1 /*- 2 * Copyright (c) 2015-2016 Nuxi, https://nuxi.nl/ 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 */ 25 26 #include <sys/cdefs.h> 27 __FBSDID("$FreeBSD$"); 28 29 #include <sys/param.h> 30 #include <sys/imgact.h> 31 #include <sys/kernel.h> 32 #include <sys/proc.h> 33 #include <sys/sysent.h> 34 35 #include <vm/vm.h> 36 #include <vm/pmap.h> 37 38 #include <machine/frame.h> 39 #include <machine/pcb.h> 40 #include <machine/vmparam.h> 41 42 #include <compat/cloudabi/cloudabi_util.h> 43 44 #include <compat/cloudabi32/cloudabi32_syscall.h> 45 #include <compat/cloudabi32/cloudabi32_util.h> 46 47 #include <compat/ia32/ia32_signal.h> 48 #include <compat/ia32/ia32_util.h> 49 50 extern const char *cloudabi32_syscallnames[]; 51 extern struct sysent cloudabi32_sysent[]; 52 53 extern unsigned long ia32_maxssiz; 54 55 static int 56 cloudabi32_fixup_tcb(uintptr_t *stack_base, struct image_params *imgp) 57 { 58 int error; 59 uint32_t args[2]; 60 61 /* Place auxiliary vector and TCB on the stack. */ 62 error = cloudabi32_fixup(stack_base, imgp); 63 if (error != 0) 64 return (error); 65 66 /* 67 * On i386, the TCB is referred to by %gs:0. Reuse the empty 68 * space normally used by the return address (args[0]) to store 69 * a single element array, containing a pointer to the TCB. %gs 70 * base will point to this. 71 * 72 * Also let the first argument of the entry point (args[1]) 73 * refer to the auxiliary vector, which is stored right after 74 * the TCB. 75 */ 76 args[0] = *stack_base; 77 args[1] = *stack_base + 78 roundup(sizeof(cloudabi32_tcb_t), sizeof(register_t)); 79 *stack_base -= roundup2(sizeof(args), sizeof(register_t)); 80 return (copyout(args, (void *)*stack_base, sizeof(args))); 81 } 82 83 static void 84 cloudabi32_proc_setregs(struct thread *td, struct image_params *imgp, 85 uintptr_t stack) 86 { 87 88 ia32_setregs(td, imgp, stack); 89 (void)cpu_set_user_tls(td, TO_PTR(stack)); 90 } 91 92 static int 93 cloudabi32_fetch_syscall_args(struct thread *td) 94 { 95 struct trapframe *frame; 96 struct syscall_args *sa; 97 int error; 98 99 frame = td->td_frame; 100 sa = &td->td_sa; 101 102 /* Obtain system call number. */ 103 sa->code = frame->tf_rax; 104 if (sa->code >= CLOUDABI32_SYS_MAXSYSCALL) 105 return (ENOSYS); 106 sa->callp = &cloudabi32_sysent[sa->code]; 107 108 /* 109 * Fetch system call arguments. 110 * 111 * The vDSO has already made sure that the arguments are 112 * eight-byte aligned. Pointers and size_t parameters are 113 * zero-extended. This makes it possible to copy in the 114 * arguments directly. As long as the call doesn't use 32-bit 115 * data structures, we can just invoke the same system call 116 * implementation used by 64-bit processes. 117 */ 118 error = copyin((void *)frame->tf_rcx, sa->args, 119 sa->callp->sy_narg * sizeof(sa->args[0])); 120 if (error != 0) 121 return (error); 122 123 /* Default system call return values. */ 124 td->td_retval[0] = 0; 125 td->td_retval[1] = 0; 126 return (0); 127 } 128 129 static void 130 cloudabi32_set_syscall_retval(struct thread *td, int error) 131 { 132 struct trapframe *frame = td->td_frame; 133 134 switch (error) { 135 case 0: 136 /* 137 * System call succeeded. 