Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

Pull arch/tile updates from Chris Metcalf:
 "These are mostly nohz_full changes, plus a smattering of minor fixes
  (notably a couple for ftrace)"

* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
  tile: nohz: warn if nohz_full uses hypervisor shared cores
  tile: ftrace: fix function_graph tracer issues
  tile: map data region shadow of kernel as R/W
  tile: support CONTEXT_TRACKING and thus NOHZ_FULL
  tile: support arch_irq_work_raise
  arch: tile: fix null pointer dereference on pt_regs pointer
  tile/elf: reorganize notify_exec()
  tile: use si_int instead of si_ptr for compat_siginfo

arch/tile/Kconfig

@@ -27,6 +27,7 @@ config TILE
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select HAVE_DEBUG_STACKOVERFLOW
 	select ARCH_WANT_FRAME_POINTERS
+	select HAVE_CONTEXT_TRACKING
 
 # FIXME: investigate whether we need/want these options.
 #	select HAVE_IOREMAP_PROT

arch/tile/include/asm/Kbuild

@@ -16,7 +16,6 @@ generic-y += ioctl.h
 generic-y += ioctls.h
 generic-y += ipcbuf.h
 generic-y += irq_regs.h
-generic-y += irq_work.h
 generic-y += local.h
 generic-y += local64.h
 generic-y += mcs_spinlock.h

arch/tile/include/asm/ftrace.h

@@ -23,6 +23,8 @@
 #ifndef __ASSEMBLY__
 extern void __mcount(void);
 
+#define ARCH_SUPPORTS_FTRACE_OPS 1
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 static inline unsigned long ftrace_call_adjust(unsigned long addr)
 {

arch/tile/include/asm/irq_work.h

+#ifndef __ASM_IRQ_WORK_H
+#define __ASM_IRQ_WORK_H
+
+static inline bool arch_irq_work_has_interrupt(void)
+{
+#ifdef CONFIG_SMP
+	extern bool self_interrupt_ok;
+	return self_interrupt_ok;
+#else
+	return false;
+#endif
+}
+
+#endif /* __ASM_IRQ_WORK_H */

arch/tile/include/asm/smp.h

@@ -69,6 +69,7 @@ static inline int xy_to_cpu(int x, int y)
 #define MSG_TAG_STOP_CPU		2
 #define MSG_TAG_CALL_FUNCTION_MANY	3
 #define MSG_TAG_CALL_FUNCTION_SINGLE	4
+#define MSG_TAG_IRQ_WORK		5
 
 /* Hook for the generic smp_call_function_many() routine. */
 static inline void arch_send_call_function_ipi_mask(struct cpumask *mask)

arch/tile/include/asm/thread_info.h

@@ -124,6 +124,7 @@ extern void _cpu_idle(void);
 #define TIF_NOTIFY_RESUME	8	/* callback before returning to user */
 #define TIF_SYSCALL_TRACEPOINT	9	/* syscall tracepoint instrumentation */
 #define TIF_POLLING_NRFLAG	10	/* idle is polling for TIF_NEED_RESCHED */
+#define TIF_NOHZ		11	/* in adaptive nohz mode */
 
 #define _TIF_SIGPENDING		(1<<TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1<<TIF_NEED_RESCHED)
@@ -136,14 +137,16 @@ extern void _cpu_idle(void);
 #define _TIF_NOTIFY_RESUME	(1<<TIF_NOTIFY_RESUME)
 #define _TIF_SYSCALL_TRACEPOINT	(1<<TIF_SYSCALL_TRACEPOINT)
 #define _TIF_POLLING_NRFLAG	(1<<TIF_POLLING_NRFLAG)
+#define _TIF_NOHZ		(1<<TIF_NOHZ)
 
 /* Work to do on any return to user space. */
 #define _TIF_ALLWORK_MASK \
-  (_TIF_SIGPENDING|_TIF_NEED_RESCHED|_TIF_SINGLESTEP|\
-   _TIF_ASYNC_TLB|_TIF_NOTIFY_RESUME)
+	(_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_SINGLESTEP | \
+	 _TIF_ASYNC_TLB | _TIF_NOTIFY_RESUME | _TIF_NOHZ)
 
