Re: [PATCH 01/17] perf: Unified API to record selective sets of arch registers

[Arnaldo Carvalho de Melo <acme@redhat.com>]

Em Sun, Jul 22, 2012 at 02:14:24PM +0200, Jiri Olsa escreveu:
> This brings a new API to help the selective dump of registers on
> event sampling, and its implementation for x86 arch.
> 
> Added HAVE_PERF_REGS config option to determine if the architecture
> provides perf registers ABI.
> 
> The information about desired registers will be passed in u64 mask.
> It's up to the architecture to map the registers into the mask bits.
> 
> For the x86 arch implementation, both 32 and 64 bit registers
> bits are defined within single enum to ensure 64 bit system can
> provide register dump for compat task if needed in the future.


Anton, Paul, Ben,

	Does this look OK for PPC?

- Arnaldo
 
> Signed-off-by: Jiri Olsa <jolsa@redhat.com>
> Original-patch-by: Frederic Weisbecker <fweisbec@gmail.com>
> ---
>  arch/Kconfig                     |    6 +++
>  arch/x86/Kconfig                 |    1 +
>  arch/x86/include/asm/perf_regs.h |   33 ++++++++++++++
>  arch/x86/kernel/Makefile         |    2 +
>  arch/x86/kernel/perf_regs.c      |   90 ++++++++++++++++++++++++++++++++++++++
>  include/linux/perf_regs.h        |   19 ++++++++
>  6 files changed, 151 insertions(+), 0 deletions(-)
>  create mode 100644 arch/x86/include/asm/perf_regs.h
>  create mode 100644 arch/x86/kernel/perf_regs.c
>  create mode 100644 include/linux/perf_regs.h
> 
> diff --git a/arch/Kconfig b/arch/Kconfig
> index 8c3d957..32f4873 100644
> --- a/arch/Kconfig
> +++ b/arch/Kconfig
> @@ -222,6 +222,12 @@ config HAVE_PERF_EVENTS_NMI
>  	  subsystem.  Also has support for calculating CPU cycle events
>  	  to determine how many clock cycles in a given period.
>  
> +config HAVE_PERF_REGS
> +	bool
> +	help
> +	  Support selective register dumps for perf events. This includes
> +	  bit-mapping of each registers and a unique architecture id.
> +
>  config HAVE_ARCH_JUMP_LABEL
>  	bool
>  
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 94de2c5..acebbd6 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -60,6 +60,7 @@ config X86
>  	select HAVE_MIXED_BREAKPOINTS_REGS
>  	select PERF_EVENTS
>  	select HAVE_PERF_EVENTS_NMI
> +	select HAVE_PERF_REGS
>  	select ANON_INODES
>  	select HAVE_ALIGNED_STRUCT_PAGE if SLUB && !M386
>  	select HAVE_CMPXCHG_LOCAL if !M386
> diff --git a/arch/x86/include/asm/perf_regs.h b/arch/x86/include/asm/perf_regs.h
> new file mode 100644
> index 0000000..3f2207b
> --- /dev/null
> +++ b/arch/x86/include/asm/perf_regs.h
> @@ -0,0 +1,33 @@
> +#ifndef _ASM_X86_PERF_REGS_H
> +#define _ASM_X86_PERF_REGS_H
> +
> +enum perf_event_x86_regs {
> +	PERF_REG_X86_AX,
> +	PERF_REG_X86_BX,
> +	PERF_REG_X86_CX,
> +	PERF_REG_X86_DX,
> +	PERF_REG_X86_SI,
> +	PERF_REG_X86_DI,
> +	PERF_REG_X86_BP,
> +	PERF_REG_X86_SP,
> +	PERF_REG_X86_IP,
> +	PERF_REG_X86_FLAGS,
> +	PERF_REG_X86_CS,
> +	PERF_REG_X86_SS,
> +	PERF_REG_X86_DS,
> +	PERF_REG_X86_ES,
> +	PERF_REG_X86_FS,
> +	PERF_REG_X86_GS,
> +	PERF_REG_X86_R8,
> +	PERF_REG_X86_R9,
> +	PERF_REG_X86_R10,
> +	PERF_REG_X86_R11,
> +	PERF_REG_X86_R12,
> +	PERF_REG_X86_R13,
> +	PERF_REG_X86_R14,
> +	PERF_REG_X86_R15,
> +
> +	PERF_REG_X86_32_MAX = PERF_REG_X86_GS + 1,
> +	PERF_REG_X86_64_MAX = PERF_REG_X86_R15 + 1,
> +};
> +#endif /* _ASM_X86_PERF_REGS_H */
> diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
> index 8215e56..8d7a619 100644
> --- a/arch/x86/kernel/Makefile
> +++ b/arch/x86/kernel/Makefile
> @@ -100,6 +100,8 @@ obj-$(CONFIG_SWIOTLB)			+= pci-swiotlb.o
