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Commit 03a34755 authored by Aurelien Jacquiot's avatar Aurelien Jacquiot Committed by Mark Salter
Browse files

C6X: signal management 



Original port to early 2.6 kernel using TI COFF toolchain.
Brought up to date by Mark Salter <msalter@redhat.com>

Signed-off-by: default avatarAurelien Jacquiot <a-jacquiot@ti.com>
Signed-off-by: default avatarMark Salter <msalter@redhat.com>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
parent 687b12ba

arch/c6x/include/asm/sigcontext.h

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/*

 *  Port on Texas Instruments TMS320C6x architecture

 *

 *  Copyright (C) 2004, 2009 Texas Instruments Incorporated

 *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.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.

 */

#ifndef _ASM_C6X_SIGCONTEXT_H

#define _ASM_C6X_SIGCONTEXT_H





struct sigcontext {

	unsigned long  sc_mask;		/* old sigmask */

	unsigned long  sc_sp;		/* old user stack pointer */



	unsigned long  sc_a4;

	unsigned long  sc_b4;

	unsigned long  sc_a6;

	unsigned long  sc_b6;

	unsigned long  sc_a8;

	unsigned long  sc_b8;



	unsigned long  sc_a0;

	unsigned long  sc_a1;

	unsigned long  sc_a2;

	unsigned long  sc_a3;

	unsigned long  sc_a5;

	unsigned long  sc_a7;

	unsigned long  sc_a9;



	unsigned long  sc_b0;

	unsigned long  sc_b1;

	unsigned long  sc_b2;

	unsigned long  sc_b3;

	unsigned long  sc_b5;

	unsigned long  sc_b7;

	unsigned long  sc_b9;



	unsigned long  sc_a16;

	unsigned long  sc_a17;

	unsigned long  sc_a18;

	unsigned long  sc_a19;

	unsigned long  sc_a20;

	unsigned long  sc_a21;

	unsigned long  sc_a22;

	unsigned long  sc_a23;

	unsigned long  sc_a24;

	unsigned long  sc_a25;

	unsigned long  sc_a26;

	unsigned long  sc_a27;

	unsigned long  sc_a28;

	unsigned long  sc_a29;

	unsigned long  sc_a30;

	unsigned long  sc_a31;



	unsigned long  sc_b16;

	unsigned long  sc_b17;

	unsigned long  sc_b18;

	unsigned long  sc_b19;

	unsigned long  sc_b20;

	unsigned long  sc_b21;

	unsigned long  sc_b22;

	unsigned long  sc_b23;

	unsigned long  sc_b24;

	unsigned long  sc_b25;

	unsigned long  sc_b26;

	unsigned long  sc_b27;

	unsigned long  sc_b28;

	unsigned long  sc_b29;

	unsigned long  sc_b30;

	unsigned long  sc_b31;



	unsigned long  sc_csr;

	unsigned long  sc_pc;

};



#endif /* _ASM_C6X_SIGCONTEXT_H */

arch/c6x/include/asm/signal.h

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#ifndef _ASM_C6X_SIGNAL_H

#define _ASM_C6X_SIGNAL_H



#include <asm-generic/signal.h>



#ifndef __ASSEMBLY__

#include <linux/linkage.h>



struct pt_regs;



extern asmlinkage int do_rt_sigreturn(struct pt_regs *regs);

extern asmlinkage void do_notify_resume(struct pt_regs *regs,

					u32 thread_info_flags,

					int syscall);

#endif



#endif /* _ASM_C6X_SIGNAL_H */

arch/c6x/kernel/signal.c

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/*

 *  Port on Texas Instruments TMS320C6x architecture

 *

 *  Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated

 *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)

 *

 *  Updated for 2.6.34: Mark Salter <msalter@redhat.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.

 */



#include <linux/kernel.h>

#include <linux/uaccess.h>

#include <linux/syscalls.h>

#include <linux/tracehook.h>



#include <asm/ucontext.h>

#include <asm/cacheflush.h>





#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))



/*

 * Do a signal return, undo the signal stack.

 */



#define RETCODE_SIZE (9 << 2)	/* 9 instructions = 36 bytes */



struct rt_sigframe {

	struct siginfo __user *pinfo;

	void __user *puc;

	struct siginfo info;

	struct ucontext uc;

	unsigned long retcode[RETCODE_SIZE >> 2];

};



static int restore_sigcontext(struct pt_regs *regs,

			      struct sigcontext __user *sc)

{

	int err = 0;



	/* The access_ok check was done by caller, so use __get_user here */

#define COPY(x)  (err |= __get_user(regs->x, &sc->sc_##x))



	COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);

	COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);

	COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);



	COPY(a16); COPY(a17); COPY(a18); COPY(a19);

	COPY(a20); COPY(a21); COPY(a22); COPY(a23);