 /* Work to do at syscall entry. */
-#define _TIF_SYSCALL_ENTRY_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT)
+#define _TIF_SYSCALL_ENTRY_WORK \
+	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_NOHZ)
 
 /* Work to do at syscall exit. */
 #define _TIF_SYSCALL_EXIT_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT)

arch/tile/include/hv/hypervisor.h

@@ -961,7 +961,11 @@ typedef enum {
   HV_INQ_TILES_HFH_CACHE       = 2,
 
   /** The set of tiles that can be legally used as a LOTAR for a PTE. */
-  HV_INQ_TILES_LOTAR           = 3
+  HV_INQ_TILES_LOTAR           = 3,
+
+  /** The set of "shared" driver tiles that the hypervisor may
+   *  periodically interrupt. */
+  HV_INQ_TILES_SHARED          = 4
 } HV_InqTileSet;
 
 /** Returns specific information about various sets of tiles within the

arch/tile/kernel/compat_signal.c

@@ -68,7 +68,7 @@ int copy_siginfo_to_user32(struct compat_siginfo __user *to, const siginfo_t *fr
 	if (from->si_code < 0) {
 		err |= __put_user(from->si_pid, &to->si_pid);
 		err |= __put_user(from->si_uid, &to->si_uid);
-		err |= __put_user(ptr_to_compat(from->si_ptr), &to->si_ptr);
+		err |= __put_user(from->si_int, &to->si_int);
 	} else {
 		/*
 		 * First 32bits of unions are always present:
@@ -93,8 +93,7 @@ int copy_siginfo_to_user32(struct compat_siginfo __user *to, const siginfo_t *fr
 			break;
 		case __SI_TIMER >> 16:
 			err |= __put_user(from->si_overrun, &to->si_overrun);
-			err |= __put_user(ptr_to_compat(from->si_ptr),
-					  &to->si_ptr);
+			err |= __put_user(from->si_int, &to->si_int);
 			break;
 			 /* This is not generated by the kernel as of now.  */
 		case __SI_RT >> 16:
@@ -110,19 +109,19 @@ int copy_siginfo_to_user32(struct compat_siginfo __user *to, const siginfo_t *fr
 int copy_siginfo_from_user32(siginfo_t *to, struct compat_siginfo __user *from)
 {
 	int err;
-	u32 ptr32;
 
 	if (!access_ok(VERIFY_READ, from, sizeof(struct compat_siginfo)))
 		return -EFAULT;
 
+	memset(to, 0, sizeof(*to));
+
 	err = __get_user(to->si_signo, &from->si_signo);
 	err |= __get_user(to->si_errno, &from->si_errno);
 	err |= __get_user(to->si_code, &from->si_code);
 
 	err |= __get_user(to->si_pid, &from->si_pid);
 	err |= __get_user(to->si_uid, &from->si_uid);
-	err |= __get_user(ptr32, &from->si_ptr);
-	to->si_ptr = compat_ptr(ptr32);
+	err |= __get_user(to->si_int, &from->si_int);
 
 	return err;
 }

arch/tile/kernel/ftrace.c

@@ -74,7 +74,11 @@ static unsigned long ftrace_gen_branch(unsigned long pc, unsigned long addr,
 			create_JumpOff_X1(pcrel_by_instr);
 	}
 
-	if (addr == FTRACE_ADDR) {
+	/*
+	 * Also put { move r10, lr; jal ftrace_stub } in a bundle, which
+	 * is used to replace the instruction in address ftrace_call.
+	 */
+	if (addr == FTRACE_ADDR || addr == (unsigned long)ftrace_stub) {
 		/* opcode: or r10, lr, zero */
 		opcode_x0 =
 			create_Dest_X0(10) |

arch/tile/kernel/mcount_64.S

@@ -81,7 +81,12 @@ STD_ENTRY(ftrace_caller)
 
