powerpc: move ppc64/kernel/signal.c to arch/powerpc

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

1 files changed, 581 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
new file mode 100644
index 000000000000..ec9d0984b6a0
--- /dev/null
+++ b/arch/powerpc/kernel/signal_64.c
@@ -0,0 +1,581 @@
+/*
+ *  linux/arch/ppc64/kernel/signal.c
+ *
+ *  PowerPC version 
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ *  Derived from "arch/i386/kernel/signal.c"
+ *    Copyright (C) 1991, 1992 Linus Torvalds
+ *    1997-11-28  Modified for POSIX.1b signals by Richard Henderson
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/errno.h>
+#include <linux/wait.h>
+#include <linux/unistd.h>
+#include <linux/stddef.h>
+#include <linux/elf.h>
+#include <linux/ptrace.h>
+#include <linux/module.h>
+
+#include <asm/sigcontext.h>
+#include <asm/ucontext.h>
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/ppcdebug.h>
+#include <asm/unistd.h>
+#include <asm/cacheflush.h>
+#include <asm/vdso.h>
+
+#define DEBUG_SIG 0
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+#define GP_REGS_SIZE	min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
+#define FP_REGS_SIZE	sizeof(elf_fpregset_t)
+
+#define TRAMP_TRACEBACK	3
+#define TRAMP_SIZE	6
+
+/*
+ * When we have signals to deliver, we set up on the user stack,
+ * going down from the original stack pointer:
+ *	1) a rt_sigframe struct which contains the ucontext	
+ *	2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller
+ *	   frame for the signal handler.
+ */
+
+struct rt_sigframe {
+	/* sys_rt_sigreturn requires the ucontext be the first field */
+	struct ucontext uc;
+	unsigned long _unused[2];
+	unsigned int tramp[TRAMP_SIZE];
+	struct siginfo *pinfo;
+	void *puc;
+	struct siginfo info;
+	/* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
+	char abigap[288];
+} __attribute__ ((aligned (16)));
+
+
+/*
+ * Atomically swap in the new signal mask, and wait for a signal.
+ */
+long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, int p3, int p4,
+		       int p6, int p7, struct pt_regs *regs)
+{
+	sigset_t saveset, newset;
+
+	/* XXX: Don't preclude handling different sized sigset_t's.  */
+	if (sigsetsize != sizeof(sigset_t))
+		return -EINVAL;
+
+	if (copy_from_user(&newset, unewset, sizeof(newset)))
+		return -EFAULT;
+	sigdelsetmask(&newset, ~_BLOCKABLE);
+
+	spin_lock_irq(&current->sighand->siglock);
+	saveset = current->blocked;
+	current->blocked = newset;
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+
+	regs->result = -EINTR;
+	regs->gpr[3] = EINTR;
+	regs->ccr |= 0x10000000;
+	while (1) {
+		current->state = TASK_INTERRUPTIBLE;
+		schedule();
+		if (do_signal(&saveset, regs))
+			return 0;
+	}
+}
+
+long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, unsigned long r5,
+		     unsigned long r6, unsigned long r7, unsigned long r8,
+		     struct pt_regs *regs)
+{
+	return do_sigaltstack(uss, uoss, regs->gpr[1]);
+}
+
+
+/*
+ * Set up the sigcontext for the signal frame.
+ */
+
+static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
+		 int signr, sigset_t *set, unsigned long handler)
+{
+	/* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
+	 * process never used altivec yet (MSR_VEC is zero in pt_regs of
+	 * the context). This is very important because we must ensure we
+	 * don't lose the VRSAVE content that may have been set prior to
+	 * the process doing its first vector operation
+	 * Userland shall check AT_HWCAP to know wether it can rely on the
+	 * v_regs pointer or not
+	 */
+#ifdef CONFIG_ALTIVEC
+	elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 15) & ~0xful);
+#endif
+	long err = 0;
+
+	flush_fp_to_thread(current);
+
+	/* Make sure signal doesn't get spurrious FP exceptions */
+	current->thread.fpscr.val = 0;
+
+#ifdef CONFIG_ALTIVEC
+	err |= __put_user(v_regs, &sc->v_regs);
+
+	/* save altivec registers */
+	if (current->thread.used_vr) {
+		flush_altivec_to_thread(current);
+		/* Copy 33 vec registers (vr0..31 and vscr) to the stack */
+		err |= __copy_to_user(v_regs, current->thread.vr, 33 * sizeof(vector128));
+		/* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
+		 * contains valid data.
