Commit 7984eaba authored by Tiezhu Yang's avatar Tiezhu Yang
Browse files

LoongArch: Add ORC stack unwinder support 

mainline inclusion
from mainline-v6.9
commit cb8a2ef0848ca80d67d6d56e2df757cfdf6b3355
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/IB3IRE

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cb8a2ef0848ca80d67d6d56e2df757cfdf6b3355



---------------------------------------------------------------------------

The kernel CONFIG_UNWINDER_ORC option enables the ORC unwinder, which is
similar in concept to a DWARF unwinder. The difference is that the format
of the ORC data is much simpler than DWARF, which in turn allows the ORC
unwinder to be much simpler and faster.

The ORC data consists of unwind tables which are generated by objtool.
After analyzing all the code paths of a .o file, it determines information
about the stack state at each instruction address in the file and outputs
that information to the .orc_unwind and .orc_unwind_ip sections.

The per-object ORC sections are combined at link time and are sorted and
post-processed at boot time. The unwinder uses the resulting data to
correlate instruction addresses with their stack states at run time.

Most of the logic are similar with x86, in order to get ra info before ra
is saved into stack, add ra_reg and ra_offset into orc_entry. At the same
time, modify some arch-specific code to silence the objtool warnings.

Co-developed-by: default avatarJinyang He <hejinyang@loongson.cn>
Signed-off-by: default avatarJinyang He <hejinyang@loongson.cn>
Co-developed-by: default avatarYouling Tang <tangyouling@loongson.cn>
Signed-off-by: default avatarYouling Tang <tangyouling@loongson.cn>
Signed-off-by: default avatarTiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 8c6f1e77

arch/loongarch/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -137,6 +137,7 @@ config LOONGARCH 
	select HAVE_KVM

	select HAVE_MOD_ARCH_SPECIFIC

	select HAVE_NMI

	select HAVE_OBJTOOL if AS_HAS_EXPLICIT_RELOCS

	select HAVE_PCI

	select HAVE_PERF_EVENTS

	select HAVE_PERF_REGS
@@ -147,6 +148,7 @@ config LOONGARCH 
	select HAVE_SAMPLE_FTRACE_DIRECT

	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI

	select HAVE_SETUP_PER_CPU_AREA if NUMA

	select HAVE_STACK_VALIDATION if HAVE_OBJTOOL

	select HAVE_STACKPROTECTOR

	select ARCH_HAS_PHYS_TO_DMA

	select HAVE_SYSCALL_TRACEPOINTS

arch/loongarch/Kconfig.debug

+11 −0
Original line number Diff line number Diff line
@@ -26,4 +26,15 @@ config UNWINDER_PROLOGUE 
	  Some of the addresses it reports may be incorrect (but better than the

	  Guess unwinder).



config UNWINDER_ORC

	bool "ORC unwinder"

	select OBJTOOL

	help

	  This option enables the ORC (Oops Rewind Capability) unwinder for

	  unwinding kernel stack traces.  It uses a custom data format which is

	  a simplified version of the DWARF Call Frame Information standard.



	  Enabling this option will increase the kernel's runtime memory usage

	  by roughly 2-4MB, depending on your kernel config.



endchoice

arch/loongarch/Makefile

+21 −2
Original line number Diff line number Diff line
@@ -25,6 +25,18 @@ endif 
32bit-emul		= elf32loongarch

64bit-emul		= elf64loongarch



ifdef CONFIG_UNWINDER_ORC

orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h

orc_hash_sh := $(srctree)/scripts/orc_hash.sh

targets += $(orc_hash_h)

quiet_cmd_orc_hash = GEN     $@

      cmd_orc_hash = mkdir -p $(dir $@); \

		     $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@

$(orc_hash_h): $(srctree)/arch/loongarch/include/asm/orc_types.h $(orc_hash_sh) FORCE

	$(call if_changed,orc_hash)

archprepare: $(orc_hash_h)

endif



ifdef CONFIG_DYNAMIC_FTRACE

KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY

CC_FLAGS_FTRACE := -fpatchable-function-entry=2
@@ -68,8 +80,6 @@ LDFLAGS_vmlinux += -static -n -nostdlib 
ifdef CONFIG_AS_HAS_EXPLICIT_RELOCS

cflags-y			+= $(call cc-option,-mexplicit-relocs)

KBUILD_CFLAGS_KERNEL		+= $(call cc-option,-mdirect-extern-access)

KBUILD_AFLAGS_MODULE		+= $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)

KBUILD_CFLAGS_MODULE		+= $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)

else

cflags-y			+= $(call cc-option,-mno-explicit-relocs)

KBUILD_AFLAGS_KERNEL		+= -Wa,-mla-global-with-pcrel
@@ -78,6 +88,15 @@ KBUILD_AFLAGS_MODULE += -Wa,-mla-global-with-abs 
KBUILD_CFLAGS_MODULE		+= -fplt -Wa,-mla-global-with-abs,-mla-local-with-abs

endif



KBUILD_AFLAGS			+= $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)

KBUILD_CFLAGS			+= $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)

KBUILD_AFLAGS			+= $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)

KBUILD_CFLAGS			+= $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)



ifdef CONFIG_OBJTOOL

KBUILD_CFLAGS			+= -fno-jump-tables

endif



ifeq ($(CONFIG_RELOCATABLE),y)

KBUILD_CFLAGS_KERNEL		+= -fPIE

LDFLAGS_vmlinux			+= -static -pie --no-dynamic-linker -z notext $(call ld-option, --apply-dynamic-relocs)

arch/loongarch/include/asm/Kbuild

+2 −0
Original line number Diff line number Diff line 
# SPDX-License-Identifier: GPL-2.0

generated-y += orc_hash.h



generic-y += dma-contiguous.h

generic-y += mcs_spinlock.h

generic-y += parport.h

arch/loongarch/include/asm/bug.h

+1 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ 
do {								\

	instrumentation_begin();				\

	__BUG_FLAGS(BUGFLAG_WARNING|(flags));			\

	annotate_reachable();					\

	instrumentation_end();					\

} while (0)