	COPY(a24); COPY(a25); COPY(a26); COPY(a27);

	COPY(a28); COPY(a29); COPY(a30); COPY(a31);

	COPY(b16); COPY(b17); COPY(b18); COPY(b19);

	COPY(b20); COPY(b21); COPY(b22); COPY(b23);

	COPY(b24); COPY(b25); COPY(b26); COPY(b27);

	COPY(b28); COPY(b29); COPY(b30); COPY(b31);



	COPY(csr); COPY(pc);



#undef COPY



	return err;

}



asmlinkage int do_rt_sigreturn(struct pt_regs *regs)

{

	struct rt_sigframe __user *frame;

	sigset_t set;



	/*

	 * Since we stacked the signal on a dword boundary,

	 * 'sp' should be dword aligned here.  If it's

	 * not, then the user is trying to mess with us.

	 */

	if (regs->sp & 7)

		goto badframe;



	frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8);



	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))

		goto badframe;

	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))

		goto badframe;



	sigdelsetmask(&set, ~_BLOCKABLE);

	spin_lock_irq(&current->sighand->siglock);

	current->blocked = set;

	recalc_sigpending();

	spin_unlock_irq(&current->sighand->siglock);



	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))

		goto badframe;



	return regs->a4;



badframe:

	force_sig(SIGSEGV, current);

	return 0;

}



static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,

			    unsigned long mask)

{

	int err = 0;



	err |= __put_user(mask, &sc->sc_mask);



	/* The access_ok check was done by caller, so use __put_user here */

#define COPY(x) (err |= __put_user(regs->x, &sc->sc_##x))



	COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);

	COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);

	COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);



	COPY(a16); COPY(a17); COPY(a18); COPY(a19);

	COPY(a20); COPY(a21); COPY(a22); COPY(a23);

	COPY(a24); COPY(a25); COPY(a26); COPY(a27);

	COPY(a28); COPY(a29); COPY(a30); COPY(a31);

	COPY(b16); COPY(b17); COPY(b18); COPY(b19);

	COPY(b20); COPY(b21); COPY(b22); COPY(b23);

	COPY(b24); COPY(b25); COPY(b26); COPY(b27);

	COPY(b28); COPY(b29); COPY(b30); COPY(b31);



	COPY(csr); COPY(pc);



#undef COPY



	return err;

}



static inline void __user *get_sigframe(struct k_sigaction *ka,

					struct pt_regs *regs,

					unsigned long framesize)

{

	unsigned long sp = regs->sp;



	/*

	 * This is the X/Open sanctioned signal stack switching.

	 */

	if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags(sp) == 0)

		sp = current->sas_ss_sp + current->sas_ss_size;



	/*

	 * No matter what happens, 'sp' must be dword

	 * aligned. Otherwise, nasty things will happen

	 */

	return (void __user *)((sp - framesize) & ~7);

}



static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,

			   sigset_t *set, struct pt_regs *regs)

{

	struct rt_sigframe __user *frame;

	unsigned long __user *retcode;

	int err = 0;



	frame = get_sigframe(ka, regs, sizeof(*frame));



	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))

		goto segv_and_exit;



	err |= __put_user(&frame->info, &frame->pinfo);

	err |= __put_user(&frame->uc, &frame->puc);

	err |= copy_siginfo_to_user(&frame->info, info);



	/* Clear all the bits of the ucontext we don't use.  */

	err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));



	err |= setup_sigcontext(&frame->uc.uc_mcontext,	regs, set->sig[0]);

	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));



	/* Set up to return from userspace */

	retcode = (unsigned long __user *) &frame->retcode;



	/* The access_ok check was done above, so use __put_user here */

#define COPY(x) (err |= __put_user(x, retcode++))



	COPY(0x0000002AUL | (__NR_rt_sigreturn << 7));

				/* MVK __NR_rt_sigreturn,B0 */

	COPY(0x10000000UL);	/* SWE */

	COPY(0x00006000UL);	/* NOP 4 */

	COPY(0x00006000UL);	/* NOP 4 */

	COPY(0x00006000UL);	/* NOP 4 */

	COPY(0x00006000UL);	/* NOP 4 */

	COPY(0x00006000UL);	/* NOP 4 */

	COPY(0x00006000UL);	/* NOP 4 */

	COPY(0x00006000UL);	/* NOP 4 */



#undef COPY



	if (err)

		goto segv_and_exit;



	flush_icache_range((unsigned long) &frame->retcode,

			   (unsigned long) &frame->retcode + RETCODE_SIZE);



	retcode = (unsigned long __user *) &frame->retcode;



	/* Change user context to branch to signal handler */

	regs->sp = (unsigned long) frame - 8;

	regs->b3 = (unsigned long) retcode;

	regs->pc = (unsigned long) ka->sa.sa_handler;



	/* Give the signal number to the handler */

	regs->a4 = signr;



	/*

	 * For realtime signals we must also set the second and third

	 * arguments for the signal handler.

