Patchwork [1/6] Prepare the PowerPC platform for HW Breakpoint infrastructure

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Submitter K.Prasad
Date May 25, 2009, 1:14 a.m.
Message ID <20090525011423.GB11078@in.ibm.com>
Download mbox | patch
Permalink /patch/27586/
State Superseded
Delegated to: David Gibson
Headers show

Comments

K.Prasad - May 25, 2009, 1:14 a.m.
Prepare the PowerPC code for HW Breakpoint infrastructure patches by including
relevant constant definitions and function declarations.

Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/hw_breakpoint.h |   57 +++++++++++++++++++++++++++++++
 arch/powerpc/include/asm/processor.h     |    1 
 arch/powerpc/include/asm/reg.h           |    3 +
 3 files changed, 61 insertions(+)
David Gibson - May 29, 2009, 3:20 a.m.
On Mon, May 25, 2009 at 06:44:23AM +0530, K.Prasad wrote:
> Prepare the PowerPC code for HW Breakpoint infrastructure patches by including
> relevant constant definitions and function declarations.
> 
> Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
> ---
>  arch/powerpc/include/asm/hw_breakpoint.h |   57 +++++++++++++++++++++++++++++++
>  arch/powerpc/include/asm/processor.h     |    1 
>  arch/powerpc/include/asm/reg.h           |    3 +
>  3 files changed, 61 insertions(+)
> 
> Index: linux-2.6-tip.hbkpt/arch/powerpc/include/asm/hw_breakpoint.h
> ===================================================================
> --- /dev/null
> +++ linux-2.6-tip.hbkpt/arch/powerpc/include/asm/hw_breakpoint.h
> @@ -0,0 +1,57 @@
> +#ifndef	_PPC64_HW_BREAKPOINT_H
> +#define	_PPC64_HW_BREAKPOINT_H
> +
> +#ifdef	__KERNEL__
> +#define	__ARCH_HW_BREAKPOINT_H
> +#ifdef CONFIG_PPC64
> +
> +struct arch_hw_breakpoint {
> +	char		*name; /* Contains name of the symbol to set bkpt */
> +	unsigned long	address;
> +	u8		type;

You might as well make this an int, it will get padded out to 4 bytes
long anyway.

> +};
> +
> +#include <linux/kdebug.h>
> +#include <asm/reg.h>
> +#include <asm-generic/hw_breakpoint.h>
> +
> +#define HW_BREAKPOINT_READ DABR_DATA_READ
> +#define HW_BREAKPOINT_WRITE DABR_DATA_WRITE
> +#define HW_BREAKPOINT_RW (DABR_DATA_READ | DABR_DATA_WRITE)
> +
> +#define HW_BREAKPOINT_ALIGN 0x7
> +#define HW_BREAKPOINT_LEN INSTRUCTION_LEN
> +
> +extern struct hw_breakpoint *hbp_kernel[HBP_NUM];
> +DECLARE_PER_CPU(struct hw_breakpoint*, this_hbp_kernel[HBP_NUM]);
> +extern unsigned int hbp_user_refcount[HBP_NUM];
> +
> +extern void arch_install_thread_hw_breakpoint(struct task_struct *tsk);
> +extern void arch_uninstall_thread_hw_breakpoint(void);
> +extern int arch_validate_hwbkpt_settings(struct hw_breakpoint *bp,
> +						struct task_struct *tsk);
> +extern void arch_update_user_hw_breakpoint(int pos, struct task_struct *tsk);
> +extern void arch_flush_thread_hw_breakpoint(struct task_struct *tsk);
> +extern void arch_update_kernel_hw_breakpoint(void *);
> +extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
> +				     unsigned long val, void *data);
> +
> +extern void flush_thread_hw_breakpoint(struct task_struct *tsk);
> +extern int copy_thread_hw_breakpoint(struct task_struct *tsk,
> +		struct task_struct *child, unsigned long clone_flags);
> +extern void load_debug_registers(void );

