37 lines
1.2 KiB
Diff
37 lines
1.2 KiB
Diff
From: Matthias Schiffer <mschiffer@universe-factory.net>
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Date: Sun, 28 Feb 2016 04:49:51 +0100
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Subject: ar71xx/lzma-loader: fix O32 ABI conformance
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According to the calling convention of the o32 ABI the caller
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function must reserve stack space for $a0-$a3 registers in case
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the callee needs to save its arguments.
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The assembly code of the loader does not reserve stack space for
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these registers thus when the 'loader_main' function needs to save
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its arguments, those will be stored in the 'workspace' area instead
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of the stack.
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Because the workspace area is also used by other part of the code, the
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saved register values gets overwritten and this often leads to failed
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kernel boots.
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Fix the code to reserve stack space for the registers to avoid this
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error.
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Backport of r48279
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diff --git a/target/linux/ar71xx/image/lzma-loader/src/head.S b/target/linux/ar71xx/image/lzma-loader/src/head.S
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index 543996a..47a7c9b 100644
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--- a/target/linux/ar71xx/image/lzma-loader/src/head.S
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+++ b/target/linux/ar71xx/image/lzma-loader/src/head.S
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@@ -109,6 +109,9 @@ __bss_check:
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/* Setup new "C" stack */
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la sp, _stack
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+ /* reserve stack space for a0-a3 registers */
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+ subu sp, 16
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+
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/* jump to the decompressor routine */
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la t0, loader_main
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jr t0
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