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Miller" Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260918_154206_990022_99A98ACE X-CRM114-Status: GOOD ( 21.16 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org To generate a .sframe section, build with -Wa,--gsframe-3 flags. Also, add unwind-table options to ensure the necessary CFI directives are emitted by the compiler, but discard .eh_frame unless CONFIG_UNWIND_TABLES is explicitly enabled. This will be used for in-kernel reliable stacktrace in cases where the frame pointer alone is insufficient. Currently, the sframe format only supports arm64, x86_64 and s390x architectures. Co-developed-by: Weinan Liu Signed-off-by: Weinan Liu Reviewed-by: Prasanna Kumar T S M Reviewed-by: Jens Remus Signed-off-by: Dylan Hatch --- Changes since v6: - Moved to beginning of series - Squashed in AS_SFRAME, AS_SFRAME3, and UNWIND_SFRAME_LOOKUP config definitions. - Squashed in STACK UNWINDING change in MAINTAINERS file. - Dropped SFRAME_REG_SP / SFRAME_REG_FP definitions. - Added -fasynchronous-unwind-tables so CFI directives are emitted by compiler. - Discard .eh_frame sections when CONFIG_UNWIND_TABLES is not set. --- MAINTAINERS | 3 ++- Makefile | 8 ++++++++ arch/Kconfig | 31 +++++++++++++++++++++++++++++ arch/arm64/Kconfig | 1 + arch/arm64/Makefile | 2 +- arch/arm64/include/asm/module.lds.h | 2 ++ arch/arm64/kernel/vdso/Makefile | 2 +- arch/arm64/kernel/vmlinux.lds.S | 12 +++++++++++ include/asm-generic/sections.h | 4 ++++ include/asm-generic/vmlinux.lds.h | 15 ++++++++++++++ 10 files changed, 77 insertions(+), 3 deletions(-) diff --git a/MAINTAINERS b/MAINTAINERS index c2414447892c2..6c1c95979e437 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -28514,10 +28514,11 @@ F: Documentation/driver-api/uio-howto.rst F: drivers/uio/ F: include/linux/uio_driver.h -USERSPACE STACK UNWINDING +STACK UNWINDING M: Josh Poimboeuf M: Steven Rostedt S: Maintained +F: arch/*/include/asm/unwind_sframe.h F: include/linux/unwind*.h F: kernel/unwind/ diff --git a/Makefile b/Makefile index 0f1b80100b479..5ed4a59e71aac 100644 --- a/Makefile +++ b/Makefile @@ -1197,6 +1197,14 @@ CFLAGS_GCOV += $(call try-run,\ endif export CFLAGS_GCOV +# build with sframe table +ifdef CONFIG_HAVE_UNWIND_KERNEL_SFRAME +CC_FLAGS_SFRAME := -Wa,--gsframe-3 +KBUILD_CFLAGS += $(CC_FLAGS_SFRAME) +KBUILD_AFLAGS += $(CC_FLAGS_SFRAME) +export CC_FLAGS_SFRAME +endif + # change __FILE__ to the relative path to the source directory ifdef building_out_of_srctree KBUILD_CPPFLAGS += -fmacro-prefix-map=$(srcroot)/= diff --git a/arch/Kconfig b/arch/Kconfig index 45c6577723623..cc59a5da80915 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -507,6 +507,37 @@ config HAVE_UNWIND_USER_FP bool select UNWIND_USER +config AS_SFRAME + bool + +config AS_SFRAME3 + def_bool $(as-instr,.cfi_startproc\n.cfi_endproc,-Wa$(comma)--gsframe-3) + select AS_SFRAME + +config UNWIND_SFRAME_LOOKUP + bool + +config ARCH_SUPPORTS_UNWIND_KERNEL_SFRAME + bool + help + An architecture can select this if it enables the SFrame (Simple + Frame) unwinder for unwinding kernel stack traces. It uses an unwind + table that is directly generated by the toolchain based on DWARF CFI + information. + +config HAVE_UNWIND_KERNEL_SFRAME + bool "Sframe unwinder" + depends on AS_SFRAME3 + depends on 64BIT + depends on ARCH_SUPPORTS_UNWIND_KERNEL_SFRAME + select UNWIND_SFRAME_LOOKUP + help + This option enables the SFrame (Simple Frame) unwinder for unwinding + kernel stack traces. It uses an unwind table that is directly + generated by the toolchain based on DWARF CFI information. In + practice, this can provide more reliable stacktrace results than + unwinding with frame pointers alone. + config HAVE_PERF_REGS bool help diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index b5a51b0ef9440..041de63a659d1 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -87,6 +87,7 @@ config ARM64 select ARCH_SUPPORTS_SCHED_SMT select ARCH_SUPPORTS_SCHED_CLUSTER select ARCH_SUPPORTS_SCHED_MC + select