Initial import

1 files changed, 812 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
new file mode 100644
index 000000000..c7c24d2e2
--- /dev/null
+++ b/arch/powerpc/kernel/signal_64.c
@@ -0,0 +1,812 @@
+/*
+ *  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/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.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/ratelimit.h>
+
+#include <asm/sigcontext.h>
+#include <asm/ucontext.h>
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/unistd.h>
+#include <asm/cacheflush.h>
+#include <asm/syscalls.h>
+#include <asm/vdso.h>
+#include <asm/switch_to.h>
+#include <asm/tm.h>
+
+#include "signal.h"
+
+
+#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;
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+	struct ucontext uc_transact;
+#endif
+	unsigned long _unused[2];
+	unsigned int tramp[TRAMP_SIZE];
+	struct siginfo __user *pinfo;
+	void __user *puc;
+	struct siginfo info;
+	/* New 64 bit little-endian ABI allows redzone of 512 bytes below sp */
+	char abigap[USER_REDZONE_SIZE];
+} __attribute__ ((aligned (16)));
+
+static const char fmt32[] = KERN_INFO \
+	"%s[%d]: bad frame in %s: %08lx nip %08lx lr %08lx\n";
+static const char fmt64[] = KERN_INFO \
+	"%s[%d]: bad frame in %s: %016lx nip %016lx lr %016lx\n";
+
+/*
+ * 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,
+		 int ctx_has_vsx_region)
+{
+	/* 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 whether 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
+	unsigned long msr = regs->msr;
+	long err = 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_state,
+				      33 * sizeof(vector128));
+		/* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
+		 * contains valid data.
+		 */
+		msr |= MSR_VEC;
+	}
+	/* We always copy to/from vrsave, it's 0 if we don't have or don't
+	 * use altivec.
+	 */
+	if (cpu_has_feature(CPU_FTR_ALTIVEC))
+		current->thread.vrsave = mfspr(SPRN_VRSAVE);
+	err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
+#else /* CONFIG_ALTIVEC */
+	err |= __put_user(0, &sc->v_regs);
+#endif /* CONFIG_ALTIVEC */
+	flush_fp_to_thread(current);
+	/* copy fpr regs and fpscr */
+	err |= copy_fpr_to_user(&sc->fp_regs, current);
+
+	/*
+	 * Clear the MSR VSX bit to indicate there is no valid state attached
+	 * to this context, except in the specific case below where we set it.
+	 */
+	msr &= ~MSR_VSX;
+#ifdef CONFIG_VSX
+	/*
+	 * Copy VSX low doubleword to local buffer for formatting,
+	 * then out to userspace.  Update v_regs to point after the
+	 * VMX data.
+	 */
+	if (current->thread.used_vsr && ctx_has_vsx_region) {
+		__giveup_vsx(current);
+		v_regs += ELF_NVRREG;
+		err |= copy_vsx_to_user(v_regs, current);
+		/* set MSR_VSX in the MSR value in the frame to
+		 * indicate that sc->vs_reg) contains valid data.
+		 */
+		msr |= MSR_VSX;
+	}
+#endif /* CONFIG_VSX */
+	err |= __put_user(&sc->gp_regs, &sc->regs);
+	WARN_ON(!FULL_REGS(regs));
+	err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
+	err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
+	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;
+}
+
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+/*
+ * As above, but Transactional Memory is in use, so deliver sigcontexts
+ * containing checkpointed and transactional register states.
+ *
+ * To do this, we treclaim (done before entering here) to gather both sets of
+ * registers and set up the 'normal' sigcontext registers with rolled-back
+ * register values such that a simple signal handler sees a correct
+ * checkpointed register state.  If interested, a TM-aware sighandler can
+ * examine the transactional registers in the 2nd sigcontext to determine the
+ * real origin of the signal.
