On Tue 03 Nov 03:19 CST 2020, Siddharth Gupta wrote: > This change adds a new kind of core dump mechanism which instead of dumping > entire program segments of the firmware, dumps sections of the remoteproc > memory which are sufficient to allow debugging the firmware. This function > thus uses section headers instead of program headers during creation of the > core dump elf. > > Signed-off-by: Rishabh Bhatnagar <[email protected]>
Co-developed-by: Rishabh > Signed-off-by: Siddharth Gupta <[email protected]> > --- > drivers/remoteproc/remoteproc_coredump.c | 140 > ++++++++++++++++++++++++++++ > drivers/remoteproc/remoteproc_elf_helpers.h | 26 ++++++ > include/linux/remoteproc.h | 1 + > 3 files changed, 167 insertions(+) > > diff --git a/drivers/remoteproc/remoteproc_coredump.c > b/drivers/remoteproc/remoteproc_coredump.c > index 34530dc..a6c0099 100644 > --- a/drivers/remoteproc/remoteproc_coredump.c > +++ b/drivers/remoteproc/remoteproc_coredump.c > @@ -323,3 +323,143 @@ void rproc_coredump(struct rproc *rproc) > */ > wait_for_completion(&dump_state.dump_done); > } > + > +/** > + * rproc_minidump() - perform minidump > + * @rproc: rproc handle > + * > + * This function will generate an ELF header for the registered sections of > + * segments and create a devcoredump device associated with rproc. Based on > + * the coredump configuration this function will directly copy the segments > + * from device memory to userspace or copy segments from device memory to > + * a separate buffer, which can then be read by userspace. > + * The first approach avoids using extra vmalloc memory. But it will stall > + * recovery flow until dump is read by userspace. > + */ > +void rproc_minidump(struct rproc *rproc) Implementation wise I think this looks good now! But the name "minidump" isn't descriptive - nor is the "perform minidump". I think you should name this rproc_coredump_using_sections() > +{ > + struct rproc_dump_segment *segment; > + void *shdr; > + void *ehdr; > + size_t data_size; > + size_t strtbl_size = 0; > + size_t strtbl_index = 1; > + size_t offset; > + void *data; > + u8 class = rproc->elf_class; > + int shnum; > + struct rproc_coredump_state dump_state; > + unsigned int dump_conf = rproc->dump_conf; > + char *str_tbl = "STR_TBL"; > + > + if (list_empty(&rproc->dump_segments) || > + dump_conf == RPROC_COREDUMP_DISABLED) > + return; > + > + if (class == ELFCLASSNONE) { > + dev_err(&rproc->dev, "Elf class is not set\n"); > + return; > + } > + > + /* > + * We allocate two extra section headers. The first one is null. > + * Second section header is for the string table. Also space is > + * allocated for string table. > + */ > + data_size = elf_size_of_hdr(class) + 2 * elf_size_of_shdr(class); > + shnum = 2; > + > + /* the extra byte is for the null character at index 0 */ > + strtbl_size += strlen(str_tbl) + 2; > + > + list_for_each_entry(segment, &rproc->dump_segments, node) { > + data_size += elf_size_of_shdr(class); > + strtbl_size += strlen(segment->priv) + 1; > + if (dump_conf == RPROC_COREDUMP_ENABLED) > + data_size += segment->size; > + shnum++; > + } > + > + data_size += strtbl_size; > + > + data = vmalloc(data_size); > + if (!data) > + return; > + > + ehdr = data; > + memset(ehdr, 0, elf_size_of_hdr(class)); > + /* e_ident field is common for both elf32 and elf64 */ > + elf_hdr_init_ident(ehdr, class); > + > + elf_hdr_set_e_type(class, ehdr, ET_CORE); > + elf_hdr_set_e_machine(class, ehdr, rproc->elf_machine); > + elf_hdr_set_e_version(class, ehdr, EV_CURRENT); > + elf_hdr_set_e_entry(class, ehdr, rproc->bootaddr); > + elf_hdr_set_e_shoff(class, ehdr, elf_size_of_hdr(class)); > + elf_hdr_set_e_ehsize(class, ehdr, elf_size_of_hdr(class)); > + elf_hdr_set_e_shentsize(class, ehdr, elf_size_of_shdr(class)); > + elf_hdr_set_e_shnum(class, ehdr, shnum); > + elf_hdr_set_e_shstrndx(class, ehdr, 1); > + > + /* > + * The zeroth index of the section header is reserved and is rarely > used. > + * Set the section header as null (SHN_UNDEF) and move to the next one. > + */ > + shdr = data + elf_hdr_get_e_shoff(class, ehdr); > + memset(shdr, 0, elf_size_of_shdr(class)); > + shdr += elf_size_of_shdr(class); > + > + /* Initialize the string table. */ > + offset = elf_hdr_get_e_shoff(class, ehdr) + > + elf_size_of_shdr(class) * elf_hdr_get_e_shnum(class, ehdr); > + memset(data + offset, 0, strtbl_size); > + > + /* Fill in the string table section header. */ > + memset(shdr, 