ARCH_SUPPORTS_UNWIND_KERNEL_SFRAME select ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT select ARCH_WANT_DEFAULT_BPF_JIT diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 6b005c8fef706..ae1c23579ad2f 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -55,7 +55,7 @@ KBUILD_CFLAGS += $(call cc-option,-mabi=lp64) KBUILD_AFLAGS += $(call cc-option,-mabi=lp64) # Avoid generating .eh_frame* sections. -ifneq ($(CONFIG_UNWIND_TABLES),y) +ifeq ($(filter y, $(CONFIG_UNWIND_TABLES) $(CONFIG_HAVE_UNWIND_KERNEL_SFRAME)),) KBUILD_CFLAGS += -fno-asynchronous-unwind-tables -fno-unwind-tables KBUILD_AFLAGS += -fno-asynchronous-unwind-tables -fno-unwind-tables KBUILD_RUSTFLAGS += -Cforce-unwind-tables=n diff --git a/arch/arm64/include/asm/module.lds.h b/arch/arm64/include/asm/module.lds.h index 603f92a8a73ed..034cb635e8bcc 100644 --- a/arch/arm64/include/asm/module.lds.h +++ b/arch/arm64/include/asm/module.lds.h @@ -10,5 +10,7 @@ SECTIONS { * put it into the .init allocation. */ .init.eh_frame 0 : { *(.eh_frame) } +#elif defined(CONFIG_HAVE_UNWIND_KERNEL_SFRAME) + /DISCARD/ : { *(.eh_frame) } #endif } diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index 7dec05dd33b70..c60ef921956fb 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -38,7 +38,7 @@ ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO CC_FLAGS_REMOVE_VDSO := $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \ $(RANDSTRUCT_CFLAGS) $(KSTACK_ERASE_CFLAGS) \ $(GCC_PLUGINS_CFLAGS) \ - $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \ + $(CC_FLAGS_LTO) $(CC_FLAGS_CFI) $(CC_FLAGS_SFRAME) \ -Wmissing-prototypes -Wmissing-declarations CC_FLAGS_ADD_VDSO := -O2 -mcmodel=tiny -fasynchronous-unwind-tables diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index af1d720209764..eb1f54829503c 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -145,14 +145,25 @@ jiffies = jiffies_64; #endif #ifdef CONFIG_UNWIND_TABLES + #define UNWIND_DATA_SECTIONS \ .eh_frame : { \ __pi___eh_frame_start = .; \ *(.eh_frame) \ __pi___eh_frame_end = .; \ } +#define SFRAME_DISCARDS + +#elif defined(CONFIG_HAVE_UNWIND_KERNEL_SFRAME) + +#define UNWIND_DATA_SECTIONS +#define SFRAME_DISCARDS *(.eh_frame) + #else + #define UNWIND_DATA_SECTIONS +#define SFRAME_DISCARDS + #endif /* @@ -184,6 +195,7 @@ SECTIONS *(.interp .dynamic) *(.dynsym .dynstr .hash .gnu.hash) *(.ARM.attributes) + SFRAME_DISCARDS } . = KIMAGE_VADDR; diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h index 0755bc39b0d80..336d27011a580 100644 --- a/include/asm-generic/sections.h +++ b/include/asm-generic/sections.h @@ -31,6 +31,7 @@ * __irqentry_text_start, __irqentry_text_end * __softirqentry_text_start, __softirqentry_text_end * __start_opd, __end_opd + * __start_sframe, __end_sframe */ extern char _text[], _stext[], _etext[]; extern char _data[], _sdata[], _edata[]; @@ -53,6 +54,9 @@ extern char __ctors_start[], __ctors_end[]; /* Start and end of .opd section - used for function descriptors. */ extern char __start_opd[], __end_opd[]; +/* Start and end of .sframe section - used for stack unwinding. */ +extern char __start_sframe[], __end_sframe[]; + /* Start and end of instrumentation protected text section */ extern char __noinstr_text_start[], __noinstr_text_end[]; diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index b2988aa12f664..278f5764d990d 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -491,6 +491,8 @@ *(.rodata1) \ } \ \ + SFRAME \ + \ /* PCI quirks */ \ .pci_fixup : AT(ADDR(.pci_fixup) - LOAD_OFFSET) { \ BOUNDED_SECTION_PRE_LABEL(.pci_fixup_early, _pci_fixups_early, __start, __end) \ @@ -912,6 +914,19 @@ #define TRACEDATA #endif +#ifdef CONFIG_HAVE_UNWIND_KERNEL_SFRAME +#define SFRAME \ + /* sframe */ \ + .sframe : AT(ADDR(.sframe) - LOAD_OFFSET) { \ + __start_sframe = .; \ + KEEP(*(.sframe)) \ + KEEP(*(.init.sframe)) \ + __end_sframe = .; \ + } +#else +#define SFRAME +#endif + #ifdef CONFIG_PRINTK_INDEX #define PRINTK_INDEX \ .printk_index : AT(ADDR(.printk_index) - LOAD_OFFSET) { \ -- 2.55.0.1082.g2b9226bbc0-goog