mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-01 16:14:13 +08:00
3b23e4991f
This patch implements FTRACE_WITH_REGS for arm64, which allows a traced
function's arguments (and some other registers) to be captured into a
struct pt_regs, allowing these to be inspected and/or modified. This is
a building block for live-patching, where a function's arguments may be
forwarded to another function. This is also necessary to enable ftrace
and in-kernel pointer authentication at the same time, as it allows the
LR value to be captured and adjusted prior to signing.
Using GCC's -fpatchable-function-entry=N option, we can have the
compiler insert a configurable number of NOPs between the function entry
point and the usual prologue. This also ensures functions are AAPCS
compliant (e.g. disabling inter-procedural register allocation).
For example, with -fpatchable-function-entry=2, GCC 8.1.0 compiles the
following:
| unsigned long bar(void);
|
| unsigned long foo(void)
| {
| return bar() + 1;
| }
... to:
| <foo>:
| nop
| nop
| stp x29, x30, [sp, #-16]!
| mov x29, sp
| bl 0 <bar>
| add x0, x0, #0x1
| ldp x29, x30, [sp], #16
| ret
This patch builds the kernel with -fpatchable-function-entry=2,
prefixing each function with two NOPs. To trace a function, we replace
these NOPs with a sequence that saves the LR into a GPR, then calls an
ftrace entry assembly function which saves this and other relevant
registers:
| mov x9, x30
| bl <ftrace-entry>
Since patchable functions are AAPCS compliant (and the kernel does not
use x18 as a platform register), x9-x18 can be safely clobbered in the
patched sequence and the ftrace entry code.
There are now two ftrace entry functions, ftrace_regs_entry (which saves
all GPRs), and ftrace_entry (which saves the bare minimum). A PLT is
allocated for each within modules.
Signed-off-by: Torsten Duwe <duwe@suse.de>
[Mark: rework asm, comments, PLTs, initialization, commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Torsten Duwe <duwe@suse.de>
Tested-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Tested-by: Torsten Duwe <duwe@suse.de>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Julien Thierry <jthierry@redhat.com>
Cc: Will Deacon <will@kernel.org>
179 lines
5.8 KiB
Makefile
179 lines
5.8 KiB
Makefile
#
|
|
# arch/arm64/Makefile
|
|
#
|
|
# This file is included by the global makefile so that you can add your own
|
|
# architecture-specific flags and dependencies.
|
|
#
|
|
# This file is subject to the terms and conditions of the GNU General Public
|
|
# License. See the file "COPYING" in the main directory of this archive
|
|
# for more details.
|
|
#
|
|
# Copyright (C) 1995-2001 by Russell King
|
|
|
|
LDFLAGS_vmlinux :=--no-undefined -X
|
|
CPPFLAGS_vmlinux.lds = -DTEXT_OFFSET=$(TEXT_OFFSET)
|
|
GZFLAGS :=-9
|
|
|
|
ifeq ($(CONFIG_RELOCATABLE), y)
|
|
# Pass --no-apply-dynamic-relocs to restore pre-binutils-2.27 behaviour
|
|
# for relative relocs, since this leads to better Image compression
|
|
# with the relocation offsets always being zero.
|
|
LDFLAGS_vmlinux += -shared -Bsymbolic -z notext -z norelro \
|
|
$(call ld-option, --no-apply-dynamic-relocs)
|
|
endif
|
|
|
|
ifeq ($(CONFIG_ARM64_ERRATUM_843419),y)
|
|
ifeq ($(call ld-option, --fix-cortex-a53-843419),)
|
|
$(warning ld does not support --fix-cortex-a53-843419; kernel may be susceptible to erratum)
|
|
else
|
|
LDFLAGS_vmlinux += --fix-cortex-a53-843419
|
|
endif
|
|
endif
|
|
|
|
# Check for binutils support for specific extensions
|
|
lseinstr := $(call as-instr,.arch_extension lse,-DCONFIG_AS_LSE=1)
|
|
|
|
ifeq ($(CONFIG_ARM64_LSE_ATOMICS), y)
|
|
ifeq ($(lseinstr),)
|
|
$(warning LSE atomics not supported by binutils)
|
|
endif
|
|
endif
|
|
|
|
cc_has_k_constraint := $(call try-run,echo \
|
|
'int main(void) { \
|
|
asm volatile("and w0, w0, %w0" :: "K" (4294967295)); \
|
|
return 0; \
|
|
}' | $(CC) -S -x c -o "$$TMP" -,,-DCONFIG_CC_HAS_K_CONSTRAINT=1)
|
|
|
|
ifeq ($(CONFIG_ARM64), y)
|
|
brokengasinst := $(call as-instr,1:\n.inst 0\n.rept . - 1b\n\nnop\n.endr\n,,-DCONFIG_BROKEN_GAS_INST=1)
|
|
|
|
ifneq ($(brokengasinst),)
|
|
$(warning Detected assembler with broken .inst; disassembly will be unreliable)
|
|
endif
|
|
endif
|
|
|
|
KBUILD_CFLAGS += -mgeneral-regs-only $(lseinstr) $(brokengasinst) \
|
|
$(compat_vdso) $(cc_has_k_constraint)
|
|
KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
|
|
KBUILD_CFLAGS += $(call cc-disable-warning, psabi)
|
|
KBUILD_AFLAGS += $(lseinstr) $(brokengasinst) $(compat_vdso)
|
|
|
|
KBUILD_CFLAGS += $(call cc-option,-mabi=lp64)
|
|
KBUILD_AFLAGS += $(call cc-option,-mabi=lp64)
|
|
|
|
ifeq ($(CONFIG_STACKPROTECTOR_PER_TASK),y)
|
|
prepare: stack_protector_prepare
|
|
stack_protector_prepare: prepare0
|
|
$(eval KBUILD_CFLAGS += -mstack-protector-guard=sysreg \
|
|
-mstack-protector-guard-reg=sp_el0 \
|
|
-mstack-protector-guard-offset=$(shell \
|
|
awk '{if ($$2 == "TSK_STACK_CANARY") print $$3;}' \
|
|
include/generated/asm-offsets.h))
