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afc76b8b80
This patch changes the current detour mechanism of dynamic ftrace which has been discussed during LPC 2020 RISCV-MC [1]. Before the patch, we used mcount for detour: <funca>: addi sp,sp,-16 sd ra,8(sp) sd s0,0(sp) addi s0,sp,16 mv a5,ra mv a0,a5 auipc ra,0x0 -> nop jalr -296(ra) <_mcount@plt> ->nop ... After the patch, we use nop call site area for detour: <funca>: nop -> REG_S ra, -SZREG(sp) nop -> auipc ra, 0x? nop -> jalr ?(ra) nop -> REG_L ra, -SZREG(sp) ... The mcount mechanism is mixed with gcc function prologue which is not very clear. The patchable function entry just put 16 bytes nop before the front of the function prologue which could be filled with a separated detour mechanism. [1] https://www.linuxplumbersconf.org/event/7/contributions/807/ Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
109 lines
2.9 KiB
Makefile
109 lines
2.9 KiB
Makefile
# This file is included by the global makefile so that you can add your own
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# architecture-specific flags and dependencies. Remember to do have actions
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# for "archclean" and "archdep" for cleaning up and making dependencies for
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# this architecture
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#
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# This file is subject to the terms and conditions of the GNU General Public
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# License. See the file "COPYING" in the main directory of this archive
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# for more details.
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#
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OBJCOPYFLAGS := -O binary
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LDFLAGS_vmlinux :=
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ifeq ($(CONFIG_DYNAMIC_FTRACE),y)
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LDFLAGS_vmlinux := --no-relax
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KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
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CC_FLAGS_FTRACE := -fpatchable-function-entry=8
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endif
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ifeq ($(CONFIG_64BIT)$(CONFIG_CMODEL_MEDLOW),yy)
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KBUILD_CFLAGS_MODULE += -mcmodel=medany
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endif
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export BITS
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ifeq ($(CONFIG_ARCH_RV64I),y)
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BITS := 64
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UTS_MACHINE := riscv64
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KBUILD_CFLAGS += -mabi=lp64
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KBUILD_AFLAGS += -mabi=lp64
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KBUILD_LDFLAGS += -melf64lriscv
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else
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BITS := 32
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UTS_MACHINE := riscv32
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KBUILD_CFLAGS += -mabi=ilp32
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KBUILD_AFLAGS += -mabi=ilp32
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KBUILD_LDFLAGS += -melf32lriscv
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endif
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# ISA string setting
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riscv-march-$(CONFIG_ARCH_RV32I) := rv32ima
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riscv-march-$(CONFIG_ARCH_RV64I) := rv64ima
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riscv-march-$(CONFIG_FPU) := $(riscv-march-y)fd
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riscv-march-$(CONFIG_RISCV_ISA_C) := $(riscv-march-y)c
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KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y))
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KBUILD_AFLAGS += -march=$(riscv-march-y)
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KBUILD_CFLAGS += -mno-save-restore
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KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)
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ifeq ($(CONFIG_CMODEL_MEDLOW),y)
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KBUILD_CFLAGS += -mcmodel=medlow
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endif
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ifeq ($(CONFIG_CMODEL_MEDANY),y)
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KBUILD_CFLAGS += -mcmodel=medany
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endif
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ifeq ($(CONFIG_PERF_EVENTS),y)
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KBUILD_CFLAGS += -fno-omit-frame-pointer
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endif
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KBUILD_CFLAGS_MODULE += $(call cc-option,-mno-relax)
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# GCC versions that support the "-mstrict-align" option default to allowing
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# unaligned accesses. While unaligned accesses are explicitly allowed in the
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# RISC-V ISA, they're emulated by machine mode traps on all extant
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# architectures. It's faster to have GCC emit only aligned accesses.
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KBUILD_CFLAGS += $(call cc-option,-mstrict-align)
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# arch specific predefines for sparse
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CHECKFLAGS += -D__riscv -D__riscv_xlen=$(BITS)
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# Default target when executing plain make
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boot := arch/riscv/boot
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KBUILD_IMAGE := $(boot)/Image.gz
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head-y := arch/riscv/kernel/head.o
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core-y += arch/riscv/
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libs-y += arch/riscv/lib/
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libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
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PHONY += vdso_install
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vdso_install:
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$(Q)$(MAKE) $(build)=arch/riscv/kernel/vdso $@
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ifeq ($(CONFIG_RISCV_M_MODE)$(CONFIG_SOC_CANAAN),yy)
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KBUILD_IMAGE := $(boot)/loader.bin
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else
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KBUILD_IMAGE := $(boot)/Image.gz
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endif
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BOOT_TARGETS := Image Image.gz loader loader.bin
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all: $(notdir $(KBUILD_IMAGE))
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$(BOOT_TARGETS): vmlinux
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$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
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@$(kecho) ' Kernel: $(boot)/$@ is ready'
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Image.%: Image
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$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
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zinstall install:
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$(Q)$(MAKE) $(build)=$(boot) $@
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archclean:
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$(Q)$(MAKE) $(clean)=$(boot)
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