+ */
+static long setup_tm_sigcontexts(struct sigcontext __user *sc,
+				 struct sigcontext __user *tm_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);
+	elf_vrreg_t __user *tm_v_regs = (elf_vrreg_t __user *)
+		(((unsigned long)tm_sc->vmx_reserve + 15) & ~0xful);
+#endif
+	unsigned long msr = regs->msr;
+	long err = 0;
+
+	BUG_ON(!MSR_TM_ACTIVE(regs->msr));
+
+	/* Remove TM bits from thread's MSR.  The MSR in the sigcontext
+	 * just indicates to userland that we were doing a transaction, but we
+	 * don't want to return in transactional state.  This also ensures
+	 * that flush_fp_to_thread won't set TIF_RESTORE_TM again.
+	 */
+	regs->msr &= ~MSR_TS_MASK;
+
+	flush_fp_to_thread(current);
+
+#ifdef CONFIG_ALTIVEC
+	err |= __put_user(v_regs, &sc->v_regs);
+	err |= __put_user(tm_v_regs, &tm_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_state,
+				      33 * sizeof(vector128));
+		/* If VEC was enabled there are transactional VRs valid too,
+		 * else they're a copy of the checkpointed VRs.
+		 */
+		if (msr & MSR_VEC)
+			err |= __copy_to_user(tm_v_regs,
+					      &current->thread.transact_vr,
+					      33 * sizeof(vector128));
+		else
+			err |= __copy_to_user(tm_v_regs,
+					      &current->thread.vr_state,
+					      33 * sizeof(vector128));
+
+		/* set MSR_VEC in the MSR value in the frame to indicate
+		 * that sc->v_reg contains valid data.
+		 */
+		msr |= MSR_VEC;
+	}
+	/* We always copy to/from vrsave, it's 0 if we don't have or don't
+	 * use altivec.
+	 */
+	if (cpu_has_feature(CPU_FTR_ALTIVEC))
+		current->thread.vrsave = mfspr(SPRN_VRSAVE);
+	err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
+	if (msr & MSR_VEC)
+		err |= __put_user(current->thread.transact_vrsave,
+				  (u32 __user *)&tm_v_regs[33]);
+	else
+		err |= __put_user(current->thread.vrsave,
+				  (u32 __user *)&tm_v_regs[33]);
+
+#else /* CONFIG_ALTIVEC */
+	err |= __put_user(0, &sc->v_regs);
+	err |= __put_user(0, &tm_sc->v_regs);
+#endif /* CONFIG_ALTIVEC */
+
+	/* copy fpr regs and fpscr */
+	err |= copy_fpr_to_user(&sc->fp_regs, current);
+	if (msr & MSR_FP)
+		err |= copy_transact_fpr_to_user(&tm_sc->fp_regs, current);
+	else
+		err |= copy_fpr_to_user(&tm_sc->fp_regs, current);
+
+#ifdef CONFIG_VSX
+	/*
+	 * Copy VSX low doubleword to local buffer for formatting,
+	 * then out to userspace.  Update v_regs to point after the
+	 * VMX data.
+	 */
+	if (current->thread.used_vsr) {
+		__giveup_vsx(current);
+		v_regs += ELF_NVRREG;
+		tm_v_regs += ELF_NVRREG;
+
+		err |= copy_vsx_to_user(v_regs, current);
+
+		if (msr & MSR_VSX)
+			err |= copy_transact_vsx_to_user(tm_v_regs, current);
+		else
+			err |= copy_vsx_to_user(tm_v_regs, current);
+
+		/* set MSR_VSX in the MSR value in the frame to
+		 * indicate that sc->vs_reg) contains valid data.
