28a0fcb4f0
Similar to r321899, reduce sv_maxuser by one page inside of CloudABI. This ensures that the stack, the vDSO and any allocations cannot touch the top page of user virtual memory. Considering that CloudABI userspace is completely oblivious to virtual memory layout, don't bother making this conditional based on the CPU of the running system. Reviewed by: kib, truckman Differential Revision: https://reviews.freebsd.org/D11808
222 lines
6.4 KiB
C
222 lines
6.4 KiB
C
/*-
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* Copyright (c) 2015 Nuxi, https://nuxi.nl/
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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 <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/imgact.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/sysent.h>
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#include <vm/vm.h>
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#include <vm/pmap.h>
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#include <machine/frame.h>
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#include <machine/pcb.h>
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#include <machine/vmparam.h>
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#include <compat/cloudabi/cloudabi_util.h>
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#include <compat/cloudabi64/cloudabi64_syscall.h>
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#include <compat/cloudabi64/cloudabi64_util.h>
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extern const char *cloudabi64_syscallnames[];
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extern struct sysent cloudabi64_sysent[];
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static int
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cloudabi64_fixup_tcb(register_t **stack_base, struct image_params *imgp)
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{
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int error;
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register_t tcbptr;
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/* Place auxiliary vector and TCB on the stack. */
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error = cloudabi64_fixup(stack_base, imgp);
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if (error != 0)
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return (error);
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/*
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* On x86-64, the TCB is referred to by %fs:0. Take some space
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* from the top of the stack to store a single element array,
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* containing a pointer to the TCB. %fs base will point to this.
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*/
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tcbptr = (register_t)*stack_base;
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return (copyout(&tcbptr, --*stack_base, sizeof(tcbptr)));
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}
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static void
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cloudabi64_proc_setregs(struct thread *td, struct image_params *imgp,
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unsigned long stack)
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{
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struct trapframe *regs;
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exec_setregs(td, imgp, stack);
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/*
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* The stack now contains a pointer to the TCB, the TCB itself,
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* and the auxiliary vector. Let %rdx point to the auxiliary
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* vector, and set %fs base to the address of the TCB.
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*/
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regs = td->td_frame;
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regs->tf_rdi = stack + sizeof(register_t) +
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roundup(sizeof(cloudabi64_tcb_t), sizeof(register_t));
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(void)cpu_set_user_tls(td, (void *)stack);
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}
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static int
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cloudabi64_fetch_syscall_args(struct thread *td)
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{
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struct trapframe *frame;
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struct syscall_args *sa;
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frame = td->td_frame;
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sa = &td->td_sa;
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/* Obtain system call number. */
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sa->code = frame->tf_rax;
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if (sa->code >= CLOUDABI64_SYS_MAXSYSCALL)
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return (ENOSYS);
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sa->callp = &cloudabi64_sysent[sa->code];
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sa->narg = sa->callp->sy_narg;
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/* Fetch system call arguments. */
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sa->args[0] = frame->tf_rdi;
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sa->args[1] = frame->tf_rsi;
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sa->args[2] = frame->tf_rdx;
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sa->args[3] = frame->tf_rcx; /* Actually %r10. */
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sa->args[4] = frame->tf_r8;
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sa->args[5] = frame->tf_r9;
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/* Default system call return values. */
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td->td_retval[0] = 0;
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td->td_retval[1] = frame->tf_rdx;
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return (0);
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}
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static void
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cloudabi64_set_syscall_retval(struct thread *td, int error)
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{
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struct trapframe *frame = td->td_frame;
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switch (error) {
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case 0:
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/* System call succeeded. */
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frame->tf_rax = td->td_retval[0];
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frame->tf_rdx = td->td_retval[1];
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frame->tf_rflags &= ~PSL_C;
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break;
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case ERESTART:
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/* Restart system call. */
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frame->tf_rip -= frame->tf_err;
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frame->tf_r10 = frame->tf_rcx;
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set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
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break;
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case EJUSTRETURN:
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break;
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default:
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/* System call returned an error. */
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frame->tf_rax = cloudabi_convert_errno(error);
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frame->tf_rflags |= PSL_C;
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break;
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}
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}
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static void
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cloudabi64_schedtail(struct thread *td)
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{
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struct trapframe *frame = td->td_frame;
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/* Initial register values for processes returning from fork. */
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frame->tf_rax = CLOUDABI_PROCESS_CHILD;
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frame->tf_rdx = td->td_tid;
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}
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int
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cloudabi64_thread_setregs(struct thread *td,
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const cloudabi64_threadattr_t *attr, uint64_t tcb)
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{
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struct trapframe *frame;
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stack_t stack;
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uint64_t tcbptr;
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int error;
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/*
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* On x86-64, the TCB is referred to by %fs:0. Take some space
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* from the top of the stack to store a single element array,
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* containing a pointer to the TCB. %fs base will point to this.
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*/
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tcbptr = rounddown(attr->stack + attr->stack_len - sizeof(tcbptr),
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_Alignof(tcbptr));
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error = copyout(&tcb, (void *)tcbptr, sizeof(tcb));
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if (error != 0)
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return (error);
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/* Perform standard register initialization. */
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stack.ss_sp = TO_PTR(attr->stack);
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stack.ss_size = tcbptr - attr->stack;
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cpu_set_upcall(td, TO_PTR(attr->entry_point), NULL, &stack);
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/*
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* Pass in the thread ID of the new thread and the argument
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* pointer provided by the parent thread in as arguments to the
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* entry point.
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*/
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frame = td->td_frame;
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frame->tf_rdi = td->td_tid;
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frame->tf_rsi = attr->argument;
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return (cpu_set_user_tls(td, (void *)tcbptr));
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}
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static struct sysentvec cloudabi64_elf_sysvec = {
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.sv_size = CLOUDABI64_SYS_MAXSYSCALL,
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.sv_table = cloudabi64_sysent,
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.sv_fixup = cloudabi64_fixup_tcb,
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.sv_name = "CloudABI ELF64",
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.sv_coredump = elf64_coredump,
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.sv_pagesize = PAGE_SIZE,
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.sv_minuser = VM_MIN_ADDRESS,
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/* Keep top page reserved to work around AMD Ryzen stability issues. */
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.sv_maxuser = VM_MAXUSER_ADDRESS - PAGE_SIZE,
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.sv_stackprot = VM_PROT_READ | VM_PROT_WRITE,
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.sv_copyout_strings = cloudabi64_copyout_strings,
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.sv_setregs = cloudabi64_proc_setregs,
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.sv_flags = SV_ABI_CLOUDABI | SV_CAPSICUM | SV_LP64,
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.sv_set_syscall_retval = cloudabi64_set_syscall_retval,
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.sv_fetch_syscall_args = cloudabi64_fetch_syscall_args,
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.sv_syscallnames = cloudabi64_syscallnames,
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.sv_schedtail = cloudabi64_schedtail,
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};
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INIT_SYSENTVEC(elf_sysvec, &cloudabi64_elf_sysvec);
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Elf64_Brandinfo cloudabi64_brand = {
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.brand = ELFOSABI_CLOUDABI,
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.machine = EM_X86_64,
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.sysvec = &cloudabi64_elf_sysvec,
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.flags = BI_CAN_EXEC_DYN | BI_BRAND_ONLY_STATIC,
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};
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