arm64: perf: factor out callchain code
authorMark Rutland <mark.rutland@arm.com>
Mon, 6 Jul 2015 11:23:54 +0000 (12:23 +0100)
committerWill Deacon <will.deacon@arm.com>
Mon, 27 Jul 2015 10:08:39 +0000 (11:08 +0100)
We currently bundle the callchain handling code with the PMU code,
despite the fact the two are distinct, and the former can be useful even
in the absence of the latter.

Follow the example of arch/arm and factor the callchain handling into
its own file dependent on CONFIG_PERF_EVENTS rather than
CONFIG_HW_PERF_EVENTS.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
arch/arm64/include/asm/perf_event.h
arch/arm64/kernel/Makefile
arch/arm64/kernel/perf_callchain.c [new file with mode: 0644]
arch/arm64/kernel/perf_event.c

index 6471773db6fd8c067833ea92f647cca865e6fb4d..7bd3cdb533ea80bd49ef6901b855e124d82cb500 100644 (file)
@@ -17,7 +17,7 @@
 #ifndef __ASM_PERF_EVENT_H
 #define __ASM_PERF_EVENT_H
 
-#ifdef CONFIG_HW_PERF_EVENTS
+#ifdef CONFIG_PERF_EVENTS
 struct pt_regs;
 extern unsigned long perf_instruction_pointer(struct pt_regs *regs);
 extern unsigned long perf_misc_flags(struct pt_regs *regs);
index 426d0763c81bf3ac9113314a25d367e997cf2e17..e89063eff14f110aef0a0d18c7c2ff497ddcb46c 100644 (file)
@@ -25,7 +25,7 @@ arm64-obj-$(CONFIG_COMPAT)            += sys32.o kuser32.o signal32.o         \
 arm64-obj-$(CONFIG_FUNCTION_TRACER)    += ftrace.o entry-ftrace.o
 arm64-obj-$(CONFIG_MODULES)            += arm64ksyms.o module.o
 arm64-obj-$(CONFIG_SMP)                        += smp.o smp_spin_table.o topology.o
-arm64-obj-$(CONFIG_PERF_EVENTS)                += perf_regs.o
+arm64-obj-$(CONFIG_PERF_EVENTS)                += perf_regs.o perf_callchain.o
 arm64-obj-$(CONFIG_HW_PERF_EVENTS)     += perf_event.o
 arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
 arm64-obj-$(CONFIG_CPU_PM)             += sleep.o suspend.o
diff --git a/arch/arm64/kernel/perf_callchain.c b/arch/arm64/kernel/perf_callchain.c
new file mode 100644 (file)
index 0000000..3aa7483
--- /dev/null
@@ -0,0 +1,196 @@
+/*
+ * arm64 callchain support
+ *
+ * Copyright (C) 2015 ARM Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/perf_event.h>
+#include <linux/uaccess.h>
+
+#include <asm/stacktrace.h>
+
+struct frame_tail {
+       struct frame_tail       __user *fp;
+       unsigned long           lr;
+} __attribute__((packed));
+
+/*
+ * Get the return address for a single stackframe and return a pointer to the
+ * next frame tail.
+ */
+static struct frame_tail __user *
+user_backtrace(struct frame_tail __user *tail,
+              struct perf_callchain_entry *entry)
+{
+       struct frame_tail buftail;
+       unsigned long err;
+
+       /* Also check accessibility of one struct frame_tail beyond */
+       if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
+               return NULL;
+
+       pagefault_disable();
+       err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail));
+       pagefault_enable();
+
+       if (err)
+               return NULL;
+
+       perf_callchain_store(entry, buftail.lr);
+
+       /*
+        * Frame pointers should strictly progress back up the stack
+        * (towards higher addresses).
+        */
+       if (tail >= buftail.fp)
+               return NULL;
+
+       return buftail.fp;
+}
+
+#ifdef CONFIG_COMPAT
+/*
+ * The registers we're interested in are at the end of the variable
+ * length saved register structure. The fp points at the end of this
+ * structure so the address of this struct is:
+ * (struct compat_frame_tail *)(xxx->fp)-1
+ *
+ * This code has been adapted from the ARM OProfile support.
+ */
+struct compat_frame_tail {
+       compat_uptr_t   fp; /* a (struct compat_frame_tail *) in compat mode */
+       u32             sp;
+       u32             lr;
+} __attribute__((packed));
+
+static struct compat_frame_tail __user *
+compat_user_backtrace(struct compat_frame_tail __user *tail,
