*
* TODO:
* - DWARF64 doesn't work.
+ * - Registers with DWARF_VAL_OFFSET rules aren't handled properly.
*/
/* #define DEBUG */
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/list.h>
+#include <linux/mempool.h>
#include <linux/mm.h>
+#include <linux/elf.h>
+#include <linux/ftrace.h>
#include <asm/dwarf.h>
#include <asm/unwinder.h>
#include <asm/sections.h>
#include <asm/unaligned.h>
-#include <asm/dwarf.h>
#include <asm/stacktrace.h>
-static LIST_HEAD(dwarf_cie_list);
-DEFINE_SPINLOCK(dwarf_cie_lock);
+/* Reserve enough memory for two stack frames */
+#define DWARF_FRAME_MIN_REQ 2
+/* ... with 4 registers per frame. */
+#define DWARF_REG_MIN_REQ (DWARF_FRAME_MIN_REQ * 4)
+
+static struct kmem_cache *dwarf_frame_cachep;
+static mempool_t *dwarf_frame_pool;
+
+static struct kmem_cache *dwarf_reg_cachep;
+static mempool_t *dwarf_reg_pool;
-static LIST_HEAD(dwarf_fde_list);
-DEFINE_SPINLOCK(dwarf_fde_lock);
+static struct rb_root cie_root;
+static DEFINE_SPINLOCK(dwarf_cie_lock);
+
+static struct rb_root fde_root;
+static DEFINE_SPINLOCK(dwarf_fde_lock);
static struct dwarf_cie *cached_cie;
-/*
- * Figure out whether we need to allocate some dwarf registers. If dwarf
- * registers have already been allocated then we may need to realloc
- * them. "reg" is a register number that we need to be able to access
- * after this call.
+/**
+ * dwarf_frame_alloc_reg - allocate memory for a DWARF register
+ * @frame: the DWARF frame whose list of registers we insert on
+ * @reg_num: the register number
*
- * Register numbers start at zero, therefore we need to allocate space
- * for "reg" + 1 registers.
+ * Allocate space for, and initialise, a dwarf reg from
+ * dwarf_reg_pool and insert it onto the (unsorted) linked-list of
+ * dwarf registers for @frame.
+ *
+ * Return the initialised DWARF reg.
*/
-static void dwarf_frame_alloc_regs(struct dwarf_frame *frame,
- unsigned int reg)
+static struct dwarf_reg *dwarf_frame_alloc_reg(struct dwarf_frame *frame,
+ unsigned int reg_num)
{
- struct dwarf_reg *regs;
- unsigned int num_regs = reg + 1;
- size_t new_size;
- size_t old_size;
-
- new_size = num_regs * sizeof(*regs);
- old_size = frame->num_regs * sizeof(*regs);
-
- /* Fast path: don't allocate any regs if we've already got enough. */
- if (frame->num_regs >= num_regs)
- return;
+ struct dwarf_reg *reg;
- regs = kzalloc(new_size, GFP_KERNEL);
- if (!regs) {
- printk(KERN_WARNING "Unable to allocate DWARF registers\n");
+ reg = mempool_alloc(dwarf_reg_pool, GFP_ATOMIC);
+ if (!reg) {
+ printk(KERN_WARNING "Unable to allocate a DWARF register\n");
/*
* Let's just bomb hard here, we have no way to
* gracefully recover.
*/
- BUG();
+ UNWINDER_BUG();
}
- if (frame->regs) {
- memcpy(regs, frame->regs, old_size);
- kfree(frame->regs);
+ reg->number = reg_num;
+ reg->addr = 0;
+ reg->flags = 0;
+
+ list_add(®->link, &frame->reg_list);
+
+ return reg;
+}
+
+static void dwarf_frame_free_regs(struct dwarf_frame *frame)
+{
+ struct dwarf_reg *reg, *n;
+
+ list_for_each_entry_safe(reg, n, &frame->reg_list, link) {
+ list_del(®->link);
+ mempool_free(reg, dwarf_reg_pool);
+ }
+}
+
+/**
+ * dwarf_frame_reg - return a DWARF register
+ * @frame: the DWARF frame to search in for @reg_num
+ * @reg_num: the register number to search for
+ *
+ * Lookup and return the dwarf reg @reg_num for this frame. Return
+ * NULL if @reg_num is an register invalid number.
