Re: [Patch 4/6] Modify process and processor handling code to recognise hardware debug registers
From: David Gibson <hidden>
Date: 2009-05-29 04:31:11
Possibly related (same subject, not in this thread)
- 2009-07-27 · [Patch 4/6] Modify process and processor handling code to recognise hardware debug registers · K.Prasad <hidden>
- 2009-06-19 · Re: [Patch 4/6] Modify process and processor handling code to recognise hardware debug registers · David Gibson <hidden>
- 2009-06-18 · Re: [Patch 4/6] Modify process and processor handling code to recognise hardware debug registers · K.Prasad <hidden>
- 2009-06-17 · Re: [Patch 4/6] Modify process and processor handling code to recognise hardware debug registers · David Gibson <hidden>
- 2009-06-10 · [Patch 4/6] Modify process and processor handling code to recognise hardware debug registers · K.Prasad <hidden>
On Mon, May 25, 2009 at 06:46:50AM +0530, K.Prasad wrote:
Modify process handling code to recognise hardware debug registers during copy and flush operations. Introduce a new TIF_DEBUG task flag to indicate a process's use of debug register. Load the debug register values into a new CPU during initialisation.
[snip]
quoted hunk ↗ jump to hunk
Index: linux-2.6-tip.hbkpt/arch/powerpc/kernel/process.c ===================================================================--- linux-2.6-tip.hbkpt.orig/arch/powerpc/kernel/process.c +++ linux-2.6-tip.hbkpt/arch/powerpc/kernel/process.c@@ -50,6 +50,7 @@ #include <asm/syscalls.h> #ifdef CONFIG_PPC64 #include <asm/firmware.h> +#include <asm/hw_breakpoint.h> #endif #include <linux/kprobes.h> #include <linux/kdebug.h>@@ -254,8 +255,10 @@ void do_dabr(struct pt_regs *regs, unsig 11, SIGSEGV) == NOTIFY_STOP) return; +#ifndef CONFIG_PPC64 if (debugger_dabr_match(regs)) return; +#endif /* Clear the DAC and struct entries. One shot trigger */ #if defined(CONFIG_BOOKE)@@ -372,8 +375,13 @@ struct task_struct *__switch_to(struct t #endif /* CONFIG_SMP */ +#ifdef CONFIG_PPC64 + if (unlikely(test_tsk_thread_flag(new, TIF_DEBUG))) + arch_install_thread_hw_breakpoint(new); +#else if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) set_dabr(new->thread.dabr); +#endif /* CONFIG_PPC64 */ #if defined(CONFIG_BOOKE) /* If new thread DAC (HW breakpoint) is the same then leave it */@@ -550,6 +558,10 @@ void show_regs(struct pt_regs * regs) void exit_thread(void) { discard_lazy_cpu_state(); +#ifdef CONFIG_PPC64 + if (unlikely(test_tsk_thread_flag(current, TIF_DEBUG))) + flush_thread_hw_breakpoint(current); +#endif /* CONFIG_PPC64 */ } void flush_thread(void)@@ -605,6 +617,9 @@ int copy_thread(unsigned long clone_flag struct pt_regs *childregs, *kregs; extern void ret_from_fork(void); unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE; +#ifdef CONFIG_PPC64 + struct task_struct *tsk = current;
I don't see any point to adding this variable, just reference current directly below.
quoted hunk ↗ jump to hunk
+#endif CHECK_FULL_REGS(regs); /* Copy registers */@@ -672,6 +687,9 @@ int copy_thread(unsigned long clone_flag * function. */ kregs->nip = *((unsigned long *)ret_from_fork); + + if (unlikely(test_tsk_thread_flag(tsk, TIF_DEBUG))) + copy_thread_hw_breakpoint(tsk, p, clone_flags); #else kregs->nip = (unsigned long)ret_from_fork; #endif
-- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson