x86/fault: Rename no_context() to kernelmode_fixup_or_oops()

The name no_context() has never been very clear.  It's only called for
faults from kernel mode, so rename it and change the no-longer-useful
user_mode(regs) check to a WARN_ON_ONCE.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/c21940efe676024bb4bc721f7d70c29c420e127e.1612924255.git.luto@kernel.org

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 187975b..3566a59 100644 (file)
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -730,17 +730,10 @@ oops:
 }
 
 static noinline void
-no_context(struct pt_regs *regs, unsigned long error_code,
-          unsigned long address, int signal, int si_code)
+kernelmode_fixup_or_oops(struct pt_regs *regs, unsigned long error_code,
+                        unsigned long address, int signal, int si_code)
 {
-       if (user_mode(regs)) {
-               /*
-                * This is an implicit supervisor-mode access from user
-                * mode.  Bypass all the kernel-mode recovery code and just
-                * OOPS.
-                */
-               goto oops;
-       }
+       WARN_ON_ONCE(user_mode(regs));
 
        /* Are we prepared to handle this kernel fault? */
        if (fixup_exception(regs, X86_TRAP_PF, error_code, address)) {
@@ -780,7 +773,6 @@ no_context(struct pt_regs *regs, unsigned long error_code,
        if (is_prefetch(regs, error_code, address))
                return;
 
-oops:
        page_fault_oops(regs, error_code, address);
 }
 
@@ -827,7 +819,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
        struct task_struct *tsk = current;
 
        if (!user_mode(regs)) {
-               no_context(regs, error_code, address, pkey, si_code);
+               kernelmode_fixup_or_oops(regs, error_code, address, pkey, si_code);
                return;
        }
 
@@ -959,7 +951,7 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
 {
        /* Kernel mode? Handle exceptions or die: */
        if (!user_mode(regs)) {
-               no_context(regs, error_code, address, SIGBUS, BUS_ADRERR);
+               kernelmode_fixup_or_oops(regs, error_code, address, SIGBUS, BUS_ADRERR);
                return;
        }
 
@@ -1421,8 +1413,8 @@ good_area:
                 * has unlocked the mm for us if we get here.
                 */
                if (!user_mode(regs))
-                       no_context(regs, error_code, address, SIGBUS,
-                                  BUS_ADRERR);
+                       kernelmode_fixup_or_oops(regs, error_code, address,
+                                                SIGBUS, BUS_ADRERR);
                return;
        }
 
@@ -1442,15 +1434,15 @@ good_area:
                return;
 
        if (fatal_signal_pending(current) && !user_mode(regs)) {
-               no_context(regs, error_code, address, 0, 0);
+               kernelmode_fixup_or_oops(regs, error_code, address, 0, 0);
                return;
        }
 
        if (fault & VM_FAULT_OOM) {
                /* Kernel mode? Handle exceptions or die: */
                if (!user_mode(regs)) {
-                       no_context(regs, error_code, address,
-                                  SIGSEGV, SEGV_MAPERR);
+                       kernelmode_fixup_or_oops(regs, error_code, address,
+                                                SIGSEGV, SEGV_MAPERR);
                        return;
                }