+		 */
+		msr |= MSR_VSX;
+	}
+#endif /* CONFIG_VSX */
+
+	err |= __put_user(&sc->gp_regs, &sc->regs);
+	err |= __put_user(&tm_sc->gp_regs, &tm_sc->regs);
+	WARN_ON(!FULL_REGS(regs));
+	err |= __copy_to_user(&tm_sc->gp_regs, regs, GP_REGS_SIZE);
+	err |= __copy_to_user(&sc->gp_regs,
+			      &current->thread.ckpt_regs, GP_REGS_SIZE);
+	err |= __put_user(msr, &tm_sc->gp_regs[PT_MSR]);
+	err |= __put_user(msr, &sc->gp_regs[PT_MSR]);
+	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;
+}
+#endif
+
+/*
+ * 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;
+	unsigned long msr;
+#ifdef CONFIG_VSX
+	int i;
+#endif
+
+	/* If this is not a signal return, we preserve the TLS in r13 */
+	if (!sig)
+		save_r13 = regs->gpr[13];
+
+	/* copy the GPRs */
+	err |= __copy_from_user(regs->gpr, sc->gp_regs, sizeof(regs->gpr));
+	err |= __get_user(regs->nip, &sc->gp_regs[PT_NIP]);
+	/* get MSR separately, transfer the LE bit if doing signal return */
+	err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
+	if (sig)
+		regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
+	err |= __get_user(regs->orig_gpr3, &sc->gp_regs[PT_ORIG_R3]);
+	err |= __get_user(regs->ctr, &sc->gp_regs[PT_CTR]);
+	err |= __get_user(regs->link, &sc->gp_regs[PT_LNK]);
+	err |= __get_user(regs->xer, &sc->gp_regs[PT_XER]);
+	err |= __get_user(regs->ccr, &sc->gp_regs[PT_CCR]);
+	/* skip SOFTE */
+	regs->trap = 0;
+	err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
+	err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
+	err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
+
+	if (!sig)
+		regs->gpr[13] = save_r13;
+	if (set != NULL)
+		err |=  __get_user(set->sig[0], &sc->oldmask);
+
+	/*
+	 * Do this before updating the thread state in
+	 * current->thread.fpr/vr.  That way, if we get preempted
+	 * and another task grabs the FPU/Altivec, it won't be
+	 * tempted to save the current CPU state into the thread_struct
+	 * and corrupt what we are writing there.
+	 */
+	discard_lazy_cpu_state();
+
+	/*
+	 * Force reload of FP/VEC.
+	 * This has to be done before copying stuff into current->thread.fpr/vr
+	 * for the reasons explained in the previous comment.
+	 */
+	regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
+
+#ifdef CONFIG_ALTIVEC
+	err |= __get_user(v_regs, &sc->v_regs);
+	if (err)
+		return err;
+	if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
+		return -EFAULT;
+	/* Copy 33 vec registers (vr0..31 and vscr) from the stack */
+	if (v_regs != NULL && (msr & MSR_VEC) != 0)
+		err |= __copy_from_user(&current->thread.vr_state, v_regs,
+					33 * sizeof(vector128));
+	else if (current->thread.used_vr)
+		memset(&current->thread.vr_state, 0, 33 * sizeof(vector128));
+	/* Always get VRSAVE back */
+	if (v_regs != NULL)
+		err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
+	else
+		current->thread.vrsave = 0;
+	if (cpu_has_feature(CPU_FTR_ALTIVEC))
+		mtspr(SPRN_VRSAVE, current->thread.vrsave);
+#endif /* CONFIG_ALTIVEC */
+	/* restore floating point */
+	err |= copy_fpr_from_user(current, &sc->fp_regs);
+#ifdef CONFIG_VSX
+	/*
+	 * Get additional VSX data. Update v_regs to point after the
+	 * VMX data.  Copy VSX low doubleword from userspace to local
+	 * buffer for formatting, then into the taskstruct.
+	 */
+	v_regs += ELF_NVRREG;
+	if ((msr & MSR_VSX) != 0)
+		err |= copy_vsx_from_user(current, v_regs);
+	else
+		for (i = 0; i < 32 ; i++)
+			current->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
+#endif
+	return err;
+}
+
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+/*
+ * Restore the two sigcontexts from the frame of a transactional processes.
