Add Perf support to Meta.
Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
---
arch/metag/Kconfig | 1 +
arch/metag/include/asm/perf_event.h | 4 ++
arch/metag/kernel/perf_callchain.c | 96 +++++++++++++++++++++++++++++++++++
3 files changed, 101 insertions(+), 0 deletions(-)
create mode 100644 arch/metag/include/asm/perf_event.h
create mode 100644 arch/metag/kernel/perf_callchain.c
diff --git a/arch/metag/Kconfig b/arch/metag/Kconfig
index 5141108..c7c84d1 100644
--- a/arch/metag/Kconfig
+++ b/arch/metag/Kconfig
@@ -9,6 +9,7 @@ config METAG
select HAVE_MEMBLOCK
select HAVE_MEMBLOCK_NODE_MAP
select HAVE_ARCH_TRACEHOOK
+ select HAVE_PERF_EVENTS
select HAVE_IRQ_WORK
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_BZIP2
diff --git a/arch/metag/include/asm/perf_event.h b/arch/metag/include/asm/perf_event.h
new file mode 100644
index 0000000..105bbff
--- /dev/null
+++ b/arch/metag/include/asm/perf_event.h
@@ -0,0 +1,4 @@
+#ifndef __ASM_METAG_PERF_EVENT_H
+#define __ASM_METAG_PERF_EVENT_H
+
+#endif /* __ASM_METAG_PERF_EVENT_H */
diff --git a/arch/metag/kernel/perf_callchain.c b/arch/metag/kernel/perf_callchain.c
new file mode 100644
index 0000000..3156334
--- /dev/null
+++ b/arch/metag/kernel/perf_callchain.c
@@ -0,0 +1,96 @@
+/*
+ * Perf callchain handling code.
+ *
+ * Based on the ARM perf implementation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/perf_event.h>
+#include <linux/uaccess.h>
+#include <asm/ptrace.h>
+#include <asm/stacktrace.h>
+
+static bool is_valid_call(unsigned long calladdr)
+{
+ unsigned int callinsn;
+
+ /* Check the possible return address is aligned. */
+ if (!(calladdr & 0x3)) {
+ if (!get_user(callinsn, (unsigned int *)calladdr)) {
+ /* Check for CALLR or SWAP PC,D1RtP. */
+ if ((callinsn & 0xff000000) == 0xab000000 ||
+ callinsn == 0xa3200aa0)
+ return true;
+ }
+ }
+ return false;
+}
+
+static struct metag_frame __user *
+user_backtrace(struct metag_frame __user *user_frame,
+ struct perf_callchain_entry *entry)
+{
+ struct metag_frame frame;
+ unsigned long calladdr;
+
+ /* We cannot rely on having frame pointers in user code. */
+ while (1) {
+ /* Also check accessibility of one struct frame beyond */
+ if (!access_ok(VERIFY_READ, user_frame, sizeof(frame)))
+ return 0;
+ if (__copy_from_user_inatomic(&frame, user_frame,
+ sizeof(frame)))
+ return 0;
+
+ --user_frame;
+
+ calladdr = frame.lr - 4;
+ if (is_valid_call(calladdr)) {
+ perf_callchain_store(entry, calladdr);
+ return user_frame;
+ }
+ }
+
+ return 0;
+}
+
+void
+perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
+{
+ unsigned long sp = regs->ctx.AX[0].U0;
+ struct metag_frame __user *frame;
+
+ frame = (struct metag_frame __user *)sp;
+
+ --frame;
+
+ while ((entry->nr < PERF_MAX_STACK_DEPTH) && frame)
+ frame = user_backtrace(frame, entry);
+}
+
+/*
+ * Gets called by walk_stackframe() for every stackframe. This will be called
+ * whist unwinding the stackframe and is like a subroutine return so we use
+ * the PC.
+ */
+static int
+callchain_trace(struct stackframe *fr,
+ void *data)
+{
+ struct perf_callchain_entry *entry = data;
+ perf_callchain_store(entry, fr->pc);
+ return 0;
+}
+
+void
+perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
+{
+ struct stackframe fr;
+
+ fr.fp = regs->ctx.AX[1].U0;
+ fr.sp = regs->ctx.AX[0].U0;
+ fr.lr = regs->ctx.DX[4].U1;
+ fr.pc = regs->ctx.CurrPC;
+ walk_stackframe(&fr, callchain_trace, entry);
+}
--
1.7.7.6
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