* This file handles the architecture-dependent parts of process handling..
*/
-#include <stdarg.h>
-
#include <linux/stackprotector.h>
#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/ptrace.h>
-#include <linux/random.h>
#include <linux/notifier.h>
#include <linux/kprobes.h>
#include <linux/kdebug.h>
#include <asm/idle.h>
#include <asm/syscalls.h>
#include <asm/ds.h>
+#include <asm/debugreg.h>
+#include <asm/hw_breakpoint.h>
asmlinkage extern void ret_from_fork(void);
BUG();
}
}
+ if (unlikely(dead_task->thread.debugreg7))
+ flush_thread_hw_breakpoint(dead_task);
}
static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr)
p->thread.fs = me->thread.fs;
p->thread.gs = me->thread.gs;
+ p->thread.io_bitmap_ptr = NULL;
savesegment(gs, p->thread.gsindex);
savesegment(fs, p->thread.fsindex);
savesegment(es, p->thread.es);
savesegment(ds, p->thread.ds);
+ err = -ENOMEM;
+ if (unlikely(test_tsk_thread_flag(me, TIF_DEBUG)))
+ if (copy_thread_hw_breakpoint(me, p, clone_flags))
+ goto out;
+
if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {
p->thread.io_bitmap_ptr = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
if (!p->thread.io_bitmap_ptr) {
goto out;
}
- ds_copy_thread(p, me);
+ clear_tsk_thread_flag(p, TIF_DS_AREA_MSR);
+ p->thread.ds_ctx = NULL;
clear_tsk_thread_flag(p, TIF_DEBUGCTLMSR);
p->thread.debugctlmsr = 0;
kfree(p->thread.io_bitmap_ptr);
p->thread.io_bitmap_max = 0;
}
+ if (err)
+ flush_thread_hw_breakpoint(p);
+
return err;
}
* done before math_state_restore, so the TS bit is up
* to date.
*/
- arch_leave_lazy_cpu_mode();
+ arch_end_context_switch(next_p);
/*
* Switch FS and GS.
*/
if (tsk_used_math(next_p) && next_p->fpu_counter > 5)
math_state_restore();
+ /*
+ * There's a problem with moving the arch_install_thread_hw_breakpoint()
+ * call before current is updated. Suppose a kernel breakpoint is
+ * triggered in between the two, the hw-breakpoint handler will see that
+ * the 'current' task does not have TIF_DEBUG flag set and will think it
+ * is leftover from an old task (lazy switching) and will erase it. Then
+ * until the next context switch, no user-breakpoints will be installed.
+ *
+ * The real problem is that it's impossible to update both current and
+ * physical debug registers at the same instant, so there will always be
+ * a window in which they disagree and a breakpoint might get triggered.
+ * Since we use lazy switching, we are forced to assume that a
+ * disagreement means that current is correct and the exception is due
+ * to lazy debug register switching.
+ */
+ if (unlikely(test_tsk_thread_flag(next_p, TIF_DEBUG)))
+ arch_install_thread_hw_breakpoint(next_p);
+
return prev_p;
}
return do_arch_prctl(current, code, addr);
}
-unsigned long arch_align_stack(unsigned long sp)
-{
- if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
- sp -= get_random_int() % 8192;
- return sp & ~0xf;
-}
-
-unsigned long arch_randomize_brk(struct mm_struct *mm)
-{
- unsigned long range_end = mm->brk + 0x02000000;
- return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
-}