fafb1ee7bd
stackpointer. Userland expects the kernel to pass it an aligned sp and pass a pointer to the arguments in x0. The kernel side was updated in r289502, 3 months ago. Sponsored by: ABT Systems Ltd
163 lines
4.5 KiB
ArmAsm
163 lines
4.5 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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__FBSDID("$FreeBSD$");
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ENTRY(.rtld_start)
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mov x19, x0 /* Put ps_strings in a callee-saved register */
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mov x20, sp /* And the stack pointer */
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sub sp, sp, #16 /* Make room for obj_main & exit proc */
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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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ldr x2, [sp] /* Load cleanup */
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ldr x1, [sp, #8] /* Load obj_main */
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mov x0, x19 /* Restore ps_strings */
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mov sp, x20 /* Restore the stack pointer */
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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 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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/* Restore the registers saved by the plt code */
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ldp xzr, x30, [sp, #(5 * 16 + 4 * 32)]
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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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/* And the part of the stack the plt entry handled */
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add sp, 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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* uint64_t _rtld_tlsdesc(struct tlsdesc *);
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*
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* struct tlsdesc {
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* uint64_t ptr;
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* uint64_t data;
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* };
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*
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* Returns the data.
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*/
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ENTRY(_rtld_tlsdesc)
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ldr x0, [x0, #8]
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ret
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END(_rtld_tlsdesc)
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/*
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* uint64_t _rtld_tlsdesc_dynamic(struct tlsdesc *);
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*
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* TODO: We could lookup the saved index here to skip saving the entire stack.
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*/
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ENTRY(_rtld_tlsdesc_dynamic)
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/* Store any registers we may use in rtld_tlsdesc_handle */
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stp x29, x30, [sp, #-(10 * 16)]!
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mov x29, sp
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stp x1, x2, [sp, #(1 * 16)]
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stp x3, x4, [sp, #(2 * 16)]
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stp x5, x6, [sp, #(3 * 16)]
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stp x7, x8, [sp, #(4 * 16)]
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stp x9, x10, [sp, #(5 * 16)]
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stp x11, x12, [sp, #(6 * 16)]
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stp x13, x14, [sp, #(7 * 16)]
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stp x15, x16, [sp, #(8 * 16)]
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stp x17, x18, [sp, #(9 * 16)]
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/* Find the tls offset */
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ldr x0, [x0, #8]
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mov x1, #1
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bl rtld_tlsdesc_handle
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/* Restore the registers */
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ldp x17, x18, [sp, #(9 * 16)]
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ldp x15, x16, [sp, #(8 * 16)]
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ldp x13, x14, [sp, #(7 * 16)]
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ldp x11, x12, [sp, #(6 * 16)]
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ldp x9, x10, [sp, #(5 * 16)]
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ldp x7, x8, [sp, #(4 * 16)]
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ldp x5, x6, [sp, #(3 * 16)]
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ldp x3, x4, [sp, #(2 * 16)]
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ldp x1, x2, [sp, #(1 * 16)]
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ldp x29, x30, [sp], #(10 * 16)
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ret
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END(_rtld_tlsdesc_dynamic)
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