diff --git a/arch/sh/include/asm/dwarf.h b/arch/sh/include/asm/dwarf.h index c367ed3373c5..aacdc746d07c 100644 --- a/arch/sh/include/asm/dwarf.h +++ b/arch/sh/include/asm/dwarf.h @@ -241,6 +241,12 @@ struct dwarf_cie { unsigned long flags; #define DWARF_CIE_Z_AUGMENTATION (1 << 0) + + /* + * 'mod' will be non-NULL if this CIE came from a module's + * .eh_frame section. + */ + struct module *mod; }; /** @@ -255,6 +261,12 @@ struct dwarf_fde { unsigned char *instructions; unsigned char *end; struct list_head link; + + /* + * 'mod' will be non-NULL if this FDE came from a module's + * .eh_frame section. + */ + struct module *mod; }; /** @@ -364,6 +376,9 @@ static inline unsigned int DW_CFA_operand(unsigned long insn) extern struct dwarf_frame *dwarf_unwind_stack(unsigned long, struct dwarf_frame *); +extern int dwarf_parse_section(char *, char *, struct module *); +extern void dwarf_module_unload(struct module *); + #endif /* !__ASSEMBLY__ */ #define CFI_STARTPROC .cfi_startproc diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c index 577302f31e6a..981315c6d656 100644 --- a/arch/sh/kernel/dwarf.c +++ b/arch/sh/kernel/dwarf.c @@ -655,7 +655,7 @@ bail: } static int dwarf_parse_cie(void *entry, void *p, unsigned long len, - unsigned char *end) + unsigned char *end, struct module *mod) { struct dwarf_cie *cie; unsigned long flags; @@ -751,6 +751,8 @@ static int dwarf_parse_cie(void *entry, void *p, unsigned long len, cie->initial_instructions = p; cie->instructions_end = end; + cie->mod = mod; + /* Add to list */ spin_lock_irqsave(&dwarf_cie_lock, flags); list_add_tail(&cie->link, &dwarf_cie_list); @@ -761,7 +763,7 @@ static int dwarf_parse_cie(void *entry, void *p, unsigned long len, static int dwarf_parse_fde(void *entry, u32 entry_type, void *start, unsigned long len, - unsigned char *end) + unsigned char *end, struct module *mod) { struct dwarf_fde *fde; struct dwarf_cie *cie; @@ -810,6 +812,8 @@ static int dwarf_parse_fde(void *entry, u32 entry_type, fde->instructions = p; fde->end = end; + fde->mod = mod; + /* Add to list. */ spin_lock_irqsave(&dwarf_fde_lock, flags); list_add_tail(&fde->link, &dwarf_fde_list); @@ -874,6 +878,124 @@ static void dwarf_unwinder_cleanup(void) kmem_cache_destroy(dwarf_frame_cachep); } +/** + * dwarf_parse_section - parse DWARF section + * @eh_frame_start: start address of the .eh_frame section + * @eh_frame_end: end address of the .eh_frame section + * @mod: the kernel module containing the .eh_frame section + * + * Parse the information in a .eh_frame section. + */ +int dwarf_parse_section(char *eh_frame_start, char *eh_frame_end, + struct module *mod) +{ + u32 entry_type; + void *p, *entry; + int count, err; + unsigned long len; + unsigned int c_entries, f_entries; + unsigned char *end; + + c_entries = 0; + f_entries = 0; + entry = eh_frame_start; + + while ((char *)entry < eh_frame_end) { + p = entry; + + count = dwarf_entry_len(p, &len); + if (count == 0) { + /* + * We read a bogus length field value. There is + * nothing we can do here apart from disabling + * the DWARF unwinder. We can't even skip this + * entry and move to the next one because 'len' + * tells us where our next entry is. + */ + err = -EINVAL; + goto out; + } else + p += count; + + /* initial length does not include itself */ + end = p + len; + + entry_type = get_unaligned((u32 *)p); + p += 4; + + if (entry_type == DW_EH_FRAME_CIE) { + err = dwarf_parse_cie(entry, p, len, end, mod); + if (err < 0) + goto out; + else + c_entries++; + } else { + err = dwarf_parse_fde(entry, entry_type, p, len, + end, mod); + if (err < 0) + goto out; + else + f_entries++; + } + + entry = (char *)entry + len + 4; + } + + printk(KERN_INFO "DWARF unwinder initialised: read %u CIEs, %u FDEs\n", + c_entries, f_entries); + + return 0; + +out: + return err; +} + +/** + * dwarf_module_unload - remove FDE/CIEs associated with @mod + * @mod: the module