 	/* arg1: self return address */
 	/* arg2: parent's return address */
-	{ move	r0, lr; move	r1, r10 }
+	/* arg3: ftrace_ops */
+	/* arg4: regs (but make it NULL) */
+	{ move	r0, lr;  moveli        r2, hw2_last(function_trace_op) }
+	{ move	r1, r10; shl16insli    r2, r2, hw1(function_trace_op) }
+	{ movei	r3, 0;   shl16insli    r2, r2, hw0(function_trace_op) }
+	ld	r2,r2
 
 	.global	ftrace_call
 ftrace_call:

arch/tile/kernel/process.c

@@ -27,6 +27,7 @@
 #include <linux/kernel.h>
 #include <linux/tracehook.h>
 #include <linux/signal.h>
+#include <linux/context_tracking.h>
 #include <asm/stack.h>
 #include <asm/switch_to.h>
 #include <asm/homecache.h>
@@ -474,6 +475,8 @@ int do_work_pending(struct pt_regs *regs, u32 thread_info_flags)
 	if (!user_mode(regs))
 		return 0;
 
+	user_exit();
+
 	/* Enable interrupts; they are disabled again on return to caller. */
 	local_irq_enable();
 
@@ -496,11 +499,12 @@ int do_work_pending(struct pt_regs *regs, u32 thread_info_flags)
 		tracehook_notify_resume(regs);
 		return 1;
 	}
-	if (thread_info_flags & _TIF_SINGLESTEP) {
+	if (thread_info_flags & _TIF_SINGLESTEP)
 		single_step_once(regs);
+
+	user_enter();
+
 	return 0;
-	}
-	panic("work_pending: bad flags %#x\n", thread_info_flags);
 }
 
 unsigned long get_wchan(struct task_struct *p)

arch/tile/kernel/ptrace.c

@@ -22,6 +22,7 @@
 #include <linux/regset.h>
 #include <linux/elf.h>
 #include <linux/tracehook.h>
+#include <linux/context_tracking.h>
 #include <asm/traps.h>
 #include <arch/chip.h>
 
@@ -252,12 +253,21 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 
 int do_syscall_trace_enter(struct pt_regs *regs)
 {
-	if (test_thread_flag(TIF_SYSCALL_TRACE)) {
+	u32 work = ACCESS_ONCE(current_thread_info()->flags);
+
+	/*
+	 * If TIF_NOHZ is set, we are required to call user_exit() before
+	 * doing anything that could touch RCU.
+	 */
+	if (work & _TIF_NOHZ)
+		user_exit();
+
+	if (work & _TIF_SYSCALL_TRACE) {
 		if (tracehook_report_syscall_entry(regs))
 			regs->regs[TREG_SYSCALL_NR] = -1;
 	}
 
-	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+	if (work & _TIF_SYSCALL_TRACEPOINT)
 		trace_sys_enter(regs, regs->regs[TREG_SYSCALL_NR]);
 
 	return regs->regs[TREG_SYSCALL_NR];
@@ -267,6 +277,12 @@ void do_syscall_trace_exit(struct pt_regs *regs)
 {
 	long errno;
 
+	/*
+	 * We may come here right after calling schedule_user()
+	 * in which case we can be in RCU user mode.
+	 */
+	user_exit();
+
 	/*
 	 * The standard tile calling convention returns the value (or negative
 	 * errno) in r0, and zero (or positive errno) in r1.
@@ -303,5 +319,7 @@ void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs)
 /* Handle synthetic interrupt delivered only by the simulator. */
 void __kprobes do_breakpoint(struct pt_regs* regs, int fault_num)
 {
+	enum ctx_state prev_state = exception_enter();
 	send_sigtrap(current, regs);
+	exception_exit(prev_state);
 }

arch/tile/kernel/setup.c

@@ -32,6 +32,7 @@
 #include <linux/hugetlb.h>
 #include <linux/start_kernel.h>
 #include <linux/screen_info.h>
+#include <linux/tick.h>
 #include <asm/setup.h>
 #include <asm/sections.h>
 #include <asm/cacheflush.h>
@@ -1390,6 +1391,28 @@ static int __init dataplane(char *str)
 
 early_param("dataplane", dataplane);
 
