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>

diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index 5afd94a..c9a0120 100644 (file)
--- 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 1c2d533..bc21ddc 100644 (file)
--- 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;