+                     struct perf_callchain_entry *entry)
+{
+       struct compat_frame_tail buftail;
+       unsigned long err;
+
+       /* Also check accessibility of one struct frame_tail beyond */
+       if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
+               return NULL;
+
+       pagefault_disable();
+       err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail));
+       pagefault_enable();
+
+       if (err)
+               return NULL;
+
+       perf_callchain_store(entry, buftail.lr);
+
+       /*
+        * Frame pointers should strictly progress back up the stack
+        * (towards higher addresses).
+        */
+       if (tail + 1 >= (struct compat_frame_tail __user *)
+                       compat_ptr(buftail.fp))
+               return NULL;
+
+       return (struct compat_frame_tail __user *)compat_ptr(buftail.fp) - 1;
+}
+#endif /* CONFIG_COMPAT */
+
+void perf_callchain_user(struct perf_callchain_entry *entry,
+                        struct pt_regs *regs)
+{
+       if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
+               /* We don't support guest os callchain now */
+               return;
+       }
+
+       perf_callchain_store(entry, regs->pc);
+
+       if (!compat_user_mode(regs)) {
+               /* AARCH64 mode */
+               struct frame_tail __user *tail;
+
+               tail = (struct frame_tail __user *)regs->regs[29];
+
+               while (entry->nr < PERF_MAX_STACK_DEPTH &&
+                      tail && !((unsigned long)tail & 0xf))
+                       tail = user_backtrace(tail, entry);
+       } else {
+#ifdef CONFIG_COMPAT
+               /* AARCH32 compat mode */
+               struct compat_frame_tail __user *tail;
+
+               tail = (struct compat_frame_tail __user *)regs->compat_fp - 1;
+
+               while ((entry->nr < PERF_MAX_STACK_DEPTH) &&
+                       tail && !((unsigned long)tail & 0x3))
+                       tail = compat_user_backtrace(tail, entry);
+#endif
+       }
+}
+
+/*
+ * 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 *frame, void *data)
+{
+       struct perf_callchain_entry *entry = data;
+       perf_callchain_store(entry, frame->pc);
+       return 0;
+}
+
+void perf_callchain_kernel(struct perf_callchain_entry *entry,
+                          struct pt_regs *regs)
+{
+       struct stackframe frame;
+
+       if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
+               /* We don't support guest os callchain now */
+               return;
+       }
+
+       frame.fp = regs->regs[29];
+       frame.sp = regs->sp;
+       frame.pc = regs->pc;
+
+       walk_stackframe(&frame, callchain_trace, entry);
+}
+
+unsigned long perf_instruction_pointer(struct pt_regs *regs)
+{
+       if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
+               return perf_guest_cbs->get_guest_ip();
+
+       return instruction_pointer(regs);
+}
+
+unsigned long perf_misc_flags(struct pt_regs *regs)
+{
+       int misc = 0;
+
+       if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
+               if (perf_guest_cbs->is_user_mode())
+                       misc |= PERF_RECORD_MISC_GUEST_USER;
+               else
+                       misc |= PERF_RECORD_MISC_GUEST_KERNEL;
+       } else {
+               if (user_mode(regs))
+                       misc |= PERF_RECORD_MISC_USER;
+               else
+                       misc |= PERF_RECORD_MISC_KERNEL;
+       }
+
+       return misc;
+}
index 563f8ce8df68da8d3fa11721cca841ca90ab34cf..1821405614164411d095fc2a9c87dedb776266a7 100644 (file)
@@ -36,7 +36,6 @@
 #include <asm/irq.h>
 #include <asm/irq_regs.h>
 #include <asm/pmu.h>
-#include <asm/stacktrace.h>
 
 /*
  * ARMv8 supports a maximum of 32 events.
@@ -1413,180 +1412,3 @@ static int __init init_hw_perf_events(void)
 }
 early_initcall(init_hw_perf_events);
 
