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From:   Tiezhu Yang <yangtiezhu@loongson.cn>
To:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc:     linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
        Xuefeng Li <lixuefeng@loongson.cn>
Subject: [RFC PATCH] MIPS: Kconfig: Select ARCH_WANT_FRAME_POINTERS
Date:   Mon, 16 Nov 2020 13:03:00 +0800
Message-Id: <1605502980-31946-1-git-send-email-yangtiezhu@loongson.cn>
Precedence: bulk

Select ARCH_WANT_FRAME_POINTERS to fix the following build error under
CONFIG_DEBUG_ATOMIC_SLEEP:

  CC      arch/mips/kernel/signal.o
{standard input}: Assembler messages:
{standard input}:1775: Error: Unable to parse register name $fp
scripts/Makefile.build:283: recipe for target 'arch/mips/kernel/signal.o' failed
make[2]: *** [arch/mips/kernel/signal.o] Error 1
scripts/Makefile.build:500: recipe for target 'arch/mips/kernel' failed
make[1]: *** [arch/mips/kernel] Error 2
Makefile:1799: recipe for target 'arch/mips' failed
make: *** [arch/mips] Error 2

I think it is useful to get debugging information as described in the
following texts:

lib/Kconfig.debug
config FRAME_POINTER
        bool "Compile the kernel with frame pointers"
        ...
        default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
        help
          If you say Y here the resulting kernel image will be slightly
          larger and slower, but it gives very useful debugging information
          in case of kernel bugs. (precise oopses/stacktraces/warnings)

Documentation/dev-tools/kgdb.rst
This option inserts code to into the compiled executable which saves
the frame information in registers or on the stack at different points
which allows a debugger such as gdb to more accurately construct stack
back traces while debugging the kernel.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 arch/mips/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index ddaff19..4a4c791 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -15,6 +15,7 @@ config MIPS
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
+	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select BUILDTIME_TABLE_SORT
 	select CLONE_BACKWARDS
-- 
2.1.0