      lwz     r8,0(r9)
-        add     r8,r8,r0
-        stw     r8,0(r9)
-        addi    r9,r9,4
+        cmpwi   r9,0
+        beq     3f
+
+        add     r9,r9,r11       /* Relocate RELA pointer */
+        mtctr   r0
+2:      lbz     r0,4+3(r9)      /* ELF32_R_INFO(reloc->r_info) */
+        cmpwi   r0,22           /* R_PPC_RELATIVE */
+        bne     3f
+        lwz     r12,0(r9)       /* reloc->r_offset */
+        lwz     r0,8(r9)        /* reloc->r_addend */
+        add     r0,r0,r11
+        stwx    r0,r11,r12
+        addi    r9,r9,12
         bdnz    2b
 
         /* Do a cache flush for our text, in case the loader didn't */
-3:      lis     r9,_start@ha
-        addi    r9,r9,_start@l
-        add     r9,r0,r9
-        lis     r8,_etext@ha
-        addi    r8,r8,_etext@l
-        add     r8,r0,r8
+3:      lwz     r9,p_start-p_base(r10)  /* note: these are relocated now */
+        lwz     r8,p_etext-p_base(r10)
 4:      dcbf    r0,r9
         icbi    r0,r9
         addi    r9,r9,0x20
@@ -64,27 +104,19 @@ _zimage_start_lib:
         isync
 
         /* Clear the BSS */
-        lis     r9,__bss_start@ha
-        addi    r9,r9,__bss_start@l
-        add     r9,r0,r9
-        lis     r8,_end@ha
-        addi    r8,r8,_end@l
-        add     r8,r0,r8
-        li      r10,0
-5:      stw     r10,0(r9)
+        lwz     r9,p_bss_start-p_base(r10)
+        lwz     r8,p_end-p_base(r10)
+        li      r0,0
+5:      stw     r0,0(r9)
         addi    r9,r9,4
         cmplw   cr0,r9,r8
         blt     5b
 
         /* Possibly set up a custom stack */
-.weak   _platform_stack_top
-        lis     r8,_platform_stack_top@ha
-        addi    r8,r8,_platform_stack_top@l
+        lwz     r8,p_pstack-p_base(r10)
         cmpwi   r8,0
         beq     6f
-        add     r8,r0,r8
         lwz     r1,0(r8)
-        add     r1,r0,r1
         li      r0,0
         stwu    r0,-16(r1)      /* establish a stack frame */
 6:
diff --git a/arch/powerpc/boot/wrapper b/arch/powerpc/boot/wrapper
index cb97e7511d7e..fef527867811 100755
--- a/arch/powerpc/boot/wrapper
+++ b/arch/powerpc/boot/wrapper
@@ -39,6 +39,7 @@ dts=
 cacheit=
 binary=
 gzip=.gz
+pie=
 
 # cross-compilation prefix
 CROSS=
@@ -157,9 +158,10 @@ pmac|chrp)
     platformo=$object/of.o
     ;;
 coff)
-    platformo=$object/of.o
+    platformo="$object/crt0.o $object/of.o"
     lds=$object/zImage.coff.lds
     link_address='0x500000'
+    pie=
     ;;
 miboot|uboot)
     # miboot and U-boot want just the bare bits, not an ELF binary
@@ -208,6 +210,7 @@ ps3)
     ksection=.kernel:vmlinux.bin
     isection=.kernel:initrd
     link_address=''
+    pie=
     ;;
 ep88xc|ep405|ep8248e)
     platformo="$object/fixed-head.o $object/$platform.o"
@@ -310,9 +313,9 @@ fi
 
 if [ "$platform" != "miboot" ]; then
     if [ -n "$link_address" ] ; then
-        text_start="-Ttext $link_address --defsym _start=$link_address"
+        text_start="-Ttext $link_address"
     fi
-    ${CROSS}ld -m elf32ppc -T $lds $text_start -o "$ofile" \
+    ${CROSS}ld -m elf32ppc -T $lds $text_start $pie -o "$ofile" \
         $platformo $tmp $object/wrapper.a
     rm $tmp
 fi
diff --git a/arch/powerpc/boot/zImage.coff.lds.S b/arch/powerpc/boot/zImage.coff.lds.S
index 856dc78b14ef..de4c9e3c9344 100644
--- a/arch/powerpc/boot/zImage.coff.lds.S
+++ b/arch/powerpc/boot/zImage.coff.lds.S
@@ -3,13 +3,13 @@ ENTRY(_zimage_start_opd)
 EXTERN(_zimage_start_opd)
 SECTIONS
 {
-  _start = .;
   .text      :
   {
+    _start = .;
     *(.text)
     *(.fixup)
+    _etext = .;
   }
-  _etext = .;
   . = ALIGN(4096);
   .data    :
   {
@@ -17,9 +17,7 @@ SECTIONS
     *(.data*)
     *(__builtin_*)
     *(.sdata*)
-    __got2_start = .;
     *(.got2)
-    __got2_end = .;
 
     _dtb_start = .;
     *(.kernel:dtb)
diff --git a/arch/powerpc/boot/zImage.lds.S b/arch/powerpc/boot/zImage.lds.S
index 0962d62bdb50..2bd8731f1365 100644
--- a/arch/powerpc/boot/zImage.lds.S
+++ b/arch/powerpc/boot/zImage.lds.S
@@ -3,49 +3,64 @@ ENTRY(_zimage_start)
 EXTERN(_zimage_start)
 SECTIONS
 {
-  _start = .;
   .text      :
   {
+    _start = .;
     *(.text)
     *(.fixup)
+    _etext = .;
   }
-  _etext = .;
   . = ALIGN(4096);
   .data    :
   {
     *(.rodata*)
     *(.data*)
     *(.sdata*)
-    __got2_start = .;
     *(.got2)
-    __got2_end = .;
   }
+  .dynsym : { *(.dynsym) }
+  .dynstr : { *(.dynstr) }
+  .dynamic :
+  {
+    __dynamic_start = .;
+    *(.dynamic)
+  }
+  .hash : { *(.hash) }
+  .interp : { *(.interp) }
+  .rela.dyn : { *(.rela*) }
 
   . = ALIGN(8);
-  _dtb_start = .;
-  .kernel:dtb : { *(.kernel:dtb) }
-  _dtb_end = .;
-
-  . = ALIGN(4096);
-  _vmlinux_start =  .;
-  .kernel:vmlinux.strip : { *(.kernel:vmlinux.strip) }
-  _vmlinux_end =  .;
+  .kernel:dtb :
+  {
+    _dtb_start = .;
+    *(.kernel:dtb)
+    _dtb_end = .;
+  }
 
   . = ALIGN(4096);
-  _initrd_start =  .;
-  .kernel:initrd : { *(.kernel:initrd) }
-  _initrd_end =  .;
+  .kernel:vmlinux.strip :
+  {
+    _vmlinux_start =  .;
+    *(.kernel:vmlinux.strip)
+    _vmlinux_end =  .;
+  }
 
   . = ALIGN(4096);
-  _edata  =  .;
+  .kernel:initrd :
+  {
+    _initrd_start =  .;
+    *(.kernel:initrd)
+    _initrd_end =  .;
+  }
 
   . = ALIGN(4096);
-  __bss_start = .;
   .bss       :
   {
-   *(.sbss)
-   *(.bss)
+    _edata  =  .;
+    __bss_start = .;
+    *(.sbss)
+    *(.bss)
+    *(COMMON)
+    _end = . ;
   }
-  . = ALIGN(4096);
-  _end = . ;
 }