+		 */
+		regs->msr |= MSR_VEC;
+	}
+	/* We always copy to/from vrsave, it's 0 if we don't have or don't
+	 * use altivec.
+	 */
+	err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
+#else /* CONFIG_ALTIVEC */
+	err |= __put_user(0, &sc->v_regs);
+#endif /* CONFIG_ALTIVEC */
+	err |= __put_user(&sc->gp_regs, &sc->regs);
+	err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
+	err |= __copy_to_user(&sc->fp_regs, &current->thread.fpr, FP_REGS_SIZE);
+	err |= __put_user(signr, &sc->signal);
+	err |= __put_user(handler, &sc->handler);
+	if (set != NULL)
+		err |=  __put_user(set->sig[0], &sc->oldmask);
+
+	return err;
+}
+
+/*
+ * Restore the sigcontext from the signal frame.
+ */
+
+static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
+			      struct sigcontext __user *sc)
+{
+#ifdef CONFIG_ALTIVEC
+	elf_vrreg_t __user *v_regs;
+#endif
+	unsigned long err = 0;
+	unsigned long save_r13 = 0;
+	elf_greg_t *gregs = (elf_greg_t *)regs;
+#ifdef CONFIG_ALTIVEC
+	unsigned long msr;
+#endif
+	int i;
+
+	/* If this is not a signal return, we preserve the TLS in r13 */
+	if (!sig)
+		save_r13 = regs->gpr[13];
+
+	/* copy everything before MSR */
+	err |= __copy_from_user(regs, &sc->gp_regs,
+				PT_MSR*sizeof(unsigned long));
+
+	/* skip MSR and SOFTE */
+	for (i = PT_MSR+1; i <= PT_RESULT; i++) {
+		if (i == PT_SOFTE)
+			continue;
+		err |= __get_user(gregs[i], &sc->gp_regs[i]);
+	}
+
+	if (!sig)
+		regs->gpr[13] = save_r13;
+	err |= __copy_from_user(&current->thread.fpr, &sc->fp_regs, FP_REGS_SIZE);
+	if (set != NULL)
+		err |=  __get_user(set->sig[0], &sc->oldmask);
+
+#ifdef CONFIG_ALTIVEC
+	err |= __get_user(v_regs, &sc->v_regs);
+	err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
+	if (err)
+		return err;
+	/* Copy 33 vec registers (vr0..31 and vscr) from the stack */
+	if (v_regs != 0 && (msr & MSR_VEC) != 0)
+		err |= __copy_from_user(current->thread.vr, v_regs,
+					33 * sizeof(vector128));
+	else if (current->thread.used_vr)
+		memset(current->thread.vr, 0, 33 * sizeof(vector128));
+	/* Always get VRSAVE back */
+	if (v_regs != 0)
+		err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
+	else
+		current->thread.vrsave = 0;
+#endif /* CONFIG_ALTIVEC */
+
+#ifndef CONFIG_SMP
+	preempt_disable();
+	if (last_task_used_math == current)
+		last_task_used_math = NULL;
+	if (last_task_used_altivec == current)
+		last_task_used_altivec = NULL;
+	preempt_enable();
+#endif
+	/* Force reload of FP/VEC */
+	regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC);
+
+	return err;
+}
+
+/*
+ * Allocate space for the signal frame
+ */
+static inline void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
+				  size_t frame_size)
+{
+        unsigned long newsp;
+
+        /* Default to using normal stack */
+        newsp = regs->gpr[1];
+
+	if (ka->sa.sa_flags & SA_ONSTACK) {
+		if (! on_sig_stack(regs->gpr[1]))
+			newsp = (current->sas_ss_sp + current->sas_ss_size);
+	}
+
+        return (void __user *)((newsp - frame_size) & -16ul);
+}
+
+/*
+ * Setup the trampoline code on the stack
+ */
+static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
+{
+	int i;
+	long err = 0;
+
+	/* addi r1, r1, __SIGNAL_FRAMESIZE  # Pop the dummy stackframe */
+	err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
+	/* li r0, __NR_[rt_]sigreturn| */
+	err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]);
+	/* sc */
+	err |= __put_user(0x44000002UL, &tramp[2]);
+
+	/* Minimal traceback info */
+	for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