+#ifdef CONFIG_NO_HZ_FULL
+/* Warn if hypervisor shared cpus are marked as nohz_full. */
+static int __init check_nohz_full_cpus(void)
+{
+	struct cpumask shared;
+	int cpu;
+
+	if (hv_inquire_tiles(HV_INQ_TILES_SHARED,
+			     (HV_VirtAddr) shared.bits, sizeof(shared)) < 0) {
+		pr_warn("WARNING: No support for inquiring hv shared tiles\n");
+		return 0;
+	}
+	for_each_cpu(cpu, &shared) {
+		if (tick_nohz_full_cpu(cpu))
+			pr_warn("WARNING: nohz_full cpu %d receives hypervisor interrupts!\n",
+			       cpu);
+	}
+	return 0;
+}
+arch_initcall(check_nohz_full_cpus);
+#endif
+
 #ifdef CONFIG_CMDLINE_BOOL
 static char __initdata builtin_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
 #endif

arch/tile/kernel/single_step.c

@@ -23,6 +23,7 @@
 #include <linux/types.h>
 #include <linux/err.h>
 #include <linux/prctl.h>
+#include <linux/context_tracking.h>
 #include <asm/cacheflush.h>
 #include <asm/traps.h>
 #include <asm/uaccess.h>
@@ -738,6 +739,7 @@ static DEFINE_PER_CPU(unsigned long, ss_saved_pc);
 
 void gx_singlestep_handle(struct pt_regs *regs, int fault_num)
 {
+	enum ctx_state prev_state = exception_enter();
 	unsigned long *ss_pc = this_cpu_ptr(&ss_saved_pc);
 	struct thread_info *info = (void *)current_thread_info();
 	int is_single_step = test_ti_thread_flag(info, TIF_SINGLESTEP);
@@ -754,6 +756,7 @@ void gx_singlestep_handle(struct pt_regs *regs, int fault_num)
 		__insn_mtspr(SPR_SINGLE_STEP_CONTROL_K, control);
 		send_sigtrap(current, regs);
 	}
+	exception_exit(prev_state);
 }
 
 

arch/tile/kernel/smp.c

@@ -18,6 +18,7 @@
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/irq.h>
+#include <linux/irq_work.h>
 #include <linux/module.h>
 #include <asm/cacheflush.h>
 #include <asm/homecache.h>
@@ -33,6 +34,8 @@ EXPORT_SYMBOL(smp_topology);
 static unsigned long __iomem *ipi_mappings[NR_CPUS];
 #endif
 
+/* Does messaging work correctly to the local cpu? */
+bool self_interrupt_ok;
 
 /*
  * Top-level send_IPI*() functions to send messages to other cpus.
@@ -147,6 +150,10 @@ void evaluate_message(int tag)
 		generic_smp_call_function_single_interrupt();
 		break;
 
+	case MSG_TAG_IRQ_WORK: /* Invoke IRQ work */
+		irq_work_run();
+		break;
+
 	default:
 		panic("Unknown IPI message tag %d", tag);
 		break;
@@ -186,6 +193,15 @@ void flush_icache_range(unsigned long start, unsigned long end)
 EXPORT_SYMBOL(flush_icache_range);
 
 
+#ifdef CONFIG_IRQ_WORK
+void arch_irq_work_raise(void)
+{
+	if (arch_irq_work_has_interrupt())
+		send_IPI_single(smp_processor_id(), MSG_TAG_IRQ_WORK);
+}
+#endif
+
+
 /* Called when smp_send_reschedule() triggers IRQ_RESCHEDULE. */
 static irqreturn_t handle_reschedule_ipi(int irq, void *token)
 {
@@ -203,8 +219,22 @@ static struct irqaction resched_action = {
 