+ */
+static struct dwarf_reg *dwarf_frame_reg(struct dwarf_frame *frame,
+ unsigned int reg_num)
+{
+ struct dwarf_reg *reg;
+
+ list_for_each_entry(reg, &frame->reg_list, link) {
+ if (reg->number == reg_num)
+ return reg;
}
- frame->regs = regs;
- frame->num_regs = num_regs;
+ return NULL;
}
/**
*/
static inline int dwarf_read_addr(unsigned long *src, unsigned long *dst)
{
- *dst = get_unaligned(src);
+ u32 val = get_unaligned(src);
+ put_unaligned(val, dst);
return sizeof(unsigned long *);
}
break;
default:
pr_debug("encoding=0x%x\n", (encoding & 0x70));
- BUG();
+ UNWINDER_BUG();
}
if ((encoding & 0x07) == 0x00)
break;
default:
pr_debug("encoding=0x%x\n", encoding);
- BUG();
+ UNWINDER_BUG();
}
return count;
*/
static struct dwarf_cie *dwarf_lookup_cie(unsigned long cie_ptr)
{
- struct dwarf_cie *cie, *n;
+ struct rb_node **rb_node = &cie_root.rb_node;
+ struct dwarf_cie *cie = NULL;
unsigned long flags;
spin_lock_irqsave(&dwarf_cie_lock, flags);
goto out;
}
- list_for_each_entry_safe(cie, n, &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;
*/
struct dwarf_fde *dwarf_lookup_fde(unsigned long pc)
{
+ struct rb_node **rb_node = &fde_root.rb_node;
+ struct dwarf_fde *fde = NULL;
unsigned long flags;
- struct dwarf_fde *fde, *n;
spin_lock_irqsave(&dwarf_fde_lock, flags);
- list_for_each_entry_safe(fde, n, &dwarf_fde_list, link) {
- unsigned long start, end;
- start = fde->initial_location;
- end = fde->initial_location + fde->address_range;
+ while (*rb_node) {
+ struct dwarf_fde *fde_tmp;
+ unsigned long tmp_start, tmp_end;
- if (pc >= start && pc < end)
- break;
- }
+ fde_tmp = rb_entry(*rb_node, struct dwarf_fde, node);
+ BUG_ON(!fde_tmp);
- /* Couldn't find the entry in the list. */
- if (&fde->link == &dwarf_fde_list)
- fde = NULL;
+ tmp_start = fde_tmp->initial_location;
+ tmp_end = fde_tmp->initial_location + fde_tmp->address_range;
+ 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;
unsigned char insn;
unsigned char *current_insn;
unsigned int count, delta, reg, expr_len, offset;
+ struct dwarf_reg *regp;
current_insn = insn_start;
count = dwarf_read_uleb128(current_insn, &offset);
current_insn += count;
offset *= cie->data_alignment_factor;
- dwarf_frame_alloc_regs(frame, reg);
- frame->regs[reg].addr = offset;
- frame->regs[reg].flags |= DWARF_REG_OFFSET;
+ regp = dwarf_frame_alloc_reg(frame, reg);
+ regp->addr = offset;
+ regp->flags |= DWARF_REG_OFFSET;
continue;
/* NOTREACHED */
case DW_CFA_restore:
case DW_CFA_undefined:
count = dwarf_read_uleb128(current_insn, ®);
current_insn += count;
+ regp = dwarf_frame_alloc_reg(frame, reg);
+ regp->flags |= DWARF_UNDEFINED;
break;
case DW_CFA_def_cfa:
count = dwarf_read_uleb128(current_insn,
count = dwarf_read_leb128(current_insn, &offset);
current_insn += count;
offset *= cie->data_alignment_factor;
- dwarf_frame_alloc_regs(frame, reg);
- frame->regs[reg].flags |= DWARF_REG_OFFSET;
- frame->regs[reg].addr = offset;
+ regp = dwarf_frame_alloc_reg(frame, reg);
+ regp->flags |= DWARF_REG_OFFSET;
+ regp->addr = offset;
break;
case DW_CFA_val_offset:
count = dwarf_read_uleb128(current_insn, ®);
current_insn += count;
count = dwarf_read_leb128(current_insn, &offset);
offset *= cie->data_alignment_factor;
- frame->regs[reg].flags |= DWARF_REG_OFFSET;
- frame->regs[reg].addr = offset;
+ regp = dwarf_frame_alloc_reg(frame, reg);
+ regp->flags |= DWARF_VAL_OFFSET;
+ regp->addr = offset;
+ break;
+ case DW_CFA_GNU_args_size:
+ count = dwarf_read_uleb128(current_insn, &offset);
+ current_insn += count;
+ break;
+ case DW_CFA_GNU_negative_offset_extended:
+ count = dwarf_read_uleb128(current_insn, ®);
+ current_insn += count;
+ count = dwarf_read_uleb128(current_insn, &offset);
+ offset *= cie->data_alignment_factor;
+
+ regp = dwarf_frame_alloc_reg(frame, reg);
+ regp->flags |= DWARF_REG_OFFSET;
+ regp->addr = -offset;
break;
default:
pr_debug("unhandled DWARF instruction 0x%x\n", insn);
+ UNWINDER_BUG();
break;
}
}
}
/**
- * 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
*
struct dwarf_frame *frame;
struct dwarf_cie *cie;
struct dwarf_fde *fde;
+ struct dwarf_reg *reg;
unsigned long addr;
- int i, offset;
/*
- * 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'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.
