[PATCH V8 2/4] perf/powerpc: add support for sampling intr machine state

[Anju T]

The perf infrastructure uses a bit mask to find out valid
registers to display. Define a register mask for supported
registers defined in asm/perf_regs.h. The bit positions also
correspond to register IDs which is used by perf infrastructure
to fetch the register values. CONFIG_HAVE_PERF_REGS enables
sampling of the interrupted machine state.

Signed-off-by: Anju T <anju@xxxxxxxxxxxxxxxxxx>
Reviewed-by  : Madhavan Srinivasan <maddy@xxxxxxxxxxxxxxxxxx>
---
 arch/powerpc/Kconfig          |  1 +
 arch/powerpc/perf/Makefile    |  1 +
 arch/powerpc/perf/perf_regs.c | 85 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 87 insertions(+)
 create mode 100644 arch/powerpc/perf/perf_regs.c

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 9a7057e..c4ce60d 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -119,6 +119,7 @@ config PPC
 	select GENERIC_ATOMIC64 if PPC32
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select HAVE_PERF_EVENTS
+	select HAVE_PERF_REGS
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_HW_BREAKPOINT if PERF_EVENTS && PPC_BOOK3S_64
 	select ARCH_WANT_IPC_PARSE_VERSION
diff --git a/arch/powerpc/perf/Makefile b/arch/powerpc/perf/Makefile
index f9c083a..2f2d3d2 100644
--- a/arch/powerpc/perf/Makefile
+++ b/arch/powerpc/perf/Makefile
@@ -8,6 +8,7 @@ obj64-$(CONFIG_PPC_PERF_CTRS)	+= power4-pmu.o ppc970-pmu.o power5-pmu.o \
 				   power8-pmu.o
 obj32-$(CONFIG_PPC_PERF_CTRS)	+= mpc7450-pmu.o
 
+obj-$(CONFIG_PERF_EVENTS)	+= perf_regs.o
 obj-$(CONFIG_FSL_EMB_PERF_EVENT) += core-fsl-emb.o
 obj-$(CONFIG_FSL_EMB_PERF_EVENT_E500) += e500-pmu.o e6500-pmu.o
 
diff --git a/arch/powerpc/perf/perf_regs.c b/arch/powerpc/perf/perf_regs.c
new file mode 100644
index 0000000..d32581763
--- /dev/null
+++ b/arch/powerpc/perf/perf_regs.c
@@ -0,0 +1,85 @@
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/perf_event.h>
+#include <linux/bug.h>
+#include <linux/stddef.h>
+#include <asm/ptrace.h>
+#include <asm/perf_regs.h>
+
+#define PT_REGS_OFFSET(id, r) [id] = offsetof(struct pt_regs, r)
+
+#define REG_RESERVED (~((1ULL << PERF_REG_POWERPC_MAX) - 1))
+
+static unsigned int pt_regs_offset[PERF_REG_POWERPC_MAX] = {
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR0, gpr[0]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR1, gpr[1]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR2, gpr[2]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR3, gpr[3]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR4, gpr[4]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR5, gpr[5]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR6, gpr[6]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR7, gpr[7]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR8, gpr[8]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR9, gpr[9]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR10, gpr[10]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR11, gpr[11]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR12, gpr[12]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR13, gpr[13]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR14, gpr[14]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR15, gpr[15]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR16, gpr[16]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR17, gpr[17]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR18, gpr[18]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR19, gpr[19]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR20, gpr[20]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR21, gpr[21]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR22, gpr[22]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR23, gpr[23]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR24, gpr[24]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR25, gpr[25]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR26, gpr[26]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR27, gpr[27]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR28, gpr[28]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR29, gpr[29]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR30, gpr[30]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_GPR31, gpr[31]),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_NIP, nip),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_MSR, msr),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_ORIG_R3, orig_gpr3),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_CTR, ctr),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_LNK, link),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_XER, xer),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_CCR, ccr),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_TRAP, trap),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_DAR, dar),
+	PT_REGS_OFFSET(PERF_REG_POWERPC_DSISR, dsisr),
+};
+
+u64 perf_reg_value(struct pt_regs *regs, int idx)
+{
+	if (WARN_ON_ONCE(idx >= PERF_REG_POWERPC_MAX))
+		return 0;
+
+	return regs_get_register(regs, pt_regs_offset[idx]);
+}
+
+int perf_reg_validate(u64 mask)
+{
+	if (!mask || mask & REG_RESERVED)
+		return -EINVAL;
+	return 0;
+}
+
+u64 perf_reg_abi(struct task_struct *task)
+{
+	return PERF_SAMPLE_REGS_ABI_64;
+}
+
+void perf_get_regs_user(struct perf_regs *regs_user,
+			struct pt_regs *regs,
+			struct pt_regs *regs_user_copy)
+{
+	regs_user->regs = task_pt_regs(current);
+	regs_user->abi  = perf_reg_abi(current);
+}
-- 
2.1.0