/* $OpenBSD: md_init.h,v 1.3 2014/12/26 13:52:01 kurt Exp $ */ /*- * Copyright (c) 2001 Ross Harvey * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``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 FOUNDATION OR CONTRIBUTORS * 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. */ #define MD_SECT_CALL_FUNC(section, func) \ __asm (".section "#section", \"ax\"\n" \ " bl " #func "\n" \ " .previous") #define MD_SECTION_PROLOGUE(sect, entry_pt) \ __asm ( \ ".section "#sect",\"ax\",@progbits \n" \ " .globl " #entry_pt " \n" \ " .type " #entry_pt ",@function \n" \ " .align 4 \n" \ #entry_pt": \n" \ " stwu %r1,-16(%r1) \n" \ " mflr %r0 \n" \ " stw %r0,12(%r1) \n" \ " /* fall thru */ \n" \ " .previous") #define MD_SECTION_EPILOGUE(sect) \ __asm ( \ ".section "#sect",\"ax\",@progbits \n" \ " lwz %r0,12(%r1) \n" \ " mtlr %r0 \n" \ " addi %r1,%r1,16 \n" \ " blr \n" \ " .previous") #include /* for SYS_mprotect */ #define STR(x) __STRING(x) #define MD_CRT0_START \ __asm( \ " .text \n" \ " .section \".text\" \n" \ " .align 2 \n" \ " .size __got_start, 0 \n" \ " .type __got_start, @object \n" \ " .size __got_end, 0 \n" \ " .type __got_end, @object \n" \ " .weak __got_start \n" \ " .weak __got_end \n" \ " .globl _start \n" \ " .type _start, @function \n" \ " .globl __start \n" \ " .type __start, @function \n" \ "_start: \n" \ "__start: \n" \ " # move argument registers to saved registers for startup flush \n" \ " # ...except r6 (auxv) as ___start() doesn't need it \n" \ " mr %r25, %r3 \n" \ " mr %r24, %r4 \n" \ " mr %r23, %r5 \n" \ " mr %r22, %r7 \n" \ " mflr %r27 /* save off old link register */ \n" \ " bl 1f \n" \ " # this instruction never gets executed but can be used \n" \ " # to find the virtual address where the page is loaded. \n" \ " bl _GLOBAL_OFFSET_TABLE_@local-4 \n" \ "1: \n" \ " mflr %r6 # this stores where we are (+4) \n" \ " lwz %r18, 0(%r6) # load the instruction at offset_sym \n" \ " # it contains an offset to the location \n" \ " # of the GOT. \n" \ " \n" \ " rlwinm %r18,%r18,0,8,30 # mask off the offset portion of the instr. \n" \ " \n" \ " /* \n" \ " * these adds effectively calculate the value the \n" \ " * bl _GLOBAL_OFFSET_TABLE_@local-4 \n" \ " * operation that would be below would calculate. \n" \ " */ \n" \ " add %r28, %r18, %r6 \n" \ " \n" \ " addi %r3,%r28,4 # calculate the actual got addr \n" \ " lwz %r0,__got_start@got(%r3) \n" \ " cmpwi %r0,0 \n" \ " beq 4f \n" \ " cmpw %r0,%r28 \n" \ " bne 4f \n" \ " lwz %r4,__got_end@got(%r3) \n" \ " cmpwi %r4,0 \n" \ " beq 2f \n" \ " \n" \ " sub %r4, %r4, %r0 \n" \ " b 3f \n" \ "2: \n" \ " li %r4, 4 \n" \ "3: \n" \ " \n" \ " /* mprotect GOT to eliminate W+X regions in static binaries */ \n" \ " li %r0, " STR(SYS_mprotect) " \n" \ " mr %r3, %r28 \n" \ " li %r5, 5 /* (PROT_READ|PROT_EXEC) */ \n" \ " sc \n" \ " \n" \ "4: \n" \ " li %r0, 0 \n" \ " # flush the blrl instruction out of the data cache \n" \ " dcbf %r6, %r18 \n" \ " sync \n" \ " isync \n" \ " # make certain that the got table addr is not in the icache \n" \ " icbi %r6, %r18 \n" \ " sync \n" \ " isync \n" \ " mtlr %r27 \n" \ " # move argument registers back from saved registers \n" \ " # putting cleanup in r6 instead of r7 \n" \ " mr %r3, %r25 \n" \ " mr %r4, %r24 \n" \ " mr %r5, %r23 \n" \ " mr %r6, %r22 \n" \ " b ___start \n" \ ) #define MD_RCRT0_START \ __asm( \ " .text \n" \ " .section \".text\" \n" \ " .align 2 \n" \ " .globl _start \n" \ " .type _start, @function \n" \ " .globl __start \n" \ " .type __start, @function \n" \ "_start: \n" \ "__start: \n" \ " mr %r19, %r1 # save stack in r19 \n" \ " stwu 1, (-16 -((9+3)*4))(%r1) # allocate dl_data \n" \ " \n" \ " # move argument registers to saved registers for startup flush \n" \ " mr %r20, %r3 # argc \n" \ " mr %r21, %r4 # argv \n" \ " mr %r22, %r5 # envp \n" \ " mflr %r27 /* save off old link register */ \n" \ " stw %r27, 4(%r19) # save in normal location \n" \ " bl 1f \n" \ " # this instruction never gets executed but can be used \n" \ " # to find the virtual address where the page is loaded. \n" \ " bl _GLOBAL_OFFSET_TABLE_@local-4 \n" \ " bl _DYNAMIC@local \n" \ "1: \n" \ " mflr %r6 # this stores where we are (+4) \n" \ " lwz %r18, 0(%r6) # load the instruction at offset_sym \n" \ " # it contains an offset to the location \n" \ " # of the GOT. \n" \ " \n" \ " rlwinm %r18,%r18,0,8,30 # mask off offset portion of the instr. \n" \ " \n" \ " /* \n" \ " * these adds effectively calculate the value the \n" \ " * bl _GLOBAL_OFFSET_TABLE_@local-4 \n" \ " * operation that would be below would calculate. \n" \ " */ \n" \ " add %r28, %r18, %r6 \n" \ " \n" \ " /* mprotect GOT-4 for correct execution of blrl instruction */ \n" \ " li %r0, " STR(SYS_mprotect) " \n" \ " mr %r3, %r28 \n" \ " li %r4, 4 \n" \ " li %r5, 7 /* (PROT_READ|PROT_WRITE|PROT_EXEC) */ \n" \ " sc \n" \ " \n" \ " li %r0, 0 \n" \ " # flush the blrl instruction out of the data cache \n" \ " dcbf %r6, %r18 \n" \ " sync \n" \ " isync \n" \ " # make certain that the got table addr is not in the icache \n" \ " icbi %r6, %r18 \n" \ " sync \n" \ " isync \n" \ " \n" \ " /* This calculates the address of _DYNAMIC the same way \n" \ " * that the GLOBAL_OFFSET_TABLE was calculated. \n" \ " */ \n" \ " lwz %r18, 4(%r6) \n" \ " rlwinm %r18,%r18,0,8,30 # mask off offset portion of the instr. \n" \ " add %r8, %r18, %r6 # address of _DYNAMIC (arg6 for _dl_boot) \n" \ " addi %r18, %r8, 4 # correction. \n" \ " lwz %r4, 4(%r28) # load addr of _DYNAMIC according to got. \n" \ " sub %r4, %r18, %r4 # determine load offset \n" \ " \n" \ " subi %r3, %r21, 4 # Get stack pointer (arg0 for _dl_boot). \n" \ " addi %r4, %r1, 8 # dl_data \n" \ " mr %r5, %r18 # dynamicp \n" \ " \n" \ " bl _dl_boot_bind@local \n" \ " \n" \ " mtlr %r27 \n" \ " # move argument registers back from saved registers \n" \ " mr %r3, %r20 \n" \ " mr %r4, %r21 \n" \ " mr %r5, %r22 \n" \ " li %r6, 0 \n" \ " b ___start \n" \ " \n" \ " .text \n" \ " .align 2 \n" \ " .globl _dl_exit \n" \ " .type _dl_exit, @function \n" \ "_dl_exit: \n" \ " li %r0, " STR(SYS_exit) " \n" \ " sc \n" \ " blr \n" \ " \n" \ " .text \n" \ " .align 2 \n" \ " .globl _dl_printf \n" \ " .type _dl_printf, @function \n" \ "_dl_printf: \n" \ " blr \n" \ )