From: marc.ceeeee@gmail.com (Marc Carino)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3] ARM: zImage: perform cache maintenance after relocating code (was: ARM: zImage: add DSB and ISB barriers after relocating code)
Date: Mon, 11 Aug 2014 17:35:47 -0700 [thread overview]
Message-ID: <1407803747-21379-1-git-send-email-marc.ceeeee@gmail.com> (raw)
The zImage loader will relocate the kernel image if it determines that
decompression will overwrite its current location. Since the act of relocation
is a form of code self-modification, we need to ensure that the CPU fetches
the updated instruction stream.
Instead of conditionally executing cache maintenance, this commit ensures that
cache maintenance is performed in all cases. Besides ensuring coherency with
the caches and main memory, performing cache maintenance ensures that any
potentially stale instructions are flushed from the instruction pipeline.
Signed-off-by: Marc Carino <marc.ceeeee@gmail.com>
---
arch/arm/boot/compressed/head.S | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 3a8b32d..8a39054 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -395,8 +395,7 @@ dtb_check_done:
add sp, sp, r6
#endif
- tst r4, #1
- bleq cache_clean_flush
+ bl cache_clean_flush
adr r0, BSYM(restart)
add r0, r0, r6
--
1.8.1.3
next reply other threads:[~2014-08-12 0:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-12 0:35 Marc Carino [this message]
2014-08-12 2:33 ` [PATCH v3] ARM: zImage: perform cache maintenance after relocating code (was: ARM: zImage: add DSB and ISB barriers after relocating code) Nicolas Pitre
2014-08-12 9:34 ` Russell King - ARM Linux
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