Messages in this thread | | | Date | Tue, 7 Oct 2008 11:40:46 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [RFC Patch 6/9] Use virtual debug registers in process/thread handling code |
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On Tue, 7 Oct 2008, K.Prasad wrote:
> This patch enables the use of abstract/virtual debug registers in > process-handling routines.
... > --- linux-bkpt-lkml-27-rc9.orig/arch/x86/kernel/process_32.c > +++ linux-bkpt-lkml-27-rc9/arch/x86/kernel/process_32.c > @@ -56,6 +56,8 @@ > #include <asm/cpu.h> > #include <asm/kdebug.h> > #include <asm/idle.h> > +#include <asm/debugreg.h> > +#include <asm/hw_breakpoint.h> > > asmlinkage void ret_from_fork(void) __asm__("ret_from_fork"); > > @@ -158,9 +160,11 @@ void cpu_idle(void) > void __show_registers(struct pt_regs *regs, int all) > { > unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L; > - unsigned long d0, d1, d2, d3, d6, d7; > + unsigned long u_debugreg[8]; > unsigned long sp; > unsigned short ss, gs; > + struct thread_hw_breakpoint *thbi = current->thread.hw_breakpoint_info; > + int i; > > if (user_mode_vm(regs)) { > sp = regs->sp; > @@ -201,17 +205,18 @@ void __show_registers(struct pt_regs *re > printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", > cr0, cr2, cr3, cr4); > > - get_debugreg(d0, 0); > - get_debugreg(d1, 1); > - get_debugreg(d2, 2); > - get_debugreg(d3, 3); > + if (thbi) { > + for (i = 0; i < HB_NUM; ++i) > + u_debugreg[i] = thbi->vdr_bps[i].info.address; > + u_debugreg[7] = thbi->vdr7; > + } > + u_debugreg[6] = current->thread.vdr6; > + > printk("DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n", > - d0, d1, d2, d3); > + u_debugreg[0], u_debugreg[1], > + u_debugreg[2], u_debugreg[3]); > > - get_debugreg(d6, 6); > - get_debugreg(d7, 7); > - printk("DR6: %08lx DR7: %08lx\n", > - d6, d7); > + printk("DR6: %08lx DR7: %08lx\n", u_debugreg[6], u_debugreg[7]);
I don't like this at all. show_registers() should display the physical register contents, not the virtualized values. Ditto for the 64-byte version of this routine.
Alan Stern
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