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/sched/task_stack.h> 11 12 #include <asm/registers.h> 13 #include <asm/thread_info.h> 14 #include <asm/unistd.h> 15 #include <linux/uaccess.h> 16 #include <asm/ucontext.h> 17 #include <asm/cacheflush.h> 18 #include <asm/signal.h> 19 #include <asm/vdso.h> 20 21 struct rt_sigframe { 22 unsigned long tramp[2]; 23 struct siginfo info; 24 struct ucontext uc; 25 }; 26 27 static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, 28 size_t frame_size) 29 { 30 unsigned long sp = sigsp(regs->r29, ksig); 31 32 return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1)); 33 } 34 35 static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) 36 { 37 unsigned long tmp; 38 int err = 0; 39 40 err |= copy_to_user(&sc->sc_regs.r0, ®s->r00, 41 32*sizeof(unsigned long)); 42 43 err |= __put_user(regs->sa0, &sc->sc_regs.sa0); 44 err |= __put_user(regs->lc0, &sc->sc_regs.lc0); 45 err |= __put_user(regs->sa1, &sc->sc_regs.sa1); 46 err |= __put_user(regs->lc1, &sc->sc_regs.lc1); 47 err |= __put_user(regs->m0, &sc->sc_regs.m0); 48 err |= __put_user(regs->m1, &sc->sc_regs.m1); 49 err |= __put_user(regs->usr, &sc->sc_regs.usr); 50 err |= __put_user(regs->preds, &sc->sc_regs.p3_0); 51 err |= __put_user(regs->gp, &sc->sc_regs.gp); 52 err |= __put_user(regs->ugp, &sc->sc_regs.ugp); 53 #if CONFIG_HEXAGON_ARCH_VERSION >= 4 54 err |= __put_user(regs->cs0, &sc->sc_regs.cs0); 55 err |= __put_user(regs->cs1, &sc->sc_regs.cs1); 56 #endif 57 tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc); 58 tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause); 59 tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva); 60 61 return err; 62 } 63 64 static int restore_sigcontext(struct pt_regs *regs, 65 struct sigcontext __user *sc) 66 { 67 unsigned long tmp; 68 int err = 0; 69 70 err |= copy_from_user(®s->r00, &sc->sc_regs.r0, 71 32 * sizeof(unsigned long)); 72 73 err |= __get_user(regs->sa0, &sc->sc_regs.sa0); 74 err |= __get_user(regs->lc0, &sc->sc_regs.lc0); 75 err |= __get_user(regs->sa1, &sc->sc_regs.sa1); 76 err |= __get_user(regs->lc1, &sc->sc_regs.lc1); 77 err |= __get_user(regs->m0, &sc->sc_regs.m0); 78 err |= __get_user(regs->m1, &sc->sc_regs.m1); 79 err |= __get_user(regs->usr, &sc->sc_regs.usr); 80 err |= __get_user(regs->preds, &sc->sc_regs.p3_0); 81 err |= __get_user(regs->gp, &sc->sc_regs.gp); 82 err |= __get_user(regs->ugp, &sc->sc_regs.ugp); 83 #if CONFIG_HEXAGON_ARCH_VERSION >= 4 84 err |= __get_user(regs->cs0, &sc->sc_regs.cs0); 85 err |= __get_user(regs->cs1, &sc->sc_regs.cs1); 86 #endif 87 err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp); 88 89 return err; 90 } 91 92 /* 93 * Setup signal stack frame with siginfo structure 94 */ 95 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, 96 struct pt_regs *regs) 97 { 98 int err = 0; 99 struct rt_sigframe __user *frame; 100 struct hexagon_vdso *vdso = current->mm->context.vdso; 101 102 frame = get_sigframe(ksig, regs, sizeof(struct rt_sigframe)); 103 104 if (!access_ok(frame, sizeof(struct rt_sigframe))) 105 return -EFAULT; 106 107 if (copy_siginfo_to_user(&frame->info, &ksig->info)) 108 return -EFAULT; 109 110 /* The on-stack signal trampoline is no longer executed; 111 * however, the libgcc signal frame unwinding code checks for 112 * the presence of these two numeric magic values. 