1 files changed, 112 insertions, 143 deletions

diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 56f72d257eb..bd198343720 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -8,84 +8,23 @@
  * 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>
 
-#include "signal.h"
+extern const unsigned long sigreturn_codes[7];
 
-/*
- * For ARM syscalls, we encode the syscall number into the instruction.
- */
-#define SWI_SYS_SIGRETURN	(0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE))
-#define SWI_SYS_RT_SIGRETURN	(0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE))
-
-/*
- * With EABI, the syscall number has to be loaded into r7.
- */
-#define MOV_R7_NR_SIGRETURN	(0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE))
-#define MOV_R7_NR_RT_SIGRETURN	(0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
-
-/*
- * For Thumb syscalls, we pass the syscall number via r7.  We therefore
- * need two 16-bit instructions.
- */
-#define SWI_THUMB_SIGRETURN	(0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
-#define SWI_THUMB_RT_SIGRETURN	(0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
-
-const unsigned long sigreturn_codes[7] = {
-	MOV_R7_NR_SIGRETURN,    SWI_SYS_SIGRETURN,    SWI_THUMB_SIGRETURN,
-	MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN,
-};
-
-/*
- * atomically swap in the new signal mask, and wait for a signal.
- */
-asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask)
-{
-	sigset_t blocked;
-	siginitset(&blocked, mask);
-	return sigsuspend(&blocked);
-}
-
-asmlinkage int 
-sys_sigaction(int sig, const struct old_sigaction __user *act,
-	      struct old_sigaction __user *oact)
-{
-	struct k_sigaction new_ka, old_ka;
-	int ret;
-
-	if (act) {
-		old_sigset_t mask;
-		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
-		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
-		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer) ||
-		    __get_user(new_ka.sa.sa_flags, &act->sa_flags) ||
-		    __get_user(mask, &act->sa_mask))
-			return -EFAULT;
-		siginitset(&new_ka.sa.sa_mask, mask);
-	}
-
-	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
-
-	if (!ret && oact) {
-		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
-		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
-		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer) ||
-		    __put_user(old_ka.sa.sa_flags, &oact->sa_flags) ||
-		    __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask))
-			return -EFAULT;
-	}
-
-	return ret;
-}
+static unsigned long signal_return_offset;
 
 #ifdef CONFIG_CRUNCH
 static int preserve_crunch_context(struct crunch_sigframe __user *frame)
@@ -300,7 +239,7 @@ asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
 	if (restore_sigframe(regs, &frame->sig))
 		goto badframe;
 
-	if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT)
+	if (restore_altstack(&frame->sig.uc.uc_stack))
 		goto badframe;
 
 	return regs->ARM_r0;
@@ -360,18 +299,12 @@ setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
 }
 
 static inline void __user *
-get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
+get_sigframe(struct ksignal *ksig, struct pt_regs *regs, int framesize)
 {
-	unsigned long sp = regs->ARM_sp;
+	unsigned long sp = sigsp(regs->ARM_sp, ksig);
 	void __user *frame;
 
 	/*
-	 * This is the X/Open sanctioned signal stack switching.
-	 */
-	if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
-		sp = current->sas_ss_sp + current->sas_ss_size;
-
-	/*
 	 * ATPCS B01 mandates 8-byte alignment
 	 */
 	frame = (void __user *)((sp - framesize) & ~7);
@@ -385,11 +318,22 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
 	return frame;
 }
 
+/*
+ * translate the signal
+ */
+static inline int map_sig(int sig)
+{
+	struct thread_info *thread = current_thread_info();
+	if (sig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
+		sig = thread->exec_domain->signal_invmap[sig];
+	return sig;
+}
+
 static int
-setup_return(struct pt_regs *regs, struct k_sigaction *ka,
-	     unsigned long __user *rc, void __user *frame, int usig)
+setup_return(struct pt_regs *regs, struct ksignal *ksig,
+	     unsigned long __user *rc, void __user *frame)
 {
-	unsigned long handler = (unsigned long)ka->sa.sa_handler;
+	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);
@@ -399,7 +343,7 @@ setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 	/*
 	 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
 	 */
-	if (ka->sa.sa_flags & SA_THIRTYTWO)
+	if (ksig->ka.sa.sa_flags & SA_THIRTYTWO)
 		cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
 
 #ifdef CONFIG_ARM_THUMB
@@ -410,36 +354,53 @@ setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 		 */
 		thumb = handler & 1;
 
-		if (thumb) {
-			cpsr |= PSR_T_BIT;
 #if __LINUX_ARM_ARCH__ >= 7
-			/* clear the If-Then Thumb-2 execution state */
-			cpsr &= ~PSR_IT_MASK;
+		/*
+		 * 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 (ka->sa.sa_flags & SA_RESTORER) {
-		retcode = (unsigned long)ka->sa.sa_restorer;
+	if (ksig->ka.sa.sa_flags & SA_RESTORER) {
+		retcode = (unsigned long)ksig->ka.sa.sa_restorer;
 	} else {
 		unsigned int idx = thumb << 1;
 
