1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Signal support for Hexagon processor 4 * 5 * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved. 6 */ 7 8 #include <linux/linkage.h> 9 #include <linux/syscalls.h> 10 #include <linux/tracehook.h> 11 #include <linux/sched/task_stack.h> 12 13 #include <asm/registers.h> 14 #include <asm/thread_info.h> 15 #include <asm/unistd.h> 16 #include <linux/uaccess.h> 17 #include <asm/ucontext.h> 18 #include <asm/cacheflush.h> 19 #include <asm/signal.h> 20 #include <asm/vdso.h> 21 22 struct rt_sigframe { 23 unsigned long tramp[2]; 24 struct siginfo info; 25 struct ucontext uc; 26 }; 27 28 static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, 29 size_t frame_size) 30 { 31 unsigned long sp = sigsp(regs->r29, ksig); 32 33 return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1)); 34 } 35 36 static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) 37 { 38 unsigned long tmp; 39 int err = 0; 40 41 err |= copy_to_user(&sc->sc_regs.r0, ®s->r00, 42 32*sizeof(unsigned long)); 43 44 err |= __put_user(regs->sa0, &sc->sc_regs.sa0); 45 err |= __put_user(regs->lc0, &sc->sc_regs.lc0); 46 err |= __put_user(regs->sa1, &sc->sc_regs.sa1); 47 err |= __put_user(regs->lc1, &sc->sc_regs.lc1); 48 err |= __put_user(regs->m0, &sc->sc_regs.m0); 49 err |= __put_user(regs->m1, &sc->sc_regs.m1); 50 err |= __put_user(regs->usr, &sc->sc_regs.usr); 51 err |= __put_user(regs->preds, &sc->sc_regs.p3_0); 52 err |= __put_user(regs->gp, &sc->sc_regs.gp); 53 err |= __put_user(regs->ugp, &sc->sc_regs.ugp); 54 #if CONFIG_HEXAGON_ARCH_VERSION >= 4 55 err |= __put_user(regs->cs0, &sc->sc_regs.cs0); 56 err |= __put_user(regs->cs1, &sc->sc_regs.cs1); 57 #endif 58 tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc); 59 tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause); 60 tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva); 61 62 return err; 63 } 64 65 static int restore_sigcontext(struct pt_regs *regs, 66 struct sigcontext __user *sc) 67 { 68 unsigned long tmp; 69 int err = 0; 70 71 err |= copy_from_user(®s->r00, &sc->sc_regs.r0, 72 32 * sizeof(unsigned long)); 73 74 err |= __get_user(regs->sa0, &sc->sc_regs.sa0); 75 err |= __get_user(regs->lc0, &sc->sc_regs.lc0); 76 err |= __get_user(regs->sa1, &sc->sc_regs.sa1); 77 err |= __get_user(regs->lc1, &sc->sc_regs.lc1); 78 err |= __get_user(regs->m0, &sc->sc_regs.m0); 79 err |= __get_user(regs->m1, &sc->sc_regs.m1); 80 err |= __get_user(regs->usr, &sc->sc_regs.usr); 81 err |= __get_user(regs->preds, &sc->sc_regs.p3_0); 82 err |= __get_user(regs->gp, &sc->sc_regs.gp); 83 err |= __get_user(regs->ugp, &sc->sc_regs.ugp); 84 #if CONFIG_HEXAGON_ARCH_VERSION >= 4 85 err |= __get_user(regs->cs0, &sc->sc_regs.cs0); 86 err |= __get_user(regs->cs1, &sc->sc_regs.cs1); 87 #endif 88 err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp); 89 90 return err; 91 } 92 93 /* 94 * Setup signal stack frame with siginfo structure 95 */ 96 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, 97 struct pt_regs *regs) 98 { 99 int err = 0; 100 struct rt_sigframe __user *frame; 101 struct hexagon_vdso *vdso = current->mm->context.vdso; 102 103 frame = get_sigframe(ksig, regs, sizeof(struct rt_sigframe)); 104 105 if (!access_ok(frame, sizeof(struct rt_sigframe))) 106 return -EFAULT; 107 108 if (copy_siginfo_to_user(&frame->info, &ksig->info)) 109 return -EFAULT; 110 111 /* The on-stack signal trampoline is no longer executed; 112 * however, the libgcc signal frame unwinding code checks for 113 * the presence of these two numeric magic values. 