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MIPS: Workaround clang inline compat branch issue

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Clang is unable to handle the situation that a chunk of inline
assembly ends with a compat branch instruction and then compiler
generates another control transfer instruction immediately after
this compat branch. The later instruction will end up in forbidden
slot and cause exception.

Workaround by add a option to control the use of compact branch.
Currently it's selected by CC_IS_CLANG and hopefully we can change
it to a version check in future if clang manages to fix it.

Fix boot on boston board.

Link: https://github.com/llvm/llvm-project/issues/61045
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Acked-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This commit is contained in:
Jiaxun Yang 2023-02-28 19:34:59 +00:00 committed by Thomas Bogendoerfer
parent 70f864d108
commit 1a2c73f483
2 changed files with 5 additions and 1 deletions
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4
arch/mips/Kconfig
View File

@ -3200,6 +3200,10 @@ config CC_HAS_MNO_BRANCH_LIKELY
def_bool y
depends on $(cc-option,-mno-branch-likely)
# https://github.com/llvm/llvm-project/issues/61045
config CC_HAS_BROKEN_INLINE_COMPAT_BRANCH
def_bool y if CC_IS_CLANG
menu "Power management options"
config ARCH_HIBERNATION_POSSIBLE

2
arch/mips/include/asm/asm.h
View File

@ -336,7 +336,7 @@ symbol = value
*/
#ifdef CONFIG_WAR_R10000_LLSC
# define SC_BEQZ beqzl
#elif MIPS_ISA_REV >= 6
#elif !defined(CONFIG_CC_HAS_BROKEN_INLINE_COMPAT_BRANCH) && MIPS_ISA_REV >= 6
# define SC_BEQZ beqzc
#else
# define SC_BEQZ beqz