diff options
Diffstat (limited to 'libexec/rtld-elf/powerpc/rtld_start.S')
| -rw-r--r-- | libexec/rtld-elf/powerpc/rtld_start.S | 319 |
1 files changed, 319 insertions, 0 deletions
diff --git a/libexec/rtld-elf/powerpc/rtld_start.S b/libexec/rtld-elf/powerpc/rtld_start.S new file mode 100644 index 000000000000..e34cc56fc40c --- /dev/null +++ b/libexec/rtld-elf/powerpc/rtld_start.S @@ -0,0 +1,319 @@ +/* $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. + */ + +#include <machine/asm.h> +#include <machine/spr.h> /* For SPR_SPEFSCR if needed. */ + +.extern _GLOBAL_OFFSET_TABLE_ +.extern _DYNAMIC + +_ENTRY(.rtld_start) + stwu %r1,-48(%r1) /* 16-byte aligned stack for reg saves + + exit_proc & obj _rtld args + + backchain & lrsave stack frame */ + stw %r3,16(%r1) /* argc */ + stw %r4,20(%r1) /* argv */ + stw %r5,24(%r1) /* envp */ +/* stw %r6,28(%r1) *//* obj (always 0) */ +/* stw %r7,32(%r1) *//* cleanup (always 0) */ + stw %r8,36(%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. + * - read GOT[0], which is the SVR4 ABI-specified link-time + * value of _DYNAMIC. Subtract this value from the absolute + * value to determine the load address + * - call reloc_non_plt_self() to fix up ld-elf.so's relocations + */ + bcl 20,31,1f +1: mflr %r30 + mr %r3,%r30 # save for _DYNAMIC + addis %r30,%r30,_GLOBAL_OFFSET_TABLE_-1b@ha + addi %r30,%r30,_GLOBAL_OFFSET_TABLE_-1b@l + addis %r3,%r3,_DYNAMIC-1b@ha # get _DYNAMIC actual address + addi %r3,%r3,_DYNAMIC-1b@l + lwz %r28,0(%r30) # get base-relative &_DYNAMIC + sub %r28,%r3,%r28 # r28 = relocbase + mr %r4,%r28 # r4 = relocbase + bl reloc_non_plt_self /* reloc_non_plt_self(&_DYNAMIC,base) */ + + /* + * 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. + */ + lwz %r4,20(%r1) /* restore argv */ + addi %r3,%r4,-4 /* locate argc ptr, &argv[-1] */ + + addi %r4,%r1,8 /* &exit_proc on stack */ + addi %r5,%r1,12 /* &obj_main on stack */ + + bl _rtld /* &_start = _rtld(sp, &exit_proc, &obj_main)*/ + mtlr %r3 + + /* + * Restore args, with new obj/exit proc + */ + lwz %r3,16(%r1) /* argc */ + lwz %r4,20(%r1) /* argv */ + lwz %r5,24(%r1) /* envp */ + lwz %r6,12(%r1) /* obj */ + lwz %r7,8(%r1) /* exit proc */ + lwz %r8,36(%r1) /* ps_strings */ + addi %r1,%r1,48 /* restore original stackptr */ + + blrl /* _start(argc, argv, envp, obj, cleanup, ps_strings) */ + + li %r0,1 /* _exit() */ + sc +_END(.rtld_start) + +#ifdef __SPE__ +/* stack space for 30 GPRs + SPEFSCR/ACC/lr/cr */ +#define NREGS 31 +#define GPRWIDTH 8 +#define FUDGE 4 /* Fudge factor for alignment */ +#else +/* stack space for 30 GPRs + lr/cr */ +#define NREGS 30 +#define GPRWIDTH 4 +#define FUDGE 4 +#endif +/* Stack frame needs the 12-byte ABI frame plus fudge factor. */ +#define STACK_SIZE (NREGS * GPRWIDTH + 4 * 2 + 12 + FUDGE) + +/* + * _rtld_bind_secureplt_start() + * + * Call into the MI binder (Secure-PLT stub). + * secure-plt expects %r11 to be the offset to the rela entry. + * bss-plt expects %r11 to be index of the rela entry. + * So for bss-plt, we multiply the index by 12 to get the offset. + */ +_ENTRY(_rtld_bind_secureplt_start) + stwu %r1,-STACK_SIZE(%r1) +#ifdef __SPE__ + evstdd %r0,24(%r1) +#else + stw %r0,20(%r1) # save r0 +#endif + + /* + * Instead of division which is costly we will use multiplicative + * inverse. a / n = ((a * inv(n)) >> 32) + * where inv(n) = (0x100000000 + n - 1) / n + */ + mr %r0,%r11 + lis %r11,0x15555556@h # load multiplicative inverse of 12 + ori %r11,%r11,0x15555556@l + mulhwu %r11,%r11,%r0 # get high half of multiplication + b 1f +_END(_rtld_bind_secureplt_start) + +/* + * _rtld_bind_start() + * + * Call into the MI binder. This routine is reached via the PLT call cell, + * and then _rtld_powerpc_pltresolve(). + * On entry, %r11 contains the index of the PLT cell, and %r12 contains + * a pointer to the ELF object for the file. + * 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) + stwu %r1,-STACK_SIZE(%r1) +#ifdef __SPE__ + evstdd %r0,24(%r1) +#else + stw %r0,20(%r1) # save r0 +#endif +1: + mflr %r0 + stw %r0,16(%r1) # save lr + mfcr %r0 + stw %r0,12(%r1) # save