x86: traps_xx: restructure do_general_protection()

 - if (cond) block -> if (!cond) goto end_of_block
 - local caching of current

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Acked-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 42 insertions, 35 deletions

diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index 5afd94a01b98..c9a0120e510c 100644
--- a/arch/x86/kernel/traps_32.c
+++ b/arch/x86/kernel/traps_32.c
@@ -598,8 +598,10 @@ DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0, 0)
 DO_ERROR_INFO(32, SIGILL, "iret exception", iret_error, ILL_BADSTK, 0, 1)
 
-void __kprobes do_general_protection(struct pt_regs *regs, long error_code)
+void __kprobes
+do_general_protection(struct pt_regs *regs, long error_code)
 {
+        struct task_struct *tsk;
         struct thread_struct *thread;
         struct tss_struct *tss;
         int cpu;
@@ -640,23 +642,24 @@ void __kprobes do_general_protection(struct pt_regs *regs, long error_code)
         if (regs->flags & X86_VM_MASK)
                 goto gp_in_vm86;
 
+        tsk = current;
         if (!user_mode(regs))
                 goto gp_in_kernel;
 
-        current->thread.error_code = error_code;
-        current->thread.trap_no = 13;
+        tsk->thread.error_code = error_code;
+        tsk->thread.trap_no = 13;
 
-        if (show_unhandled_signals && unhandled_signal(current, SIGSEGV) &&
-            printk_ratelimit()) {
+        if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
+                        printk_ratelimit()) {
                 printk(KERN_INFO
-                    "%s[%d] general protection ip:%lx sp:%lx error:%lx",
-                    current->comm, task_pid_nr(current),
-                    regs->ip, regs->sp, error_code);
+                        "%s[%d] general protection ip:%lx sp:%lx error:%lx",
+                        tsk->comm, task_pid_nr(tsk),
+                        regs->ip, regs->sp, error_code);
                 print_vma_addr(" in ", regs->ip);
                 printk("\n");
         }
 
-        force_sig(SIGSEGV, current);
+        force_sig(SIGSEGV, tsk);
         return;
 
 gp_in_vm86:
@@ -665,14 +668,15 @@ gp_in_vm86:
         return;
 
 gp_in_kernel:
-        if (!fixup_exception(regs)) {
-                current->thread.error_code = error_code;
-                current->thread.trap_no = 13;
-                if (notify_die(DIE_GPF, "general protection fault", regs,
+        if (fixup_exception(regs))
+                return;
+
+        tsk->thread.error_code = error_code;
+        tsk->thread.trap_no = 13;
+        if (notify_die(DIE_GPF, "general protection fault", regs,
                                 error_code, 13, SIGSEGV) == NOTIFY_STOP)
-                        return;
-                die("general protection fault", regs, error_code);
-        }
+                return;
+        die("general protection fault", regs, error_code);
 }
 
 static notrace __kprobes void
diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c
index 1c2d533fe7ff..bc21ddc97a02 100644
--- a/arch/x86/kernel/traps_64.c
+++ b/arch/x86/kernel/traps_64.c
@@ -733,31 +733,34 @@ asmlinkage void do_double_fault(struct pt_regs * regs, long error_code)
                 die(str, regs, error_code);
 }
 
-asmlinkage void __kprobes do_general_protection(struct pt_regs * regs,
-                                                long error_code)
+asmlinkage void __kprobes
+do_general_protection(struct pt_regs *regs, long error_code)
 {
-        struct task_struct *tsk = current;
+        struct task_struct *tsk;
 
         conditional_sti(regs);
 
-        if (user_mode(regs)) {
-                tsk->thread.error_code = error_code;
-                tsk->thread.trap_no = 13;
-
-                if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
-                    printk_ratelimit()) {
-                        printk(KERN_INFO
-                       "%s[%d] general protection ip:%lx sp:%lx error:%lx",
-                               tsk->comm, tsk->pid,
-                               regs->ip, regs->sp, error_code);
-                        print_vma_addr(" in ", regs->ip);
-                        printk("\n");
-                }
+        tsk = current;
+        if (!user_mode(regs))
+                goto gp_in_kernel;
 
-                force_sig(SIGSEGV, tsk);
-                return;
-        } 
+        tsk->thread.error_code = error_code;
+        tsk->thread.trap_no = 13;
+
+        if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
+                        printk_ratelimit()) {
+                printk(KERN_INFO
+                        "%s[%d] general protection ip:%lx sp:%lx error:%lx",
+                        tsk->comm, tsk->pid,
+                        regs->ip, regs->sp, error_code);
+                print_vma_addr(" in ", regs->ip);
+                printk("\n");
+        }
+
+        force_sig(SIGSEGV, tsk);
+        return;
 
+gp_in_kernel:
         if (fixup_exception(regs))
                 return;