113 */ 114 err |= __put_user(0x7800d166, &frame->tramp[0]); 115 err |= __put_user(0x5400c004, &frame->tramp[1]); 116 err |= setup_sigcontext(regs, &frame->uc.uc_mcontext); 117 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 118 err |= __save_altstack(&frame->uc.uc_stack, user_stack_pointer(regs)); 119 if (err) 120 return -EFAULT; 121 122 /* Load r0/r1 pair with signumber/siginfo pointer... */ 123 regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32) 124 | (unsigned long long)ksig->sig; 125 regs->r02 = (unsigned long) &frame->uc; 126 regs->r31 = (unsigned long) vdso->rt_signal_trampoline; 127 pt_psp(regs) = (unsigned long) frame; 128 pt_set_elr(regs, (unsigned long)ksig->ka.sa.sa_handler); 129 130 return 0; 131 } 132 133 /* 134 * Setup invocation of signal handler 135 */ 136 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) 137 { 138 int ret; 139 140 /* 141 * If we're handling a signal that aborted a system call, 142 * set up the error return value before adding the signal 143 * frame to the stack. 144 */ 145 146 if (regs->syscall_nr >= 0) { 147 switch (regs->r00) { 148 case -ERESTART_RESTARTBLOCK: 149 case -ERESTARTNOHAND: 150 regs->r00 = -EINTR; 151 break; 152 case -ERESTARTSYS: 153 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { 154 regs->r00 = -EINTR; 155 break; 156 } 157 fallthrough; 158 case -ERESTARTNOINTR: 159 regs->r06 = regs->syscall_nr; 160 pt_set_elr(regs, pt_elr(regs) - 4); 161 regs->r00 = regs->restart_r0; 162 break; 163 default: 164 break; 165 } 166 } 167 168 /* 169 * Set up the stack frame; not doing the SA_SIGINFO thing. We 170 * only set up the rt_frame flavor. 171 */ 172 /* If there was an error on setup, no signal was delivered. */ 173 ret = setup_rt_frame(ksig, sigmask_to_save(), regs); 174 175 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); 176 } 177 178 /* 179 * Called from return-from-event code. 180 */ 181 void do_signal(struct pt_regs *regs) 182 { 183 struct ksignal ksig; 184 185 if (!user_mode(regs)) 186 return; 187 188 if (get_signal(&ksig)) { 189 handle_signal(&ksig, regs); 190 return; 191 } 192 193 /* 194 * No (more) signals; if we came from a system call, handle the restart. 195 */ 196 197 if (regs->syscall_nr >= 0) { 198 switch (regs->r00) { 199 case -ERESTARTNOHAND: 200 case -ERESTARTSYS: 201 case -ERESTARTNOINTR: 202 regs->r06 = regs->syscall_nr; 203 break; 204 case -ERESTART_RESTARTBLOCK: 205 regs->r06 = __NR_restart_syscall; 206 break; 207 default: 208 goto no_restart; 209 } 210 pt_set_elr(regs, pt_elr(regs) - 4); 211 regs->r00 = regs->restart_r0; 212 } 213 214 no_restart: 215 /* If there's no signal to deliver, put the saved sigmask back */ 216 restore_saved_sigmask(); 217 } 218 219 /* 220 * Architecture-specific wrappers for signal-related system calls 221 */ 222 223 SYSCALL_DEFINE0(rt_sigreturn) 224 { 225 struct pt_regs *regs = current_pt_regs(); 226 struct rt_sigframe __user *frame; 227 sigset_t blocked; 228 229 /* Always make any pending restarted system calls return -EINTR */ 230 current->restart_block.fn = do_no_restart_syscall; 231 232 frame = (struct rt_sigframe __user *)pt_psp(regs); 233 if (!access_ok(frame, sizeof(*frame))) 234 goto badframe; 235 if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked))) 236 goto badframe; 237 238 set_current_blocked(&blocked); 239 240 if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) 241 goto badframe; 242 243 /* Restore the user's stack as well */ 244 pt_psp(regs) = regs->r29; 245 246 regs->syscall_nr = -1; 247 248 if (restore_altstack(&frame->uc.uc_stack)) 249 goto badframe; 250 251 return regs->r00; 252 253 badframe: 254 force_sig(SIGSEGV); 255 return 0; 256 } 257