diff options
Diffstat (limited to 'arch/arc/kernel/signal.c')
| -rw-r--r-- | arch/arc/kernel/signal.c | 252 |
1 files changed, 168 insertions, 84 deletions
diff --git a/arch/arc/kernel/signal.c b/arch/arc/kernel/signal.c index ee6ef2f60a28..fefa705a8638 100644 --- a/arch/arc/kernel/signal.c +++ b/arch/arc/kernel/signal.c @@ -1,25 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Signal Handling for ARC * * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - * * vineetg: Jan 2010 (Restarting of timer related syscalls) * * vineetg: Nov 2009 (Everything needed for TIF_RESTORE_SIGMASK) * -do_signal() supports TIF_RESTORE_SIGMASK - * -do_signal() no loner needs oldset, required by OLD sys_sigsuspend - * -sys_rt_sigsuspend() now comes from generic code, so discard arch implemen + * -do_signal() no longer needs oldset, required by OLD sys_sigsuspend + * -sys_rt_sigsuspend() now comes from generic code, so discard arch + * implementation * -sys_sigsuspend() no longer needs to fudge ptregs, hence that arg removed * -sys_sigsuspend() no longer loops for do_signal(), sets TIF_xxx and leaves * the job to do_signal() * * vineetg: July 2009 * -Modified Code to support the uClibc provided userland sigreturn stub - * to avoid kernel synthesing it on user stack at runtime, costing TLB + * to avoid kernel synthesizing it on user stack at runtime, costing TLB * probes and Cache line flushes. * * vineetg: July 2009 @@ -34,7 +32,7 @@ * -ViXS were still seeing crashes when using insmod to load drivers. * It turned out that the code to change Execute permssions for TLB entries * of user was not guarded for interrupts (mod_tlb_permission) - * This was cauing TLB entries to be overwritten on unrelated indexes + * This was causing TLB entries to be overwritten on unrelated indexes * * Vineetg: July 15th 2008: Bug #94183 * -Exception happens in Delay slot of a JMP, and before user space resumes, @@ -52,8 +50,11 @@ #include <linux/personality.h> #include <linux/uaccess.h> #include <linux/syscalls.h> -#include <linux/tracehook.h> +#include <linux/resume_user_mode.h> +#include <linux/sched/task_stack.h> + #include <asm/ucontext.h> +#include <asm/entry.h> struct rt_sigframe { struct siginfo info; @@ -62,31 +63,126 @@ struct rt_sigframe { unsigned int sigret_magic; }; +static int save_arcv2_regs(struct sigcontext __user *mctx, struct pt_regs *regs) +{ + int err = 0; +#ifndef CONFIG_ISA_ARCOMPACT + struct user_regs_arcv2 v2abi; + + v2abi.r30 = regs->r30; +#ifdef CONFIG_ARC_HAS_ACCL_REGS + v2abi.r58 = regs->r58; + v2abi.r59 = regs->r59; +#else + v2abi.r58 = v2abi.r59 = 0; +#endif + err = __copy_to_user(&mctx->v2abi, (void const *)&v2abi, sizeof(v2abi)); +#endif + return err; +} + +static int restore_arcv2_regs(struct sigcontext __user *mctx, struct pt_regs *regs) +{ + int err = 0; +#ifndef CONFIG_ISA_ARCOMPACT + struct user_regs_arcv2 v2abi; + + err = __copy_from_user(&v2abi, &mctx->v2abi, sizeof(v2abi)); + + regs->r30 = v2abi.r30; +#ifdef CONFIG_ARC_HAS_ACCL_REGS + regs->r58 = v2abi.r58; + regs->r59 = v2abi.r59; +#endif +#endif + return err; +} + static int stash_usr_regs(struct rt_sigframe __user *sf, struct pt_regs *regs, sigset_t *set) { int err; - err = __copy_to_user(&(sf->uc.uc_mcontext.regs), regs, + struct user_regs_struct uregs; + + uregs.scratch.bta = regs->bta; + uregs.scratch.lp_start = regs->lp_start; + uregs.scratch.lp_end = regs->lp_end; + uregs.scratch.lp_count = regs->lp_count; + uregs.scratch.status32 = regs->status32; + uregs.scratch.ret = regs->ret; + uregs.scratch.blink = regs->blink; + uregs.scratch.fp = regs->fp; + uregs.scratch.gp = regs->r26; + uregs.scratch.r12 = regs->r12; + uregs.scratch.r11 = regs->r11; + uregs.scratch.r10 = regs->r10; + uregs.scratch.r9 = regs->r9; + uregs.scratch.r8 = regs->r8; + uregs.scratch.r7 = regs->r7; + uregs.scratch.r6 = regs->r6; + uregs.scratch.r5 = regs->r5; + uregs.scratch.r4 = regs->r4; + uregs.scratch.r3 = regs->r3; + uregs.scratch.r2 = regs->r2; + uregs.scratch.r1 = regs->r1; + uregs.scratch.r0 = regs->r0; + uregs.scratch.sp = regs->sp; + + err = __copy_to_user(&(sf->uc.uc_mcontext.regs.scratch), &uregs.scratch, sizeof(sf->uc.uc_mcontext.regs.scratch)); + + if (is_isa_arcv2()) + err |= save_arcv2_regs(&(sf->uc.uc_mcontext), regs); + err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(sigset_t)); - return err; + return err ? -EFAULT : 0; } static int restore_usr_regs(struct pt_regs *regs, struct rt_sigframe __user *sf) { sigset_t set; int err; + struct user_regs_struct uregs; err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set)); - if (!err) - set_current_blocked(&set); - - err |= __copy_from_user(regs, &(sf->uc.uc_mcontext.regs), + err |= __copy_from_user(&uregs.scratch, + &(sf->uc.uc_mcontext.regs.scratch), sizeof(sf->uc.uc_mcontext.regs.scratch)); - return err; + if (is_isa_arcv2()) + err |= restore_arcv2_regs(&(sf->uc.uc_mcontext), regs); + + if (err) + return -EFAULT; + + set_current_blocked(&set); + regs->bta = uregs.scratch.bta; + regs->lp_start = uregs.scratch.lp_start; + regs->lp_end = uregs.scratch.lp_end; + regs->lp_count = uregs.scratch.lp_count; + regs->status32 = uregs.scratch.status32; + regs->ret = uregs.scratch.ret; + regs->blink = uregs.scratch.blink; + regs->fp = uregs.scratch.fp; + regs->r26 = uregs.scratch.gp; + regs->r12 = uregs.scratch.r12; + regs->r11 = uregs.scratch.r11; + regs->r10 = uregs.scratch.r10; + regs->r9 = uregs.scratch.r9; + regs->r8 = uregs.scratch.r8; + regs->r7 = uregs.scratch.r7; + regs->r6 = uregs.scratch.r6; + regs->r5 = uregs.scratch.r5; + regs->r4 = uregs.scratch.r4; + regs->r3 = uregs.scratch.r3; + regs->r2 = uregs.scratch.r2; + regs->r1 = uregs.scratch.r1; + regs->r0 = uregs.scratch.r0; + regs->sp = uregs.scratch.sp; + + return 0; } static inline int is_do_ss_needed(unsigned int magic) @@ -101,11 +197,10 @@ SYSCALL_DEFINE0(rt_sigreturn) { struct rt_sigframe __user *sf; unsigned int magic; - int err; struct pt_regs *regs = current_pt_regs(); /* Always make any pending restarted system calls return -EINTR */ - current_thread_info()->restart_block.fn = do_no_restart_syscall; + current->restart_block.fn = do_no_restart_syscall; /* Since we stacked the signal on a word boundary, * then 'sp' should be word aligned here. If it's @@ -116,42 +211,48 @@ SYSCALL_DEFINE0(rt_sigreturn) sf = (struct rt_sigframe __force __user *)(regs->sp); - if (!access_ok(VERIFY_READ, sf, sizeof(*sf))) + if (!access_ok(sf, sizeof(*sf))) goto badframe; - err = restore_usr_regs(regs, sf); - err |= __get_user(magic, &sf->sigret_magic); - if (err) + if (__get_user(magic, &sf->sigret_magic)) goto badframe; if (unlikely(is_do_ss_needed(magic))) if (restore_altstack(&sf->uc.uc_stack)) goto badframe; + if (restore_usr_regs(regs, sf)) + goto badframe; + /* Don't restart from sigreturn */ syscall_wont_restart(regs); + /* + * Ensure that sigreturn