 void __init ipi_init(void)
 {
+	int cpu = smp_processor_id();
+	HV_Recipient recip = { .y = cpu_y(cpu), .x = cpu_x(cpu),
+			       .state = HV_TO_BE_SENT };
+	int tag = MSG_TAG_CALL_FUNCTION_SINGLE;
+
+	/*
+	 * Test if we can message ourselves for arch_irq_work_raise.
+	 * This functionality is only available in the Tilera hypervisor
+	 * in versions 4.3.4 and following.
+	 */
+	if (hv_send_message(&recip, 1, (HV_VirtAddr)&tag, sizeof(tag)) == 1)
+		self_interrupt_ok = true;
+	else
+		pr_warn("Older hypervisor: disabling fast irq_work_raise\n");
+
 #if CHIP_HAS_IPI()
-	int cpu;
 	/* Map IPI trigger MMIO addresses. */
 	for_each_possible_cpu(cpu) {
 		HV_Coord tile;

arch/tile/kernel/stack.c

@@ -108,14 +108,15 @@ static struct pt_regs *valid_fault_handler(struct KBacktraceIterator* kbt)
 		   p->sp < PAGE_OFFSET && p->sp != 0) {
 		if (kbt->verbose)
 			pr_err("  <%s while in user mode>\n", fault);
-	} else if (kbt->verbose) {
+	} else {
+		if (kbt->verbose)
 			pr_err("  (odd fault: pc %#lx, sp %#lx, ex1 %#lx?)\n",
 			       p->pc, p->sp, p->ex1);
-		p = NULL;
+		return NULL;
 	}
-	if (!kbt->profile || ((1ULL << p->faultnum) & QUEUED_INTERRUPTS) == 0)
-		return p;
+	if (kbt->profile && ((1ULL << p->faultnum) & QUEUED_INTERRUPTS) != 0)
 		return NULL;
+	return p;
 }
 
 /* Is the pc pointing to a sigreturn trampoline? */

arch/tile/kernel/traps.c

@@ -20,6 +20,7 @@
 #include <linux/reboot.h>
 #include <linux/uaccess.h>
 #include <linux/ptrace.h>
+#include <linux/context_tracking.h>
 #include <asm/stack.h>
 #include <asm/traps.h>
 #include <asm/setup.h>
@@ -253,6 +254,7 @@ static int do_bpt(struct pt_regs *regs)
 void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 		       unsigned long reason)
 {
+	enum ctx_state prev_state = exception_enter();
 	siginfo_t info = { 0 };
 	int signo, code;
 	unsigned long address = 0;
@@ -261,7 +263,7 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 
 	/* Handle breakpoints, etc. */
 	if (is_kernel && fault_num == INT_ILL && do_bpt(regs))
-		return;
+		goto done;
 
 	/* Re-enable interrupts, if they were previously enabled. */
 	if (!(regs->flags & PT_FLAGS_DISABLE_IRQ))
@@ -275,7 +277,7 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 		const char *name;
 		char buf[100];
 		if (fixup_exception(regs))  /* ILL_TRANS or UNALIGN_DATA */
-			return;
+			goto done;
 		if (fault_num >= 0 &&
 		    fault_num < ARRAY_SIZE(int_name) &&
 		    int_name[fault_num] != NULL)
@@ -294,7 +296,6 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 			 fault_num, name, regs->pc, buf);
 		show_regs(regs);
 		do_exit(SIGKILL);  /* FIXME: implement i386 die() */
-		return;
 	}
 
 	switch (fault_num) {
@@ -308,7 +309,6 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 			pr_err("Unreadable instruction for INT_ILL: %#lx\n",
 			       regs->pc);
 			do_exit(SIGKILL);
-			return;
 		}
 		if (!special_ill(instr, &signo, &code)) {
 			signo = SIGILL;
@@ -319,7 +319,7 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 	case INT_GPV:
 #if CHIP_HAS_TILE_DMA()
 		if (retry_gpv(reason))
-			return;
+			goto done;
 #endif
 		/*FALLTHROUGH*/
 	case INT_UDN_ACCESS:
@@ -346,7 +346,7 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 			if (!state ||
 			    (void __user *)(regs->pc) != state->buffer) {
 				single_step_once(regs);
-				return;
+				goto done;
 			}
 		}
 #endif
@@ -380,7 +380,6 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 #endif
 	default:
 		panic("Unexpected do_trap interrupt number %d", fault_num);
-		return;
 	}
 
