Add sframe table to mod_arch_specific and support sframe PC lookups when an .sframe section can be found on incoming modules. SFRAME_F_FDE_SORTED is not set for module .sframe, so FDES are sorted right after the sframe header is read.
Signed-off-by: Weinan Liu <[email protected]> Suggested-by: Jens Remus <[email protected]> Reviewed-by: Jens Remus <[email protected]> Signed-off-by: Dylan Hatch <[email protected]> --- arch/arm64/include/asm/module.h | 6 +++ arch/arm64/kernel/module.c | 8 +++ include/linux/sframe.h | 3 ++ kernel/unwind/sframe.c | 90 +++++++++++++++++++++++++++++++-- 4 files changed, 104 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/module.h b/arch/arm64/include/asm/module.h index fb9b88eebeb1..07f309c51eee 100644 --- a/arch/arm64/include/asm/module.h +++ b/arch/arm64/include/asm/module.h @@ -6,6 +6,7 @@ #define __ASM_MODULE_H #include <asm-generic/module.h> +#include <linux/sframe.h> struct mod_plt_sec { int plt_shndx; @@ -17,6 +18,11 @@ struct mod_arch_specific { struct mod_plt_sec core; struct mod_plt_sec init; +#ifdef CONFIG_HAVE_UNWIND_KERNEL_SFRAME + struct sframe_section sframe_sec; + bool sframe_init; +#endif + /* for CONFIG_DYNAMIC_FTRACE */ struct plt_entry *ftrace_trampolines; struct plt_entry *init_ftrace_trampolines; diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c index 24adb581af0e..427f187e9531 100644 --- a/arch/arm64/kernel/module.c +++ b/arch/arm64/kernel/module.c @@ -18,6 +18,7 @@ #include <linux/moduleloader.h> #include <linux/random.h> #include <linux/scs.h> +#include <linux/sframe.h> #include <asm/alternative.h> #include <asm/insn.h> @@ -515,5 +516,12 @@ int module_finalize(const Elf_Ehdr *hdr, } } + s = find_section(hdr, sechdrs, ".sframe"); + if (s) { + struct module_memory *t = &me->mem[MOD_TEXT]; + + sframe_module_init(me, (void *)s->sh_addr, s->sh_size, + t->base, t->size); + } return module_init_ftrace_plt(hdr, sechdrs, me); } diff --git a/include/linux/sframe.h b/include/linux/sframe.h index 5b7341b61a7c..27f5a66190af 100644 --- a/include/linux/sframe.h +++ b/include/linux/sframe.h @@ -28,6 +28,7 @@ struct sframe_section { unsigned long fres_start; unsigned long fres_end; unsigned int num_fdes; + bool fdes_sorted; signed char ra_off; signed char fp_off; @@ -80,6 +81,8 @@ extern int sframe_find_kernel(unsigned long ip, struct unwind_frame *frame); #else static inline void __init init_sframe_table(void) {} +static inline void sframe_module_init(struct module *mod, void *sframe, size_t sframe_size, + void *text, size_t text_size) {} #endif /* CONFIG_HAVE_UNWIND_KERNEL_SFRAME */ diff --git a/kernel/unwind/sframe.c b/kernel/unwind/sframe.c index c8ec1e9989fc..dfa013450705 100644 --- a/kernel/unwind/sframe.c +++ b/kernel/unwind/sframe.c @@ -12,6 +12,7 @@ #include <linux/mm.h> #include <linux/string_helpers.h> #include <linux/sframe.h> +#include <linux/sort.h> #include <linux/syscalls.h> #include <linux/unwind_types.h> #include <asm/unwind_sframe.h> @@ -186,6 +187,9 @@ static __always_inline int __find_fde(struct sframe_section *sec, struct sframe_fde_v3 *first, *low, *high, *found = NULL; int ret; + if (!sec->fdes_sorted) + return -EINVAL; + first = (void *)sec->fdes_start; low = first; high = first + sec->num_fdes - 1; @@ -740,7 +744,6 @@ static int sframe_read_header(struct sframe_section *sec) if (shdr.preamble.magic != SFRAME_MAGIC || shdr.preamble.version != SFRAME_VERSION_3 || - !