138 * 139 * Simply copy out the 64-bit return values into the 140 * same buffer provided for system call arguments. The 141 * vDSO will copy them to the right spot, truncating 142 * pointers and size_t values to 32 bits. 143 */ 144 frame->tf_rax = copyout(td->td_retval, (void *)frame->tf_rcx, 145 sizeof(td->td_retval)) == 0 ? 0 : CLOUDABI_EFAULT; 146 break; 147 case ERESTART: 148 /* Restart system call. */ 149 frame->tf_rip -= frame->tf_err; 150 frame->tf_r10 = frame->tf_rcx; 151 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 152 break; 153 case EJUSTRETURN: 154 break; 155 default: 156 /* System call returned an error. */ 157 frame->tf_rax = cloudabi_convert_errno(error); 158 break; 159 } 160 } 161 162 static void 163 cloudabi32_schedtail(struct thread *td) 164 { 165 struct trapframe *frame = td->td_frame; 166 register_t retval[2]; 167 168 /* Return values for processes returning from fork. */ 169 if ((td->td_pflags & TDP_FORKING) != 0) { 170 retval[0] = CLOUDABI_PROCESS_CHILD; 171 retval[1] = td->td_tid; 172 copyout(retval, (void *)frame->tf_rcx, sizeof(retval)); 173 } 174 } 175 176 int 177 cloudabi32_thread_setregs(struct thread *td, 178 const cloudabi32_threadattr_t *attr, uint32_t tcb) 179 { 180 stack_t stack; 181 uint32_t args[3]; 182 void *frameptr; 183 int error; 184 185 /* Perform standard register initialization. */ 186 stack.ss_sp = TO_PTR(attr->stack); 187 stack.ss_size = attr->stack_len - sizeof(args); 188 cpu_set_upcall(td, TO_PTR(attr->entry_point), NULL, &stack); 189 190 /* 191 * Copy the arguments for the thread entry point onto the stack 192 * (args[1] and args[2]). Similar to process startup, use the 193 * otherwise unused return address (args[0]) for TLS. 194 */ 195 args[0] = tcb; 196 args[1] = td->td_tid; 197 args[2] = attr->argument; 198 frameptr = (void *)td->td_frame->tf_rsp; 199 error = copyout(args, frameptr, sizeof(args)); 200 if (error != 0) 201 return (error); 202 203 return (cpu_set_user_tls(td, frameptr)); 204 } 205 206 static struct sysentvec cloudabi32_elf_sysvec = { 207 .sv_size = CLOUDABI32_SYS_MAXSYSCALL, 208 .sv_table = cloudabi32_sysent, 209 .sv_fixup = cloudabi32_fixup_tcb, 210 .sv_name = "CloudABI ELF32", 211 .sv_coredump = elf32_coredump, 212 .sv_minuser = FREEBSD32_MINUSER, 213 .sv_maxuser = FREEBSD32_MAXUSER, 214 .sv_stackprot = VM_PROT_READ | VM_PROT_WRITE, 215 .sv_copyout_strings = cloudabi32_copyout_strings, 216 .sv_setregs = cloudabi32_proc_setregs, 217 .sv_fixlimit = ia32_fixlimit, 218 .sv_maxssiz = &ia32_maxssiz, 219 .sv_flags = SV_ABI_CLOUDABI | SV_CAPSICUM | SV_IA32 | SV_ILP32, 220 .sv_set_syscall_retval = cloudabi32_set_syscall_retval, 221 .sv_fetch_syscall_args = cloudabi32_fetch_syscall_args, 222 .sv_syscallnames = cloudabi32_syscallnames, 223 .sv_schedtail = cloudabi32_schedtail, 224 }; 225 226 INIT_SYSENTVEC(elf_sysvec, &cloudabi32_elf_sysvec); 227 228 Elf32_Brandinfo cloudabi32_brand = { 229 .brand = ELFOSABI_CLOUDABI, 230 .machine = EM_386, 231 .sysvec = &cloudabi32_elf_sysvec, 232 .flags = BI_BRAND_ONLY_STATIC, 233 }; 234