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libucontext
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x86_64: modernize implementation

pull/17/head
Ariadne Conill 2020-03-29 14:27:40 +00:00
parent 2411cdfb54
commit e00902b5b1
6 changed files with 132 additions and 92 deletions
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36
arch/x86_64/defs.h Normal file
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@ -0,0 +1,36 @@
#ifndef __ARCH_X86_64_DEFS_H
#define __ARCH_X86_64_DEFS_H
#ifndef _GNU_SOURCE
# define REG_R8 (0)
# define REG_R9 (1)
# define REG_R10 (2)
# define REG_R11 (3)
# define REG_R12 (4)
# define REG_R13 (5)
# define REG_R14 (6)
# define REG_R15 (7)
# define REG_RDI (8)
# define REG_RSI (9)
# define REG_RBP (10)
# define REG_RBX (11)
# define REG_RDX (12)
# define REG_RAX (13)
# define REG_RCX (14)
# define REG_RSP (15)
# define REG_RIP (16)
# define REG_EFL (17)
# define REG_CSGSFS (18)
# define REG_ERR (19)
# define REG_TRAPNO (20)
# define REG_OLDMASK (21)
# define REG_CR2 (22)
#endif
#define MCONTEXT_GREGS (40)
#define SZ_REG (8)
#include "common-defs.h"
#endif

48
arch/x86_64/getcontext.S
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2018 Ariadne Conill <ariadne@dereferenced.org>
* Copyright (c) 2018, 2020 Ariadne Conill <ariadne@dereferenced.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
@ -10,39 +10,39 @@
* from the use of this software.
*/
.globl __getcontext;
__getcontext:
#include "defs.h"
ALIAS(getcontext, __getcontext)
FUNC(__getcontext)
/* copy all of the current registers into the ucontext structure */
movq %r8, 40(%rdi)
movq %r9, 48(%rdi)
movq %r10, 56(%rdi)
movq %r11, 64(%rdi)
movq %r12, 72(%rdi)
movq %r13, 80(%rdi)
movq %r14, 88(%rdi)
movq %r15, 96(%rdi)
movq %rdi, 104(%rdi)
movq %rsi, 112(%rdi)
movq %rbp, 120(%rdi)
movq %rbx, 128(%rdi)
movq %rdx, 136(%rdi)
movq $1, 144(%rdi) /* $1 is %rax */
movq %rcx, 152(%rdi)
movq %r8, REG_OFFSET(REG_R8)(%rdi)
movq %r9, REG_OFFSET(REG_R9)(%rdi)
movq %r10, REG_OFFSET(REG_R10)(%rdi)
movq %r11, REG_OFFSET(REG_R11)(%rdi)
movq %r12, REG_OFFSET(REG_R12)(%rdi)
movq %r13, REG_OFFSET(REG_R13)(%rdi)
movq %r14, REG_OFFSET(REG_R14)(%rdi)
movq %r15, REG_OFFSET(REG_R15)(%rdi)
movq %rdi, REG_OFFSET(REG_RDI)(%rdi)
movq %rsi, REG_OFFSET(REG_RSI)(%rdi)
movq %rbp, REG_OFFSET(REG_RBP)(%rdi)
movq %rbx, REG_OFFSET(REG_RBX)(%rdi)
movq %rdx, REG_OFFSET(REG_RDX)(%rdi)
movq %rax, REG_OFFSET(REG_RAX)(%rdi)
movq %rcx, REG_OFFSET(REG_RCX)(%rdi)
/* the first argument on the stack is the jump target (%rip), so we store it in the RIP
register in the ucontext structure. */
movq (%rsp), %rcx
movq %rcx, 168(%rdi)
movq %rcx, REG_OFFSET(REG_RIP)(%rdi)
/* finally take the stack pointer address (%rsp) offsetting by 8 to skip over the jump
target. */
leaq 8(%rsp), %rcx
movq %rcx, 160(%rdi)
movq %rcx, REG_OFFSET(REG_RSP)(%rdi)
/* we're all done here, return 0 */
xorl %eax, %eax
ret
.weak getcontext;
getcontext = __getcontext;
END(__getcontext)