+ */
+
+static long restore_tm_sigcontexts(struct pt_regs *regs,
+				   struct sigcontext __user *sc,
+				   struct sigcontext __user *tm_sc)
+{
+#ifdef CONFIG_ALTIVEC
+	elf_vrreg_t __user *v_regs, *tm_v_regs;
+#endif
+	unsigned long err = 0;
+	unsigned long msr;
+#ifdef CONFIG_VSX
+	int i;
+#endif
+	/* copy the GPRs */
+	err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr));
+	err |= __copy_from_user(&current->thread.ckpt_regs, sc->gp_regs,
+				sizeof(regs->gpr));
+
+	/*
+	 * TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP.
+	 * TEXASR was set by the signal delivery reclaim, as was TFIAR.
+	 * Users doing anything abhorrent like thread-switching w/ signals for
+	 * TM-Suspended code will have to back TEXASR/TFIAR up themselves.
+	 * For the case of getting a signal and simply returning from it,
+	 * we don't need to re-copy them here.
+	 */
+	err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]);
+	err |= __get_user(current->thread.tm_tfhar, &sc->gp_regs[PT_NIP]);
+
+	/* get MSR separately, transfer the LE bit if doing signal return */
+	err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
+	/* pull in MSR TM from user context */
+	regs->msr = (regs->msr & ~MSR_TS_MASK) | (msr & MSR_TS_MASK);
+
+	/* pull in MSR LE from user context */
+	regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
+
+	/* The following non-GPR non-FPR non-VR state is also checkpointed: */
+	err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]);
+	err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]);
+	err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]);
+	err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]);
+	err |= __get_user(current->thread.ckpt_regs.ctr,
+			  &sc->gp_regs[PT_CTR]);
+	err |= __get_user(current->thread.ckpt_regs.link,
+			  &sc->gp_regs[PT_LNK]);
+	err |= __get_user(current->thread.ckpt_regs.xer,
+			  &sc->gp_regs[PT_XER]);
+	err |= __get_user(current->thread.ckpt_regs.ccr,
+			  &sc->gp_regs[PT_CCR]);
+
+	/* These regs are not checkpointed; they can go in 'regs'. */
+	err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]);
+	err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
+	err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
+	err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
+
+	/*
+	 * Do this before updating the thread state in
+	 * current->thread.fpr/vr.  That way, if we get preempted
+	 * and another task grabs the FPU/Altivec, it won't be
+	 * tempted to save the current CPU state into the thread_struct
+	 * and corrupt what we are writing there.
+	 */
+	discard_lazy_cpu_state();
+
+	/*
+	 * Force reload of FP/VEC.
+	 * This has to be done before copying stuff into current->thread.fpr/vr
+	 * for the reasons explained in the previous comment.
+	 */
+	regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
+
+#ifdef CONFIG_ALTIVEC
+	err |= __get_user(v_regs, &sc->v_regs);
+	err |= __get_user(tm_v_regs, &tm_sc->v_regs);
+	if (err)
+		return err;
+	if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
+		return -EFAULT;
+	if (tm_v_regs && !access_ok(VERIFY_READ,
+				    tm_v_regs, 34 * sizeof(vector128)))
+		return -EFAULT;
+	/* Copy 33 vec registers (vr0..31 and vscr) from the stack */
+	if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) {
+		err |= __copy_from_user(&current->thread.vr_state, v_regs,
+					33 * sizeof(vector128));
+		err |= __copy_from_user(&current->thread.transact_vr, tm_v_regs,
+					33 * sizeof(vector128));
+	}
+	else if (current->thread.used_vr) {
+		memset(&current->thread.vr_state, 0, 33 * sizeof(vector128));
+		memset(&current->thread.transact_vr, 0, 33 * sizeof(vector128));
+	}
+	/* Always get VRSAVE back */
+	if (v_regs != NULL && tm_v_regs != NULL) {
+		err |= __get_user(current->thread.vrsave,
+				  (u32 __user *)&v_regs[33]);
+		err |= __get_user(current->thread.transact_vrsave,
+				  (u32 __user *)&tm_v_regs[33]);
+	}
+	else {
+		current->thread.vrsave = 0;
+		current->thread.transact_vrsave = 0;
+	}
+	if (cpu_has_feature(CPU_FTR_ALTIVEC))
+		mtspr(SPRN_VRSAVE, current->thread.vrsave);
+#endif /* CONFIG_ALTIVEC */
+	/* restore floating point */
+	err |= copy_fpr_from_user(current, &sc->fp_regs);
+	err |= copy_transact_fpr_from_user(current, &tm_sc->fp_regs);
+#ifdef CONFIG_VSX
+	/*
+	 * Get additional VSX data. Update v_regs to point after the
+	 * VMX data.  Copy VSX low doubleword from userspace to local
+	 * buffer for formatting, then into the taskstruct.
