Initial import

1 files changed, 624 insertions, 0 deletions

diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
new file mode 100644
index 000000000..423663e23
--- /dev/null
+++ b/arch/arm/kernel/signal.c
@@ -0,0 +1,624 @@
+/*
+ *  linux/arch/arm/kernel/signal.c
+ *
+ *  Copyright (C) 1995-2009 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/errno.h>
+#include <linux/random.h>
+#include <linux/signal.h>
+#include <linux/personality.h>
+#include <linux/uaccess.h>
+#include <linux/tracehook.h>
+#include <linux/uprobes.h>
+
+#include <asm/elf.h>
+#include <asm/cacheflush.h>
+#include <asm/traps.h>
+#include <asm/ucontext.h>
+#include <asm/unistd.h>
+#include <asm/vfp.h>
+
+extern const unsigned long sigreturn_codes[7];
+
+static unsigned long signal_return_offset;
+
+#ifdef CONFIG_CRUNCH
+static int preserve_crunch_context(struct crunch_sigframe __user *frame)
+{
+	char kbuf[sizeof(*frame) + 8];
+	struct crunch_sigframe *kframe;
+
+	/* the crunch context must be 64 bit aligned */
+	kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
+	kframe->magic = CRUNCH_MAGIC;
+	kframe->size = CRUNCH_STORAGE_SIZE;
+	crunch_task_copy(current_thread_info(), &kframe->storage);
+	return __copy_to_user(frame, kframe, sizeof(*frame));
+}
+
+static int restore_crunch_context(struct crunch_sigframe __user *frame)
+{
+	char kbuf[sizeof(*frame) + 8];
+	struct crunch_sigframe *kframe;
+
+	/* the crunch context must be 64 bit aligned */
+	kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7);
+	if (__copy_from_user(kframe, frame, sizeof(*frame)))
+		return -1;
+	if (kframe->magic != CRUNCH_MAGIC ||
+	    kframe->size != CRUNCH_STORAGE_SIZE)
+		return -1;
+	crunch_task_restore(current_thread_info(), &kframe->storage);
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_IWMMXT
+
+static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame)
+{
+	char kbuf[sizeof(*frame) + 8];
+	struct iwmmxt_sigframe *kframe;
+
+	/* the iWMMXt context must be 64 bit aligned */
+	kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
+	kframe->magic = IWMMXT_MAGIC;
+	kframe->size = IWMMXT_STORAGE_SIZE;
+	iwmmxt_task_copy(current_thread_info(), &kframe->storage);
+	return __copy_to_user(frame, kframe, sizeof(*frame));
+}
+
+static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame)
+{
+	char kbuf[sizeof(*frame) + 8];
+	struct iwmmxt_sigframe *kframe;
+
+	/* the iWMMXt context must be 64 bit aligned */
+	kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
+	if (__copy_from_user(kframe, frame, sizeof(*frame)))
+		return -1;
+	if (kframe->magic != IWMMXT_MAGIC ||
+	    kframe->size != IWMMXT_STORAGE_SIZE)
+		return -1;
+	iwmmxt_task_restore(current_thread_info(), &kframe->storage);
+	return 0;
+}
+
+#endif
+
+#ifdef CONFIG_VFP
+
+static int preserve_vfp_context(struct vfp_sigframe __user *frame)
+{
+	const unsigned long magic = VFP_MAGIC;
+	const unsigned long size = VFP_STORAGE_SIZE;
+	int err = 0;
+
+	__put_user_error(magic, &frame->magic, err);
+	__put_user_error(size, &frame->size, err);
+
+	if (err)
+		return -EFAULT;
+
+	return vfp_preserve_user_clear_hwstate(&frame->ufp, &frame->ufp_exc);
+}
+
+static int restore_vfp_context(struct vfp_sigframe __user *frame)
+{
+	unsigned long magic;
+	unsigned long size;
+	int err = 0;
+
+	__get_user_error(magic, &frame->magic, err);
+	__get_user_error(size, &frame->size, err);
+
+	if (err)
+		return -EFAULT;
+	if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE)
+		return -EINVAL;
+
+	return vfp_restore_user_hwstate(&frame->ufp, &frame->ufp_exc);
+}
+
+#endif
+
+/*
+ * Do a signal return; undo the signal stack.  These are aligned to 64-bit.