1
arch/x86_64/makecontext.c
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@ -17,6 +17,7 @@
#include <string.h>
#include <stdint.h>
#include "defs.h"
extern void __start_context(void);

47
arch/x86_64/setcontext.S
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2018 Ariadne Conill <ariadne@dereferenced.org>
* Copyright (c) 2018, 2020 Ariadne Conill <ariadne@dereferenced.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
@ -10,35 +10,36 @@
* from the use of this software.
*/
.globl __setcontext;
__setcontext:
#include "defs.h"
ALIAS(setcontext, __setcontext)
FUNC(__setcontext)
/* set all of the registers */
movq 40(%rdi), %r8
movq 48(%rdi), %r9
movq 56(%rdi), %r10
movq 64(%rdi), %r11
movq 72(%rdi), %r12
movq 80(%rdi), %r13
movq 88(%rdi), %r14
movq 96(%rdi), %r15
movq 112(%rdi), %rsi
movq 120(%rdi), %rbp
movq 128(%rdi), %rbx
movq 136(%rdi), %rdx
movq 144(%rdi), %rax
movq 152(%rdi), %rcx
movq 160(%rdi), %rsp
movq REG_OFFSET(REG_R8)(%rdi), %r8
movq REG_OFFSET(REG_R9)(%rdi), %r9
movq REG_OFFSET(REG_R10)(%rdi), %r10
movq REG_OFFSET(REG_R11)(%rdi), %r11
movq REG_OFFSET(REG_R12)(%rdi), %r12
movq REG_OFFSET(REG_R13)(%rdi), %r13
movq REG_OFFSET(REG_R14)(%rdi), %r14
movq REG_OFFSET(REG_R15)(%rdi), %r15
movq REG_OFFSET(REG_RSI)(%rdi), %rsi
movq REG_OFFSET(REG_RBP)(%rdi), %rbp
movq REG_OFFSET(REG_RBX)(%rdi), %rbx
movq REG_OFFSET(REG_RDX)(%rdi), %rdx
movq REG_OFFSET(REG_RAX)(%rdi), %rax
movq REG_OFFSET(REG_RCX)(%rdi), %rcx
movq REG_OFFSET(REG_RSP)(%rdi), %rsp
/* set the jump target by pushing it to the stack.
ret will pop the new %rip from the stack, causing us to jump there. */
pushq 168(%rdi)
pushq REG_OFFSET(REG_RIP)(%rdi)
/* finally, set %rdi correctly. */
movq 104(%rdi), %rdi
movq REG_OFFSET(REG_RDI)(%rdi), %rdi
/* we're all done here, return 0 */
xorl %eax, %eax
ret
.weak setcontext;
setcontext = __setcontext;
END(__setcontext)

8
arch/x86_64/startcontext.S
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2018 Ariadne Conill <ariadne@dereferenced.org>
* Copyright (c) 2018, 2020 Ariadne Conill <ariadne@dereferenced.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
@ -10,8 +10,9 @@
* from the use of this software.
*/
.globl __start_context;
__start_context:
#include "defs.h"
FUNC(__start_context)
/* get the proper context into position and test for NULL */
movq %rbx, %rsp
movq (%rsp), %rdi
@ -30,3 +31,4 @@ no_linked_context:
/* something is really hosed, call hlt to force termination */
hlt
END(__start_context)