114 */ 115 err |= __put_user(0x7800d166, &frame->tramp[0]); 116 err |= __put_user(0x5400c004, &frame->tramp[1]); 117 err |= setup_sigcontext(regs, &frame->uc.uc_mcontext); 118 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 119 err |= __save_altstack(&frame->uc.uc_stack, user_stack_pointer(regs)); 120 if (err) 121 return -EFAULT; 122 123 /* Load r0/r1 pair with signumber/siginfo pointer... */ 124 regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32) 125 | (unsigned long long)ksig->sig; 126 regs->r02 = (unsigned long) &frame->uc; 127 regs->r31 = (unsigned long) vdso->rt_signal_trampoline; 128 pt_psp(regs) = (unsigned long) frame; 129 pt_set_elr(regs, (unsigned long)ksig->ka.sa.sa_handler); 130 131 return 0; 132 } 133 134 /* 135 * Setup invocation of signal handler 136 */ 137 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) 138 { 139 int ret; 140 141 /* 142 * If we're handling a signal that aborted a system call, 143 * set up the error return value before adding the signal 144 * frame to the stack. 145 */ 146 147 if (regs->syscall_nr >= 0) { 148 switch (regs->r00) { 149 case -ERESTART_RESTARTBLOCK: 150 case -ERESTARTNOHAND: 151 regs->r00 = -EINTR; 152 break; 153 case -ERESTARTSYS: 154 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { 155 regs->r00 = -EINTR; 156 break; 157 } 158 fallthrough; 159 case -ERESTARTNOINTR: 160 regs->r06 = regs->syscall_nr; 161 pt_set_elr(regs, pt_elr(regs) - 4); 162 regs->r00 = regs->restart_r0; 163 break; 164 default: 165 break; 166 } 167 } 168 169 /* 170 * Set up the stack frame; not doing the SA_SIGINFO thing. We 171 * only set up the rt_frame flavor. 172 */ 173 /* If there was an error on setup, no signal was delivered. */ 174 ret = setup_rt_frame(ksig, sigmask_to_save(), regs); 175 176 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); 177 } 178 179 /* 180 * Called from return-from-event code. 181 */ 182 void do_signal(struct pt_regs *regs) 183 { 184 struct ksignal ksig; 185 186 if (!user_mode(regs)) 187 return; 188 189 if (get_signal(&ksig)) { 190 handle_signal(&ksig, regs); 191 return; 192 } 193 194 /* 195 * No (more) signals; if we came from a system call, handle the restart. 196 */ 197 198 if (regs->syscall_nr >= 0) { 199 switch (regs->r00) { 200 case -ERESTARTNOHAND: 201 case -ERESTARTSYS: 202 case -ERESTARTNOINTR: 203 regs->r06 = regs->syscall_nr; 204 break; 205 case -ERESTART_RESTARTBLOCK: 206 regs->r06 = __NR_restart_syscall; 207 break; 208 default: 209 goto no_restart; 210 } 211 pt_set_elr(regs, pt_elr(regs) - 4); 212 regs->r00 = regs->restart_r0; 213 } 214 215 no_restart: 216 /* If there's no signal to deliver, put the saved sigmask back */ 217 restore_saved_sigmask(); 218 } 219 220 /* 221 * Architecture-specific wrappers for signal-related system calls 222 */ 223 224 asmlinkage int sys_rt_sigreturn(void) 225 { 226 struct pt_regs *regs = current_pt_regs(); 227 struct rt_sigframe __user *frame; 228 sigset_t blocked; 229 230 /* Always make any pending restarted system calls return -EINTR */ 231 current->restart_block.fn = do_no_restart_syscall; 232 233 frame = (struct rt_sigframe __user *)pt_psp(regs); 234 if (!access_ok(frame, sizeof(*frame))) 235 goto badframe; 236 if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked))) 237 goto badframe; 238 239 set_current_blocked(&blocked); 240 241 if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) 242 goto badframe; 243 244 /* Restore the user's stack as well */ 245 pt_psp(regs) = regs->r29; 246 247 regs->syscall_nr = -1; 248 249 if (restore_altstack(&frame->uc.uc_stack)) 250 goto badframe; 251 252 return regs->r00; 253 254 badframe: 255 force_sig(SIGSEGV); 256 return 0; 257 } 258