signal.c

/*
 * Copyright (C) 2003 PathScale, Inc.
 * Licensed under the GPL
 */

#include "linux/stddef.h"
#include "linux/errno.h"
#include "linux/personality.h"
#include "linux/ptrace.h"
#include "asm/current.h"
#include "asm/uaccess.h"
#include "asm/sigcontext.h"
#include "asm/ptrace.h"
#include "asm/arch/ucontext.h"
#include "choose-mode.h"
#include "sysdep/ptrace.h"
#include "frame_kern.h"

#ifdef CONFIG_MODE_SKAS

#include "skas.h"

static int copy_sc_from_user_skas(struct pt_regs *regs,
                                 struct sigcontext __user *from)
{
       int err = 0;

#define GETREG(regs, regno, sc, regname) \
       __get_user((regs)->regs.skas.regs[(regno) / sizeof(unsigned long)], \
                  &(sc)->regname)

       err |= GETREG(regs, R8, from, r8);
       err |= GETREG(regs, R9, from, r9);
       err |= GETREG(regs, R10, from, r10);
       err |= GETREG(regs, R11, from, r11);
       err |= GETREG(regs, R12, from, r12);
       err |= GETREG(regs, R13, from, r13);
       err |= GETREG(regs, R14, from, r14);
       err |= GETREG(regs, R15, from, r15);
       err |= GETREG(regs, RDI, from, rdi);
       err |= GETREG(regs, RSI, from, rsi);
       err |= GETREG(regs, RBP, from, rbp);
       err |= GETREG(regs, RBX, from, rbx);
       err |= GETREG(regs, RDX, from, rdx);
       err |= GETREG(regs, RAX, from, rax);
       err |= GETREG(regs, RCX, from, rcx);
       err |= GETREG(regs, RSP, from, rsp);
       err |= GETREG(regs, RIP, from, rip);
       err |= GETREG(regs, EFLAGS, from, eflags);
       err |= GETREG(regs, CS, from, cs);

#undef GETREG

       return err;
}

int copy_sc_to_user_skas(struct sigcontext __user *to,
			 struct _fpstate __user *to_fp,
			 struct pt_regs *regs, unsigned long mask,
			 unsigned long sp)
{
        struct faultinfo * fi = &current->thread.arch.faultinfo;
	int err = 0;

	err |= __put_user(0, &to->gs);
	err |= __put_user(0, &to->fs);

#define PUTREG(regs, regno, sc, regname) \
       __put_user((regs)->regs.skas.regs[(regno) / sizeof(unsigned long)], \
                  &(sc)->regname)

	err |= PUTREG(regs, RDI, to, rdi);
	err |= PUTREG(regs, RSI, to, rsi);
	err |= PUTREG(regs, RBP, to, rbp);
        /* Must use orignal RSP, which is passed in, rather than what's in
         * the pt_regs, because that's already been updated to point at the
         * signal frame.
         */
	err |= __put_user(sp, &to->rsp);
	err |= PUTREG(regs, RBX, to, rbx);
	err |= PUTREG(regs, RDX, to, rdx);
	err |= PUTREG(regs, RCX, to, rcx);
	err |= PUTREG(regs, RAX, to, rax);
	err |= PUTREG(regs, R8, to, r8);
	err |= PUTREG(regs, R9, to, r9);
	err |= PUTREG(regs, R10, to, r10);
	err |= PUTREG(regs, R11, to, r11);
	err |= PUTREG(regs, R12, to, r12);
	err |= PUTREG(regs, R13, to, r13);
	err |= PUTREG(regs, R14, to, r14);
	err |= PUTREG(regs, R15, to, r15);
	err |= PUTREG(regs, CS, to, cs); /* XXX x86_64 doesn't do this */

        err |= __put_user(fi->cr2, &to->cr2);
        err |= __put_user(fi->error_code, &to->err);
        err |= __put_user(fi->trap_no, &to->trapno);

	err |= PUTREG(regs, RIP, to, rip);
	err |= PUTREG(regs, EFLAGS, to, eflags);
#undef PUTREG

	err |= __put_user(mask, &to->oldmask);

	return(err);
}

#endif

#ifdef CONFIG_MODE_TT
int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext __user *from,
			 int fpsize)
{
	struct _fpstate *to_fp;
	struct _fpstate __user *from_fp;
	unsigned long sigs;
	int err;

	to_fp = to->fpstate;
	sigs = to->oldmask;
	err = copy_from_user(to, from, sizeof(*to));
	from_fp = to->fpstate;
	to->fpstate = to_fp;
	to->oldmask = sigs;
	if(to_fp != NULL)
		err |= copy_from_user(to_fp, from_fp, fpsize);
	return(err);
}

int copy_sc_to_user_tt(struct sigcontext __user *to, struct _fpstate __user *fp,
		       struct sigcontext *from, int fpsize, unsigned long sp)
{
	struct _fpstate __user *to_fp;
	struct _fpstate *from_fp;
	int err;

	to_fp = (fp ? fp : (struct _fpstate __user *) (to + 1));
	from_fp = from->fpstate;
	err = copy_to_user(to, from, sizeof(*to));
	/* The SP in the sigcontext is the updated one for the signal
	 * delivery.  The sp passed in is the original, and this needs
	 * to be restored, so we stick it in separately.
	 */
	err |= copy_to_user(&SC_SP(to), &sp, sizeof(sp));

	if(from_fp != NULL){
		err |= copy_to_user(&to->fpstate, &to_fp, sizeof(to->fpstate));
		err |= copy_to_user(to_fp, from_fp, fpsize);
	}
	return err;
}

