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authorDave Martin <dave.martin@linaro.org>2011-06-14 17:20:44 +0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-06-21 14:33:20 +0400
commit946a105e16651c35e9cc670bff23812761f1ad35 (patch)
treecc5c434db14553737808d7b86bb2d6938b06ca53 /arch/arm
parent573619d165b85152eeddd3b3871002c48cd94e42 (diff)
downloadlinux-946a105e16651c35e9cc670bff23812761f1ad35.tar.xz
ARM: 6961/1: zImage: Add build-time check for correctly-sized proc_type entries
It is easy to mis-maintain the proc_types table such that the entries become wrongly-sized and misaligned when the kernel is built in Thumb-2. This patch adds an assembly-time check which will turn most common size/alignment mistakes in this table into build failures, to avoid having to debug the boot-time kernel hang which would happen if the resulting kernel were actually booted. Signed-off-by: Dave Martin <dave.martin@linaro.org> Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/boot/compressed/head.S14
1 files changed, 13 insertions, 1 deletions
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 942fad97e447..940b20178107 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -597,6 +597,8 @@ __common_mmu_cache_on:
sub pc, lr, r0, lsr #32 @ properly flush pipeline
#endif
+#define PROC_ENTRY_SIZE (4*5)
+
/*
* Here follow the relocatable cache support functions for the
* various processors. This is a generic hook for locating an
@@ -624,7 +626,7 @@ call_cache_fn: adr r12, proc_types
ARM( addeq pc, r12, r3 ) @ call cache function
THUMB( addeq r12, r3 )
THUMB( moveq pc, r12 ) @ call cache function
- add r12, r12, #4*5
+ add r12, r12, #PROC_ENTRY_SIZE
b 1b
/*
@@ -794,6 +796,16 @@ proc_types:
.size proc_types, . - proc_types
+ /*
+ * If you get a "non-constant expression in ".if" statement"
+ * error from the assembler on this line, check that you have
+ * not accidentally written a "b" instruction where you should
+ * have written W(b).
+ */
+ .if (. - proc_types) % PROC_ENTRY_SIZE != 0
+ .error "The size of one or more proc_types entries is wrong."
+ .endif
+
/*
* Turn off the Cache and MMU. ARMv3 does not support
* reading the control register, but ARMv4 does.