initial_commit

1 files changed, 479 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
new file mode 100644
index 00000000..e91c736c
--- /dev/null
+++ b/arch/powerpc/kernel/signal_64.c
@@ -0,0 +1,479 @@
+/*
+ *  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/module.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 "signal.h"
+
+#define DEBUG_SIG 0
+
+#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 __user *pinfo;
+	void __user *puc;
+	struct siginfo info;
+	/* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
+	char abigap[288];
+} __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 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
+	unsigned long msr = regs->msr;
+	long err = 0;
+
+	flush_fp_to_thread(current);
+
+#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.
+		 */
+		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 */
+	flush_fp_to_thread(current);
+	/* copy fpr regs and fpscr */
+	err |= copy_fpr_to_user(&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 && 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;
+}
+
+/*
+ * 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 != 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 */
+	/* 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.fpr[i][TS_VSRLOWOFFSET] = 0;
+#endif
+	return err;
+}
+
+/*
+ * 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);
+	restore_sigmask(&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;
+
+	/* 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]);
+
+	set_thread_flag(TIF_RESTOREALL);
+	return 0;
+
+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
+	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(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), 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, 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, 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.fpscr.val = 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];
+	}
+	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);
+	/* enter the signal handler in big-endian mode */
+	regs->msr &= ~MSR_LE;
+	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;
+
+	return 1;
+
+badframe:
+#if DEBUG_SIG
+	printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n",
+	       regs, frame, newsp);
+#endif
+	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);
+
+	force_sigsegv(signr, current);
+	return 0;
+}