	 *   -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06

	 */

	regs->b4 = (unsigned long)&frame->info;

	regs->a6 = (unsigned long)&frame->uc;



	return 0;



segv_and_exit:

	force_sigsegv(signr, current);

	return -EFAULT;

}



static inline void

handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)

{

	switch (regs->a4) {

	case -ERESTARTNOHAND:

		if (!has_handler)

			goto do_restart;

		regs->a4 = -EINTR;

		break;



	case -ERESTARTSYS:

		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {

			regs->a4 = -EINTR;

			break;

		}

	/* fallthrough */

	case -ERESTARTNOINTR:

do_restart:

		regs->a4 = regs->orig_a4;

		regs->pc -= 4;

		break;

	}

}



/*

 * handle the actual delivery of a signal to userspace

 */

static int handle_signal(int sig,

			 siginfo_t *info, struct k_sigaction *ka,

			 sigset_t *oldset, struct pt_regs *regs,

			 int syscall)

{

	int ret;



	/* Are we from a system call? */

	if (syscall) {

		/* If so, check system call restarting.. */

		switch (regs->a4) {

		case -ERESTART_RESTARTBLOCK:

		case -ERESTARTNOHAND:

			regs->a4 = -EINTR;

			break;



		case -ERESTARTSYS:

			if (!(ka->sa.sa_flags & SA_RESTART)) {

				regs->a4 = -EINTR;

				break;

			}



			/* fallthrough */

		case -ERESTARTNOINTR:

			regs->a4 = regs->orig_a4;

			regs->pc -= 4;

		}

	}



	/* Set up the stack frame */

	ret = setup_rt_frame(sig, ka, info, oldset, regs);

	if (ret == 0) {

		spin_lock_irq(&current->sighand->siglock);

		sigorsets(&current->blocked, &current->blocked,

			  &ka->sa.sa_mask);

		if (!(ka->sa.sa_flags & SA_NODEFER))

			sigaddset(&current->blocked, sig);

		recalc_sigpending();

		spin_unlock_irq(&current->sighand->siglock);

	}



	return ret;

}



/*

 * handle a potential signal

 */

static void do_signal(struct pt_regs *regs, int syscall)

{

	struct k_sigaction ka;

	siginfo_t info;

	sigset_t *oldset;

	int signr;



	/* we want the common case to go fast, which is why we may in certain

	 * cases get here from kernel mode */

	if (!user_mode(regs))

		return;



	if (test_thread_flag(TIF_RESTORE_SIGMASK))

		oldset = &current->saved_sigmask;

	else

		oldset = &current->blocked;



	signr = get_signal_to_deliver(&info, &ka, regs, NULL);

	if (signr > 0) {

		if (handle_signal(signr, &info, &ka, oldset,

				  regs, syscall) == 0) {

			/* a signal was successfully delivered; the saved

			 * sigmask will have been stored in the signal frame,

			 * and will be restored by sigreturn, so we can simply

			 * clear the TIF_RESTORE_SIGMASK flag */

			if (test_thread_flag(TIF_RESTORE_SIGMASK))

				clear_thread_flag(TIF_RESTORE_SIGMASK);



			tracehook_signal_handler(signr, &info, &ka, regs, 0);

		}



		return;

	}



	/* did we come from a system call? */

	if (syscall) {

		/* restart the system call - no handlers present */

		switch (regs->a4) {

		case -ERESTARTNOHAND:

		case -ERESTARTSYS:

		case -ERESTARTNOINTR:

			regs->a4 = regs->orig_a4;

			regs->pc -= 4;

			break;



		case -ERESTART_RESTARTBLOCK:

			regs->a4 = regs->orig_a4;

			regs->b0 = __NR_restart_syscall;

			regs->pc -= 4;

			break;

		}

	}



	/* if there's no signal to deliver, we just put the saved sigmask

	 * back */

	if (test_thread_flag(TIF_RESTORE_SIGMASK)) {

		clear_thread_flag(TIF_RESTORE_SIGMASK);

		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);

	}

}



/*

 * notification of userspace execution resumption

 * - triggered by current->work.notify_resume

 */

asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,

				 int syscall)

{

	/* deal with pending signal delivery */

	if (thread_info_flags & ((1 << TIF_SIGPENDING) |

				 (1 << TIF_RESTORE_SIGMASK)))

		do_signal(regs, syscall);



	if (thread_info_flags & (1 << TIF_NOTIFY_RESUME)) {

		clear_thread_flag(TIF_NOTIFY_RESUME);

		tracehook_notify_resume(regs);

		if (current->replacement_session_keyring)

			key_replace_session_keyring();

	}

}