linux-kernel - [PATCH v2 4/8] MIPS: Remove "weak" from get_c0_perfcount

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Date:	Tue, 14 Jul 2015 11:46:47 -0500
From:	Bjorn Helgaas <bhelgaas@...gle.com>
To:	Ralf Baechle <ralf@...ux-mips.org>
Cc:	Andrew Bresticker <abrestic@...omium.org>,
	linux-mips@...ux-mips.org, James Hogan <james.hogan@...tec.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 4/8] MIPS: Remove "weak" from get_c0_perfcount_int()
 declaration

Weak header file declarations are error-prone because they make every
definition weak, and the linker chooses one based on link order (see
10629d711ed7 ("PCI: Remove __weak annotation from pcibios_get_phb_of_node
decl")).

get_c0_perfcount_int() is defined in several files.  Every definition is
weak, so I assume Kconfig prevents two or more from being included.  The
callers contain identical default code used when get_c0_perfcount_int()
isn't defined at all.

Add a weak get_c0_perfcount_int() definition with the default code and
remove the weak annotation from the declaration.

Then the platform implementations will be strong and will override the weak
default.  If multiple platforms are ever configured in, we'll get a link
error instead of calling a random platform's implementation.

Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
CC: Andrew Bresticker <abrestic@...omium.org>
---
 arch/mips/include/asm/time.h         |    2 +-
 arch/mips/kernel/perf_event_mipsxx.c |    7 +------
 arch/mips/kernel/time.c              |    9 ++++++++-
 arch/mips/oprofile/op_model_mipsxx.c |    8 +-------
 4 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/arch/mips/include/asm/time.h b/arch/mips/include/asm/time.h
index 8ab2874..ce6a7d5 100644
--- a/arch/mips/include/asm/time.h
+++ b/arch/mips/include/asm/time.h
@@ -46,7 +46,7 @@ extern unsigned int mips_hpt_frequency;
  * so it lives here.
  */
 extern int (*perf_irq)(void);
-extern int __weak get_c0_perfcount_int(void);
+extern int get_c0_perfcount_int(void);
 
 /*
  * Initialize the calling CPU's compare interrupt as clockevent device
diff --git a/arch/mips/kernel/perf_event_mipsxx.c b/arch/mips/kernel/perf_event_mipsxx.c
index cc1b6fa..c126b1c 100644
--- a/arch/mips/kernel/perf_event_mipsxx.c
+++ b/arch/mips/kernel/perf_event_mipsxx.c
@@ -1682,12 +1682,7 @@ init_hw_perf_events(void)
 		counters = counters_total_to_per_cpu(counters);
 #endif
 
-	if (get_c0_perfcount_int)
-		irq = get_c0_perfcount_int();
-	else if (cp0_perfcount_irq >= 0)
-		irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
-	else
-		irq = -1;
+	irq = get_c0_perfcount_int();
 
 	mipspmu.map_raw_event = mipsxx_pmu_map_raw_event;
 
diff --git a/arch/mips/kernel/time.c b/arch/mips/kernel/time.c
index 8d01709..6fff600 100644
--- a/arch/mips/kernel/time.c
+++ b/arch/mips/kernel/time.c
@@ -27,6 +27,7 @@
 #include <asm/cpu-type.h>
 #include <asm/div64.h>
 #include <asm/time.h>
+#include <asm/irq.h>
 
 /*
  * forward reference
@@ -55,9 +56,15 @@ static int null_perf_irq(void)
 }
 
 int (*perf_irq)(void) = null_perf_irq;
-
 EXPORT_SYMBOL(perf_irq);
 
+int __weak get_c0_perfcount_int(void)
+{
+	if (cp0_perfcount_irq >= 0)
+		return MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
+	return -1;
+}
+
 /*
  * time_init() - it does the following things.
  *
diff --git a/arch/mips/oprofile/op_model_mipsxx.c b/arch/mips/oprofile/op_model_mipsxx.c
index 6a6e2cc..c0cffa9 100644
--- a/arch/mips/oprofile/op_model_mipsxx.c
+++ b/arch/mips/oprofile/op_model_mipsxx.c
@@ -438,13 +438,7 @@ static int __init mipsxx_init(void)
 	save_perf_irq = perf_irq;
 	perf_irq = mipsxx_perfcount_handler;
 
-	if (get_c0_perfcount_int)
-		perfcount_irq = get_c0_perfcount_int();
-	else if (cp0_perfcount_irq >= 0)
-		perfcount_irq = MIPS_CPU_IRQ_BASE + cp0_perfcount_irq;
-	else
-		perfcount_irq = -1;
-
+	perfcount_irq = get_c0_perfcount_int();
 	if (perfcount_irq >= 0)
 		return request_irq(perfcount_irq, mipsxx_perfcount_int,
 				   IRQF_PERCPU | IRQF_NOBALANCING |

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