--- zzzz-none-000/linux-3.10.107/arch/mips/mm/fault.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/mips/mm/fault.c	2021-02-04 17:41:59.000000000 +0000
@@ -5,6 +5,7 @@
  *
  * Copyright (C) 1995 - 2000 by Ralf Baechle
  */
+#include <linux/context_tracking.h>
 #include <linux/signal.h>
 #include <linux/sched.h>
 #include <linux/interrupt.h>
@@ -13,27 +14,34 @@
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/ptrace.h>
+#include <linux/ratelimit.h>
 #include <linux/mman.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
 #include <linux/module.h>
 #include <linux/kprobes.h>
 #include <linux/perf_event.h>
+#include <linux/uaccess.h>
 
 #include <asm/branch.h>
 #include <asm/mmu_context.h>
-#include <asm/uaccess.h>
 #include <asm/ptrace.h>
 #include <asm/highmem.h>		/* For VMALLOC_END */
 #include <linux/kdebug.h>
 
+#if defined(CONFIG_AVM_SIMPLE_PROFILING) 
+#include <avm/profile/profile.h>
+#endif /*--- #if defined(CONFIG_AVM_SIMPLE_PROFILING) ---*/ 
+
+int show_unhandled_signals = 1;
+
 /*
  * This routine handles page faults.  It determines the address,
  * and the problem, and then passes it off to one of the appropriate
  * routines.
  */
-asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, unsigned long write,
-			      unsigned long address)
+static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write,
+	unsigned long address)
 {
 	struct vm_area_struct * vma = NULL;
 	struct task_struct *tsk = current;
@@ -43,6 +51,8 @@
 	int fault;
 	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
 
+	static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
+
 #if 0
 	printk("Cpu%d[%s:%d:%0*lx:%ld:%0*lx]\n", raw_smp_processor_id(),
 	       current->comm, current->pid, field, address, write,
@@ -51,12 +61,10 @@
 
 #ifdef CONFIG_KPROBES
 	/*
-	 * This is to notify the fault handler of the kprobes.	The
-	 * exception code is redundant as it is also carried in REGS,
-	 * but we pass it anyhow.
+	 * This is to notify the fault handler of the kprobes.
 	 */
 	if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
-		       (regs->cp0_cause >> 2) & 0x1f, SIGSEGV) == NOTIFY_STOP)
+		       current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
 		return;
 #endif
 
@@ -88,7 +96,7 @@
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (faulthandler_disabled() || !mm)
 		goto bad_area_nosemaphore;
 
 	if (user_mode(regs))
@@ -127,7 +135,8 @@
 #endif
 				goto bad_area;
 			}
-			if (!(vma->vm_flags & VM_READ)) {
+			if (!(vma->vm_flags & VM_READ) &&
+			    exception_epc(regs) != address) {
 #if 0
 				pr_notice("Cpu%d[%s:%d:%0*lx:%ld:%0*lx] RI violation\n",
 					  raw_smp_processor_id(),
@@ -148,7 +157,13 @@
 	 * make sure we exit gracefully rather than endlessly redo
 	 * the fault.
 	 */
+#if defined(CONFIG_AVM_SIMPLE_PROFILING) 
+    avm_simple_profiling_log(avm_profile_data_type_hw_irq_begin, (unsigned int)regs->cp0_epc, AVM_PROFILE_PAGE_FAULT_ID);
+#endif/*--- #if defined(CONFIG_AVM_SIMPLE_PROFILING)  ---*/
 	fault = handle_mm_fault(mm, vma, address, flags);
+#if defined(CONFIG_AVM_SIMPLE_PROFILING) 
+    avm_simple_profiling_log(avm_profile_data_type_hw_irq_end, regs->cp0_epc, AVM_PROFILE_PAGE_FAULT_ID);
+#endif/*--- #endif ---*//*--- #if defined(CONFIG_AVM_SIMPLE_PROFILING)  ---*/
 
 	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
 		return;
@@ -202,15 +217,22 @@
 	if (user_mode(regs)) {
 		tsk->thread.cp0_badvaddr = address;
 		tsk->thread.error_code = write;
-#if 0
-		printk("do_page_fault() #2: sending SIGSEGV to %s for "
-		       "invalid %s\n%0*lx (epc == %0*lx, ra == %0*lx)\n",
-		       tsk->comm,
-		       write ? "write access to" : "read access from",
-		       field, address,
-		       field, (unsigned long) regs->cp0_epc,
-		       field, (unsigned long) regs->regs[31]);
-#endif
+		if (show_unhandled_signals &&
+		    unhandled_signal(tsk, SIGSEGV) &&
+		    __ratelimit(&ratelimit_state)) {
+			pr_info("\ndo_page_fault(): sending SIGSEGV to %s for invalid %s %0*lx",
+				tsk->comm,
+				write ? "write access to" : "read access from",
+				field, address);
+			pr_info("epc = %0*lx in", field,
+				(unsigned long) regs->cp0_epc);
+			print_vma_addr(" ", regs->cp0_epc);
+			pr_info("ra  = %0*lx in", field,
+				(unsigned long) regs->regs[31]);
+			print_vma_addr(" ", regs->regs[31]);
+			pr_info("\n");
+		}
+		current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
 		info.si_signo = SIGSEGV;
 		info.si_errno = 0;
 		/* info.si_code has been set above */
@@ -269,6 +291,7 @@
 		       field, (unsigned long) regs->cp0_epc,
 		       field, (unsigned long) regs->regs[31]);
 #endif
+	current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
 	tsk->thread.cp0_badvaddr = address;
 	info.si_signo = SIGBUS;
 	info.si_errno = 0;
@@ -318,3 +341,13 @@
 	}
 #endif
 }
+
+asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
+	unsigned long write, unsigned long address)
+{
+	enum ctx_state prev_state;
+
+	prev_state = exception_enter();
+	__do_page_fault(regs, write, address);
+	exception_exit(prev_state);
+}