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Commit 622844bf authored by Wu Zhangjin's avatar Wu Zhangjin Committed by Ralf Baechle
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MIPS: Loongson: Add CPU_LOONGSON2F_WORKAROUNDS 

As documented in the  Loongson 2F User Manual [2, 3], the old Loongson2F
series (2F01 / 2F02) have the NOP & JUMP issues which requires workarounds
in the kernel and binutils.  This issue has been rectified in Loongson 2F
series 2F03 so no workarounds needed.

Now that the workarounds [1] adding the the -mfix-loongson2f-nop and
-mfix-loongson2f-jump options have been comitted to the binutils the CVS
repository), we can add the workarounds in the kernel.

The workarounds have no significant side effect on the system but may
decrease performance so we control them through a a new
CPU_LOONGSON2F_WORKAROUNDS config option allowing the users to only enable
it as necessary.

[1] "Fixups of Loongson2F" patch for binutils(actually for gas)
    http://sourceware.org/ml/binutils/2009-11/msg00387.html
[2] Chapter 15 of "Loongson2F User Manual"(Chinese Version)
    http://www.loongson.cn/uploadfile/file/200808211
[3] English Version of the above chapter 15
    http://groups.google.com.hk/group/loongson-dev/msg/e0d2e220958f10a6?dmode=source



Signed-off-by: default avatarWu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips <linux-mips@linux-mips.org>
Patchwork: http://patchwork.linux-mips.org/patch/1105/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent c619366e

arch/mips/Kconfig

+27 −0
Original line number Diff line number Diff line
@@ -1307,6 +1307,33 @@ config CPU_CAVIUM_OCTEON 


endchoice



if CPU_LOONGSON2F

config CPU_NOP_WORKAROUNDS

	bool



config CPU_JUMP_WORKAROUNDS

	bool



config CPU_LOONGSON2F_WORKAROUNDS

	bool "Loongson 2F Workarounds"

	default y

	select CPU_NOP_WORKAROUNDS

	select CPU_JUMP_WORKAROUNDS

	help

	  Loongson 2F01 / 2F02 processors have the NOP & JUMP issues which

	  require workarounds.  Without workarounds the system may hang

	  unexpectedly.  For more information please refer to the gas

	  -mfix-loongson2f-nop and -mfix-loongson2f-jump options.



	  Loongson 2F03 and later have fixed these issues and no workarounds

	  are needed.  The workarounds have no significant side effect on them

	  but may decrease the performance of the system so this option should

	  be disabled unless the kernel is intended to be run on 2F01 or 2F02

	  systems.



	  If unsure, please say Y.

endif # CPU_LOONGSON2F



config SYS_SUPPORTS_ZBOOT

	bool

	select HAVE_KERNEL_GZIP