linux/arch/loongarch/Makefile
Qing Zhang 4733f09d88 LoongArch/ftrace: Add dynamic function tracer support
The compiler has inserted 2 NOPs before the regular function prologue.
T series registers are available and safe because of LoongArch's psABI.

At runtime, we can replace nop with bl to enable ftrace call and replace
bl with nop to disable ftrace call. The bl instruction requires us to
save the original RA value, so it saves RA at t0 here.

Details are:

| Compiled   |       Disabled         |        Enabled         |
+------------+------------------------+------------------------+
| nop        | move     t0, ra        | move    t0, ra         |
| nop        | nop                    | bl      ftrace_caller  |
| func_body  | func_body              | func_body              |

The RA value will be recovered by ftrace_regs_entry, and restored into
RA before returning to the regular function prologue. When a function is
not being traced, the "move t0, ra" is not harmful.

1) ftrace_make_call, ftrace_make_nop (in kernel/ftrace.c)
   The two functions turn each recorded call site of filtered functions
   into a call to ftrace_caller or nops.

2) ftracce_update_ftrace_func (in kernel/ftrace.c)
   turns the nops at ftrace_call into a call to a generic entry for
   function tracers.

3) ftrace_caller (in kernel/mcount_dyn.S)
   The entry where each _mcount call sites calls to once they are
   filtered to be traced.

Co-developed-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-12-14 08:41:53 +08:00

139 lines
4.1 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
#
# Author: Huacai Chen <chenhuacai@loongson.cn>
# Copyright (C) 2020-2022 Loongson Technology Corporation Limited
boot := arch/loongarch/boot
KBUILD_DEFCONFIG := loongson3_defconfig
image-name-y := vmlinux
image-name-$(CONFIG_EFI_ZBOOT) := vmlinuz
ifndef CONFIG_EFI_STUB
KBUILD_IMAGE := $(boot)/vmlinux.elf
else
KBUILD_IMAGE := $(boot)/$(image-name-y).efi
endif
#
# Select the object file format to substitute into the linker script.
#
64bit-tool-archpref = loongarch64
32bit-bfd = elf32-loongarch
64bit-bfd = elf64-loongarch
32bit-emul = elf32loongarch
64bit-emul = elf64loongarch
ifdef CONFIG_DYNAMIC_FTRACE
KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
CC_FLAGS_FTRACE := -fpatchable-function-entry=2
endif
ifdef CONFIG_64BIT
tool-archpref = $(64bit-tool-archpref)
UTS_MACHINE := loongarch64
endif
ifneq ($(SUBARCH),$(ARCH))
ifeq ($(CROSS_COMPILE),)
CROSS_COMPILE := $(call cc-cross-prefix, $(tool-archpref)-linux- $(tool-archpref)-linux-gnu- $(tool-archpref)-unknown-linux-gnu-)
endif
endif
ifdef CONFIG_64BIT
ld-emul = $(64bit-emul)
cflags-y += -mabi=lp64s
endif
cflags-y += -G0 -pipe -msoft-float
LDFLAGS_vmlinux += -G0 -static -n -nostdlib
# When the assembler supports explicit relocation hint, we must use it.
# GCC may have -mexplicit-relocs off by default if it was built with an old
# assembler, so we force it via an option.
#
# When the assembler does not supports explicit relocation hint, we can't use
# it. Disable it if the compiler supports it.
#
# If you've seen "unknown reloc hint" message building the kernel and you are
# now wondering why "-mexplicit-relocs" is not wrapped with cc-option: the
# combination of a "new" assembler and "old" compiler is not supported. Either
# upgrade the compiler or downgrade the assembler.
ifdef CONFIG_AS_HAS_EXPLICIT_RELOCS
cflags-y += -mexplicit-relocs
KBUILD_CFLAGS_KERNEL += -mdirect-extern-access
else
cflags-y += $(call cc-option,-mno-explicit-relocs)
KBUILD_AFLAGS_KERNEL += -Wa,-mla-global-with-pcrel
KBUILD_CFLAGS_KERNEL += -Wa,-mla-global-with-pcrel
KBUILD_AFLAGS_MODULE += -Wa,-mla-global-with-abs
KBUILD_CFLAGS_MODULE += -fplt -Wa,-mla-global-with-abs,-mla-local-with-abs
endif
cflags-y += -ffreestanding
cflags-y += $(call cc-option, -mno-check-zero-division)
ifndef CONFIG_PHYSICAL_START
load-y = 0x9000000000200000
else
load-y = $(CONFIG_PHYSICAL_START)
endif
bootvars-y = VMLINUX_LOAD_ADDRESS=$(load-y)
drivers-$(CONFIG_PCI) += arch/loongarch/pci/
KBUILD_AFLAGS += $(cflags-y)
KBUILD_CFLAGS += $(cflags-y)
KBUILD_CPPFLAGS += -DVMLINUX_LOAD_ADDRESS=$(load-y)
# This is required to get dwarf unwinding tables into .debug_frame
# instead of .eh_frame so we don't discard them.
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
# Don't emit unaligned accesses.
# Not all LoongArch cores support unaligned access, and as kernel we can't
# rely on others to provide emulation for these accesses.
KBUILD_CFLAGS += $(call cc-option,-mstrict-align)
KBUILD_CFLAGS += -isystem $(shell $(CC) -print-file-name=include)
KBUILD_LDFLAGS += -m $(ld-emul)
ifdef CONFIG_LOONGARCH
CHECKFLAGS += $(shell $(CC) $(KBUILD_CFLAGS) -dM -E -x c /dev/null | \
grep -E -vw '__GNUC_(MINOR_|PATCHLEVEL_)?_' | \
sed -e "s/^\#define /-D'/" -e "s/ /'='/" -e "s/$$/'/" -e 's/\$$/&&/g')
endif
libs-y += arch/loongarch/lib/
libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
# suspend and hibernation support
drivers-$(CONFIG_PM) += arch/loongarch/power/
ifeq ($(KBUILD_EXTMOD),)
prepare: vdso_prepare
vdso_prepare: prepare0
$(Q)$(MAKE) $(build)=arch/loongarch/vdso include/generated/vdso-offsets.h
endif
PHONY += vdso_install
vdso_install:
$(Q)$(MAKE) $(build)=arch/loongarch/vdso $@
all: $(notdir $(KBUILD_IMAGE))
vmlinux.elf vmlinux.efi vmlinuz.efi: vmlinux
$(Q)$(MAKE) $(build)=$(boot) $(bootvars-y) $(boot)/$@
install:
$(Q)install -D -m 755 $(KBUILD_IMAGE) $(INSTALL_PATH)/$(image-name-y)-$(KERNELRELEASE)
$(Q)install -D -m 644 .config $(INSTALL_PATH)/config-$(KERNELRELEASE)
$(Q)install -D -m 644 System.map $(INSTALL_PATH)/System.map-$(KERNELRELEASE)
define archhelp
echo ' install - install kernel into $(INSTALL_PATH)'
echo
endef