+ */
+struct sigframe {
+	struct ucontext uc;
+	unsigned long retcode[2];
+};
+
+struct rt_sigframe {
+	struct siginfo info;
+	struct sigframe sig;
+};
+
+static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
+{
+	struct aux_sigframe __user *aux;
+	sigset_t set;
+	int err;
+
+	err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
+	if (err == 0)
+		set_current_blocked(&set);
+
+	__get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
+	__get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
+	__get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
+	__get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
+	__get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
+	__get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
+	__get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
+	__get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
+	__get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
+	__get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
+	__get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
+	__get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
+	__get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
+	__get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
+	__get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
+	__get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
+	__get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
+
+	err |= !valid_user_regs(regs);
+
+	aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
+#ifdef CONFIG_CRUNCH
+	if (err == 0)
+		err |= restore_crunch_context(&aux->crunch);
+#endif
+#ifdef CONFIG_IWMMXT
+	if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
+		err |= restore_iwmmxt_context(&aux->iwmmxt);
+#endif
+#ifdef CONFIG_VFP
+	if (err == 0)
+		err |= restore_vfp_context(&aux->vfp);
+#endif
+
+	return err;
+}
+
+asmlinkage int sys_sigreturn(struct pt_regs *regs)
+{
+	struct sigframe __user *frame;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current->restart_block.fn = do_no_restart_syscall;
+
+	/*
+	 * Since we stacked the signal on a 64-bit boundary,
+	 * then 'sp' should be word aligned here.  If it's
+	 * not, then the user is trying to mess with us.
+	 */
+	if (regs->ARM_sp & 7)
+		goto badframe;
+
+	frame = (struct sigframe __user *)regs->ARM_sp;
+
+	if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
+		goto badframe;
+
+	if (restore_sigframe(regs, frame))
+		goto badframe;
+
+	return regs->ARM_r0;
+
+badframe:
+	force_sig(SIGSEGV, current);
+	return 0;
+}
+
+asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
+{
+	struct rt_sigframe __user *frame;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current->restart_block.fn = do_no_restart_syscall;
+
+	/*
+	 * Since we stacked the signal on a 64-bit boundary,
+	 * then 'sp' should be word aligned here.  If it's
+	 * not, then the user is trying to mess with us.
+	 */
+	if (regs->ARM_sp & 7)
+		goto badframe;
+
+	frame = (struct rt_sigframe __user *)regs->ARM_sp;
+
+	if (!access_ok(VERIFY_READ, frame, sizeof (*frame)))
+		goto badframe;
+
+	if (restore_sigframe(regs, &frame->sig))
+		goto badframe;
+
+	if (restore_altstack(&frame->sig.uc.uc_stack))
+		goto badframe;
+
+	return regs->ARM_r0;
+
+badframe:
+	force_sig(SIGSEGV, current);
+	return 0;
+}
+
+static int
+setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
+{
+	struct aux_sigframe __user *aux;
+	int err = 0;
+
+	__put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
+	__put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
+	__put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
+	__put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
+	__put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
+	__put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
+	__put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
+	__put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
+	__put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
+	__put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
+	__put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
+	__put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
+	__put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
+	__put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
+	__put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
+	__put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
+	__put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
+
+	__put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
+	__put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
+	__put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
+	__put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
+
+	err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
+
+	aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
+#ifdef CONFIG_CRUNCH
+	if (err == 0)
+		err |= preserve_crunch_context(&aux->crunch);
+#endif
+#ifdef CONFIG_IWMMXT
+	if (err == 0 && test_thread_flag(TIF_USING_IWMMXT))
+		err |= preserve_iwmmxt_context(&aux->iwmmxt);
+#endif
+#ifdef CONFIG_VFP
+	if (err == 0)
+		err |= preserve_vfp_context(&aux->vfp);
+#endif
+	__put_user_error(0, &aux->end_magic, err);
+
+	return err;
+}
+
+static inline void __user *
+get_sigframe(struct ksignal *ksig, struct pt_regs *regs, int framesize)
+{
+	unsigned long sp = sigsp(regs->ARM_sp, ksig);
+	void __user *frame;
+
+	/*
+	 * ATPCS B01 mandates 8-byte alignment
+	 */
+	frame = (void __user *)((sp - framesize) & ~7);
+
+	/*
+	 * Check that we can actually write to the signal frame.