-/*
- * Callchain handling code.
- */
-struct frame_tail {
-       struct frame_tail       __user *fp;
-       unsigned long           lr;
-} __attribute__((packed));
-
-/*
- * Get the return address for a single stackframe and return a pointer to the
- * next frame tail.
- */
-static struct frame_tail __user *
-user_backtrace(struct frame_tail __user *tail,
-              struct perf_callchain_entry *entry)
-{
-       struct frame_tail buftail;
-       unsigned long err;
-
-       /* Also check accessibility of one struct frame_tail beyond */
-       if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
-               return NULL;
-
-       pagefault_disable();
-       err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail));
-       pagefault_enable();
-
-       if (err)
-               return NULL;
-
-       perf_callchain_store(entry, buftail.lr);
-
-       /*
-        * Frame pointers should strictly progress back up the stack
-        * (towards higher addresses).
-        */
-       if (tail >= buftail.fp)
-               return NULL;
-
-       return buftail.fp;
-}
-
-#ifdef CONFIG_COMPAT
-/*
- * The registers we're interested in are at the end of the variable
- * length saved register structure. The fp points at the end of this
- * structure so the address of this struct is:
- * (struct compat_frame_tail *)(xxx->fp)-1
- *
- * This code has been adapted from the ARM OProfile support.
- */
-struct compat_frame_tail {
-       compat_uptr_t   fp; /* a (struct compat_frame_tail *) in compat mode */
-       u32             sp;
-       u32             lr;
-} __attribute__((packed));
-
-static struct compat_frame_tail __user *
-compat_user_backtrace(struct compat_frame_tail __user *tail,
-                     struct perf_callchain_entry *entry)
-{
-       struct compat_frame_tail buftail;
-       unsigned long err;
-
-       /* Also check accessibility of one struct frame_tail beyond */
-       if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
-               return NULL;
-
-       pagefault_disable();
-       err = __copy_from_user_inatomic(&buftail, tail, sizeof(buftail));
-       pagefault_enable();
-
-       if (err)
-               return NULL;
-
-       perf_callchain_store(entry, buftail.lr);
-
-       /*
-        * Frame pointers should strictly progress back up the stack
-        * (towards higher addresses).
-        */
-       if (tail + 1 >= (struct compat_frame_tail __user *)
-                       compat_ptr(buftail.fp))
-               return NULL;
-
-       return (struct compat_frame_tail __user *)compat_ptr(buftail.fp) - 1;
-}
-#endif /* CONFIG_COMPAT */
-
-void perf_callchain_user(struct perf_callchain_entry *entry,
-                        struct pt_regs *regs)
-{
-       if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
-               /* We don't support guest os callchain now */
-               return;
-       }
-
-       perf_callchain_store(entry, regs->pc);
-
-       if (!compat_user_mode(regs)) {
-               /* AARCH64 mode */
-               struct frame_tail __user *tail;
-
-               tail = (struct frame_tail __user *)regs->regs[29];
-
-               while (entry->nr < PERF_MAX_STACK_DEPTH &&
-                      tail && !((unsigned long)tail & 0xf))
-                       tail = user_backtrace(tail, entry);
-       } else {
-#ifdef CONFIG_COMPAT
-               /* AARCH32 compat mode */
-               struct compat_frame_tail __user *tail;
-
-               tail = (struct compat_frame_tail __user *)regs->compat_fp - 1;
-
-               while ((entry->nr < PERF_MAX_STACK_DEPTH) &&
-                       tail && !((unsigned long)tail & 0x3))
-                       tail = compat_user_backtrace(tail, entry);
-#endif
-       }
-}
-
-/*
- * 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 *frame, void *data)
-{
-       struct perf_callchain_entry *entry = data;
-       perf_callchain_store(entry, frame->pc);
-       return 0;
-}
-
-void perf_callchain_kernel(struct perf_callchain_entry *entry,
-                          struct pt_regs *regs)
-{
-       struct stackframe frame;
-
-       if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
-               /* We don't support guest os callchain now */
-               return;
-       }
-
-       frame.fp = regs->regs[29];
-       frame.sp = regs->sp;
-       frame.pc = regs->pc;
-
-       walk_stackframe(&frame, callchain_trace, entry);
-}
-
-unsigned long perf_instruction_pointer(struct pt_regs *regs)
-{
-       if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
-               return perf_guest_cbs->get_guest_ip();
-
-       return instruction_pointer(regs);
-}
-
-unsigned long perf_misc_flags(struct pt_regs *regs)
-{
-       int misc = 0;
-
-       if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
-               if (perf_guest_cbs->is_user_mode())
-                       misc |= PERF_RECORD_MISC_GUEST_USER;
-               else
-                       misc |= PERF_RECORD_MISC_GUEST_KERNEL;
-       } else {
-               if (user_mode(regs))
-                       misc |= PERF_RECORD_MISC_USER;
-               else
-                       misc |= PERF_RECORD_MISC_KERNEL;
-       }
-
-       return misc;
-}