diff options
Diffstat (limited to 'arch/sh/kernel/dwarf.c')
| -rw-r--r-- | arch/sh/kernel/dwarf.c | 407 |
1 files changed, 323 insertions, 84 deletions
diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c index 03b3616c80a..67a049e75ec 100644 --- a/arch/sh/kernel/dwarf.c +++ b/arch/sh/kernel/dwarf.c @@ -20,6 +20,10 @@ #include <linux/list.h> #include <linux/mempool.h> #include <linux/mm.h> +#include <linux/elf.h> +#include <linux/ftrace.h> +#include <linux/module.h> +#include <linux/slab.h> #include <asm/dwarf.h> #include <asm/unwinder.h> #include <asm/sections.h> @@ -37,14 +41,16 @@ static mempool_t *dwarf_frame_pool; static struct kmem_cache *dwarf_reg_cachep; static mempool_t *dwarf_reg_pool; -static LIST_HEAD(dwarf_cie_list); +static struct rb_root cie_root; static DEFINE_SPINLOCK(dwarf_cie_lock); -static LIST_HEAD(dwarf_fde_list); +static struct rb_root fde_root; static DEFINE_SPINLOCK(dwarf_fde_lock); static struct dwarf_cie *cached_cie; +static unsigned int dwarf_unwinder_ready; + /** * dwarf_frame_alloc_reg - allocate memory for a DWARF register * @frame: the DWARF frame whose list of registers we insert on @@ -299,7 +305,8 @@ static inline int dwarf_entry_len(char *addr, unsigned long *len) */ static struct dwarf_cie *dwarf_lookup_cie(unsigned long cie_ptr) { - struct dwarf_cie *cie; + struct rb_node **rb_node = &cie_root.rb_node; + struct dwarf_cie *cie = NULL; unsigned long flags; spin_lock_irqsave(&dwarf_cie_lock, flags); @@ -313,16 +320,24 @@ static struct dwarf_cie *dwarf_lookup_cie(unsigned long cie_ptr) goto out; } - list_for_each_entry(cie, &dwarf_cie_list, link) { - if (cie->cie_pointer == cie_ptr) { - cached_cie = cie; - break; + while (*rb_node) { + struct dwarf_cie *cie_tmp; + + cie_tmp = rb_entry(*rb_node, struct dwarf_cie, node); + BUG_ON(!cie_tmp); + + if (cie_ptr == cie_tmp->cie_pointer) { + cie = cie_tmp; + cached_cie = cie_tmp; + goto out; + } else { + if (cie_ptr < cie_tmp->cie_pointer) + rb_node = &(*rb_node)->rb_left; + else + rb_node = &(*rb_node)->rb_right; } } - /* Couldn't find the entry in the list. */ - if (&cie->link == &dwarf_cie_list) - cie = NULL; out: spin_unlock_irqrestore(&dwarf_cie_lock, flags); return cie; @@ -334,25 +349,34 @@ out: */ struct dwarf_fde *dwarf_lookup_fde(unsigned long pc) { - struct dwarf_fde *fde; + struct rb_node **rb_node = &fde_root.rb_node; + struct dwarf_fde *fde = NULL; unsigned long flags; spin_lock_irqsave(&dwarf_fde_lock, flags); - list_for_each_entry(fde, &dwarf_fde_list, link) { - unsigned long start, end; + while (*rb_node) { + struct dwarf_fde *fde_tmp; + unsigned long tmp_start, tmp_end; - start = fde->initial_location; - end = fde->initial_location + fde->address_range; + fde_tmp = rb_entry(*rb_node, struct dwarf_fde, node); + BUG_ON(!fde_tmp); - if (pc >= start && pc < end) - break; - } + tmp_start = fde_tmp->initial_location; + tmp_end = fde_tmp->initial_location + fde_tmp->address_range; - /* Couldn't find the entry in the list. */ - if (&fde->link == &dwarf_fde_list) - fde = NULL; + if (pc < tmp_start) { + rb_node = &(*rb_node)->rb_left; + } else { + if (pc < tmp_end) { + fde = fde_tmp; + goto out; + } else + rb_node = &(*rb_node)->rb_right; + } + } +out: spin_unlock_irqrestore(&dwarf_fde_lock, flags); return fde; @@ -529,7 +553,20 @@ static int dwarf_cfa_execute_insns(unsigned char *insn_start, } /** - * dwarf_unwind_stack - recursively unwind the stack + * dwarf_free_frame - free the memory allocated for @frame + * @frame: the frame to free + */ +void dwarf_free_frame(struct dwarf_frame *frame) +{ + dwarf_frame_free_regs(frame); + mempool_free(frame, dwarf_frame_pool); +} + +extern void ret_from_irq(void); + +/** + * dwarf_unwind_stack - unwind the stack + * * @pc: address of the function to unwind * @prev: struct dwarf_frame of the previous stackframe on the callstack * @@ -537,8 +574,8 @@ static int dwarf_cfa_execute_insns(unsigned char *insn_start, * on the callstack. Each of the lower (older) stack frames are * linked via the "prev" member. */ -struct dwarf_frame * dwarf_unwind_stack(unsigned long pc, - struct dwarf_frame *prev) +struct dwarf_frame *dwarf_unwind_stack(unsigned long pc, + struct dwarf_frame *prev) { struct dwarf_frame *frame; struct dwarf_cie *cie; @@ -547,16 +584,44 @@ struct dwarf_frame * dwarf_unwind_stack(unsigned long pc, unsigned long addr; /* - * If this is the first invocation of this recursive function we - * need get the contents of a physical register to get the CFA - * in order to begin the virtual unwinding of the stack. + * If we've been called in to before initialization has + * completed, bail out immediately. + */ + if (!dwarf_unwinder_ready) + return NULL; + + /* + * If we're starting at the top of the stack we need get the + * contents of a physical register to get the CFA in order to + * begin the virtual unwinding of the stack. * * NOTE: the return address is guaranteed to be setup by the * time this function makes its first function call. */ - if (!pc && !prev) + if (!pc || !prev) pc = (unsigned long)current_text_addr(); +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + /* + * If our stack has been patched by the function graph tracer + * then we might see the address of return_to_handler() where we + * expected to find the real return address. + */ + if (pc == (unsigned long)&return_to_handler) { + int index = current->curr_ret_stack; + + /* + * We currently have no way of tracking how many + * return_to_handler()'s we've seen. If there is more + * than one patched return address on our stack, + * complain loudly. + */ + WARN_ON(index > 0); + + pc = current->ret_stack[index].ret; + } +#endif + frame = mempool_alloc(dwarf_frame_pool, GFP_ATOMIC); if (!frame) { printk(KERN_ERR "Unable to allocate a dwarf frame\n"); @@ -571,9 +636,8 @@ struct dwarf_frame * dwarf_unwind_stack(unsigned long pc, fde = dwarf_lookup_fde(pc); if (!fde) { /* - * This is our normal exit path - the one that stops the - * recursion. There's two reasons why we might exit - * here, + * This is our normal exit path. There are two reasons + * why we might exit here, * * a) pc has no asscociated DWARF frame info and so * we don't know how to unwind this frame. This is @@ -615,10 +679,10 @@ struct dwarf_frame * dwarf_unwind_stack(unsigned long pc, } else { /* - * Again, this is the first invocation of this - * recurisve function. We need to physically - * read the contents of a register in order to - * get the Canonical Frame Address for this + * Again, we're starting from the top of the + * stack. We need to physically read + * the contents of a register in order to get + * the Canonical Frame Address for this * function. */ frame->cfa = dwarf_read_arch_reg(frame->cfa_register); @@ -645,17 +709,36 @@ struct dwarf_frame * dwarf_unwind_stack(unsigned long pc, addr = frame->cfa + reg->addr; frame->return_addr = __raw_readl(addr); + /* + * Ah, the joys of unwinding through interrupts. + * + * Interrupts are tricky - the DWARF info needs to be _really_ + * accurate and unfortunately I'm seeing a lot of bogus DWARF + * info. For example, I've seen interrupts occur in epilogues + * just after the frame pointer (r14) had been restored. The + * problem was that the DWARF info claimed that the CFA could be + * reached by using the value of the frame pointer before it was + * restored. + * + * So until the compiler can be trusted to produce reliable + * DWARF info when it really matters, let's stop unwinding once + * we've calculated the function that was interrupted. + */ + if (prev && prev->pc == (unsigned long)ret_from_irq) + frame->return_addr = 0; + return frame; bail: - dwarf_frame_free_regs(frame); - mempool_free(frame, dwarf_frame_pool); + dwarf_free_frame(frame); return NULL; } static int dwarf_parse_cie(void *entry, void *p, unsigned long len, - unsigned char *end) + unsigned char *end, struct module *mod) { + struct rb_node **rb_node = &cie_root.rb_node; + struct rb_node *parent = *rb_node; struct dwarf_cie *cie; unsigned long flags; int count; @@ -752,7 +835,30 @@ static int dwarf_parse_cie(void *entry, void *p, unsigned long