(shdr.preamble.flags & SFRAME_F_FDE_SORTED) || !(shdr.preamble.flags & SFRAME_F_FDE_FUNC_START_PCREL) || shdr.auxhdr_len) { dbg_sec("bad/unsupported sframe header\n"); @@ -770,6 +773,7 @@ static int sframe_read_header(struct sframe_section *sec) return -EINVAL; } + sec->fdes_sorted = shdr.preamble.flags & SFRAME_F_FDE_SORTED; sec->num_fdes = num_fdes; sec->fdes_start = fdes_start; sec->fres_start = fres_start; @@ -984,10 +988,27 @@ SYSCALL_DEFINE5(stacktrace_setup, int, op, unsigned long, addr_start, int sframe_find_kernel(unsigned long ip, struct unwind_frame *frame) { - if (!frame || !sframe_init) + struct sframe_section *sec; + + if (!frame) return -EINVAL; - return __sframe_find(&kernel_sfsec, ip, frame); + if (is_ksym_addr(ip)) { + if (!sframe_init) + return -EINVAL; + + sec = &kernel_sfsec; + } else { + struct module *mod; + + mod = __module_address(ip); + if (!mod || !mod->arch.sframe_init) + return -EINVAL; + + sec = &mod->arch.sframe_sec; + } + + return __sframe_find(sec, ip, frame); } void __init init_sframe_table(void) @@ -1004,4 +1025,67 @@ void __init init_sframe_table(void) sframe_init = true; } +static int sframe_sort_cmp_fde(const void *a, const void *b) +{ + const struct sframe_fde_v3 *fde_a = a, *fde_b = b; + unsigned long func_start_a, func_start_b; + + func_start_a = (unsigned long)fde_a + fde_a->func_start_off; + func_start_b = (unsigned long)fde_b + fde_b->func_start_off; + + return cmp_int(func_start_a, func_start_b); +} + +static void sframe_sort_swap_fde(void *a, void *b, int size) +{ + struct sframe_fde_v3 *fde_a = a, *fde_b = b; + struct sframe_fde_v3 temp; + long delta; + + /* Swap potentially unaligned FDE */ + memcpy(&temp, fde_a, sizeof(struct sframe_fde_v3)); + memcpy(fde_a, fde_b, sizeof(struct sframe_fde_v3)); + memcpy(fde_b, &temp, sizeof(struct sframe_fde_v3)); + + /* Adjust FDE function start offset from FDE */ + delta = (long)((unsigned long)fde_b - (unsigned long)fde_a); + fde_a->func_start_off += delta; + fde_b->func_start_off -= delta; +} + +static int sframe_sort_fdes(struct sframe_section *sec) +{ + void *fdes = (void *)sec->fdes_start; + size_t num_fdes = sec->num_fdes; + + if (sec->sec_type != SFRAME_KERNEL) + return -EINVAL; + if (sec->fdes_sorted) + return 0; + + sort(fdes, num_fdes, sizeof(struct sframe_fde_v3), + sframe_sort_cmp_fde, sframe_sort_swap_fde); + sec->fdes_sorted = true; + return 0; +} + +void sframe_module_init(struct module *mod, void *sframe, size_t sframe_size, + void *text, size_t text_size) +{ + struct sframe_section *sec = &mod->arch.sframe_sec; + + sec->sec_type = SFRAME_KERNEL; + sec->sframe_start = (unsigned long)sframe; + sec->sframe_end = (unsigned long)sframe + sframe_size; + sec->text_start = (unsigned long)text; + sec->text_end = (unsigned long)text + text_size; + + if (WARN_ON(sframe_read_header(sec))) + return; + if (WARN_ON(sframe_sort_fdes(sec))) + return; + + mod->arch.sframe_init = true; +} + #endif /* CONFIG_HAVE_UNWIND_KERNEL_SFRAME */ -- 2.54.0.563.g4f69b47b94-goog
