arch/mips/kernel/signal_n32.c

Source file repositories/reference/linux-study-clean/arch/mips/kernel/signal_n32.c

File Facts

System
Linux kernel
Corpus path
arch/mips/kernel/signal_n32.c
Extension
.c
Size
3692 bytes
Lines
147
Domain
Architecture Layer
Bucket
arch/mips
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

struct ucontextn32 {
	u32		    uc_flags;
	s32		    uc_link;
	compat_stack_t      uc_stack;
	struct sigcontext   uc_mcontext;
	compat_sigset_t	    uc_sigmask;	  /* mask last for extensibility */
};

struct rt_sigframe_n32 {
	u32 rs_ass[4];			/* argument save space for o32 */
	u32 rs_pad[2];			/* Was: signal trampoline */
	struct compat_siginfo rs_info;
	struct ucontextn32 rs_uc;
};

asmlinkage void sysn32_rt_sigreturn(void)
{
	struct rt_sigframe_n32 __user *frame;
	struct pt_regs *regs;
	sigset_t set;
	int sig;

	regs = current_pt_regs();
	frame = (struct rt_sigframe_n32 __user *)regs->regs[29];
	if (!access_ok(frame, sizeof(*frame)))
		goto badframe;
	if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
		goto badframe;

	set_current_blocked(&set);

	sig = restore_sigcontext(regs, &frame->rs_uc.uc_mcontext);
	if (sig < 0)
		goto badframe;
	else if (sig)
		force_sig(sig);

	if (compat_restore_altstack(&frame->rs_uc.uc_stack))
		goto badframe;

	/*
	 * Don't let your children do this ...
	 */
	__asm__ __volatile__(
		"move\t$29, %0\n\t"
		"j\tsyscall_exit"
		: /* no outputs */
		: "r" (regs));
	/* Unreached */

badframe:
	force_sig(SIGSEGV);
}

static int setup_rt_frame_n32(void *sig_return, struct ksignal *ksig,
			      struct pt_regs *regs, sigset_t *set)
{
	struct rt_sigframe_n32 __user *frame;
	int err = 0;

	frame = get_sigframe(ksig, regs, sizeof(*frame));
	if (!access_ok(frame, sizeof (*frame)))
		return -EFAULT;

	/* Create siginfo.  */
	err |= copy_siginfo_to_user32(&frame->rs_info, &ksig->info);

	/* Create the ucontext.	 */
	err |= __put_user(0, &frame->rs_uc.uc_flags);
	err |= __put_user(0, &frame->rs_uc.uc_link);
	err |= __compat_save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
	err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);

	if (err)
		return -EFAULT;

	/*
	 * Arguments to signal handler:
	 *
	 *   a0 = signal number
	 *   a1 = 0 (should be cause)
	 *   a2 = pointer to ucontext
	 *
	 * $25 and c0_epc point to the signal handler, $29 points to
	 * the struct rt_sigframe.
	 */
	regs->regs[ 4] = ksig->sig;
	regs->regs[ 5] = (unsigned long) &frame->rs_info;
	regs->regs[ 6] = (unsigned long) &frame->rs_uc;

Annotation

Implementation Notes