len, /* Add to list */ spin_lock_irqsave(&dwarf_cie_lock, flags); - list_add_tail(&cie->link, &dwarf_cie_list); + + while (*rb_node) { + struct dwarf_cie *cie_tmp; + + cie_tmp = rb_entry(*rb_node, struct dwarf_cie, node); + + parent = *rb_node; + + if (cie->cie_pointer < cie_tmp->cie_pointer) + rb_node = &parent->rb_left; + else if (cie->cie_pointer >= cie_tmp->cie_pointer) + rb_node = &parent->rb_right; + else + WARN_ON(1); + } + + rb_link_node(&cie->node, parent, rb_node); + rb_insert_color(&cie->node, &cie_root); + +#ifdef CONFIG_MODULES + if (mod != NULL) + list_add_tail(&cie->link, &mod->arch.cie_list); +#endif + spin_unlock_irqrestore(&dwarf_cie_lock, flags); return 0; @@ -760,8 +866,10 @@ 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 rb_node **rb_node = &fde_root.rb_node; + struct rb_node *parent = *rb_node; struct dwarf_fde *fde; struct dwarf_cie *cie; unsigned long flags; @@ -811,7 +919,38 @@ static int dwarf_parse_fde(void *entry, u32 entry_type, /* Add to list. */ spin_lock_irqsave(&dwarf_fde_lock, flags); - list_add_tail(&fde->link, &dwarf_fde_list); + + while (*rb_node) { + struct dwarf_fde *fde_tmp; + unsigned long tmp_start, tmp_end; + unsigned long start, end; + + fde_tmp = rb_entry(*rb_node, struct dwarf_fde, node); + + start = fde->initial_location; + end = fde->initial_location + fde->address_range; + + tmp_start = fde_tmp->initial_location; + tmp_end = fde_tmp->initial_location + fde_tmp->address_range; + + parent = *rb_node; + + if (start < tmp_start) + rb_node = &parent->rb_left; + else if (start >= tmp_end) + rb_node = &parent->rb_right; + else + WARN_ON(1); + } + + rb_link_node(&fde->node, parent, rb_node); + rb_insert_color(&fde->node, &fde_root); + +#ifdef CONFIG_MODULES + if (mod != NULL) + list_add_tail(&fde->link, &mod->arch.fde_list); +#endif + spin_unlock_irqrestore(&dwarf_fde_lock, flags); return 0; @@ -832,10 +971,8 @@ static void dwarf_unwinder_dump(struct task_struct *task, while (1) { frame = dwarf_unwind_stack(return_addr, _frame); - if (_frame) { - dwarf_frame_free_regs(_frame); - mempool_free(_frame, dwarf_frame_pool); - } + if (_frame) + dwarf_free_frame(_frame); _frame = frame; @@ -845,6 +982,9 @@ static void dwarf_unwinder_dump(struct task_struct *task, return_addr = frame->return_addr; ops->address(data, return_addr, 1); } + + if (frame) + dwarf_free_frame(frame); } static struct unwinder dwarf_unwinder = { @@ -855,67 +995,47 @@ static struct unwinder dwarf_unwinder = { static void dwarf_unwinder_cleanup(void) { - struct dwarf_cie *cie; - struct dwarf_fde *fde; + struct dwarf_fde *fde, *next_fde; + struct dwarf_cie *cie, *next_cie; /* * Deallocate all the memory allocated for the DWARF unwinder. * Traverse all the FDE/CIE lists and remove and free all the * memory associated with those data structures. */ - list_for_each_entry(cie, &dwarf_cie_list, link) - kfree(cie); - - list_for_each_entry(fde, &dwarf_fde_list, link) + rbtree_postorder_for_each_entry_safe(fde, next_fde, &fde_root, node) kfree(fde); + rbtree_postorder_for_each_entry_safe(cie, next_cie, &cie_root, node) + kfree(cie); + kmem_cache_destroy(dwarf_reg_cachep); kmem_cache_destroy(dwarf_frame_cachep); } /** - * dwarf_unwinder_init - initialise the dwarf unwinder + * 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 * - * Build the data structures describing the .dwarf_frame section to - * make it easier to lookup CIE and FDE entries. Because the - * .eh_frame section is packed as tightly as possible it is not - * easy to lookup the FDE for a given PC, so we build a list of FDE - * and CIE entries that make it easier. + * Parse the information in a .eh_frame section. */ -static int __init dwarf_unwinder_init(void) +static int dwarf_parse_section(char *eh_frame_start, char *eh_frame_end, + struct module *mod) { u32 entry_type; void *p, *entry; int count, err = 0; - unsigned long len; + unsigned long len = 0; unsigned int c_entries, f_entries; unsigned char *end; - INIT_LIST_HEAD(&dwarf_cie_list); - INIT_LIST_HEAD(&dwarf_fde_list); c_entries = 0; f_entries = 0; - entry = &__start_eh_frame; + entry = eh_frame_start; - dwarf_frame_cachep = kmem_cache_create("dwarf_frames", - sizeof(struct dwarf_frame), 0, - SLAB_PANIC | SLAB_HWCACHE_ALIGN | SLAB_NOTRACK, NULL); - - dwarf_reg_cachep = kmem_cache_create("dwarf_regs", - sizeof(struct dwarf_reg), 0, - SLAB_PANIC | SLAB_HWCACHE_ALIGN | SLAB_NOTRACK, NULL); - - dwarf_frame_pool = mempool_create(DWARF_FRAME_MIN_REQ, - mempool_alloc_slab, - mempool_free_slab, - dwarf_frame_cachep); - - dwarf_reg_pool = mempool_create(DWARF_REG_MIN_REQ, - mempool_alloc_slab, - mempool_free_slab, - dwarf_reg_cachep); - - while ((char *)entry < __stop_eh_frame) { + while ((char *)entry < eh_frame_end) { p = entry; count = dwarf_entry_len(p, &len); @@ -927,6 +1047,7 @@ static int __init dwarf_unwinder_init(void) * entry and move to the next one because 'len' * tells us where our next entry is. */ + err = -EINVAL; goto out; } else p += count; @@ -938,13 +1059,14 @@ static int __init dwarf_unwinder_init(void) p += 4; if (entry_type == DW_EH_FRAME_CIE) { - err = dwarf_parse_cie(entry, p, len, end); + 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); + err = dwarf_parse_fde(entry, entry_type, p, len, + end, mod); if (err < 0) goto out; else @@ -957,15 +1079,132 @@ static int __init dwarf_unwinder_init(void) printk(KERN_INFO "DWARF unwinder initialised: read %u CIEs, %u FDEs\n", c_entries, f_entries); + return 0; + +out: + return err; +} + +#ifdef CONFIG_MODULES +int module_dwarf_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, + struct module *me) +{ + 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) { + INIT_LIST_HEAD(&me->arch.cie_list); + INIT_LIST_HEAD(&me->arch.fde_list); + err = dwarf_parse_section((char *)start, (char *)end, me); + if (err) { + printk(KERN_WARNING "%s: failed to parse DWARF info\n", + me->name); + return err; + } + } + + return 0; +} + +/** + * module_dwarf_cleanup - 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 module_dwarf_cleanup(struct module *mod) +{ + struct dwarf_fde *fde, *ftmp; + struct dwarf_cie *cie, *ctmp; + unsigned long flags; + + spin_lock_irqsave(&dwarf_cie_lock, flags); + + list_for_each_entry_safe(cie, ctmp, &mod->arch.cie_list, link) { + list_del(&cie->link); + rb_erase(&cie->node, &cie_root); + kfree(cie); + } + + spin_unlock_irqrestore(&dwarf_cie_lock, flags); + + spin_lock_irqsave(&dwarf_fde_lock, flags); + + list_for_each_entry_safe(fde, ftmp, &mod->arch.fde_list, link) { + list_del(&fde->link); + rb_erase(&fde->node, &fde_root); + kfree(fde); + } + + spin_unlock_irqrestore(&dwarf_fde_lock, flags); +} +#endif /* CONFIG_MODULES */ + +/** + * dwarf_unwinder_init - initialise the dwarf unwinder + * + * Build the data structures describing the .dwarf_frame section to + * make it easier to lookup CIE and FDE entries. Because the + * .eh_frame section is packed as tightly as possible it is not + * easy to lookup the FDE for a given PC, so we build a list of FDE + * and CIE entries that make it easier. + */ +static int __init dwarf_unwinder_init(void) +{ + int err = -ENOMEM; + + dwarf_frame_cachep = kmem_cache_create("dwarf_frames", + sizeof(struct dwarf_frame), 0, + SLAB_PANIC | SLAB_HWCACHE_ALIGN | SLAB_NOTRACK, NULL); + + dwarf_reg_cachep = kmem_cache_create("dwarf_regs", + sizeof(struct dwarf_reg), 0, + SLAB_PANIC | SLAB_HWCACHE_ALIGN | SLAB_NOTRACK, NULL); + + dwarf_frame_pool = mempool_create(DWARF_FRAME_MIN_REQ, + mempool_alloc_slab, + mempool_free_slab, + dwarf_frame_cachep); + if (!dwarf_frame_pool) + goto out; + + dwarf_reg_pool = mempool_create(DWARF_REG_MIN_REQ, + mempool_alloc_slab, + mempool_free_slab, + dwarf_reg_cachep); + if (!dwarf_reg_pool) + goto out; + + err = dwarf_parse_section(__start_eh_frame, __stop_eh_frame, NULL); + if (err) + goto out; + err = unwinder_register(&dwarf_unwinder); if (err) goto out; + dwarf_unwinder_ready = 1; + return 0; out: printk(KERN_ERR "Failed to initialise DWARF unwinder: %d\n", err); dwarf_unwinder_cleanup(); - return -EINVAL; + return err; } early_initcall(dwarf_unwinder_init); |