+	 */
+	if (!access_ok(VERIFY_WRITE, frame, framesize))
+		frame = NULL;
+
+	return frame;
+}
+
+static int
+setup_return(struct pt_regs *regs, struct ksignal *ksig,
+	     unsigned long __user *rc, void __user *frame)
+{
+	unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
+	unsigned long retcode;
+	int thumb = 0;
+	unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
+
+	cpsr |= PSR_ENDSTATE;
+
+	/*
+	 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
+	 */
+	if (ksig->ka.sa.sa_flags & SA_THIRTYTWO)
+		cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
+
+#ifdef CONFIG_ARM_THUMB
+	if (elf_hwcap & HWCAP_THUMB) {
+		/*
+		 * The LSB of the handler determines if we're going to
+		 * be using THUMB or ARM mode for this signal handler.
+		 */
+		thumb = handler & 1;
+
+#if __LINUX_ARM_ARCH__ >= 7
+		/*
+		 * Clear the If-Then Thumb-2 execution state
+		 * ARM spec requires this to be all 000s in ARM mode
+		 * Snapdragon S4/Krait misbehaves on a Thumb=>ARM
+		 * signal transition without this.
+		 */
+		cpsr &= ~PSR_IT_MASK;
+#endif
+
+		if (thumb) {
+			cpsr |= PSR_T_BIT;
+		} else
+			cpsr &= ~PSR_T_BIT;
+	}
+#endif
+
+	if (ksig->ka.sa.sa_flags & SA_RESTORER) {
+		retcode = (unsigned long)ksig->ka.sa.sa_restorer;
+	} else {
+		unsigned int idx = thumb << 1;
+
+		if (ksig->ka.sa.sa_flags & SA_SIGINFO)
+			idx += 3;
+
+		/*
+		 * Put the sigreturn code on the stack no matter which return
+		 * mechanism we use in order to remain ABI compliant
+		 */
+		if (__put_user(sigreturn_codes[idx],   rc) ||
+		    __put_user(sigreturn_codes[idx+1], rc+1))
+			return 1;
+
+#ifdef CONFIG_MMU
+		if (cpsr & MODE32_BIT) {
+			struct mm_struct *mm = current->mm;
+
+			/*
+			 * 32-bit code can use the signal return page
+			 * except when the MPU has protected the vectors
+			 * page from PL0
+			 */
+			retcode = mm->context.sigpage + signal_return_offset +
+				  (idx << 2) + thumb;
+		} else
+#endif
+		{
+			/*
+			 * Ensure that the instruction cache sees
+			 * the return code written onto the stack.
+			 */
+			flush_icache_range((unsigned long)rc,
+					   (unsigned long)(rc + 2));
+
+			retcode = ((unsigned long)rc) + thumb;
+		}
+	}
+
+	regs->ARM_r0 = ksig->sig;
+	regs->ARM_sp = (unsigned long)frame;
+	regs->ARM_lr = retcode;
+	regs->ARM_pc = handler;
+	regs->ARM_cpsr = cpsr;
+
+	return 0;
+}
+
+static int
+setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
+{
+	struct sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
+	int err = 0;
+
+	if (!frame)
+		return 1;
+
+	/*
+	 * Set uc.uc_flags to a value which sc.trap_no would never have.
+	 */
+	__put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err);
+
+	err |= setup_sigframe(frame, regs, set);
+	if (err == 0)
+		err = setup_return(regs, ksig, frame->retcode, frame);
+
+	return err;
+}
+
+static int
+setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
+{
+	struct rt_sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
+	int err = 0;
+
+	if (!frame)
+		return 1;
+
+	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+
+	__put_user_error(0, &frame->sig.uc.uc_flags, err);
+	__put_user_error(NULL, &frame->sig.uc.uc_link, err);
+
+	err |= __save_altstack(&frame->sig.uc.uc_stack, regs->ARM_sp);
+	err |= setup_sigframe(&frame->sig, regs, set);
+	if (err == 0)
+		err = setup_return(regs, ksig, frame->sig.retcode, frame);
+
+	if (err == 0) {
+		/*
+		 * For realtime signals we must also set the second and third
+		 * arguments for the signal handler.
+		 *   -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
+		 */
+		regs->ARM_r1 = (unsigned long)&frame->info;
+		regs->ARM_r2 = (unsigned long)&frame->sig.uc;
+	}
+
+	return err;
+}
+
+/*
+ * OK, we're invoking a handler
+ */	
+static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
+{
+	sigset_t *oldset = sigmask_to_save();
+	int ret;
+
+	/*
+	 * Set up the stack frame
+	 */
+	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
+		ret = setup_rt_frame(ksig, oldset, regs);
+	else
+		ret = setup_frame(ksig, oldset, regs);
+
+	/*
+	 * Check that the resulting registers are actually sane.
