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author | nwhitehorn <nwhitehorn@FreeBSD.org> | 2010-07-10 17:43:24 +0000 |
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committer | nwhitehorn <nwhitehorn@FreeBSD.org> | 2010-07-10 17:43:24 +0000 |
commit | 615d4b84bcef2f3f5b08ebb0d3f3a4c48c3ba25a (patch) | |
tree | 11b3fdc9a007b4e33b98f36eaec3ed1f7d427a4b /libexec/rtld-elf/powerpc64/rtld_start.S | |
parent | 4895e1982dab6f0e5df6b297363fe7dcfb922dbd (diff) | |
download | FreeBSD-src-615d4b84bcef2f3f5b08ebb0d3f3a4c48c3ba25a.zip FreeBSD-src-615d4b84bcef2f3f5b08ebb0d3f3a4c48c3ba25a.tar.gz |
RTLD support for powerpc64. A few small modifications to the Makefile
and symbol map are required to support various consequences of the dot
symbol scheme:
- Symbols beginning with a dot are reserved, so start private symbols with
an underscore.
- In order to set RTLD breakpoints, gdb must be able to locate the text
entry point, not the data section function descriptor, so add
.r_debug_state to the symbol map on powerpc64.
Obtained from: projects/ppc64
Diffstat (limited to 'libexec/rtld-elf/powerpc64/rtld_start.S')
-rw-r--r-- | libexec/rtld-elf/powerpc64/rtld_start.S | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/libexec/rtld-elf/powerpc64/rtld_start.S b/libexec/rtld-elf/powerpc64/rtld_start.S new file mode 100644 index 0000000..c44f880 --- /dev/null +++ b/libexec/rtld-elf/powerpc64/rtld_start.S @@ -0,0 +1,161 @@ +/* $NetBSD: rtld_start.S,v 1.4 2001/09/26 04:06:43 mycroft Exp $ */ + +/*- + * Copyright (C) 1998 Tsubai Masanari + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * $FreeBSD$ + */ + +#include <machine/asm.h> + +.extern _GLOBAL_OFFSET_TABLE_ +.extern _DYNAMIC + +_ENTRY(_rtld_start) + stdu %r1,-96(%r1) /* 16-byte aligned stack for reg saves + + exit_proc & obj _rtld args + + backchain & lrsave stack frame */ + std %r3,48(%r1) /* argc */ + std %r4,56(%r1) /* argv */ + std %r5,64(%r1) /* envp */ +/* std %r6,72(%r1) *//* obj (always 0) */ +/* std %r7,80(%r1) *//* cleanup (always 0) */ + std %r8,88(%r1) /* ps_strings */ + + /* + * Perform initial relocation of ld-elf.so. Not as easy as it + * sounds. + * - perform small forward branch to put PC into link reg + * - use link-time constants to determine offset to the + * _DYNAMIC section and the GOT. Add these to the PC to + * convert to absolute addresses. + * - call reloc_non_plt_self() to fix up ld-elf.so's relocations + */ + + bl 1f + .llong _DYNAMIC-. +1: + mflr %r3 /* PC value at .llong */ + ld %r4,0(%r3) /* offset to _DYNAMIC */ + add %r3,%r4,%r3 /* r3 = &_DYNAMIC, absolute value */ + + ld %r4,-0x8000(%r2) /* First TOC entry is TOC base */ + subf %r4,%r4,%r2 /* Subtract from real TOC base to get base */ + + bl .reloc_non_plt_self /* reloc_non_plt_self(&_DYNAMIC,base) */ + nop + + /* + * The _rtld() function likes to see a stack layout containing + * { argc, argv[0], argv[1] ... argv[N], 0, env[0], ... , env[N] } + * Since the PowerPC stack was 16-byte aligned at exec time, the + * original stack layout has to be found by moving back a word + * from the argv pointer. + */ + ld %r4,56(%r1) + addi %r3,%r4,-8 /* locate argc ptr, &argv[-1] */ + addi %r4,%r1,80 /* &exit_proc on stack */ + addi %r5,%r1,72 /* &obj_main on stack */ + + bl ._rtld /* &_start = _rtld(sp, &exit_proc, &obj_main)*/ + nop + ld %r2,8(%r3) + ld %r11,16(%r3) + ld %r3,0(%r3) + mtlr %r3 + + /* + * Restore args, with new obj/exit proc + */ + ld %r3,48(%r1) /* argc */ + ld %r4,56(%r1) /* argv */ + ld %r5,64(%r1) /* envp */ + ld %r6,72(%r1) /* obj */ + ld %r7,80(%r1) /* exit proc */ + ld %r8,88(%r1) /* ps_strings */ + + blrl /* _start(argc, argv, envp, obj, cleanup, ps_strings) */ + + li %r0,1 /* _exit() */ + sc + +/* + * _rtld_bind_start() + * + * Call into the MI binder. This routine is reached via the PLT call cell + * On entry, %r11 contains a pointer to the (object, relocation) tuple. + * + * Save all registers, call into the binder to resolve and fixup the external + * routine, and then transfer to the external routine on return. + */ + .globl _rtld_bind + +_ENTRY(_rtld_bind_start) + mflr %r0 + std %r0,16(%r1) # save lr + mfcr %r0 + std %r0,8(%r1) # save cr + + stdu %r1,-48-9*8(%r1) # stack space for 8 regs + header + std %r3,48+0*8(%r1) # save r3-r31 + std %r4,48+1*8(%r1) + std %r5,48+2*8(%r1) + std %r6,48+3*8(%r1) + std %r7,48+4*8(%r1) + std %r8,48+5*8(%r1) + std %r9,48+6*8(%r1) + std %r10,48+7*8(%r1) + std %r12,48+8*8(%r1) + + ld %r3,0(%r11) + ld %r4,8(%r11) + bl ._rtld_bind # target addr = _rtld_bind(obj, reloff) + nop + + ld %r2,8(%r3) + ld %r11,16(%r3) + ld %r3,0(%r3) + mtctr %r3 # move absolute target addr into ctr + + ld %r3,48+0*8(%r1) # restore r3-r31 + ld %r4,48+1*8(%r1) + ld %r5,48+2*8(%r1) + ld %r6,48+3*8(%r1) + ld %r7,48+4*8(%r1) + ld %r8,48+5*8(%r1) + ld %r9,48+6*8(%r1) + ld %r10,48+7*8(%r1) + ld %r12,48+8*8(%r1) + + addi %r1,%r1,48+9*8 # restore stack + + ld %r0,8(%r1) # restore cr + mtcr %r0 + ld %r0,16(%r1) # restore lr + mtlr %r0 + + bctr # jump to target + |