Build with -Wa,--gsframe-3 flags to generate a .sframe section. 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. Signed-off-by: Weinan Liu <[email protected]> Reviewed-by: Prasanna Kumar T S M <[email protected]> Reviewed-by: Jens Remus <[email protected]> Signed-off-by: Dylan Hatch <[email protected]> --- MAINTAINERS | 1 + Makefile | 8 ++++++++ arch/Kconfig | 21 +++++++++++++++++++++ arch/arm64/Kconfig | 1 + arch/arm64/include/asm/unwind_sframe.h | 8 ++++++++ arch/arm64/kernel/vdso/Makefile | 2 +- include/asm-generic/sections.h | 4 ++++ include/asm-generic/vmlinux.lds.h | 15 +++++++++++++++ 8 files changed, 59 insertions(+), 1 deletion(-) create mode 100644 arch/arm64/include/asm/unwind_sframe.h diff --git a/MAINTAINERS b/MAINTAINERS index cfc7dec88da4..a7d75f9cb5f4 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -27561,6 +27561,7 @@ STACK UNWINDING M: Josh Poimboeuf <[email protected]> M: Steven Rostedt <[email protected]> S: Maintained +F: arch/*/include/asm/unwind_sframe.h F: include/linux/sframe.h F: include/linux/unwind*.h F: kernel/unwind/ diff --git a/Makefile b/Makefile index 2b15f0b4a0cb..6c94a5257679 100644 --- a/Makefile +++ b/Makefile @@ -1110,6 +1110,14 @@ endif # Ensure compilers do not transform certain loops into calls to wcslen() KBUILD_CFLAGS += -fno-builtin-wcslen +# 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 d7caf2e245ce..8d27b3249e7a 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -520,6 +520,27 @@ config SFRAME_VALIDATION If unsure, say N. +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 unwind an 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 38dba5f7e4d2..f7ae8eaaadc4 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -112,6 +112,7 @@ 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/include/asm/unwind_sframe.h b/arch/arm64/include/asm/unwind_sframe.h new file mode 100644 index 000000000000..876412881196 --- /dev/null +++ b/arch/arm64/include/asm/unwind_sframe.h @@ -0,0 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_ARM64_UNWIND_SFRAME_H +#define _ASM_ARM64_UNWIND_SFRAME_H + +#define SFRAME_REG_SP 31 +#define SFRAME_REG_FP 29 + +#endif /* _ASM_ARM64_UNWIND_SFRAME_H */ diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index 7dec05dd33b7..c60ef921956f 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/include/asm-generic/sections.h b/include/asm-generic/sections.h index 0755bc39b0d8..336d27011a58 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 1e1580febe4b..090da633db92 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) \ @@ -911,6 +913,19 @@ #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) { \ -- 2.54.0.545.g6539524ca2-goog