-		if (ka->sa.sa_flags & SA_SIGINFO)
+		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 new high-page
-			 * signal return code support.
+			 * 32-bit code can use the signal return page
+			 * except when the MPU has protected the vectors
+			 * page from PL0
 			 */
-			retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb;
-		} else {
+			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.
@@ -451,7 +412,7 @@ setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 		}
 	}
 
-	regs->ARM_r0 = usig;
+	regs->ARM_r0 = map_sig(ksig->sig);
 	regs->ARM_sp = (unsigned long)frame;
 	regs->ARM_lr = retcode;
 	regs->ARM_pc = handler;
@@ -461,9 +422,9 @@ setup_return(struct pt_regs *regs, struct k_sigaction *ka,
 }
 
 static int
-setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
+setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
 {
-	struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
+	struct sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
 	int err = 0;
 
 	if (!frame)
@@ -476,36 +437,29 @@ setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *reg
 
 	err |= setup_sigframe(frame, regs, set);
 	if (err == 0)
-		err = setup_return(regs, ka, frame->retcode, frame, usig);
+		err = setup_return(regs, ksig, frame->retcode, frame);
 
 	return err;
 }
 
 static int
-setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
-	       sigset_t *set, struct pt_regs *regs)
+setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
 {
-	struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
-	stack_t stack;
+	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, info);
+	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);
 
-	memset(&stack, 0, sizeof(stack));
-	stack.ss_sp = (void __user *)current->sas_ss_sp;
-	stack.ss_flags = sas_ss_flags(regs->ARM_sp);
-	stack.ss_size = current->sas_ss_size;
-	err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
-
+	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, ka, frame->sig.retcode, frame, usig);
+		err = setup_return(regs, ksig, frame->sig.retcode, frame);
 
 	if (err == 0) {
 		/*
@@ -523,40 +477,25 @@ setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
 /*
  * OK, we're invoking a handler
  */	
-static void
-handle_signal(unsigned long sig, struct k_sigaction *ka,
-	      siginfo_t *info, struct pt_regs *regs)
+static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 {
-	struct thread_info *thread = current_thread_info();
-	struct task_struct *tsk = current;
 	sigset_t *oldset = sigmask_to_save();
-	int usig = sig;
 	int ret;
 
 	/*
-	 * translate the signal
-	 */
-	if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
-		usig = thread->exec_domain->signal_invmap[usig];
-
-	/*
 	 * Set up the stack frame
 	 */
-	if (ka->sa.sa_flags & SA_SIGINFO)
-		ret = setup_rt_frame(usig, ka, info, oldset, regs);
+	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
+		ret = setup_rt_frame(ksig, oldset, regs);
 	else
-		ret = setup_frame(usig, ka, oldset, regs);
+		ret = setup_frame(ksig, oldset, regs);
 
 	/*
 	 * Check that the resulting registers are actually sane.
 	 */
 	ret |= !valid_user_regs(regs);
 
-	if (ret != 0) {
-		force_sigsegv(sig, tsk);
-		return;
-	}
-	signal_delivered(sig, info, ka, regs, 0);
+	signal_setup_done(ret, ksig, 0);
 }
 
 /*
@@ -571,9 +510,7 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
 static int do_signal(struct pt_regs *regs, int syscall)
 {
 	unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
-	struct k_sigaction ka;
-	siginfo_t info;
-	int signr;
+	struct ksignal ksig;
 	int restart = 0;
 
 	/*
@@ -605,33 +542,32 @@ static int do_signal(struct pt_regs *regs, int syscall)
 	 * Get the signal to deliver.  When running under ptrace, at this
 	 * point the debugger may change all our registers ...
 	 */
-	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 	/*
 	 * 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 (regs->ARM_pc != restart_addr)
-		restart = 0;
-	if (signr > 0) {
-		if (unlikely(restart)) {
+	if (get_signal(&ksig)) {
+		/* handler */
+		if (unlikely(restart) && regs->ARM_pc == restart_addr) {
 			if (retval == -ERESTARTNOHAND ||
 			    retval == -ERESTART_RESTARTBLOCK
 			    || (retval == -ERESTARTSYS
-				&& !(ka.sa.sa_flags & SA_RESTART))) {
+				&& !(ksig.ka.sa.sa_flags & SA_RESTART))) {
 				regs->ARM_r0 = -EINTR;
 				regs->ARM_pc = continue_addr;
 			}
 		}
-
-		handle_signal(signr, &ka, &info, regs);
-		return 0;
+		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;
+		}
 	}
-
-	restore_saved_sigmask();
-	if (unlikely(restart))
-		regs->ARM_pc = continue_addr;
-	return restart;
+	return 0;
 }
 
 asmlinkage int
@@ -655,6 +591,9 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 					return restart;
 				}
 				syscall = 0;
+			} else if (thread_flags & _TIF_UPROBE) {
+				clear_thread_flag(TIF_UPROBE);
+				uprobe_notify_resume(regs);
 			} else {
 				clear_thread_flag(TIF_NOTIFY_RESUME);
 				tracehook_notify_resume(regs);
@@ -665,3 +604,33 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
 	} 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;
+}