It looks as though a lot of these arch hooks ought to have prototypes
in the generic part of the infrastructure.
K.Prasad - May 29, 2009, 9:53 a.m.
On Fri, May 29, 2009 at 01:20:48PM +1000, David Gibson wrote:
> On Mon, May 25, 2009 at 06:44:23AM +0530, K.Prasad wrote:
> > Prepare the PowerPC code for HW Breakpoint infrastructure patches by including
> > relevant constant definitions and function declarations.
> > 
> > Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com>
> > ---
> >  arch/powerpc/include/asm/hw_breakpoint.h |   57 +++++++++++++++++++++++++++++++
> >  arch/powerpc/include/asm/processor.h     |    1 
> >  arch/powerpc/include/asm/reg.h           |    3 +
> >  3 files changed, 61 insertions(+)
> > 
> > Index: linux-2.6-tip.hbkpt/arch/powerpc/include/asm/hw_breakpoint.h
> > ===================================================================
> > --- /dev/null
> > +++ linux-2.6-tip.hbkpt/arch/powerpc/include/asm/hw_breakpoint.h
> > @@ -0,0 +1,57 @@
> > +#ifndef	_PPC64_HW_BREAKPOINT_H
> > +#define	_PPC64_HW_BREAKPOINT_H
> > +
> > +#ifdef	__KERNEL__
> > +#define	__ARCH_HW_BREAKPOINT_H
> > +#ifdef CONFIG_PPC64
> > +
> > +struct arch_hw_breakpoint {
> > +	char		*name; /* Contains name of the symbol to set bkpt */
> > +	unsigned long	address;
> > +	u8		type;
> 
> You might as well make this an int, it will get padded out to 4 bytes
> long anyway.
> 

Okay.

> > +};
> > +
> > +#include <linux/kdebug.h>
> > +#include <asm/reg.h>
> > +#include <asm-generic/hw_breakpoint.h>
> > +
> > +#define HW_BREAKPOINT_READ DABR_DATA_READ
> > +#define HW_BREAKPOINT_WRITE DABR_DATA_WRITE
> > +#define HW_BREAKPOINT_RW (DABR_DATA_READ | DABR_DATA_WRITE)
> > +
> > +#define HW_BREAKPOINT_ALIGN 0x7
> > +#define HW_BREAKPOINT_LEN INSTRUCTION_LEN
> > +
> > +extern struct hw_breakpoint *hbp_kernel[HBP_NUM];
> > +DECLARE_PER_CPU(struct hw_breakpoint*, this_hbp_kernel[HBP_NUM]);
> > +extern unsigned int hbp_user_refcount[HBP_NUM];
> > +
> > +extern void arch_install_thread_hw_breakpoint(struct task_struct *tsk);
> > +extern void arch_uninstall_thread_hw_breakpoint(void);
> > +extern int arch_validate_hwbkpt_settings(struct hw_breakpoint *bp,
> > +						struct task_struct *tsk);
> > +extern void arch_update_user_hw_breakpoint(int pos, struct task_struct *tsk);
> > +extern void arch_flush_thread_hw_breakpoint(struct task_struct *tsk);
> > +extern void arch_update_kernel_hw_breakpoint(void *);
> > +extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
> > +				     unsigned long val, void *data);
> > +
> > +extern void flush_thread_hw_breakpoint(struct task_struct *tsk);
> > +extern int copy_thread_hw_breakpoint(struct task_struct *tsk,
> > +		struct task_struct *child, unsigned long clone_flags);
> > +extern void load_debug_registers(void );
> 
> It looks as though a lot of these arch hooks ought to have prototypes
> in the generic part of the infrastructure.
> 

As I said before, the signatures of some of these functions are
different. But I agree that we may want to eventually consolidate them
into the generic header file, during future enhancements.

