327 lines
8.1 KiB
C
327 lines
8.1 KiB
C
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/*
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* Port on Texas Instruments TMS320C6x architecture
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*
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* Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
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* Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
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*
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* Updated for 2.6.34: Mark Salter <msalter@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/uaccess.h>
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#include <linux/syscalls.h>
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#include <linux/tracehook.h>
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#include <asm/ucontext.h>
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#include <asm/cacheflush.h>
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/*
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* Do a signal return, undo the signal stack.
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*/
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#define RETCODE_SIZE (9 << 2) /* 9 instructions = 36 bytes */
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struct rt_sigframe {
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struct siginfo __user *pinfo;
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void __user *puc;
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struct siginfo info;
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struct ucontext uc;
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unsigned long retcode[RETCODE_SIZE >> 2];
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};
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static int restore_sigcontext(struct pt_regs *regs,
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struct sigcontext __user *sc)
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{
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int err = 0;
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/* The access_ok check was done by caller, so use __get_user here */
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#define COPY(x) (err |= __get_user(regs->x, &sc->sc_##x))
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COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
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COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
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COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
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COPY(a16); COPY(a17); COPY(a18); COPY(a19);
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COPY(a20); COPY(a21); COPY(a22); COPY(a23);
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COPY(a24); COPY(a25); COPY(a26); COPY(a27);
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COPY(a28); COPY(a29); COPY(a30); COPY(a31);
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COPY(b16); COPY(b17); COPY(b18); COPY(b19);
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COPY(b20); COPY(b21); COPY(b22); COPY(b23);
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COPY(b24); COPY(b25); COPY(b26); COPY(b27);
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COPY(b28); COPY(b29); COPY(b30); COPY(b31);
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COPY(csr); COPY(pc);
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#undef COPY
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return err;
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}
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asmlinkage int do_rt_sigreturn(struct pt_regs *regs)
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{
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struct rt_sigframe __user *frame;
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sigset_t set;
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/* Always make any pending restarted system calls return -EINTR */
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current_thread_info()->restart_block.fn = do_no_restart_syscall;
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/*
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* Since we stacked the signal on a dword boundary,
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* 'sp' should be dword aligned here. If it's
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* not, then the user is trying to mess with us.
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*/
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if (regs->sp & 7)
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goto badframe;
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frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8);
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if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
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goto badframe;
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if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
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goto badframe;
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set_current_blocked(&set);
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if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
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goto badframe;
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return regs->a4;
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badframe:
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force_sig(SIGSEGV, current);
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return 0;
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}
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static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
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unsigned long mask)
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{
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int err = 0;
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err |= __put_user(mask, &sc->sc_mask);
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/* The access_ok check was done by caller, so use __put_user here */
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#define COPY(x) (err |= __put_user(regs->x, &sc->sc_##x))
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COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
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COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
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COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
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COPY(a16); COPY(a17); COPY(a18); COPY(a19);
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COPY(a20); COPY(a21); COPY(a22); COPY(a23);
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COPY(a24); COPY(a25); COPY(a26); COPY(a27);
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COPY(a28); COPY(a29); COPY(a30); COPY(a31);
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COPY(b16); COPY(b17); COPY(b18); COPY(b19);
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COPY(b20); COPY(b21); COPY(b22); COPY(b23);
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COPY(b24); COPY(b25); COPY(b26); COPY(b27);
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COPY(b28); COPY(b29); COPY(b30); COPY(b31);
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COPY(csr); COPY(pc);
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#undef COPY
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return err;
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}
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static inline void __user *get_sigframe(struct ksignal *ksig,
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struct pt_regs *regs,
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unsigned long framesize)
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{
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unsigned long sp = sigsp(regs->sp, ksig);
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/*
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* No matter what happens, 'sp' must be dword
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* aligned. Otherwise, nasty things will happen
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*/
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return (void __user *)((sp - framesize) & ~7);
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}
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static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
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struct pt_regs *regs)
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{
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struct rt_sigframe __user *frame;
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unsigned long __user *retcode;
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int err = 0;
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frame = get_sigframe(ksig, regs, sizeof(*frame));
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if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
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return -EFAULT;
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err |= __put_user(&frame->info, &frame->pinfo);
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err |= __put_user(&frame->uc, &frame->puc);
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err |= copy_siginfo_to_user(&frame->info, &ksig->info);
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/* Clear all the bits of the ucontext we don't use. */
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err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
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err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
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err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
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/* Set up to return from userspace */
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retcode = (unsigned long __user *) &frame->retcode;
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/* The access_ok check was done above, so use __put_user here */
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#define COPY(x) (err |= __put_user(x, retcode++))
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COPY(0x0000002AUL | (__NR_rt_sigreturn << 7));
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/* MVK __NR_rt_sigreturn,B0 */
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COPY(0x10000000UL); /* SWE */
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COPY(0x00006000UL); /* NOP 4 */
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COPY(0x00006000UL); /* NOP 4 */
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COPY(0x00006000UL); /* NOP 4 */
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COPY(0x00006000UL); /* NOP 4 */
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COPY(0x00006000UL); /* NOP 4 */
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COPY(0x00006000UL); /* NOP 4 */
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COPY(0x00006000UL); /* NOP 4 */
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#undef COPY
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if (err)
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return -EFAULT;
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flush_icache_range((unsigned long) &frame->retcode,
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(unsigned long) &frame->retcode + RETCODE_SIZE);
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retcode = (unsigned long __user *) &frame->retcode;
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/* Change user context to branch to signal handler */
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regs->sp = (unsigned long) frame - 8;
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regs->b3 = (unsigned long) retcode;
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regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
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/* Give the signal number to the handler */
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regs->a4 = ksig->sig;
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/*
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* For realtime signals we must also set the second and third
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* arguments for the signal handler.
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* -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
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*/
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regs->b4 = (unsigned long)&frame->info;
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regs->a6 = (unsigned long)&frame->uc;
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return 0;
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}
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static inline void
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handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
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{
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switch (regs->a4) {
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case -ERESTARTNOHAND:
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if (!has_handler)
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goto do_restart;
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regs->a4 = -EINTR;
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break;
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case -ERESTARTSYS:
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if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
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regs->a4 = -EINTR;
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break;
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}
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/* fallthrough */
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case -ERESTARTNOINTR:
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do_restart:
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regs->a4 = regs->orig_a4;
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regs->pc -= 4;
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break;
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}
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}
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/*
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* handle the actual delivery of a signal to userspace
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*/
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static void handle_signal(struct ksignal *ksig, struct pt_regs *regs,
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int syscall)
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{
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int ret;
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/* Are we from a system call? */
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if (syscall) {
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/* If so, check system call restarting.. */
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switch (regs->a4) {
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case -ERESTART_RESTARTBLOCK:
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case -ERESTARTNOHAND:
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regs->a4 = -EINTR;
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break;
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case -ERESTARTSYS:
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if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
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regs->a4 = -EINTR;
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break;
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}
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/* fallthrough */
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case -ERESTARTNOINTR:
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regs->a4 = regs->orig_a4;
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regs->pc -= 4;
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}
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}
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/* Set up the stack frame */
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ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
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signal_setup_done(ret, ksig, 0);
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}
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/*
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* handle a potential signal
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*/
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static void do_signal(struct pt_regs *regs, int syscall)
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{
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struct ksignal ksig;
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/* we want the common case to go fast, which is why we may in certain
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* cases get here from kernel mode */
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if (!user_mode(regs))
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return;
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if (get_signal(&ksig)) {
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handle_signal(&ksig, regs, syscall);
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return;
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}
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/* did we come from a system call? */
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if (syscall) {
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/* restart the system call - no handlers present */
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switch (regs->a4) {
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case -ERESTARTNOHAND:
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case -ERESTARTSYS:
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case -ERESTARTNOINTR:
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regs->a4 = regs->orig_a4;
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regs->pc -= 4;
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break;
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case -ERESTART_RESTARTBLOCK:
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regs->a4 = regs->orig_a4;
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regs->b0 = __NR_restart_syscall;
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regs->pc -= 4;
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break;
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}
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}
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/* if there's no signal to deliver, we just put the saved sigmask
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* back */
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restore_saved_sigmask();
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}
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/*
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* notification of userspace execution resumption
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* - triggered by current->work.notify_resume
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*/
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asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
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int syscall)
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{
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/* deal with pending signal delivery */
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if (thread_info_flags & (1 << TIF_SIGPENDING))
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do_signal(regs, syscall);
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if (thread_info_flags & (1 << TIF_NOTIFY_RESUME)) {
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clear_thread_flag(TIF_NOTIFY_RESUME);
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tracehook_notify_resume(regs);
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}
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}
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