|
|
endif
|
|
|
|
ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
|
|
KBUILD_CPPFLAGS += -mbig-endian
|
|
CHECKFLAGS += -D__AARCH64EB__
|
|
AS += -EB
|
|
# Prefer the baremetal ELF build target, but not all toolchains include
|
|
# it so fall back to the standard linux version if needed.
|
|
KBUILD_LDFLAGS += -EB $(call ld-option, -maarch64elfb, -maarch64linuxb)
|
|
UTS_MACHINE := aarch64_be
|
|
else
|
|
KBUILD_CPPFLAGS += -mlittle-endian
|
|
CHECKFLAGS += -D__AARCH64EL__
|
|
AS += -EL
|
|
# Same as above, prefer ELF but fall back to linux target if needed.
|
|
KBUILD_LDFLAGS += -EL $(call ld-option, -maarch64elf, -maarch64linux)
|
|
UTS_MACHINE := aarch64
|
|
endif
|
|
|
|
CHECKFLAGS += -D__aarch64__
|
|
|
|
ifeq ($(CONFIG_ARM64_MODULE_PLTS),y)
|
|
KBUILD_LDS_MODULE += $(srctree)/arch/arm64/kernel/module.lds
|
|
endif
|
|
|
|
ifeq ($(CONFIG_DYNAMIC_FTRACE_WITH_REGS),y)
|
|
KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
|
|
CC_FLAGS_FTRACE := -fpatchable-function-entry=2
|
|
endif
|
|
|
|
# Default value
|
|
head-y := arch/arm64/kernel/head.o
|
|
|
|
# The byte offset of the kernel image in RAM from the start of RAM.
|
|
ifeq ($(CONFIG_ARM64_RANDOMIZE_TEXT_OFFSET), y)
|
|
TEXT_OFFSET := $(shell awk "BEGIN {srand(); printf \"0x%06x\n\", \
|
|
int(2 * 1024 * 1024 / (2 ^ $(CONFIG_ARM64_PAGE_SHIFT)) * \
|
|
rand()) * (2 ^ $(CONFIG_ARM64_PAGE_SHIFT))}")
|
|
else
|
|
TEXT_OFFSET := 0x00080000
|
|
endif
|
|
|
|
ifeq ($(CONFIG_KASAN_SW_TAGS), y)
|
|
KASAN_SHADOW_SCALE_SHIFT := 4
|
|
else
|
|
KASAN_SHADOW_SCALE_SHIFT := 3
|
|
endif
|
|
|
|
KBUILD_CFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
|
|
KBUILD_CPPFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
|
|
KBUILD_AFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
|
|
|
|
export TEXT_OFFSET GZFLAGS
|
|
|
|
core-y += arch/arm64/
|
|
libs-y := arch/arm64/lib/ $(libs-y)
|
|
core-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
|
|
|
|
# Default target when executing plain make
|
|
boot := arch/arm64/boot
|
|
KBUILD_IMAGE := $(boot)/Image.gz
|
|
|
|
all: Image.gz
|
|
|
|
|
|
Image: vmlinux
|
|
$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
|
|
|
|
Image.%: Image
|
|
$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
|
|
|
|
zinstall install:
|
|
$(Q)$(MAKE) $(build)=$(boot) $@
|
|
|
|
PHONY += vdso_install
|
|
vdso_install:
|
|
$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso $@
|
|
|
|
# We use MRPROPER_FILES and CLEAN_FILES now
|
|
archclean:
|
|
$(Q)$(MAKE) $(clean)=$(boot)
|
|
|
|
ifeq ($(KBUILD_EXTMOD),)
|
|
# We need to generate vdso-offsets.h before compiling certain files in kernel/.
|
|
# In order to do that, we should use the archprepare target, but we can't since
|
|
# asm-offsets.h is included in some files used to generate vdso-offsets.h, and
|
|
# asm-offsets.h is built in prepare0, for which archprepare is a dependency.
|
|
# Therefore we need to generate the header after prepare0 has been made, hence
|
|
# this hack.
|
|
prepare: vdso_prepare
|
|
vdso_prepare: prepare0
|
|
$(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso include/generated/vdso-offsets.h
|
|
$(if $(CONFIG_COMPAT_VDSO),$(Q)$(MAKE) \
|
|
$(build)=arch/arm64/kernel/vdso32 \
|
|
include/generated/vdso32-offsets.h)
|
|
endif
|
|
|
|
define archhelp
|
|
echo '* Image.gz - Compressed kernel image (arch/$(ARCH)/boot/Image.gz)'
|
|
echo ' Image - Uncompressed kernel image (arch/$(ARCH)/boot/Image)'
|
|
echo ' install - Install uncompressed kernel'
|
|
echo ' zinstall - Install compressed kernel'
|
|
echo ' Install using (your) ~/bin/installkernel or'
|
|
echo ' (distribution) /sbin/installkernel or'
|
|
echo ' install to $$(INSTALL_PATH) and run lilo'
|
|
endef
|