Thanks,
K.Prasad


> -- 
> 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

Patch

Index: linux-2.6-tip.hbkpt/arch/powerpc/include/asm/hw_breakpoint.h
===================================================================
--- /dev/null
+++ linux-2.6-tip.hbkpt/arch/powerpc/include/asm/hw_breakpoint.h
@@ -0,0 +1,57 @@ 
+#ifndef	_PPC64_HW_BREAKPOINT_H
+#define	_PPC64_HW_BREAKPOINT_H
+
+#ifdef	__KERNEL__
+#define	__ARCH_HW_BREAKPOINT_H
+#ifdef CONFIG_PPC64
+
+struct arch_hw_breakpoint {
+	char		*name; /* Contains name of the symbol to set bkpt */
+	unsigned long	address;
+	u8		type;
+};
+
+#include <linux/kdebug.h>
+#include <asm/reg.h>
+#include <asm-generic/hw_breakpoint.h>
+
+#define HW_BREAKPOINT_READ DABR_DATA_READ
+#define HW_BREAKPOINT_WRITE DABR_DATA_WRITE
+#define HW_BREAKPOINT_RW (DABR_DATA_READ | DABR_DATA_WRITE)
+
+#define HW_BREAKPOINT_ALIGN 0x7
+#define HW_BREAKPOINT_LEN INSTRUCTION_LEN
+
+extern struct hw_breakpoint *hbp_kernel[HBP_NUM];
+DECLARE_PER_CPU(struct hw_breakpoint*, this_hbp_kernel[HBP_NUM]);
+extern unsigned int hbp_user_refcount[HBP_NUM];
+
+extern void arch_install_thread_hw_breakpoint(struct task_struct *tsk);
+extern void arch_uninstall_thread_hw_breakpoint(void);
+extern int arch_validate_hwbkpt_settings(struct hw_breakpoint *bp,
+						struct task_struct *tsk);
+extern void arch_update_user_hw_breakpoint(int pos, struct task_struct *tsk);
+extern void arch_flush_thread_hw_breakpoint(struct task_struct *tsk);
+extern void arch_update_kernel_hw_breakpoint(void *);
+extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused,
+				     unsigned long val, void *data);
+
+extern void flush_thread_hw_breakpoint(struct task_struct *tsk);
+extern int copy_thread_hw_breakpoint(struct task_struct *tsk,
+		struct task_struct *child, unsigned long clone_flags);
+extern void load_debug_registers(void );
+
+static inline void hw_breakpoint_disable(void)
+{
+	set_dabr(0);
+}
+
+#else
+static inline void hw_breakpoint_disable(void)
+{
+	/* Function is defined only on PPC64 for now */
+}
+#endif	/* CONFIG_PPC64 */
+#endif	/* __KERNEL__ */
+#endif	/* _PPC64_HW_BREAKPOINT_H */
+
Index: linux-2.6-tip.hbkpt/arch/powerpc/include/asm/processor.h
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/include/asm/processor.h
+++ linux-2.6-tip.hbkpt/arch/powerpc/include/asm/processor.h
@@ -177,6 +177,7 @@  struct thread_struct {
 #ifdef CONFIG_PPC64
 	unsigned long	start_tb;	/* Start purr when proc switched in */
 	unsigned long	accum_tb;	/* Total accumilated purr for process */
+	struct hw_breakpoint *hbp[HBP_NUM];
 #endif
 	unsigned long	dabr;		/* Data address breakpoint register */
 #ifdef CONFIG_ALTIVEC
Index: linux-2.6-tip.hbkpt/arch/powerpc/include/asm/reg.h
===================================================================
--- linux-2.6-tip.hbkpt.orig/arch/powerpc/include/asm/reg.h
+++ linux-2.6-tip.hbkpt/arch/powerpc/include/asm/reg.h
@@ -26,6 +26,8 @@ 
 #include <asm/reg_8xx.h>
 #endif /* CONFIG_8xx */
 
+#define INSTRUCTION_LEN	4		/* Length of any instruction */
+
 #define MSR_SF_LG	63              /* Enable 64 bit mode */
 #define MSR_ISF_LG	61              /* Interrupt 64b mode valid on 630 */
 #define MSR_HV_LG 	60              /* Hypervisor state */
@@ -184,6 +186,7 @@ 
 #define   CTRL_TE	0x00c00000	/* thread enable */
 #define   CTRL_RUNLATCH	0x1
 #define SPRN_DABR	0x3F5	/* Data Address Breakpoint Register */
+#define   HBP_NUM	1	/* Number of physical HW breakpoint registers */
 #define   DABR_TRANSLATION	(1UL << 2)
 #define   DABR_DATA_WRITE	(1UL << 1)
 #define   DABR_DATA_READ	(1UL << 0)