From: Alan Stern This patch enables the use of abstract/virtual debug registers in process-handling routines. [K.Prasad: Split-out from the bigger patch and minor changes following re-basing] Signed-off-by: K.Prasad Signed-off-by: Alan Stern --- arch/x86/kernel/process.c | 21 ++++----------------- arch/x86/kernel/process_32.c | 19 +++++++++++++++++++ arch/x86/kernel/process_64.c | 14 ++++++++++++++ 3 files changed, 37 insertions(+), 17 deletions(-) Index: linux-2.6-tip/arch/x86/kernel/process.c =================================================================== --- linux-2.6-tip.orig/arch/x86/kernel/process.c +++ linux-2.6-tip/arch/x86/kernel/process.c @@ -82,6 +82,8 @@ void exit_thread(void) t->io_bitmap_max = 0; put_cpu(); } + if (unlikely(t.hw_breakpoint_info)) + flush_thread_hw_breakpoint(me); ds_exit_thread(current); } @@ -102,14 +104,9 @@ void flush_thread(void) } #endif - clear_tsk_thread_flag(tsk, TIF_DEBUG); + if (unlikely(tsk->thread.hw_breakpoint_info)) + flush_thread_hw_breakpoint(tsk); - tsk->thread.debugreg0 = 0; - tsk->thread.debugreg1 = 0; - tsk->thread.debugreg2 = 0; - tsk->thread.debugreg3 = 0; - tsk->thread.debugreg6 = 0; - tsk->thread.debugreg7 = 0; memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array)); /* * Forget coprocessor state.. @@ -191,16 +188,6 @@ void __switch_to_xtra(struct task_struct else if (next->debugctlmsr != prev->debugctlmsr) update_debugctlmsr(next->debugctlmsr); - if (test_tsk_thread_flag(next_p, TIF_DEBUG)) { - set_debugreg(next->debugreg0, 0); - set_debugreg(next->debugreg1, 1); - set_debugreg(next->debugreg2, 2); - set_debugreg(next->debugreg3, 3); - /* no 4 and 5 */ - set_debugreg(next->debugreg6, 6); - set_debugreg(next->debugreg7, 7); - } - if (test_tsk_thread_flag(prev_p, TIF_NOTSC) ^ test_tsk_thread_flag(next_p, TIF_NOTSC)) { /* prev and next are different */ Index: linux-2.6-tip/arch/x86/kernel/process_32.c =================================================================== --- linux-2.6-tip.orig/arch/x86/kernel/process_32.c +++ linux-2.6-tip/arch/x86/kernel/process_32.c @@ -59,6 +59,8 @@ #include #include #include +#include +#include asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); @@ -263,7 +265,15 @@ int copy_thread(int nr, unsigned long cl task_user_gs(p) = get_user_gs(regs); + p->thread.hw_breakpoint_info = NULL; + p->thread.io_bitmap_ptr = NULL; + tsk = current; + err = -ENOMEM; + if (unlikely(tsk->thread.hw_breakpoint_info)) { + if (copy_thread_hw_breakpoint(tsk, p, clone_flags)) + goto out; + } if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) { p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr, IO_BITMAP_BYTES, GFP_KERNEL); @@ -283,10 +293,13 @@ int copy_thread(int nr, unsigned long cl err = do_set_thread_area(p, -1, (struct user_desc __user *)childregs->si, 0); +out: if (err && p->thread.io_bitmap_ptr) { kfree(p->thread.io_bitmap_ptr); p->thread.io_bitmap_max = 0; } + if (err) + flush_thread_hw_breakpoint(p); ds_copy_thread(p, current); @@ -424,6 +437,12 @@ __switch_to(struct task_struct *prev_p, lazy_load_gs(next->gs); percpu_write(current_task, next_p); + /* + * Handle debug registers. This must be done _after_ current + * is updated. + */ + if (unlikely(test_tsk_thread_flag(next_p, TIF_DEBUG))) + switch_to_thread_hw_breakpoint(next_p); return prev_p; } Index: linux-2.6-tip/arch/x86/kernel/process_64.c =================================================================== --- linux-2.6-tip.orig/arch/x86/kernel/process_64.c +++ linux-2.6-tip/arch/x86/kernel/process_64.c @@ -55,6 +55,8 @@ #include #include #include +#include +#include asmlinkage extern void ret_from_fork(void); @@ -248,6 +250,8 @@ void release_thread(struct task_struct * BUG(); } } + if (unlikely(me->thread.hw_breakpoint_info)) + flush_thread_hw_breakpoint(me); } static inline void set_32bit_tls(struct task_struct *t, int tls, u32 addr) @@ -303,12 +307,19 @@ int copy_thread(int nr, unsigned long cl p->thread.fs = me->thread.fs; p->thread.gs = me->thread.gs; + p->thread.hw_breakpoint_info = NULL; + 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(me->thread.hw_breakpoint_info)) { + 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) { @@ -346,6 +357,9 @@ out: kfree(p->thread.io_bitmap_ptr); p->thread.io_bitmap_max = 0; } + if (err) + flush_thread_hw_breakpoint(p); + return err; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/