+	 */
+	ret |= !valid_user_regs(regs);
+
+	signal_setup_done(ret, ksig, 0);
+}
+
+/*
+ * 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.
+ *
+ * Note that we go through the signals twice: once to check the signals that
+ * the kernel can handle, and then we build all the user-level signal handling
+ * stack-frames in one go after that.
+ */
+static int do_signal(struct pt_regs *regs, int syscall)
+{
+	unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
+	struct ksignal ksig;
+	int restart = 0;
+
+	/*
+	 * If we were from a system call, check for system call restarting...
+	 */
+	if (syscall) {
+		continue_addr = regs->ARM_pc;
+		restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
+		retval = regs->ARM_r0;
+
+		/*
+		 * Prepare for system call restart.  We do this here so that a
+		 * debugger will see the already changed PSW.
+		 */
+		switch (retval) {
+		case -ERESTART_RESTARTBLOCK:
+			restart -= 2;
+		case -ERESTARTNOHAND:
+		case -ERESTARTSYS:
+		case -ERESTARTNOINTR:
+			restart++;
+			regs->ARM_r0 = regs->ARM_ORIG_r0;
+			regs->ARM_pc = restart_addr;
+			break;
+		}
+	}
+
+	/*
+	 * Get the signal to deliver.  When running under ptrace, at this
+	 * point the debugger may change all our registers ...
+	 */
+	/*
+	 * Depending on the signal settings we may need to revert the
+	 * decision to restart the system call.  But skip this if a
+	 * debugger has chosen to restart at a different PC.
+	 */
+	if (get_signal(&ksig)) {
+		/* handler */
+		if (unlikely(restart) && regs->ARM_pc == restart_addr) {
+			if (retval == -ERESTARTNOHAND ||
+			    retval == -ERESTART_RESTARTBLOCK
+			    || (retval == -ERESTARTSYS
+				&& !(ksig.ka.sa.sa_flags & SA_RESTART))) {
+				regs->ARM_r0 = -EINTR;
+				regs->ARM_pc = continue_addr;
+			}
+		}
+		handle_signal(&ksig, regs);
+	} else {
+		/* no handler */
+		restore_saved_sigmask();
+		if (unlikely(restart) && regs->ARM_pc == restart_addr) {
+			regs->ARM_pc = continue_addr;
+			return restart;
+		}
+	}
+	return 0;
+}
+
+asmlinkage int
+do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
+{
+	do {
+		if (likely(thread_flags & _TIF_NEED_RESCHED)) {
+			schedule();
+		} else {
+			if (unlikely(!user_mode(regs)))
+				return 0;
+			local_irq_enable();
+			if (thread_flags & _TIF_SIGPENDING) {
+				int restart = do_signal(regs, syscall);
+				if (unlikely(restart)) {
+					/*
+					 * Restart without handlers.
+					 * Deal with it without leaving
+					 * the kernel space.
+					 */
+					return restart;
+				}
+				syscall = 0;
+			} else if (thread_flags & _TIF_UPROBE) {
+				uprobe_notify_resume(regs);
+			} else {
+				clear_thread_flag(TIF_NOTIFY_RESUME);
+				tracehook_notify_resume(regs);
+			}
+		}
+		local_irq_disable();
+		thread_flags = current_thread_info()->flags;
+	} while (thread_flags & _TIF_WORK_MASK);
+	return 0;
+}
+
+struct page *get_signal_page(void)
+{
+	unsigned long ptr;
+	unsigned offset;
+	struct page *page;
+	void *addr;
+
+	page = alloc_pages(GFP_KERNEL, 0);
+
+	if (!page)
+		return NULL;
+
+	addr = page_address(page);
+
+	/* Give the signal return code some randomness */
+	offset = 0x200 + (get_random_int() & 0x7fc);
+	signal_return_offset = offset;
+
+	/*
+	 * Copy signal return handlers into the vector page, and
+	 * set sigreturn to be a pointer to these.
+	 */
+	memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes));
+
+	ptr = (unsigned long)addr + offset;
+	flush_icache_range(ptr, ptr + sizeof(sigreturn_codes));
+
+	return page;
+}