Merge branch 'linus' into tracing/hw-breakpoints

[sfrench/cifs-2.6.git] / arch / x86 / kernel / traps.c

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index f4d683b630ba0ea9056864b5fd1f1f35b5a3b48b..286d64eba31b7bdd28d8a41a31cdca2b718127fa 100644 (file)
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -45,6 +45,7 @@
 #include <linux/edac.h>
 #endif
 
+#include <asm/kmemcheck.h>
 #include <asm/stacktrace.h>
 #include <asm/processor.h>
 #include <asm/debugreg.h>
@@ -529,73 +530,56 @@ asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
 dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
 {
        struct task_struct *tsk = current;
-       unsigned long condition;
+       unsigned long dr6;
        int si_code;
 
-       get_debugreg(condition, 6);
+       get_debugreg(dr6, 6);
 
+       /* Catch kmemcheck conditions first of all! */
+       if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
+               return;
+
+       /* DR6 may or may not be cleared by the CPU */
+       set_debugreg(0, 6);
        /*
         * The processor cleared BTF, so don't mark that we need it set.
         */
        clear_tsk_thread_flag(tsk, TIF_DEBUGCTLMSR);
        tsk->thread.debugctlmsr = 0;
 
-       if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
-                                               SIGTRAP) == NOTIFY_STOP)
+       /* Store the virtualized DR6 value */
+       tsk->thread.debugreg6 = dr6;
+
+       if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
+                                                       SIGTRAP) == NOTIFY_STOP)
                return;
 
        /* It's safe to allow irq's after DR6 has been saved */
        preempt_conditional_sti(regs);
 
-       /* Mask out spurious debug traps due to lazy DR7 setting */
-       if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
-               if (!tsk->thread.debugreg7)
-                       goto clear_dr7;
+       if (regs->flags & X86_VM_MASK) {
+               handle_vm86_trap((struct kernel_vm86_regs *) regs,
+                               error_code, 1);
+               return;
        }
 
-#ifdef CONFIG_X86_32
-       if (regs->flags & X86_VM_MASK)
-               goto debug_vm86;
-#endif
-
-       /* Save debug status register where ptrace can see it */
-       tsk->thread.debugreg6 = condition;
-
        /*
-        * Single-stepping through TF: make sure we ignore any events in
-        * kernel space (but re-enable TF when returning to user mode).
+        * Single-stepping through system calls: ignore any exceptions in
+        * kernel space, but re-enable TF when returning to user mode.
+        *
+        * We already checked v86 mode above, so we can check for kernel mode
+        * by just checking the CPL of CS.
         */
-       if (condition & DR_STEP) {
-               if (!user_mode(regs))
-                       goto clear_TF_reenable;
+       if ((dr6 & DR_STEP) && !user_mode(regs)) {
+               tsk->thread.debugreg6 &= ~DR_STEP;
+               set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+               regs->flags &= ~X86_EFLAGS_TF;
        }
-
-       si_code = get_si_code(condition);
-       /* Ok, finally something we can handle */
-       send_sigtrap(tsk, regs, error_code, si_code);
-
-       /*
-        * Disable additional traps. They'll be re-enabled when
-        * the signal is delivered.
-        */
-clear_dr7:
-       set_debugreg(0, 7);
+       si_code = get_si_code(tsk->thread.debugreg6);
+       if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS))
+               send_sigtrap(tsk, regs, error_code, si_code);
        preempt_conditional_cli(regs);
-       return;
-
-#ifdef CONFIG_X86_32
-debug_vm86:
-       /* reenable preemption: handle_vm86_trap() might sleep */
-       dec_preempt_count();
-       handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1);
-       conditional_cli(regs);
-       return;
-#endif
 
-clear_TF_reenable:
-       set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
-       regs->flags &= ~X86_EFLAGS_TF;
-       preempt_conditional_cli(regs);
        return;
 }
 
@@ -839,9 +823,6 @@ asmlinkage void math_state_restore(void)
        }
 
        clts();                         /* Allow maths ops (or we recurse) */
-#ifdef CONFIG_X86_32
-       restore_fpu(tsk);
-#else
        /*
         * Paranoid restore. send a SIGSEGV if we fail to restore the state.
         */
@@ -850,7 +831,7 @@ asmlinkage void math_state_restore(void)
                force_sig(SIGSEGV, tsk);
                return;
        }
-#endif
+
        thread->status |= TS_USEDFPU;   /* So we fnsave on switch_to() */
        tsk->fpu_counter++;
 }
@@ -945,8 +926,13 @@ void __init trap_init(void)
 #endif
        set_intr_gate(19, &simd_coprocessor_error);
 
+       /* Reserve all the builtin and the syscall vector: */
+       for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
+               set_bit(i, used_vectors);
+
 #ifdef CONFIG_IA32_EMULATION
        set_system_intr_gate(IA32_SYSCALL_VECTOR, ia32_syscall);
+       set_bit(IA32_SYSCALL_VECTOR, used_vectors);
 #endif
 
 #ifdef CONFIG_X86_32
@@ -963,14 +949,9 @@ void __init trap_init(void)
        }
 
        set_system_trap_gate(SYSCALL_VECTOR, &system_call);
+       set_bit(SYSCALL_VECTOR, used_vectors);
 #endif
 
-       /* Reserve all the builtin and the syscall vector: */
-       for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
-               set_bit(i, used_vectors);
-
-       set_bit(IA32_SYSCALL_VECTOR, used_vectors);
-
        /*
         * Should be a barrier for any external CPU state:
         */