 	info.si_signo = signo;
@@ -391,6 +390,9 @@ void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 	if (signo != SIGTRAP)
 		trace_unhandled_signal("trap", regs, address, signo);
 	force_sig_info(signo, &info, current);
+
+done:
+	exception_exit(prev_state);
 }
 
 void kernel_double_fault(int dummy, ulong pc, ulong lr, ulong sp, ulong r52)

arch/tile/kernel/unaligned.c

@@ -25,6 +25,7 @@
 #include <linux/module.h>
 #include <linux/compat.h>
 #include <linux/prctl.h>
+#include <linux/context_tracking.h>
 #include <asm/cacheflush.h>
 #include <asm/traps.h>
 #include <asm/uaccess.h>
@@ -1448,6 +1449,7 @@ void jit_bundle_gen(struct pt_regs *regs, tilegx_bundle_bits bundle,
 
 void do_unaligned(struct pt_regs *regs, int vecnum)
 {
+	enum ctx_state prev_state = exception_enter();
 	tilegx_bundle_bits __user  *pc;
 	tilegx_bundle_bits bundle;
 	struct thread_info *info = current_thread_info();
@@ -1487,12 +1489,11 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
 						(int)unaligned_fixup,
 						(unsigned long long)regs->ex1,
 						(unsigned long long)regs->pc);
-				return;
-			}
+			} else {
 				/* Not fixable. Go panic. */
 				panic("Unalign exception in Kernel. pc=%lx",
 				      regs->pc);
-			return;
+			}
 		} else {
 			/*
 			 * Try to fix the exception. If we can't, panic the
@@ -1501,8 +1502,8 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
 			bundle = GX_INSN_BSWAP(
 				*((tilegx_bundle_bits *)(regs->pc)));
 			jit_bundle_gen(regs, bundle, align_ctl);
-			return;
 		}
+		goto done;
 	}
 
 	/*
@@ -1526,7 +1527,7 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
 
 		trace_unhandled_signal("unaligned fixup trap", regs, 0, SIGBUS);
 		force_sig_info(info.si_signo, &info, current);
-		return;
+		goto done;
 	}
 
 
@@ -1543,7 +1544,7 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
 		trace_unhandled_signal("segfault in unalign fixup", regs,
 				       (unsigned long)info.si_addr, SIGSEGV);
 		force_sig_info(info.si_signo, &info, current);
-		return;
+		goto done;
 	}
 
 	if (!info->unalign_jit_base) {
@@ -1578,7 +1579,7 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
 
 		if (IS_ERR((void __force *)user_page)) {
 			pr_err("Out of kernel pages trying do_mmap\n");
-			return;
+			goto done;
 		}
 
 		/* Save the address in the thread_info struct */
@@ -1591,6 +1592,9 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
 
 	/* Generate unalign JIT */
 	jit_bundle_gen(regs, GX_INSN_BSWAP(bundle), align_ctl);
+
+done:
+	exception_exit(prev_state);
 }
 
 #endif /* __tilegx__ */

arch/tile/mm/elf.c

@@ -17,6 +17,7 @@
 #include <linux/binfmts.h>
 #include <linux/compat.h>
 #include <linux/mman.h>
+#include <linux/file.h>
 #include <linux/elf.h>
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
@@ -39,30 +40,34 @@ static void sim_notify_exec(const char *binary_name)
 
 static int notify_exec(struct mm_struct *mm)
 {
+	int ret = 0;
 	char *buf, *path;
 	struct vm_area_struct *vma;
+	struct file *exe_file;
 
 	if (!sim_is_simulator())
 		return 1;
 
-	if (mm->exe_file == NULL)
-		return 0;
-
-	for (vma = current->mm->mmap; ; vma = vma->vm_next) {
-		if (vma == NULL)
-			return 0;
-		if (vma->vm_file == mm->exe_file)
-			break;
-	}
-
 	buf = (char *) __get_free_page(GFP_KERNEL);
 	if (buf == NULL)
 		return 0;
 