82
arch/x86_64/swapcontext.S
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2018 Ariadne Conill <ariadne@dereferenced.org>
* Copyright (c) 2018, 2020 Ariadne Conill <ariadne@dereferenced.org>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
@ -10,65 +10,65 @@
* from the use of this software.
*/
.globl __swapcontext;
__swapcontext:
#include "defs.h"
ALIAS(swapcontext, __swapcontext)
FUNC(__swapcontext)
/* copy all of the current registers into the ucontext structure pointed by
the first argument */
movq %r8, 40(%rdi)
movq %r9, 48(%rdi)
movq %r10, 56(%rdi)
movq %r11, 64(%rdi)
movq %r12, 72(%rdi)
movq %r13, 80(%rdi)
movq %r14, 88(%rdi)
movq %r15, 96(%rdi)
movq %rdi, 104(%rdi)
movq %rsi, 112(%rdi)
movq %rbp, 120(%rdi)
movq %rbx, 128(%rdi)
movq %rdx, 136(%rdi)
movq $1, 144(%rdi) /* $1 is %rax */
movq %rcx, 152(%rdi)
movq %r8, REG_OFFSET(REG_R8)(%rdi)
movq %r9, REG_OFFSET(REG_R9)(%rdi)
movq %r10, REG_OFFSET(REG_R10)(%rdi)
movq %r11, REG_OFFSET(REG_R11)(%rdi)
movq %r12, REG_OFFSET(REG_R12)(%rdi)
movq %r13, REG_OFFSET(REG_R13)(%rdi)
movq %r14, REG_OFFSET(REG_R14)(%rdi)
movq %r15, REG_OFFSET(REG_R15)(%rdi)
movq %rdi, REG_OFFSET(REG_RDI)(%rdi)
movq %rsi, REG_OFFSET(REG_RSI)(%rdi)
movq %rbp, REG_OFFSET(REG_RBP)(%rdi)
movq %rbx, REG_OFFSET(REG_RBX)(%rdi)
movq %rdx, REG_OFFSET(REG_RDX)(%rdi)
movq %rax, REG_OFFSET(REG_RAX)(%rdi)
movq %rcx, REG_OFFSET(REG_RCX)(%rdi)
/* the first argument on the stack is the jump target (%rip), so we store it in the RIP
register in the ucontext structure. */
movq (%rsp), %rcx
movq %rcx, 168(%rdi)
movq %rcx, REG_OFFSET(REG_RIP)(%rdi)
/* finally take the stack pointer address (%rsp) offsetting by 8 to skip over the jump
target. */
leaq 8(%rsp), %rcx
movq %rcx, 160(%rdi)
movq %rcx, REG_OFFSET(REG_RSP)(%rdi)
/* set all of the registers to their new states, stored in the second
ucontext structure */
movq 40(%rsi), %r8
movq 48(%rsi), %r9
movq 56(%rsi), %r10
movq 64(%rsi), %r11
movq 72(%rsi), %r12
movq 80(%rsi), %r13
movq 88(%rsi), %r14
movq 96(%rsi), %r15
movq 104(%rsi), %rdi
movq 120(%rsi), %rbp
movq 128(%rsi), %rbx
movq 136(%rsi), %rdx
movq 144(%rsi), %rax
movq 152(%rsi), %rcx
movq 160(%rsi), %rsp
movq REG_OFFSET(REG_R8)(%rsi), %r8
movq REG_OFFSET(REG_R9)(%rsi), %r9
movq REG_OFFSET(REG_R10)(%rsi), %r10
movq REG_OFFSET(REG_R11)(%rsi), %r11
movq REG_OFFSET(REG_R12)(%rsi), %r12
movq REG_OFFSET(REG_R13)(%rsi), %r13
movq REG_OFFSET(REG_R14)(%rsi), %r14
movq REG_OFFSET(REG_R15)(%rsi), %r15
movq REG_OFFSET(REG_RDI)(%rsi), %rdi
movq REG_OFFSET(REG_RBP)(%rsi), %rbp
movq REG_OFFSET(REG_RBX)(%rsi), %rbx
movq REG_OFFSET(REG_RDX)(%rsi), %rdx
movq REG_OFFSET(REG_RAX)(%rsi), %rax
movq REG_OFFSET(REG_RCX)(%rsi), %rcx
movq REG_OFFSET(REG_RSP)(%rsi), %rsp
/* set the jump target by pushing it to the stack.
ret will pop the new %rip from the stack, causing us to jump there. */
pushq 168(%rsi)
pushq REG_OFFSET(REG_RIP)(%rsi)
/* finally, set %rsi correctly since we do not need it anymore. */
movq 112(%rsi), %rsi
movq REG_OFFSET(REG_RSI)(%rsi), %rsi
/* we're all done here, return 0 */
xorl %eax, %eax
ret
.weak swapcontext;
swapcontext = __swapcontext;
END(__swapcontext)