* [PATCH AUTOSEL 4.4 10/23] ACPI: fix false-positive -Wuninitialized warning
[not found] <20190726134522.13308-1-sashal@kernel.org>
@ 2019-07-26 13:45 ` Sasha Levin
0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2019-07-26 13:45 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Arnd Bergmann, Andy Shevchenko, Nathan Chancellor,
Rafael J . Wysocki, Sasha Levin, linux-acpi, clang-built-linux
From: Arnd Bergmann <arnd@arndb.de>
[ Upstream commit dfd6f9ad36368b8dbd5f5a2b2f0a4705ae69a323 ]
clang gets confused by an uninitialized variable in what looks
to it like a never executed code path:
arch/x86/kernel/acpi/boot.c:618:13: error: variable 'polarity' is uninitialized when used here [-Werror,-Wuninitialized]
polarity = polarity ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
^~~~~~~~
arch/x86/kernel/acpi/boot.c:606:32: note: initialize the variable 'polarity' to silence this warning
int rc, irq, trigger, polarity;
^
= 0
arch/x86/kernel/acpi/boot.c:617:12: error: variable 'trigger' is uninitialized when used here [-Werror,-Wuninitialized]
trigger = trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE;
^~~~~~~
arch/x86/kernel/acpi/boot.c:606:22: note: initialize the variable 'trigger' to silence this warning
int rc, irq, trigger, polarity;
^
= 0
This is unfortunately a design decision in clang and won't be fixed.
Changing the acpi_get_override_irq() macro to an inline function
reliably avoids the issue.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/acpi.h | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 3672893b275e..6a30f1e03aa9 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -226,7 +226,10 @@ void acpi_set_irq_model(enum acpi_irq_model_id model,
#ifdef CONFIG_X86_IO_APIC
extern int acpi_get_override_irq(u32 gsi, int *trigger, int *polarity);
#else
-#define acpi_get_override_irq(gsi, trigger, polarity) (-1)
+static inline int acpi_get_override_irq(u32 gsi, int *trigger, int *polarity)
+{
+ return -1;
+}
#endif
/*
* This function undoes the effect of one call to acpi_register_gsi().
--
2.20.1
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2019-07-26 13:45 ` [PATCH AUTOSEL 4.4 10/23] ACPI: fix false-positive -Wuninitialized warning Sasha Levin
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