/*
The lucet_context_swap function is taken from Xudong Huang's
generator-rs project. Its MIT license is provided below.
Copyright (c) 2017 Xudong Huang
Permission is hereby granted, free of charge, to any
person obtaining a copy of this software and associated
documentation files (the "Software"), to deal in the
Software without restriction, including without
limitation the rights to use, copy, modify, merge,
publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software
is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice
shall be included in all copies or substantial portions
of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
*/
.text
.globl lucet_context_bootstrap
#ifdef __ELF__
.type lucet_context_bootstrap,@function
#else
.globl _lucet_context_bootstrap
#endif
.align 16
lucet_context_bootstrap:
_lucet_context_bootstrap:
// Move each of the argument values into the corresponding call
// argument register.
pop %r9
pop %r8
pop %rcx
pop %rdx
pop %rsi
pop %rdi
/* the next thing on the stack is the guest function - return to it */
ret
#ifdef __ELF__
.size lucet_context_bootstrap,.-lucet_context_bootstrap
#endif
.text
.globl lucet_context_backstop
#ifdef __ELF__
.type lucet_context_backstop,@function
#else
.globl _lucet_context_backstop
#endif
.align 16
lucet_context_backstop:
_lucet_context_backstop:
// Note that `rbp` here really has no relation to any stack!
// Instead, it's a pointer to the guest context.
mov (10*8 + 8*16 + 8*2 + 16)(%rbp), %rdi // load the parent context to forward values in return value registers
mov %rax, (10*8 + 8*16 + 8*0)(%rbp) /* store return values before swapping back -- offset is offsetof(struct lucet_context, retvals) */
mov %rdx, (10*8 + 8*16 + 8*1)(%rbp)
movdqu %xmm0, (10*8 + 8*16 + 8*2)(%rbp) /* floating-point return value */
// load `backstop_callback`, but skip calling it if it's null
mov (10*8 + 8*16 + 8*2 + 16 + 8)(%rbp), %rsi
test %rsi, %rsi
#ifdef __ELF__
jz no_backstop_callback@PLT
#else
jz no_backstop_callback
#endif
// load `backstop_data`, arg 1
mov (10*8 + 8*16 + 8*2 + 16 + 8 + 8)(%rbp), %rdi
// call `backstop_callback`
call *%rsi
no_backstop_callback:
mov %rbp, %rdi // load the guest context to the "from" argument
mov (10*8 + 8*16 + 8*2 + 16)(%rbp), %rsi // load the parent context to the "to" argument
#ifdef __ELF__
jmp lucet_context_swap@PLT
#else
jmp lucet_context_swap
#endif
#ifdef __ELF__
.size lucet_context_backstop,.-lucet_context_backstop
#endif
.text
.globl lucet_context_swap
#ifdef __ELF__
.type lucet_context_swap,@function
#else
.globl _lucet_context_swap
#endif
.align 16
lucet_context_swap:
_lucet_context_swap:
// store everything in offsets from rdi (1st arg)
mov %rbx, (0*8)(%rdi)
mov %rsp, (1*8)(%rdi)
mov %rbp, (2*8)(%rdi)
mov %rdi, (3*8)(%rdi)
mov %r12, (4*8)(%rdi)
mov %r13, (5*8)(%rdi)
mov %r14, (6*8)(%rdi)
mov %r15, (7*8)(%rdi)
mov %rsi, (8*8)(%rdi)
movdqu %xmm0, (10*8 + 0*16)(%rdi)
movdqu %xmm1, (10*8 + 1*16)(%rdi)
movdqu %xmm2, (10*8 + 2*16)(%rdi)
movdqu %xmm3, (10*8 + 3*16)(%rdi)
movdqu %xmm4, (10*8 + 4*16)(%rdi)
movdqu %xmm5, (10*8 + 5*16)(%rdi)
movdqu %xmm6, (10*8 + 6*16)(%rdi)
movdqu %xmm7, (10*8 + 7*16)(%rdi)
// load everything from offsets from rsi (2nd arg)
mov (0*8)(%rsi), %rbx
mov (1*8)(%rsi), %rsp
mov (2*8)(%rsi), %rbp
mov (3*8)(%rsi), %rdi
mov (4*8)(%rsi), %r12
mov (5*8)(%rsi), %r13
mov (6*8)(%rsi), %r14
mov (7*8)(%rsi), %r15
movdqu (10*8 + 0*16)(%rsi), %xmm0
movdqu (10*8 + 1*16)(%rsi), %xmm1
movdqu (10*8 + 2*16)(%rsi), %xmm2
movdqu (10*8 + 3*16)(%rsi), %xmm3
movdqu (10*8 + 4*16)(%rsi), %xmm4
movdqu (10*8 + 5*16)(%rsi), %xmm5
movdqu (10*8 + 6*16)(%rsi), %xmm6
movdqu (10*8 + 7*16)(%rsi), %xmm7
// restore rsi when we're done with the context pointer
mov (8*8)(%rsi), %rsi
ret
#ifdef __ELF__
.size lucet_context_swap,.-lucet_context_swap
#endif
.text
.globl lucet_context_set
#ifdef __ELF__
.type lucet_context_set,@function
#else
.globl _lucet_context_set
#endif
.align 16
lucet_context_set:
_lucet_context_set:
// load everything from offsets from rdi (1st arg)
mov (0*8)(%rdi), %rbx
mov (1*8)(%rdi), %rsp
mov (2*8)(%rdi), %rbp
mov (4*8)(%rdi), %r12
mov (5*8)(%rdi), %r13
mov (6*8)(%rdi), %r14
mov (7*8)(%rdi), %r15
mov (8*8)(%rdi), %rsi
movdqu (10*8 + 0*16)(%rdi), %xmm0
movdqu (10*8 + 1*16)(%rdi), %xmm1
movdqu (10*8 + 2*16)(%rdi), %xmm2
movdqu (10*8 + 3*16)(%rdi), %xmm3
movdqu (10*8 + 4*16)(%rdi), %xmm4
movdqu (10*8 + 5*16)(%rdi), %xmm5
movdqu (10*8 + 6*16)(%rdi), %xmm6
movdqu (10*8 + 7*16)(%rdi), %xmm7
// load rdi from itself last
mov (3*8)(%rdi), %rdi
ret
#ifdef __ELF__
.size lucet_context_set,.-lucet_context_set
#endif
.text
.globl lucet_context_activate
#ifdef __ELF__
.type lucet_context_activate,@function
#else
.globl _lucet_context_activate
#endif
.align 16
// lucet_context_activate is essentially a function with two arguments:
// in rdi, the address of this guest's "running" flag.
// in rsi, the address of the guest code to resume at.
lucet_context_activate:
_lucet_context_activate:
movb $1, (%rdi)
jmp *%rsi
#ifdef __ELF__
.size lucet_context_activate,.-lucet_context_activate
#endif
/* Mark that we don't need executable stack. */
#if defined(__linux__) && defined(__ELF__)
.section .note.GNU-stack,"",%progbits
#endif