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/*-
* Copyright (c) 2014 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Andrew Turner under
* sponsorship from the FreeBSD Foundation.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <machine/asm.h>
__FBSDID("$FreeBSD$");
ENTRY(.rtld_start)
mov x19, x0 /* Put ps_strings in a callee-saved register */
mov x20, sp /* And the stack pointer */
sub sp, sp, #16 /* Make room for obj_main & exit proc */
mov x1, sp /* exit_proc */
add x2, x1, #8 /* obj_main */
bl _rtld /* Call the loader */
mov x8, x0 /* Backup the entry point */
ldr x2, [sp] /* Load cleanup */
ldr x1, [sp, #8] /* Load obj_main */
mov x0, x19 /* Restore ps_strings */
mov sp, x20 /* Restore the stack pointer */
br x8 /* Jump to the entry point */
END(.rtld_start)
/*
* sp + 0 = &GOT[x + 3]
* sp + 8 = RA
* x16 = &GOT[2]
* x17 = &_rtld_bind_start
*/
ENTRY(_rtld_bind_start)
mov x17, sp
/* Save the arguments */
stp x0, x1, [sp, #-16]!
stp x2, x3, [sp, #-16]!
stp x4, x5, [sp, #-16]!
stp x6, x7, [sp, #-16]!
stp x8, xzr, [sp, #-16]!
/* Save any floating-point arguments */
stp q0, q1, [sp, #-32]!
stp q2, q3, [sp, #-32]!
stp q4, q5, [sp, #-32]!
stp q6, q7, [sp, #-32]!
/* Calculate reloff */
ldr x2, [x17, #0] /* Get the address of the entry */
sub x1, x2, x16 /* Find its offset */
sub x1, x1, #8 /* Adjust for x16 not being at offset 0 */
/* Each rela item has 3 entriesso we need reloff = 3 * index */
lsl x3, x1, #1 /* x3 = 2 * offset */
add x1, x1, x3 /* x1 = x3 + offset = 3 * offset */
/* Load obj */
ldr x0, [x16, #-8]
/* Call into rtld */
bl _rtld_bind
/* Restore the registers saved by the plt code */
ldp xzr, x30, [sp, #(5 * 16 + 4 * 32)]
/* Backup the address to branch to */
mov x16, x0
/* restore the arguments */
ldp q6, q7, [sp], #32
ldp q4, q5, [sp], #32
ldp q2, q3, [sp], #32
ldp q0, q1, [sp], #32
ldp x8, xzr, [sp], #16
ldp x6, x7, [sp], #16
ldp x4, x5, [sp], #16
ldp x2, x3, [sp], #16
ldp x0, x1, [sp], #16
/* And the part of the stack the plt entry handled */
add sp, sp, #16
/* Call into the correct function */
br x16
END(_rtld_bind_start)
/*
* uint64_t _rtld_tlsdesc(struct tlsdesc *);
*
* struct tlsdesc {
* uint64_t ptr;
* uint64_t data;
* };
*
* Returns the data.
*/
ENTRY(_rtld_tlsdesc)
ldr x0, [x0, #8]
ret
END(_rtld_tlsdesc)
/*
* uint64_t _rtld_tlsdesc_dynamic(struct tlsdesc *);
*
* TODO: We could lookup the saved index here to skip saving the entire stack.
*/
ENTRY(_rtld_tlsdesc_dynamic)
/* Store any registers we may use in rtld_tlsdesc_handle */
stp x29, x30, [sp, #-(10 * 16)]!
mov x29, sp
stp x1, x2, [sp, #(1 * 16)]
stp x3, x4, [sp, #(2 * 16)]
stp x5, x6, [sp, #(3 * 16)]
stp x7, x8, [sp, #(4 * 16)]
stp x9, x10, [sp, #(5 * 16)]
stp x11, x12, [sp, #(6 * 16)]
stp x13, x14, [sp, #(7 * 16)]
stp x15, x16, [sp, #(8 * 16)]
stp x17, x18, [sp, #(9 * 16)]
/* Find the tls offset */
ldr x0, [x0, #8]
mov x1, #1
bl rtld_tlsdesc_handle
/* Restore the registers */
ldp x17, x18, [sp, #(9 * 16)]
ldp x15, x16, [sp, #(8 * 16)]
ldp x13, x14, [sp, #(7 * 16)]
ldp x11, x12, [sp, #(6 * 16)]
ldp x9, x10, [sp, #(5 * 16)]
ldp x7, x8, [sp, #(4 * 16)]
ldp x5, x6, [sp, #(3 * 16)]
ldp x3, x4, [sp, #(2 * 16)]
ldp x1, x2, [sp, #(1 * 16)]
ldp x29, x30, [sp], #(10 * 16)
ret
END(_rtld_tlsdesc_dynamic)
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