From: James Morse <james.morse@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Will Deacon <will.deacon@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
James Morse <james.morse@arm.com>,
Mark Rutland <mark.rutland@arm.com>
Subject: [PATCH] asm-generic/pgtable-nop?d.h: define folded with a value for use in C
Date: Wed, 3 Oct 2018 18:50:52 +0100 [thread overview]
Message-ID: <20181003175052.31917-1-james.morse@arm.com> (raw)
Message-ID: <20181003175052.c5wsw-adHPkSLr0wKc1RMItpkvKn2BJFA2rDn3RzF_g@z> (raw)
It turns out "if (__is_defined(__PAGETABLE_PMD_FOLDED))" isn't equivalent
to "#ifdef __PAGETABLE_PMD_FOLDED". (who knew!)
kconfig.h's __is_defined() expects a define of the form
"#define CONFIG_BOOGER 1". But these nop?d headers just have
"#define __PAGETABLE_PMD_FOLDED".
This means ____is_defined()'s triplet passed to __take_second_arg() is
'empty-string, 1 0' in both cases, meaning these symbols can't be used
from C. (they are always false).
asm-generic gets away with this as its using the pre-processor's
defined() macro on this, not the C __is_defined().
Add the expected '1'.
Signed-off-by: James Morse <james.morse@arm.com>
CC: Mark Rutland <mark.rutland@arm.com>
---
This fixes an issue with patches queued for arm64. Can it go via the arm64 tree?
Link: lore.kernel.org/r/0f9a3abc-4890-faf5-ee7e-18434641b858@arm.com
include/asm-generic/pgtable-nopmd.h | 2 +-
include/asm-generic/pgtable-nopud.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/pgtable-nopmd.h b/include/asm-generic/pgtable-nopmd.h
index f35f6e8149e4..fcb4769a075a 100644
--- a/include/asm-generic/pgtable-nopmd.h
+++ b/include/asm-generic/pgtable-nopmd.h
@@ -8,7 +8,7 @@
struct mm_struct;
-#define __PAGETABLE_PMD_FOLDED
+#define __PAGETABLE_PMD_FOLDED 1
/*
* Having the pmd type consist of a pud gets the size right, and allows
diff --git a/include/asm-generic/pgtable-nopud.h b/include/asm-generic/pgtable-nopud.h
index e950b9c50f34..d300dbcddaf3 100644
--- a/include/asm-generic/pgtable-nopud.h
+++ b/include/asm-generic/pgtable-nopud.h
@@ -9,7 +9,7 @@
#else
#include <asm-generic/pgtable-nop4d.h>
-#define __PAGETABLE_PUD_FOLDED
+#define __PAGETABLE_PUD_FOLDED 1
/*
* Having the pud type consist of a p4d gets the size right, and allows
--
2.19.0
next reply other threads:[~2018-10-04 0:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-03 17:50 James Morse [this message]
2018-10-03 17:50 ` [PATCH] asm-generic/pgtable-nop?d.h: define folded with a value for use in C James Morse
2018-10-04 9:45 ` Catalin Marinas
2018-10-04 9:45 ` Catalin Marinas
2018-10-05 11:02 ` Mark Rutland
2018-10-05 11:02 ` Mark Rutland
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