cr +#ifdef __SPE__ + evstdd %r3, 32(%r1) + evstdd %r4, 40(%r1) + evstdd %r5, 48(%r1) + evstdd %r6, 56(%r1) + evstdd %r7, 64(%r1) + evstdd %r8, 72(%r1) + evstdd %r9, 80(%r1) + evstdd %r10, 88(%r1) + evstdd %r11, 96(%r1) + evstdd %r12, 104(%r1) + evstdd %r13, 112(%r1) + evstdd %r14, 120(%r1) + evstdd %r15, 128(%r1) + evstdd %r16, 136(%r1) + evstdd %r17, 144(%r1) + evstdd %r18, 152(%r1) + evstdd %r19, 160(%r1) + evstdd %r20, 168(%r1) + evstdd %r21, 176(%r1) + evstdd %r22, 184(%r1) + evstdd %r23, 192(%r1) + evstdd %r24, 200(%r1) + evstdd %r25, 208(%r1) + evstdd %r26, 216(%r1) + evstdd %r27, 224(%r1) + evstdd %r28, 232(%r1) + evstdd %r29, 240(%r1) + evstdd %r30, 248(%r1) + li %r3, 256 + evstddx %r31, %r1, %r3 + evxor %r0, %r0, %r0 + li %r3, 264 + evmwumiaa %r0, %r0, %r0 + evstddx %r0, %r1, %r3 + mfspr %r3, SPR_SPEFSCR + stw %r3, 20(%r1) +#else + stmw %r3,24(%r1) # save r3-r31 +#endif + + mr %r3,%r12 # obj + mulli %r4,%r11,12 # rela index * sizeof(Elf_Rela) + bl _rtld_bind # target addr = _rtld_bind(obj, reloff) + mtctr %r3 # move absolute target addr into ctr + +#ifdef __SPE__ + lwz %r3, 20(%r1) + mtspr SPR_SPEFSCR, %r3 + li %r3, 264 + evlddx %r0, %r3, %r1 + evmra %r0, %r0 + evldd %r3, 32(%r1) + evldd %r4, 40(%r1) + evldd %r5, 48(%r1) + evldd %r6, 56(%r1) + evldd %r7, 64(%r1) + evldd %r8, 72(%r1) + evldd %r9, 80(%r1) + evldd %r10, 88(%r1) + evldd %r11, 96(%r1) + evldd %r12, 104(%r1) + evldd %r13, 112(%r1) + evldd %r14, 120(%r1) + evldd %r15, 128(%r1) + evldd %r16, 136(%r1) + evldd %r17, 144(%r1) + evldd %r18, 152(%r1) + evldd %r19, 160(%r1) + evldd %r20, 168(%r1) + evldd %r21, 176(%r1) + evldd %r22, 184(%r1) + evldd %r23, 192(%r1) + evldd %r24, 200(%r1) + evldd %r25, 208(%r1) + evldd %r26, 216(%r1) + evldd %r27, 224(%r1) + evldd %r28, 232(%r1) + evldd %r29, 240(%r1) + evldd %r30, 248(%r1) + li %r0, 256 + evlddx %r31, %r1, %r0 +#else + lmw %r3,24(%r1) # restore r3-r31 +#endif + lwz %r0,12(%r1) # restore cr + mtcr %r0 + lwz %r0,16(%r1) # restore lr + mtlr %r0 +#ifdef __SPE__ + evldd %r0,24(%r1) +#else + lwz %r0,20(%r1) # restore r0 +#endif + + addi %r1,%r1,STACK_SIZE # restore stack + bctr # jump to target +_END(_rtld_bind_start) + + +/* + * _rtld_powerpc_pltresolve() + * + * This routine is copied into the latter part of the 72-byte reserved + * area at the start of the PLT. The absolute address of the _rtld_bind_start + * routine, and the ELF object for the loaded file, are inserted into + * the code by the reloc.c:init_pltgot() routine. + * The first time an external routine is called, the PLT slot will + * set up %r11 to the offset of the slot, and will jump to this routine. + * The ELF object is shifted into %r11, and _rtld_bind_start is called + * to complete the binding. + */ +_ENTRY(_rtld_powerpc_pltlongresolve) + lis %r12,0 # lis 12,jmptab@ha + addi %r12,%r12,0 # addi 12,12,jmptab@l + subf %r11,%r12,%r11 # reloff + li %r12,2 + srw %r11,%r11,%r12 # index = reloff/sizeof(Elf_Addr) +_END(_rtld_powerpc_pltlongresolve) +_ENTRY(_rtld_powerpc_pltresolve) + lis %r12,0 # lis 12,_rtld_bind_start@ha + addi %r12,%r12,0 # addi 12,12,_rtld_bind_start@l + mtctr %r12 + lis %r12,0 # lis 12,obj@ha + addi %r12,%r12,0 # addi 12,12,obj@l + bctr +_END(_rtld_powerpc_pltresolve) + +/* + * _rtld_powerpc_pltcall() + * + * This routine is copied into the 72-byte reserved area at the + * start of the PLT. The reloc.c:init_pltgot() routine inserts + * the absolute address of the jumptable. + * Control is transferred to this routine when the binder has + * located the external routine, but determined that it is > 32Mb + * from the PLT slot. Code is inserted into the PLT slot to set up + * %r11 with the jumptable index, and jump to here, where the + * absolute address of the external routine is loaded from the + * jumptable and transferred to + */ +_ENTRY(_rtld_powerpc_pltcall) + slwi %r11,%r11,2 # jmptab offset = index * 4 + addis %r11,%r11,0 # addis 11,11,jmptab@ha + lwz %r11,0(%r11) # lwz 11,jmptab@l(11) + mtctr %r11 + bctr # (*jmptab[index])() +_END(_rtld_powerpc_pltcall) + + .section .note.GNU-stack,"",%progbits |