that is being unloaded + * + * Remove any FDEs and CIEs from the global lists that came from + * @mod's .eh_frame section because @mod is being unloaded. + */ +void dwarf_module_unload(struct module *mod) +{ + struct dwarf_fde *fde; + struct dwarf_cie *cie; + unsigned long flags; + + spin_lock_irqsave(&dwarf_cie_lock, flags); + +again_cie: + list_for_each_entry(cie, &dwarf_cie_list, link) { + if (cie->mod == mod) + break; + } + + if (&cie->link != &dwarf_cie_list) { + list_del(&cie->link); + kfree(cie); + goto again_cie; + } + + spin_unlock_irqrestore(&dwarf_cie_lock, flags); + + spin_lock_irqsave(&dwarf_fde_lock, flags); + +again_fde: + list_for_each_entry(fde, &dwarf_fde_list, link) { + if (fde->mod == mod) + break; + } + + if (&fde->link != &dwarf_fde_list) { + list_del(&fde->link); + kfree(fde); + goto again_fde; + } + + spin_unlock_irqrestore(&dwarf_fde_lock, flags); +} + /** * dwarf_unwinder_init - initialise the dwarf unwinder * @@ -885,19 +1007,10 @@ static void dwarf_unwinder_cleanup(void) */ static int __init dwarf_unwinder_init(void) { - u32 entry_type; - void *p, *entry; - int count, err; - unsigned long len; - unsigned int c_entries, f_entries; - unsigned char *end; + int err; INIT_LIST_HEAD(&dwarf_cie_list); INIT_LIST_HEAD(&dwarf_fde_list); - c_entries = 0; - f_entries = 0; - entry = &__start_eh_frame; - dwarf_frame_cachep = kmem_cache_create("dwarf_frames", sizeof(struct dwarf_frame), 0, SLAB_PANIC, NULL); dwarf_reg_cachep = kmem_cache_create("dwarf_regs", @@ -913,47 +1026,9 @@ static int __init dwarf_unwinder_init(void) mempool_free_slab, dwarf_reg_cachep); - while ((char *)entry < __stop_eh_frame) { - p = entry; - - count = dwarf_entry_len(p, &len); - if (count == 0) { - /* - * We read a bogus length field value. There is - * nothing we can do here apart from disabling - * the DWARF unwinder. We can't even skip this - * entry and move to the next one because 'len' - * tells us where our next entry is. - */ - goto out; - } else - p += count; - - /* initial length does not include itself */ - end = p + len; - - entry_type = get_unaligned((u32 *)p); - p += 4; - - if (entry_type == DW_EH_FRAME_CIE) { - err = dwarf_parse_cie(entry, p, len, end); - if (err < 0) - goto out; - else - c_entries++; - } else { - err = dwarf_parse_fde(entry, entry_type, p, len, end); - if (err < 0) - goto out; - else - f_entries++; - } - - entry = (char *)entry + len + 4; - } - - printk(KERN_INFO "DWARF unwinder initialised: read %u CIEs, %u FDEs\n", - c_entries, f_entries); + err = dwarf_parse_section(__start_eh_frame, __stop_eh_frame, NULL); + if (err) + goto out; err = unwinder_register(&dwarf_unwinder); if (err) diff --git a/arch/sh/kernel/module.c b/arch/sh/kernel/module.c index c2efdcde266f..d297a148d16c 100644 --- a/arch/sh/kernel/module.c +++ b/arch/sh/kernel/module.c @@ -32,6 +32,7 @@ #include #include #include +#include void *module_alloc(unsigned long size) { @@ -145,10 +146,41 @@ int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *me) { +#ifdef CONFIG_DWARF_UNWINDER + unsigned int i, err; + unsigned long start, end; + char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; + + start = end = 0; + + for (i = 1; i < hdr->e_shnum; i++) { + /* Alloc bit cleared means "ignore it." */ + if ((sechdrs[i].sh_flags & SHF_ALLOC) + && !strcmp(secstrings+sechdrs[i].sh_name, ".eh_frame")) { + start = sechdrs[i].sh_addr; + end = start + sechdrs[i].sh_size; + break; + } + } + + /* Did we find the .eh_frame section? */ + if (i != hdr->e_shnum) { + err = dwarf_parse_section((char *)start, (char *)end, me); + if (err) + printk(KERN_WARNING "%s: failed to parse DWARF info\n", + me->name); + } + +#endif /* CONFIG_DWARF_UNWINDER */ + return module_bug_finalize(hdr, sechdrs, me); } void module_arch_cleanup(struct module *mod) { module_bug_cleanup(mod); + +#ifdef CONFIG_DWARF_UNWINDER + dwarf_module_unload(mod); +#endif /* CONFIG_DWARF_UNWINDER */ }