0, elf_size_of_shdr(class)); > + elf_shdr_set_sh_type(class, shdr, SHT_STRTAB); > + elf_shdr_set_sh_offset(class, shdr, offset); > + elf_shdr_set_sh_size(class, shdr, strtbl_size); > + elf_shdr_set_sh_entsize(class, shdr, 0); > + elf_shdr_set_sh_flags(class, shdr, 0); > + elf_shdr_set_sh_name(class, shdr, set_section_name(str_tbl, ehdr, > class, &strtbl_index)); > + offset += elf_shdr_get_sh_size(class, shdr); > + shdr += elf_size_of_shdr(class); > + > + list_for_each_entry(segment, &rproc->dump_segments, node) { > + memset(shdr, 0, elf_size_of_shdr(class)); > + elf_shdr_set_sh_type(class, shdr, SHT_PROGBITS); > + elf_shdr_set_sh_offset(class, shdr, offset); > + elf_shdr_set_sh_addr(class, shdr, segment->da); > + elf_shdr_set_sh_size(class, shdr, segment->size); > + elf_shdr_set_sh_entsize(class, shdr, 0); > + elf_shdr_set_sh_flags(class, shdr, SHF_WRITE); > + elf_shdr_set_sh_name(class, shdr, > + set_section_name(segment->priv, ehdr, > class, &strtbl_index)); > + > + /* No need to copy segments for inline dumps */ > + if (dump_conf == RPROC_COREDUMP_ENABLED) > + rproc_copy_segment(rproc, data + offset, segment, 0, > + segment->size); > + offset += elf_shdr_get_sh_size(class, shdr); > + shdr += elf_size_of_shdr(class); > + } > + > + if (dump_conf == RPROC_COREDUMP_ENABLED) { > + dev_coredumpv(&rproc->dev, data, data_size, GFP_KERNEL); > + return; > + } > + > + /* Initialize the dump state struct to be used by rproc_coredump_read */ > + dump_state.rproc = rproc; > + dump_state.header = data; > + init_completion(&dump_state.dump_done); > + > + dev_coredumpm(&rproc->dev, NULL, &dump_state, data_size, GFP_KERNEL, > + rproc_coredump_read, rproc_coredump_free); > + > + /* Wait until the dump is read and free is called. Data is freed > + * by devcoredump framework automatically after 5 minutes. > + */ > + wait_for_completion(&dump_state.dump_done); > +} > +EXPORT_SYMBOL(rproc_minidump); > diff --git a/drivers/remoteproc/remoteproc_elf_helpers.h > b/drivers/remoteproc/remoteproc_elf_helpers.h > index 4b6be7b..fa669ad 100644 > --- a/drivers/remoteproc/remoteproc_elf_helpers.h > +++ b/drivers/remoteproc/remoteproc_elf_helpers.h > @@ -65,6 +65,7 @@ ELF_GEN_FIELD_GET_SET(hdr, e_type, u16) > ELF_GEN_FIELD_GET_SET(hdr, e_version, u32) > ELF_GEN_FIELD_GET_SET(hdr, e_ehsize, u32) > ELF_GEN_FIELD_GET_SET(hdr, e_phentsize, u16) > +ELF_GEN_FIELD_GET_SET(hdr, e_shentsize, u16) > > ELF_GEN_FIELD_GET_SET(phdr, p_paddr, u64) > ELF_GEN_FIELD_GET_SET(phdr, p_vaddr, u64) > @@ -75,6 +76,9 @@ ELF_GEN_FIELD_GET_SET(phdr, p_offset, u64) > ELF_GEN_FIELD_GET_SET(phdr, p_flags, u32) > ELF_GEN_FIELD_GET_SET(phdr, p_align, u64) > > +ELF_GEN_FIELD_GET_SET(shdr, sh_type, u32) > +ELF_GEN_FIELD_GET_SET(shdr, sh_flags, u32) > +ELF_GEN_FIELD_GET_SET(shdr, sh_entsize, u16) > ELF_GEN_FIELD_GET_SET(shdr, sh_size, u64) > ELF_GEN_FIELD_GET_SET(shdr, sh_offset, u64) > ELF_GEN_FIELD_GET_SET(shdr, sh_name, u32) > @@ -93,4 +97,26 @@ ELF_STRUCT_SIZE(shdr) > ELF_STRUCT_SIZE(phdr) > ELF_STRUCT_SIZE(hdr) > > +static inline unsigned int set_section_name(const char *name, void *ehdr, u8 > class, size_t *index) I think set_section_name() is a rather generic name for a function living in a header file. So I think you should prefix this with "elf_". Also, doesn't this function just "adds strings to a string table", rather than "set a section name"? Is it elf_strtbl_add() ? Regards, Bjorn > +{ > + u16 shstrndx = elf_hdr_get_e_shstrndx(class, ehdr); > + void *shdr; > + char *strtab; > + size_t idx, ret; > + > + shdr = ehdr + elf_size_of_hdr(class) + shstrndx * > elf_size_of_shdr(class); > + strtab = ehdr + elf_shdr_get_sh_offset(class, shdr); > + idx = index ? *index : 0; > + if (!strtab || !name) > + return 0; > + > + ret = idx; > + strcpy((strtab + idx), name); > + idx += strlen(name) + 1; > + if (index) > + *index = idx; > + > + return ret; > +} > + > #endif /* REMOTEPROC_ELF_LOADER_H */ > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h > index a419878..844021e 100644 > --- a/include/linux/remoteproc.h > +++ b/include/linux/remoteproc.h > @@ -656,6 +656,7 @@ rproc_of_resm_mem_entry_init(struct device *dev, u32 > of_resm_idx, size_t len, > int rproc_boot(struct rproc *rproc); > void rproc_shutdown(struct rproc *rproc); > void rproc_report_crash(struct rproc *rproc, enum rproc_crash_type type); > +void rproc_minidump(struct rproc *rproc); > int rproc_coredump_add_segment(struct rproc *rproc, dma_addr_t da, size_t > size); > int rproc_coredump_add_custom_segment(struct rproc *rproc, > dma_addr_t da, size_t size, > -- > Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project >
