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From: Ralf Baechle <ralf@linux-mips.org>
To: linux-mips@linux-mips.org, Huacai Chen <chenhc@lemote.com>,
	Aurelien Jarno <aurelien@aurel32.net>,
	Fuxin Zhang <zhangfx@lemote.com>,
	Zhangjin Wu <wuzhangjin@gmail.com>
Subject: [PATCH] MIPS: Longson 3: Fix fast refill handler for 32 bit kernels
Date: Wed, 1 Jun 2016 23:11:20 +0200	[thread overview]
Message-ID: <20160601211120.GA16149@linux-mips.org> (raw)

A recent merge has broken the LLVMLinux build for 32-bit little endian. I've
bisected it to 380cd58 and it looks like a bug in the kernel to me. Clang is
rejecting the inline assembly in the expansion of 'write_c0_kpgd
(swapper_pg_dir)' of tlbex.c. The relevant inline assembly can be found in
__write_64bit_c0_split() and is attempting to use the 'L' and 'M' print
modifiers on swapper_pg_dir which is a 32-bit unsigned long. These print
modifiers only make sense for 64-bit values so I think the kernel source is
incorrect.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Reported-by: Daniel Sanders <Daniel.Sanders@imgtec.com>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
---
I don't have Loongson 3 hardware for testing, could somebody of the Loongson
folks please review / test this?  Thanks!

 arch/mips/include/asm/mipsregs.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h
index e1ca65c..044fab6 100644
--- a/arch/mips/include/asm/mipsregs.h
+++ b/arch/mips/include/asm/mipsregs.h
@@ -1652,8 +1652,8 @@ do {									\
 #define read_c0_pgd()		__read_64bit_c0_register($9, 7)
 #define write_c0_pgd(val)	__write_64bit_c0_register($9, 7, val)
 
-#define read_c0_kpgd()		__read_64bit_c0_register($31, 7)
-#define write_c0_kpgd(val)	__write_64bit_c0_register($31, 7, val)
+#define read_c0_kpgd()		__read_ulong_c0_register($31, 7)
+#define write_c0_kpgd(val)	__write_ulong_c0_register($31, 7, val)
 
 /* Cavium OCTEON (cnMIPS) */
 #define read_c0_cvmcount()	__read_ulong_c0_register($9, 6)

             reply	other threads:[~2016-06-01 21:11 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-01 21:11 Ralf Baechle [this message]
2016-06-02  7:12 ` [PATCH] MIPS: Longson 3: Fix fast refill handler for 32 bit kernels Huacai Chen

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