#endif

static int copy_sc_from_user(struct pt_regs *to, void __user *from)
{
       int ret;

       ret = CHOOSE_MODE(copy_sc_from_user_tt(UPT_SC(&to->regs), from,
                                              sizeof(struct _fpstate)),
                         copy_sc_from_user_skas(to, from));
       return(ret);
}

static int copy_sc_to_user(struct sigcontext __user *to,
			   struct _fpstate __user *fp,
			   struct pt_regs *from, unsigned long mask,
			   unsigned long sp)
{
       return(CHOOSE_MODE(copy_sc_to_user_tt(to, fp, UPT_SC(&from->regs),
                                             sizeof(*fp), sp),
                          copy_sc_to_user_skas(to, fp, from, mask, sp)));
}

struct rt_sigframe
{
       char __user *pretcode;
       struct ucontext uc;
       struct siginfo info;
};

#define round_down(m, n) (((m) / (n)) * (n))

int setup_signal_stack_si(unsigned long stack_top, int sig,
			  struct k_sigaction *ka, struct pt_regs * regs,
			  siginfo_t *info, sigset_t *set)
{
	struct rt_sigframe __user *frame;
	struct _fpstate __user *fp = NULL;
	unsigned long save_sp = PT_REGS_RSP(regs);
	int err = 0;
	struct task_struct *me = current;

	frame = (struct rt_sigframe __user *)
		round_down(stack_top - sizeof(struct rt_sigframe), 16);
	/* Subtract 128 for a red zone and 8 for proper alignment */
        frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);

	if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
		goto out;

#if 0 /* XXX */
	if (save_i387(fp) < 0)
		err |= -1;
#endif
	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto out;

	if (ka->sa.sa_flags & SA_SIGINFO) {
		err |= copy_siginfo_to_user(&frame->info, info);
		if (err)
			goto out;
	}

	/* Update SP now because the page fault handler refuses to extend
	 * the stack if the faulting address is too far below the current
	 * SP, which frame now certainly is.  If there's an error, the original
	 * value is restored on the way out.
	 * When writing the sigcontext to the stack, we have to write the
	 * original value, so that's passed to copy_sc_to_user, which does
	 * the right thing with it.
	 */
	PT_REGS_RSP(regs) = (unsigned long) frame;

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(0, &frame->uc.uc_link);
	err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(save_sp),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= copy_sc_to_user(&frame->uc.uc_mcontext, fp, regs, set->sig[0],
		save_sp);
	err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
	if (sizeof(*set) == 16) {
		__put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
		__put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
	}
	else
		err |= __copy_to_user(&frame->uc.uc_sigmask, set,
				      sizeof(*set));

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	/* x86-64 should always use SA_RESTORER. */
	if (ka->sa.sa_flags & SA_RESTORER)
		err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
	else
		/* could use a vstub here */
		goto restore_sp;

	if (err)
		goto restore_sp;

	/* Set up registers for signal handler */
	{
		struct exec_domain *ed = current_thread_info()->exec_domain;
		if (unlikely(ed && ed->signal_invmap && sig < 32))
			sig = ed->signal_invmap[sig];
	}

	PT_REGS_RDI(regs) = sig;
	/* In case the signal handler was declared without prototypes */
	PT_REGS_RAX(regs) = 0;

	/* This also works for non SA_SIGINFO handlers because they expect the
	   next argument after the signal number on the stack. */
	PT_REGS_RSI(regs) = (unsigned long) &frame->info;
	PT_REGS_RDX(regs) = (unsigned long) &frame->uc;
	PT_REGS_RIP(regs) = (unsigned long) ka->sa.sa_handler;
 out:
	return err;

restore_sp:
	PT_REGS_RSP(regs) = save_sp;
	return err;
}

long sys_rt_sigreturn(struct pt_regs *regs)
{
	unsigned long sp = PT_REGS_SP(&current->thread.regs);
	struct rt_sigframe __user *frame =
		(struct rt_sigframe __user *)(sp - 8);
	struct ucontext __user *uc = &frame->uc;
	sigset_t set;

	if(copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
		goto segfault;

	sigdelsetmask(&set, ~_BLOCKABLE);

	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if(copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
		goto segfault;

	/* Avoid ERESTART handling */
	PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
	return(PT_REGS_SYSCALL_RET(&current->thread.regs));

 segfault:
	force_sig(SIGSEGV, current);
	return 0;
}
/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * Emacs will notice this stuff at the end of the file and automatically
 * adjust the settings for this buffer only.  This must remain at the end
 * of the file.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-file-style: "linux"
 * End:
 */