+	 */
+	if (v_regs && ((msr & MSR_VSX) != 0)) {
+		v_regs += ELF_NVRREG;
+		tm_v_regs += ELF_NVRREG;
+		err |= copy_vsx_from_user(current, v_regs);
+		err |= copy_transact_vsx_from_user(current, tm_v_regs);
+	} else {
+		for (i = 0; i < 32 ; i++) {
+			current->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
+			current->thread.transact_fp.fpr[i][TS_VSRLOWOFFSET] = 0;
+		}
+	}
+#endif
+	tm_enable();
+	/* Make sure the transaction is marked as failed */
+	current->thread.tm_texasr |= TEXASR_FS;
+	/* This loads the checkpointed FP/VEC state, if used */
+	tm_recheckpoint(&current->thread, msr);
+
+	/* This loads the speculative FP/VEC state, if used */
+	if (msr & MSR_FP) {
+		do_load_up_transact_fpu(&current->thread);
+		regs->msr |= (MSR_FP | current->thread.fpexc_mode);
+	}
+#ifdef CONFIG_ALTIVEC
+	if (msr & MSR_VEC) {
+		do_load_up_transact_altivec(&current->thread);
+		regs->msr |= MSR_VEC;
+	}
+#endif
+
+	return err;
+}
+#endif
+
+/*
+ * 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;
+}
+
+/*
+ * Userspace code may pass a ucontext which doesn't include VSX added
+ * at the end.  We need to check for this case.
+ */
+#define UCONTEXTSIZEWITHOUTVSX \
+		(sizeof(struct ucontext) - 32*sizeof(long))
+
+/*
+ * 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;
+	unsigned long new_msr = 0;
+	int ctx_has_vsx_region = 0;
+
+	if (new_ctx &&
+	    get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
+		return -EFAULT;
+	/*
+	 * Check that the context is not smaller than the original
+	 * size (with VMX but without VSX)
+	 */
+	if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
+		return -EINVAL;
+	/*
+	 * If the new context state sets the MSR VSX bits but
+	 * it doesn't provide VSX state.