always returns to user mode (in case the + * regs saved on user stack got fudged between save and sigreturn) + * Otherwise it is easy to panic the kernel with a custom + * signal handler and/or restorer which clobberes the status32/ret + * to return to a bogus location in kernel mode. + */ + regs->status32 |= STATUS_U_MASK; + return regs->r0; badframe: - force_sig(SIGSEGV, current); + force_sig(SIGSEGV); return 0; } /* * Determine which stack to use.. */ -static inline void __user *get_sigframe(struct k_sigaction *ka, +static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize) { - unsigned long sp = regs->sp; + unsigned long sp = sigsp(regs->sp, ksig); void __user *frame; - /* This is the X/Open sanctioned signal stack switching */ - if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) - sp = current->sas_ss_sp + current->sas_ss_size; - /* No matter what happens, 'sp' must be word * aligned otherwise nasty things could happen */ @@ -160,44 +261,40 @@ static inline void __user *get_sigframe(struct k_sigaction *ka, frame = (void __user *)((sp - framesize) & ~7); /* Check that we can actually write to the signal frame */ - if (!access_ok(VERIFY_WRITE, frame, framesize)) + if (!access_ok(frame, framesize)) frame = NULL; return frame; } -/* - * translate the signal - */ -static inline int map_sig(int sig) -{ - struct thread_info *thread = current_thread_info(); - if (thread->exec_domain && thread->exec_domain->signal_invmap - && sig < 32) - sig = thread->exec_domain->signal_invmap[sig]; - return sig; -} - static int -setup_rt_frame(int signo, struct k_sigaction *ka, siginfo_t *info, - sigset_t *set, struct pt_regs *regs) +setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) { struct rt_sigframe __user *sf; unsigned int magic = 0; int err = 0; - sf = get_sigframe(ka, regs, sizeof(struct rt_sigframe)); + sf = get_sigframe(ksig, regs, sizeof(struct rt_sigframe)); if (!sf) return 1; /* + * w/o SA_SIGINFO, struct ucontext is partially populated (only + * uc_mcontext/uc_sigmask) for kernel's normal user state preservation + * during signal handler execution. This works for SA_SIGINFO as well + * although the semantics are now overloaded (the same reg state can be + * inspected by userland: but are they allowed to fiddle with it ? + */ + err |= stash_usr_regs(sf, regs, set); + + /* * SA_SIGINFO requires 3 args to signal handler: * #1: sig-no (common to any handler) * #2: struct siginfo * #3: struct ucontext (completely populated) */ - if (unlikely(ka->sa.sa_flags & SA_SIGINFO)) { - err |= copy_siginfo_to_user(&sf->info, info); + if (unlikely(ksig->ka.sa.sa_flags & SA_SIGINFO)) { + err |= copy_siginfo_to_user(&sf->info, &ksig->info); err |= __put_user(0, &sf->uc.uc_flags); err |= __put_user(NULL, &sf->uc.uc_link); err |= __save_altstack(&sf->uc.uc_stack, regs->sp); @@ -207,35 +304,30 @@ setup_rt_frame(int signo, struct k_sigaction *ka, siginfo_t *info, regs->r2 = (unsigned long)&sf->uc; /* - * small optim to avoid unconditonally calling do_sigaltstack + * small optim to avoid unconditionally calling do_sigaltstack * in sigreturn path, now that we only have rt_sigreturn */ magic = MAGIC_SIGALTSTK; } - /* - * w/o SA_SIGINFO, struct ucontext is partially populated (only - * uc_mcontext/uc_sigmask) for kernel's normal user state preservation - * during signal handler execution. This works for SA_SIGINFO as well - * although the semantics are now overloaded (the same reg state can be - * inspected by userland: but are they allowed to fiddle with it ? - */ - err |= stash_usr_regs(sf, regs, set); err |= __put_user(magic, &sf->sigret_magic); if (err) return err; /* #1 arg to the user Signal handler */ - regs->r0 = map_sig(signo); + regs->r0 = ksig->sig; /* setup PC of user space signal handler */ - regs->ret = (unsigned long)ka->sa.sa_handler; + regs->ret = (unsigned long)ksig->ka.sa.sa_handler; /* - * handler returns using sigreturn stub provided already by userpsace + * handler returns using sigreturn stub provided already by userspace + * If not, nuke the process right away */ - BUG_ON(!(ka->sa.sa_flags & SA_RESTORER)); - regs->blink = (unsigned long)ka->sa.sa_restorer; + if(!(ksig->ka.sa.sa_flags & SA_RESTORER)) + return 1; + + regs->blink = (unsigned long)ksig->ka.sa.sa_restorer; /* User Stack for signal handler will be above the frame just carved */ regs->sp = (unsigned long)sf; @@ -274,7 +366,7 @@ static void arc_restart_syscall(struct k_sigaction *ka, struct pt_regs *regs) regs->r0 = -EINTR; break; } - /* fallthrough */ + fallthrough; case -ERESTARTNOINTR: /* @@ -288,7 +380,7 @@ static void arc_restart_syscall(struct k_sigaction *ka, struct pt_regs *regs) * their orig user space value when we ret from kernel */ regs->r0 = regs->orig_r0; - regs->ret -= 4; + regs->ret -= is_isa_arcv2() ? 2 : 4; break; } } @@ -297,38 +389,30 @@ static void arc_restart_syscall(struct k_sigaction *ka, struct pt_regs *regs) * OK, we're invoking a handler */ static void -handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, - struct pt_regs *regs) +handle_signal(struct ksignal *ksig, struct pt_regs *regs) { sigset_t *oldset = sigmask_to_save(); - int ret; + int failed; /* Set up the stack frame */ - ret = setup_rt_frame(sig, ka, info, oldset, regs); + failed = setup_rt_frame(ksig, oldset, regs); - if (ret) - force_sigsegv(sig, current); - else - signal_delivered(sig, info, ka, regs, 0); + signal_setup_done(failed, ksig, 0); } void do_signal(struct pt_regs *regs) { - struct k_sigaction ka; - siginfo_t info; - int signr; + struct ksignal ksig; int restart_scall; - signr = get_signal_to_deliver(&info, &ka, regs, NULL); - restart_scall = in_syscall(regs) && syscall_restartable(regs); - if (signr > 0) { + if (test_thread_flag(TIF_SIGPENDING) && get_signal(&ksig)) { if (restart_scall) { - arc_restart_syscall(&ka, regs); + arc_restart_syscall(&ksig.ka, regs); syscall_wont_restart(regs); /* No more restarts */ } - handle_signal(signr, &ka, &info, regs); + handle_signal(&ksig, regs); return; } @@ -337,10 +421,10 @@ void do_signal(struct pt_regs *regs) if (regs->r0 == -ERESTARTNOHAND || regs->r0 == -ERESTARTSYS || regs->r0 == -ERESTARTNOINTR) { regs->r0 = regs->orig_r0; - regs->ret -= 4; + regs->ret -= is_isa_arcv2() ? 2 : 4; } else if (regs->r0 == -ERESTART_RESTARTBLOCK) { regs->r8 = __NR_restart_syscall; - regs->ret -= 4; + regs->ret -= is_isa_arcv2() ? 2 : 4; } syscall_wont_restart(regs); /* No more restarts */ } @@ -352,9 +436,9 @@ void do_signal(struct pt_regs *regs) void do_notify_resume(struct pt_regs *regs) { /* - * ASM glue gaurantees that this is only called when returning to + * ASM glue guarantees that this is only called when returning to * user mode */ - if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) - tracehook_notify_resume(regs); + if (test_thread_flag(TIF_NOTIFY_RESUME)) + resume_user_mode_work(regs); } |