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252 lines
6.6 KiB
ArmAsm
252 lines
6.6 KiB
ArmAsm
/*-
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* Copyright (c) 2014 The FreeBSD Foundation
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* All rights reserved.
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*
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* This software was developed by Andrew Turner under
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* sponsorship from the FreeBSD Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <machine/asm.h>
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ENTRY(.rtld_start)
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.cfi_undefined x30
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mov x19, x0 /* Put ps_strings in a callee-saved register */
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sub sp, sp, #16 /* Make room for obj_main & exit proc */
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.cfi_adjust_cfa_offset 16
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mov x1, sp /* exit_proc */
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add x2, x1, #8 /* obj_main */
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bl _rtld /* Call the loader */
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mov x8, x0 /* Backup the entry point */
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ldp x2, x1, [sp], #16 /* Load cleanup, obj_main */
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.cfi_adjust_cfa_offset 0
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mov x0, x19 /* Restore ps_strings */
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br x8 /* Jump to the entry point */
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END(.rtld_start)
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/*
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* sp + 0 = &GOT[x + 3]
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* sp + 8 = RA
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* x16 = &GOT[2]
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* x17 = &_rtld_bind_start
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*/
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ENTRY(_rtld_bind_start)
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mov x17, sp
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/* Save frame pointer and SP */
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stp x29, x30, [sp, #-16]!
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mov x29, sp
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.cfi_def_cfa x29, 16
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.cfi_offset x30, -8
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.cfi_offset x29, -16
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/* Save the arguments */
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stp x0, x1, [sp, #-16]!
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stp x2, x3, [sp, #-16]!
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stp x4, x5, [sp, #-16]!
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stp x6, x7, [sp, #-16]!
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stp x8, xzr, [sp, #-16]!
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/* Save any floating-point arguments */
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stp q0, q1, [sp, #-32]!
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stp q2, q3, [sp, #-32]!
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stp q4, q5, [sp, #-32]!
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stp q6, q7, [sp, #-32]!
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/* Calculate reloff */
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ldr x2, [x17, #0] /* Get the address of the entry */
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sub x1, x2, x16 /* Find its offset */
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sub x1, x1, #8 /* Adjust for x16 not being at offset 0 */
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/* Each rela item has 3 entriesso we need reloff = 3 * index */
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lsl x3, x1, #1 /* x3 = 2 * offset */
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add x1, x1, x3 /* x1 = x3 + offset = 3 * offset */
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/* Load obj */
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ldr x0, [x16, #-8]
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/* Call into rtld */
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bl _rtld_bind
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/* Backup the address to branch to */
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mov x16, x0
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/* restore the arguments */
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ldp q6, q7, [sp], #32
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ldp q4, q5, [sp], #32
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ldp q2, q3, [sp], #32
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ldp q0, q1, [sp], #32
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ldp x8, xzr, [sp], #16
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ldp x6, x7, [sp], #16
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ldp x4, x5, [sp], #16
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ldp x2, x3, [sp], #16
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ldp x0, x1, [sp], #16
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/* Restore frame pointer */
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ldp x29, xzr, [sp], #16
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/* Restore link register saved by the plt code */
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ldp xzr, x30, [sp], #16
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/* Call into the correct function */
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br x16
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END(_rtld_bind_start)
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/*
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* struct rel_tlsdesc {
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* uint64_t resolver_fnc;
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* uint64_t resolver_arg;
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*
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*
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* uint64_t _rtld_tlsdesc_static(struct rel_tlsdesc *);
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*
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* Resolver function for TLS symbols resolved at load time
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*/
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ENTRY(_rtld_tlsdesc_static)
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ldr x0, [x0, #8]
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ret
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END(_rtld_tlsdesc_static)
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/*
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* uint64_t _rtld_tlsdesc_undef(void);
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*
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* Resolver function for weak and undefined TLS symbols
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*/
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ENTRY(_rtld_tlsdesc_undef)
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str x1, [sp, #-16]!
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.cfi_adjust_cfa_offset 16
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mrs x1, tpidr_el0
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ldr x0, [x0, #8]
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sub x0, x0, x1
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ldr x1, [sp], #16
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.cfi_adjust_cfa_offset -16
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ret
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END(_rtld_tlsdesc_undef)
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/*
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* uint64_t _rtld_tlsdesc_dynamic(struct rel_tlsdesc *);
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*
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* Resolver function for TLS symbols from dlopen()
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*/
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ENTRY(_rtld_tlsdesc_dynamic)
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/* Save registers used in fast path */
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stp x1, x2, [sp, #(-2 * 16)]!
