1 files changed, 35 insertions, 24 deletions

diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index 6d8ae86ae978..ce073150dc20 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -16,6 +16,7 @@
 #include <kern_util.h>
 #include <os.h>
 #include <skas.h>
+#include <arch.h>
 
 /*
  * Note this is constrained to return 0, -EFAULT, -EACCES, -ENOMEM by
@@ -113,7 +114,7 @@ good_area:
 #if 0
 	WARN_ON(!pte_young(*pte) || (is_write && !pte_dirty(*pte)));
 #endif
-	flush_tlb_page(vma, address);
+
 out:
 	mmap_read_unlock(mm);
 out_nosemaphore:
@@ -175,12 +176,14 @@ void fatal_sigsegv(void)
  * @sig:	the signal number
  * @unused_si:	the signal info struct; unused in this handler
  * @regs:	the ptrace register information
+ * @mc:		the mcontext of the signal
  *
  * The handler first extracts the faultinfo from the UML ptrace regs struct.
  * If the userfault did not happen in an UML userspace process, bad_segv is called.
  * Otherwise the signal did happen in a cloned userspace process, handle it.
  */
-void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
+void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs,
+		  void *mc)
 {
 	struct faultinfo * fi = UPT_FAULTINFO(regs);
 
@@ -189,7 +192,7 @@ void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 		bad_segv(*fi, UPT_IP(regs));
 		return;
 	}
-	segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs);
+	segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs, mc);
 }
 
 /*
@@ -199,9 +202,8 @@ void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
  * give us bad data!
  */
 unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
-		   struct uml_pt_regs *regs)
+		   struct uml_pt_regs *regs, void *mc)
 {
-	jmp_buf *catcher;
 	int si_code;
 	int err;
 	int is_write = FAULT_WRITE(fi);
@@ -210,11 +212,33 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
 	if (!is_user && regs)
 		current->thread.segv_regs = container_of(regs, struct pt_regs, regs);
 
-	if (!is_user && (address >= start_vm) && (address < end_vm)) {
-		flush_tlb_kernel_vm();
+	if (!is_user && init_mm.context.sync_tlb_range_to) {
+		/*
+		 * Kernel has pending updates from set_ptes that were not
+		 * flushed yet. Syncing them should fix the pagefault (if not
+		 * we'll get here again and panic).
+		 */
+		err = um_tlb_sync(&init_mm);
+		if (err == -ENOMEM)
+			report_enomem();
+		if (err)
+			panic("Failed to sync kernel TLBs: %d", err);
 		goto out;
 	}
 	else if (current->mm == NULL) {
+		if (current->pagefault_disabled) {
+			if (!mc) {
+				show_regs(container_of(regs, struct pt_regs, regs));
+				panic("Segfault with pagefaults disabled but no mcontext");
+			}
+			if (!current->thread.segv_continue) {
+				show_regs(container_of(regs, struct pt_regs, regs));
+				panic("Segfault without recovery target");
+			}
+			mc_set_rip(mc, current->thread.segv_continue);
+			current->thread.segv_continue = NULL;
+			goto out;
+		}
 		show_regs(container_of(regs, struct pt_regs, regs));
 		panic("Segfault with no mm");
 	}
@@ -237,15 +261,8 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
 		address = 0;
 	}
 
-	catcher = current->thread.fault_catcher;
 	if (!err)
 		goto out;
-	else if (catcher != NULL) {
-		current->thread.fault_addr = (void *) address;
-		UML_LONGJMP(catcher, 1);
-	}
-	else if (current->thread.fault_addr != NULL)
-		panic("fault_addr set but no fault catcher");
 	else if (!is_user && arch_fixup(ip, regs))
 		goto out;
 
@@ -273,7 +290,8 @@ out:
 	return 0;
 }
 
-void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs)
+void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs,
+		  void *mc)
 {
 	int code, err;
 	if (!UPT_IS_USER(regs)) {
@@ -301,15 +319,8 @@ void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs)
 	}
 }
 
-void bus_handler(int sig, struct siginfo *si, struct uml_pt_regs *regs)
-{
-	if (current->thread.fault_catcher != NULL)
-		UML_LONGJMP(current->thread.fault_catcher, 1);
-	else
-		relay_signal(sig, si, regs);
-}
-
-void winch(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
+void winch(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs,
+	   void *mc)
 {
 	do_IRQ(WINCH_IRQ, regs);
 }