[PATCH AUTOSEL 4.14 15/37] ACPI: blacklist: fix clang warning for unused DMI table

[PATCH AUTOSEL 4.14 15/37] ACPI: blacklist: fix clang warning for unused DMI table

[Sasha Levin]

From: Arnd Bergmann <arnd@arndb.de>

[ Upstream commit b80d6a42bdc97bdb6139107d6034222e9843c6e2 ]

When CONFIG_DMI is disabled, we only have a tentative declaration,
which causes a warning from clang:

drivers/acpi/blacklist.c:20:35: error: tentative array definition assumed to have one element [-Werror]
static const struct dmi_system_id acpi_rev_dmi_table[] __initconst;

As the variable is not actually used here, hide it entirely
in an #ifdef to shut up the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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>
---
 drivers/acpi/blacklist.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/acpi/blacklist.c b/drivers/acpi/blacklist.c
index 995c4d8922b1..761f0c19a451 100644
--- a/drivers/acpi/blacklist.c
+++ b/drivers/acpi/blacklist.c
@@ -30,7 +30,9 @@
 
 #include "internal.h"
 
+#ifdef CONFIG_DMI
 static const struct dmi_system_id acpi_rev_dmi_table[] __initconst;
+#endif
 
 /*
  * POLICY: If *anything* doesn't work, put it on the blacklist.
@@ -74,7 +76,9 @@ int __init acpi_blacklisted(void)
 	}
 
 	(void)early_acpi_osi_init();
+#ifdef CONFIG_DMI
 	dmi_check_system(acpi_rev_dmi_table);
+#endif
 
 	return blacklisted;
 }
-- 
2.20.1

[PATCH AUTOSEL 4.14 18/37] ACPI: fix false-positive -Wuninitialized warning

[Sasha Levin]

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 13c105121a18..d7a9700b9333 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -324,7 +324,10 @@ 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