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stp x3, x4, [sp, #(1 * 16)]
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.cfi_adjust_cfa_offset 2 * 16
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.cfi_rel_offset x1, 0
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.cfi_rel_offset x2, 8
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.cfi_rel_offset x3, 16
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.cfi_rel_offset x4, 24
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/* Test fastpath - inlined version of tls_get_addr_common(). */
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ldr x1, [x0, #8] /* tlsdesc ptr */
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mrs x4, tpidr_el0
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ldr x0, [x4] /* DTV pointer */
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ldr x2, [x0] /* dtv[0] (generation count) */
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ldr x3, [x1] /* tlsdec->dtv_gen */
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cmp x2, x3
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b.ne 1f /* dtv[0] != tlsdec->dtv_gen */
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ldr w2, [x1, #8] /* tlsdec->tls_index */
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add w2, w2, #1
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ldr x3, [x0, w2, sxtw #3] /* dtv[tlsdesc->tls_index + 1] */
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cbz x3, 1f
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/* Return (dtv[tlsdesc->tls_index + 1] + tlsdesc->tls_offs - tp) */
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ldr x2, [x1, #16] /* tlsdec->tls_offs */
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add x2, x2, x3
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sub x0, x2, x4
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/* Restore registers and return */
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ldp x3, x4, [sp, #(1 * 16)]
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ldp x1, x2, [sp], #(2 * 16)
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.cfi_adjust_cfa_offset -2 * 16
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ret
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/*
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* Slow path
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* return(
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* tls_get_addr_common(tp, tlsdesc->tls_index, tlsdesc->tls_offs));
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*
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*/
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1:
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/* Save all integer registers */
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stp x29, x30, [sp, #-(8 * 16)]!
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.cfi_adjust_cfa_offset 8 * 16
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.cfi_rel_offset x29, 0
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.cfi_rel_offset x30, 8
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mov x29, sp
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stp x5, x6, [sp, #(1 * 16)]
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stp x7, x8, [sp, #(2 * 16)]
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stp x9, x10, [sp, #(3 * 16)]
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stp x11, x12, [sp, #(4 * 16)]
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stp x13, x14, [sp, #(5 * 16)]
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stp x15, x16, [sp, #(6 * 16)]
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stp x17, x18, [sp, #(7 * 16)]
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.cfi_rel_offset x5, 16
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.cfi_rel_offset x6, 24
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.cfi_rel_offset x7, 32
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.cfi_rel_offset x8, 40
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.cfi_rel_offset x9, 48
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.cfi_rel_offset x10, 56
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.cfi_rel_offset x11, 64
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.cfi_rel_offset x12, 72
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.cfi_rel_offset x13, 80
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.cfi_rel_offset x14, 88
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.cfi_rel_offset x15, 96
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.cfi_rel_offset x16, 104
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.cfi_rel_offset x17, 112
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.cfi_rel_offset x18, 120
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/* Find the tls offset */
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mov x0, x4 /* tp */
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mov x3, x1 /* tlsdesc ptr */
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ldr w1, [x3, #8] /* tlsdec->tls_index */
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ldr x2, [x3, #16] /* tlsdec->tls_offs */
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bl tls_get_addr_common
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mrs x1, tpidr_el0
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sub x0, x0, x1
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/* Restore slow patch registers */
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ldp x17, x18, [sp, #(7 * 16)]
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ldp x15, x16, [sp, #(6 * 16)]
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ldp x13, x14, [sp, #(5 * 16)]
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ldp x11, x12, [sp, #(4 * 16)]
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ldp x9, x10, [sp, #(3 * 16)]
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ldp x7, x8, [sp, #(2 * 16)]
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ldp x5, x6, [sp, #(1 * 16)]
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ldp x29, x30, [sp], #(8 * 16)
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.cfi_adjust_cfa_offset -8 * 16
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.cfi_restore x29
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.cfi_restore x30
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/* Restore fast path registers and return */
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ldp x3, x4, [sp, #16]
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ldp x1, x2, [sp], #(2 * 16)
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.cfi_adjust_cfa_offset -2 * 16
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ret
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END(_rtld_tlsdesc_dynamic)
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