c0385b24af
In order to patch in the new atomic instructions at runtime, we need to generate wrappers around the out-of-line exclusive load/store atomics. This patch adds a new Kconfig option, CONFIG_ARM64_LSE_ATOMICS. which causes our atomic functions to branch to the out-of-line ll/sc implementations. To avoid the register spill overhead of the PCS, the out-of-line functions are compiled with specific compiler flags to force out-of-line save/restore of any registers that are usually caller-saved. Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
18 lines
939 B
Makefile
18 lines
939 B
Makefile
lib-y := bitops.o clear_user.o delay.o copy_from_user.o \
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copy_to_user.o copy_in_user.o copy_page.o \
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clear_page.o memchr.o memcpy.o memmove.o memset.o \
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memcmp.o strcmp.o strncmp.o strlen.o strnlen.o \
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strchr.o strrchr.o
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# Tell the compiler to treat all general purpose registers as
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# callee-saved, which allows for efficient runtime patching of the bl
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# instruction in the caller with an atomic instruction when supported by
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# the CPU. Result and argument registers are handled correctly, based on
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# the function prototype.
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lib-$(CONFIG_ARM64_LSE_ATOMICS) += atomic_ll_sc.o
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CFLAGS_atomic_ll_sc.o := -fcall-used-x0 -ffixed-x1 -ffixed-x2 \
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-ffixed-x3 -ffixed-x4 -ffixed-x5 -ffixed-x6 \
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-ffixed-x7 -fcall-saved-x8 -fcall-saved-x9 \
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-fcall-saved-x10 -fcall-saved-x11 -fcall-saved-x12 \
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-fcall-saved-x13 -fcall-saved-x14 -fcall-saved-x15 \
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-fcall-saved-x16 -fcall-saved-x17 -fcall-saved-x18
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