-	path = d_path(&mm->exe_file->f_path, buf, PAGE_SIZE);
-	if (IS_ERR(path)) {
-		free_page((unsigned long)buf);
-		return 0;
+	exe_file = get_mm_exe_file(mm);
+	if (exe_file == NULL)
+		goto done_free;
+
+	path = d_path(&exe_file->f_path, buf, PAGE_SIZE);
+	if (IS_ERR(path))
+		goto done_put;
+
+	down_read(&mm->mmap_sem);
+	for (vma = current->mm->mmap; ; vma = vma->vm_next) {
+		if (vma == NULL) {
+			up_read(&mm->mmap_sem);
+			goto done_put;
+		}
+		if (vma->vm_file == exe_file)
+			break;
 	}
 
 	/*
@@ -80,14 +85,20 @@ static int notify_exec(struct mm_struct *mm)
 			__insn_mtspr(SPR_SIM_CONTROL,
 				     (SIM_CONTROL_DLOPEN
 				      | (c << _SIM_CONTROL_OPERATOR_BITS)));
-			if (c == '\0')
+			if (c == '\0') {
+				ret = 1; /* success */
 				break;
 			}
 		}
+	}
+	up_read(&mm->mmap_sem);
 
 	sim_notify_exec(path);
+done_put:
+	fput(exe_file);
+done_free:
 	free_page((unsigned long)buf);
-	return 1;
+	return ret;
 }
 
 /* Notify a running simulator, if any, that we loaded an interpreter. */
@@ -109,8 +120,6 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
 	struct mm_struct *mm = current->mm;
 	int retval = 0;
 
-	down_write(&mm->mmap_sem);
-
 	/*
 	 * Notify the simulator that an exec just occurred.
 	 * If we can't find the filename of the mapping, just use
@@ -119,6 +128,8 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
 	if (!notify_exec(mm))
 		sim_notify_exec(bprm->filename);
 
+	down_write(&mm->mmap_sem);
+
 	retval = setup_vdso_pages();
 
 #ifndef __tilegx__

arch/tile/mm/fault.c

@@ -35,6 +35,7 @@
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>
 #include <linux/kdebug.h>
+#include <linux/context_tracking.h>
 
 #include <asm/pgalloc.h>
 #include <asm/sections.h>
@@ -702,6 +703,7 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
 		   unsigned long address, unsigned long write)
 {
 	int is_page_fault;
+	enum ctx_state prev_state = exception_enter();
 
 #ifdef CONFIG_KPROBES
 	/*
@@ -711,7 +713,7 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
 	 */
 	if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
 		       regs->faultnum, SIGSEGV) == NOTIFY_STOP)
-		return;
+		goto done;
 #endif
 
 #ifdef __tilegx__
@@ -750,7 +752,6 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
 				 current->comm, current->pid, pc, address);
 			show_regs(regs);
 			do_group_exit(SIGKILL);
-			return;
 		}
 	}
 #else
@@ -834,12 +835,15 @@ void do_page_fault(struct pt_regs *regs, int fault_num,
 			async->is_fault = is_page_fault;
 			async->is_write = write;
 			async->address = address;
-			return;
+			goto done;
 		}
 	}
 #endif
 
 	handle_page_fault(regs, fault_num, is_page_fault, address, write);
+
+done:
+	exception_exit(prev_state);
 }
 
 

arch/tile/mm/init.c

@@ -233,9 +233,12 @@ static pgprot_t __init init_pgprot(ulong address)
 	if (kdata_huge)
 		return construct_pgprot(PAGE_KERNEL, PAGE_HOME_HASH);
 
-	/* We map the aliased pages of permanent text inaccessible. */
+	/*
+	 * We map the aliased pages of permanent text so we can
+	 * update them if necessary, for ftrace, etc.
+	 */
 	if (address < (ulong) _sinittext - CODE_DELTA)
-		return PAGE_NONE;
+		return construct_pgprot(PAGE_KERNEL, PAGE_HOME_HASH);
 
 	/* We map read-only data non-coherent for performance. */
 	if ((address >= (ulong) __start_rodata &&