+		err |= __put_user(0, &tramp[i]);
+
+	if (!err)
+		flush_icache_range((unsigned long) &tramp[0],
+			   (unsigned long) &tramp[TRAMP_SIZE]);
+
+	return err;
+}
+
+/*
+ * Restore the user process's signal mask (also used by signal32.c)
+ */
+void restore_sigmask(sigset_t *set)
+{
+	sigdelsetmask(set, ~_BLOCKABLE);
+	spin_lock_irq(&current->sighand->siglock);
+	current->blocked = *set;
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+}
+
+
+/*
+ * Handle {get,set,swap}_context operations
+ */
+int sys_swapcontext(struct ucontext __user *old_ctx,
+		    struct ucontext __user *new_ctx,
+		    long ctx_size, long r6, long r7, long r8, struct pt_regs *regs)
+{
+	unsigned char tmp;
+	sigset_t set;
+
+	/* Context size is for future use. Right now, we only make sure
+	 * we are passed something we understand
+	 */
+	if (ctx_size < sizeof(struct ucontext))
+		return -EINVAL;
+
+	if (old_ctx != NULL) {
+		if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
+		    || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0)
+		    || __copy_to_user(&old_ctx->uc_sigmask,
+				      &current->blocked, sizeof(sigset_t)))
+			return -EFAULT;
+	}
+	if (new_ctx == NULL)
+		return 0;
+	if (!access_ok(VERIFY_READ, new_ctx, sizeof(*new_ctx))
+	    || __get_user(tmp, (u8 __user *) new_ctx)
+	    || __get_user(tmp, (u8 __user *) (new_ctx + 1) - 1))
+		return -EFAULT;
+
+	/*
+	 * If we get a fault copying the context into the kernel's
+	 * image of the user's registers, we can't just return -EFAULT
+	 * because the user's registers will be corrupted.  For instance
+	 * the NIP value may have been updated but not some of the
+	 * other registers.  Given that we have done the access_ok
+	 * and successfully read the first and last bytes of the region
+	 * above, this should only happen in an out-of-memory situation
+	 * or if another thread unmaps the region containing the context.
+	 * We kill the task with a SIGSEGV in this situation.
+	 */
+
+	if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
+		do_exit(SIGSEGV);
+	restore_sigmask(&set);
+	if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext))
+		do_exit(SIGSEGV);
+
+	/* This returns like rt_sigreturn */
+	return 0;
+}
+
+
+/*
+ * Do a signal return; undo the signal stack.
+ */
+
+int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
+		     unsigned long r6, unsigned long r7, unsigned long r8,
+		     struct pt_regs *regs)
+{
+	struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
+	sigset_t set;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
+	if (!access_ok(VERIFY_READ, uc, sizeof(*uc)))
+		goto badframe;
+
+	if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
+		goto badframe;
+	restore_sigmask(&set);
+	if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext))
+		goto badframe;
+
+	/* do_sigaltstack expects a __user pointer and won't modify
+	 * what's in there anyway
+	 */
+	do_sigaltstack(&uc->uc_stack, NULL, regs->gpr[1]);
+
+	return regs->result;
+
+badframe:
+#if DEBUG_SIG
+	printk("badframe in sys_rt_sigreturn, regs=%p uc=%p &uc->uc_mcontext=%p\n",
+	       regs, uc, &uc->uc_mcontext);
+#endif
+	force_sig(SIGSEGV, current);
+	return 0;
+}
+
+static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
+		sigset_t *set, struct pt_regs *regs)
+{
+	/* Handler is *really* a pointer to the function descriptor for
+	 * the signal routine.  The first entry in the function
+	 * descriptor is the entry address of signal and the second
+	 * entry is the TOC value we need to use.
+	 */
+	func_descr_t __user *funct_desc_ptr;
+	struct rt_sigframe __user *frame;
+	unsigned long newsp = 0;
+	long err = 0;
+
+	frame = get_sigframe(ka, regs, sizeof(*frame));
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+		goto badframe;
+
+	err |= __put_user(&frame->info, &frame->pinfo);
+	err |= __put_user(&frame->uc, &frame->puc);
+	err |= copy_siginfo_to_user(&frame->info, info);
+	if (err)
+		goto badframe;
+
+	/* Create the ucontext.  */
+	err |= __put_user(0, &frame->uc.uc_flags);
+	err |= __put_user(0, &frame->uc.uc_link);
+	err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
+	err |= __put_user(sas_ss_flags(regs->gpr[1]),
+			  &frame->uc.uc_stack.ss_flags);
+	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
+	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, signr, NULL,
+				(unsigned long)ka->sa.sa_handler);
+	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+	if (err)
+		goto badframe;
+
+	/* Set up to return from userspace. */
+	if (vdso64_rt_sigtramp && current->thread.vdso_base) {
+		regs->link = current->thread.vdso_base + vdso64_rt_sigtramp;
+	} else {
+		err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
+		if (err)
+			goto badframe;
+		regs->link = (unsigned long) &frame->tramp[0];
+	}
+	funct_desc_ptr = (func_descr_t __user *) ka->sa.sa_handler;
+
+	/* Allocate a dummy caller frame for the signal handler. */
+	newsp = (unsigned long)frame - __SIGNAL_FRAMESIZE;
+	err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
+
+	/* Set up "regs" so we "return" to the signal handler. */
+	err |= get_user(regs->nip, &funct_desc_ptr->entry);
+	regs->gpr[1] = newsp;
+	err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
+	regs->gpr[3] = signr;
+	regs->result = 0;
+	if (ka->sa.sa_flags & SA_SIGINFO) {
+		err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
+		err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
+		regs->gpr[6] = (unsigned long) frame;
+	} else {
+		regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
+	}
+	if (err)
+		goto badframe;
+
+	if (test_thread_flag(TIF_SINGLESTEP))
+		ptrace_notify(SIGTRAP);
+
+	return 1;
+
+badframe:
+#if DEBUG_SIG
+	printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n",
+	       regs, frame, newsp);
+#endif
+	force_sigsegv(signr, current);
+	return 0;
+}
+
+
+/*
+ * OK, we're invoking a handler
+ */
+static int handle_signal(unsigned long sig, struct k_sigaction *ka,
+			 siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
+{
+	int ret;
+
+	/* Set up Signal Frame */
+	ret = setup_rt_frame(sig, ka, info, oldset, regs);
+
+	if (ret) {
+		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;
+}
+
+static inline void syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
+{
+	switch ((int)regs->result) {
+	case -ERESTART_RESTARTBLOCK:
+	case -ERESTARTNOHAND:
+		/* ERESTARTNOHAND means that the syscall should only be
+		 * restarted if there was no handler for the signal, and since
+		 * we only get here if there is a handler, we dont restart.
+		 */
+		regs->result = -EINTR;
+		break;
+	case -ERESTARTSYS:
+		/* ERESTARTSYS means to restart the syscall if there is no
+		 * handler or the handler was registered with SA_RESTART
+		 */
+		if (!(ka->sa.sa_flags & SA_RESTART)) {
+			regs->result = -EINTR;
+			break;
+		}
+		/* fallthrough */
+	case -ERESTARTNOINTR:
+		/* ERESTARTNOINTR means that the syscall should be
+		 * called again after the signal handler returns.
+		 */
+		regs->gpr[3] = regs->orig_gpr3;
+		regs->nip -= 4;
+		regs->result = 0;
+		break;
+	}
+}
+
+/*
+ * Note that 'init' is a special process: it doesn't get signals it doesn't
+ * want to handle. Thus you cannot kill init even with a SIGKILL even by
+ * mistake.
+ */
+int do_signal(sigset_t *oldset, struct pt_regs *regs)
+{
+	siginfo_t info;
+	int signr;
+	struct k_sigaction ka;
+
+	/*
+	 * If the current thread is 32 bit - invoke the
+	 * 32 bit signal handling code
+	 */
+	if (test_thread_flag(TIF_32BIT))
+		return do_signal32(oldset, regs);
+
+	if (!oldset)
+		oldset = &current->blocked;
+
+	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
+	if (signr > 0) {
+		/* Whee!  Actually deliver the signal.  */
+		if (TRAP(regs) == 0x0C00)
+			syscall_restart(regs, &ka);
+
+		/*
+		 * Reenable the DABR before delivering the signal to
+		 * user space. The DABR will have been cleared if it
+		 * triggered inside the kernel.
+		 */
+		if (current->thread.dabr)
+			set_dabr(current->thread.dabr);
+
+		return handle_signal(signr, &ka, &info, oldset, regs);
+	}
+
+	if (TRAP(regs) == 0x0C00) {	/* System Call! */
+		if ((int)regs->result == -ERESTARTNOHAND ||
+		    (int)regs->result == -ERESTARTSYS ||
+		    (int)regs->result == -ERESTARTNOINTR) {
+			regs->gpr[3] = regs->orig_gpr3;
+			regs->nip -= 4; /* Back up & retry system call */
+			regs->result = 0;
+		} else if ((int)regs->result == -ERESTART_RESTARTBLOCK) {
+			regs->gpr[0] = __NR_restart_syscall;
+			regs->nip -= 4;
+			regs->result = 0;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(do_signal);