>  obj-$(CONFIG_OF)			+= devicetree.o
>  obj-$(CONFIG_UPROBES)			+= uprobes.o
>  
> +obj-$(CONFIG_PERF_EVENTS)		+= perf_regs.o
> +
>  ###
>  # 64 bit specific files
>  ifeq ($(CONFIG_X86_64),y)
> diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c
> new file mode 100644
> index 0000000..c00c92a
> --- /dev/null
> +++ b/arch/x86/kernel/perf_regs.c
> @@ -0,0 +1,90 @@
> +
> +#include <linux/kernel.h>
> +#include <linux/bug.h>
> +#include <linux/stddef.h>
> +#include <asm/perf_regs.h>
> +#include <asm/ptrace.h>
> +
> +#ifdef CONFIG_X86_32
> +#define PERF_REG_X86_MAX PERF_REG_X86_32_MAX
> +#else
> +#define PERF_REG_X86_MAX PERF_REG_X86_64_MAX
> +#endif
> +
> +#define PT_REGS_OFFSET(id, r) [id] = offsetof(struct pt_regs, r)
> +
> +static unsigned int pt_regs_offset[PERF_REG_X86_MAX] = {
> +	PT_REGS_OFFSET(PERF_REG_X86_AX, ax),
> +	PT_REGS_OFFSET(PERF_REG_X86_BX, bx),
> +	PT_REGS_OFFSET(PERF_REG_X86_CX, cx),
> +	PT_REGS_OFFSET(PERF_REG_X86_DX, dx),
> +	PT_REGS_OFFSET(PERF_REG_X86_SI, si),
> +	PT_REGS_OFFSET(PERF_REG_X86_DI, di),
> +	PT_REGS_OFFSET(PERF_REG_X86_BP, bp),
> +	PT_REGS_OFFSET(PERF_REG_X86_SP, sp),
> +	PT_REGS_OFFSET(PERF_REG_X86_IP, ip),
> +	PT_REGS_OFFSET(PERF_REG_X86_FLAGS, flags),
> +	PT_REGS_OFFSET(PERF_REG_X86_CS, cs),
> +	PT_REGS_OFFSET(PERF_REG_X86_SS, ss),
> +#ifdef CONFIG_X86_32
> +	PT_REGS_OFFSET(PERF_REG_X86_DS, ds),
> +	PT_REGS_OFFSET(PERF_REG_X86_ES, es),
> +	PT_REGS_OFFSET(PERF_REG_X86_FS, fs),
> +	PT_REGS_OFFSET(PERF_REG_X86_GS, gs),
> +#else
> +	/*
> +	 * The pt_regs struct does not store
> +	 * ds, es, fs, gs in 64 bit mode.
> +	 */
> +	(unsigned int) -1,
> +	(unsigned int) -1,
> +	(unsigned int) -1,
> +	(unsigned int) -1,
> +#endif
> +#ifdef CONFIG_X86_64
> +	PT_REGS_OFFSET(PERF_REG_X86_R8, r8),
> +	PT_REGS_OFFSET(PERF_REG_X86_R9, r9),
> +	PT_REGS_OFFSET(PERF_REG_X86_R10, r10),
> +	PT_REGS_OFFSET(PERF_REG_X86_R11, r11),
> +	PT_REGS_OFFSET(PERF_REG_X86_R12, r12),
> +	PT_REGS_OFFSET(PERF_REG_X86_R13, r13),
> +	PT_REGS_OFFSET(PERF_REG_X86_R14, r14),
> +	PT_REGS_OFFSET(PERF_REG_X86_R15, r15),
> +#endif
> +};
> +
> +u64 perf_reg_value(struct pt_regs *regs, int idx)
> +{
> +	if (WARN_ON_ONCE(idx > ARRAY_SIZE(pt_regs_offset)))
> +		return 0;
> +
> +	return regs_get_register(regs, pt_regs_offset[idx]);
> +}
> +
> +#define REG_RESERVED (~((1ULL << PERF_REG_X86_MAX) - 1ULL))
> +
> +#ifdef CONFIG_X86_32
> +int perf_reg_validate(u64 mask)
> +{
> +	if (!mask || mask & REG_RESERVED)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +#else /* CONFIG_X86_64 */
> +#define REG_NOSUPPORT ((1ULL << PERF_REG_X86_DS) | \
> +		       (1ULL << PERF_REG_X86_ES) | \
> +		       (1ULL << PERF_REG_X86_FS) | \
> +		       (1ULL << PERF_REG_X86_GS))
> +
> +int perf_reg_validate(u64 mask)
> +{
> +	if (!mask || mask & REG_RESERVED)
> +		return -EINVAL;
> +
> +	if (mask & REG_NOSUPPORT)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +#endif /* CONFIG_X86_32 */
> diff --git a/include/linux/perf_regs.h b/include/linux/perf_regs.h
> new file mode 100644
> index 0000000..a2f1a98
> --- /dev/null
> +++ b/include/linux/perf_regs.h
> @@ -0,0 +1,19 @@
> +#ifndef _LINUX_PERF_REGS_H
> +#define _LINUX_PERF_REGS_H
> +
> +#ifdef CONFIG_HAVE_PERF_REGS
> +#include <asm/perf_regs.h>
> +u64 perf_reg_value(struct pt_regs *regs, int idx);
> +int perf_reg_validate(u64 mask);
> +#else
> +static inline u64 perf_reg_value(struct pt_regs *regs, int idx)
> +{
> +	return 0;
> +}
> +
> +static inline int perf_reg_validate(u64 mask)
> +{
> +	return mask ? -ENOSYS : 0;
> +}
> +#endif /* CONFIG_HAVE_PERF_REGS */
> +#endif /* _LINUX_PERF_REGS_H */
> -- 
> 1.7.7.6