+	 */
+	if ((ctx_size < sizeof(struct ucontext)) &&
+	    (new_msr & MSR_VSX))
+		return -EINVAL;
+	/* Does the context have enough room to store VSX data? */
+	if (ctx_size >= sizeof(struct ucontext))
+		ctx_has_vsx_region = 1;
+
+	if (old_ctx != NULL) {
+		if (!access_ok(VERIFY_WRITE, old_ctx, ctx_size)
+		    || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0,
+					ctx_has_vsx_region)
+		    || __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, ctx_size)
+	    || __get_user(tmp, (u8 __user *) new_ctx)
+	    || __get_user(tmp, (u8 __user *) new_ctx + ctx_size - 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);
+	set_current_blocked(&set);
+	if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext))
+		do_exit(SIGSEGV);
+
+	/* This returns like rt_sigreturn */
+	set_thread_flag(TIF_RESTOREALL);
+	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;
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+	unsigned long msr;
+#endif
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current->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;
+	set_current_blocked(&set);
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+	if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR]))
+		goto badframe;
+	if (MSR_TM_ACTIVE(msr)) {
+		/* We recheckpoint on return. */
+		struct ucontext __user *uc_transact;
+		if (__get_user(uc_transact, &uc->uc_link))
+			goto badframe;
+		if (restore_tm_sigcontexts(regs, &uc->uc_mcontext,
+					   &uc_transact->uc_mcontext))
+			goto badframe;
+	}
+	else
+	/* Fall through, for non-TM restore */
+#endif
+	if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext))
+		goto badframe;
+
+	if (restore_altstack(&uc->uc_stack))
+		goto badframe;
+
+	set_thread_flag(TIF_RESTOREALL);
+	return 0;
+
+badframe:
+	if (show_unhandled_signals)
+		printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
+				   current->comm, current->pid, "rt_sigreturn",
+				   (long)uc, regs->nip, regs->link);
+
+	force_sig(SIGSEGV, current);
+	return 0;
+}
+
+int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
+{
+	struct rt_sigframe __user *frame;
+	unsigned long newsp = 0;
+	long err = 0;
+
+	frame = get_sigframe(ksig, get_tm_stackpointer(regs), sizeof(*frame), 0);
+	if (unlikely(frame == NULL))
+		goto badframe;
+
+	err |= __put_user(&frame->info, &frame->pinfo);
+	err |= __put_user(&frame->uc, &frame->puc);
+	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+	if (err)
+		goto badframe;
+
+	/* Create the ucontext.  */
+	err |= __put_user(0, &frame->uc.uc_flags);
+	err |= __save_altstack(&frame->uc.uc_stack, regs->gpr[1]);
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+	if (MSR_TM_ACTIVE(regs->msr)) {
+		/* The ucontext_t passed to userland points to the second
+		 * ucontext_t (for transactional state) with its uc_link ptr.
+		 */
+		err |= __put_user(&frame->uc_transact, &frame->uc.uc_link);
+		err |= setup_tm_sigcontexts(&frame->uc.uc_mcontext,
+					    &frame->uc_transact.uc_mcontext,
+					    regs, ksig->sig,
+					    NULL,
+					    (unsigned long)ksig->ka.sa.sa_handler);
+	} else
+#endif
+	{
+		err |= __put_user(0, &frame->uc.uc_link);
+		err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, ksig->sig,
+					NULL, (unsigned long)ksig->ka.sa.sa_handler,
+					1);
+	}
+	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+	if (err)
+		goto badframe;
+
+	/* Make sure signal handler doesn't get spurious FP exceptions */
+	current->thread.fp_state.fpscr = 0;
+
+	/* Set up to return from userspace. */
+	if (vdso64_rt_sigtramp && current->mm->context.vdso_base) {
+		regs->link = current->mm->context.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];
+	}
+
+	/* 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. */
+	if (is_elf2_task()) {
+		regs->nip = (unsigned long) ksig->ka.sa.sa_handler;
+		regs->gpr[12] = regs->nip;
+	} else {
+		/* 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 =
+			(func_descr_t __user *) ksig->ka.sa.sa_handler;
+
+		err |= get_user(regs->nip, &funct_desc_ptr->entry);
+		err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
+	}
+
+	/* enter the signal handler in native-endian mode */
+	regs->msr &= ~MSR_LE;
+	regs->msr |= (MSR_KERNEL & MSR_LE);
+	regs->gpr[1] = newsp;
+	regs->gpr[3] = ksig->sig;
+	regs->result = 0;
+	if (ksig->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;
+
+	return 0;
+
+badframe:
+	if (show_unhandled_signals)
+		printk_ratelimited(regs->msr & MSR_64BIT ? fmt64 : fmt32,
+				   current->comm, current->pid, "setup_rt_frame",
+				   (long)frame, regs->nip, regs->link);
+
+	return 1;
+}