*
- * The constant DWARF_ARCH_UNWIND_OFFSET is added to the address of
- * this function because the return address register
- * (DWARF_ARCH_RA_REG) will probably not be initialised until a
- * few instructions into the prologue.
+ * NOTE: the return address is guaranteed to be setup by the
+ * time this function makes its first function call.
*/
- if (!pc && !prev) {
- pc = (unsigned long)&dwarf_unwind_stack;
- pc += DWARF_ARCH_UNWIND_OFFSET;
+ 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 = kzalloc(sizeof(*frame), GFP_KERNEL);
- if (!frame)
- return NULL;
+ frame = mempool_alloc(dwarf_frame_pool, GFP_ATOMIC);
+ if (!frame) {
+ printk(KERN_ERR "Unable to allocate a dwarf frame\n");
+ UNWINDER_BUG();
+ }
+ INIT_LIST_HEAD(&frame->reg_list);
+ frame->flags = 0;
frame->prev = prev;
+ frame->return_addr = 0;
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
* case above, which sucks because we could print a
* warning here.
*/
- return NULL;
+ goto bail;
}
cie = dwarf_lookup_cie(fde->cie_pointer);
/* CIE initial instructions */
dwarf_cfa_execute_insns(cie->initial_instructions,
- cie->instructions_end, cie, fde, frame, pc);
+ cie->instructions_end, cie, fde,
+ frame, pc);
/* FDE instructions */
dwarf_cfa_execute_insns(fde->instructions, fde->end, cie,
switch (frame->flags) {
case DWARF_FRAME_CFA_REG_OFFSET:
if (prev) {
- BUG_ON(!prev->regs[frame->cfa_register].flags);
+ reg = dwarf_frame_reg(prev, frame->cfa_register);
+ UNWINDER_BUG_ON(!reg);
+ UNWINDER_BUG_ON(reg->flags != DWARF_REG_OFFSET);
- addr = prev->cfa;
- addr += prev->regs[frame->cfa_register].addr;
+ addr = prev->cfa + reg->addr;
frame->cfa = __raw_readl(addr);
} 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);
frame->cfa += frame->cfa_offset;
break;
default:
- BUG();
+ UNWINDER_BUG();
}
- /* If we haven't seen the return address reg, we're screwed. */
- BUG_ON(!frame->regs[DWARF_ARCH_RA_REG].flags);
-
- for (i = 0; i <= frame->num_regs; i++) {
- struct dwarf_reg *reg = &frame->regs[i];
+ reg = dwarf_frame_reg(frame, DWARF_ARCH_RA_REG);
- if (!reg->flags)
- continue;
+ /*
+ * If we haven't seen the return address register or the return
+ * address column is undefined then we must assume that this is
+ * the end of the callstack.
+ */
+ if (!reg || reg->flags == DWARF_UNDEFINED)
+ goto bail;
- offset = reg->addr;
- offset += frame->cfa;
- }
+ UNWINDER_BUG_ON(reg->flags != DWARF_REG_OFFSET);
- addr = frame->cfa + frame->regs[DWARF_ARCH_RA_REG].addr;
+ addr = frame->cfa + reg->addr;
frame->return_addr = __raw_readl(addr);
- frame->next = dwarf_unwind_stack(frame->return_addr, frame);
+ /*
+ * 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_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;
struct dwarf_cie *cie;
unsigned long flags;
int count;
cie->cie_pointer = (unsigned long)entry;
cie->version = *(char *)p++;
- BUG_ON(cie->version != 1);
+ UNWINDER_BUG_ON(cie->version != 1);
cie->augmentation = p;
p += strlen(cie->augmentation) + 1;
count = dwarf_read_uleb128(p, &length);
p += count;
- BUG_ON((unsigned char *)p > end);
+ UNWINDER_BUG_ON((unsigned char *)p > end);
cie->initial_instructions = p + length;
cie->augmentation++;
* routine in the CIE
* augmentation.
*/
- BUG();
+ UNWINDER_BUG();
} else if (*cie->augmentation == 'S') {
- BUG();
+ UNWINDER_BUG();
} else {
/*
* Unknown augmentation. Assume
* 'z' augmentation.
*/
p = cie->initial_instructions;
- BUG_ON(!p);
+ UNWINDER_BUG_ON(!p);
break;
}
}
/* 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);
+
+ if (mod != NULL)
+ list_add_tail(&cie->link, &mod->arch.cie_list);
+
spin_unlock_irqrestore(&dwarf_cie_lock, flags);
return 0;
}
static int dwarf_parse_fde(void *entry, u32 entry_type,
- void *start, unsigned long len)
+ void *start, unsigned long len,
+ unsigned char *end, struct module *mod)
{
+ struct rb_node **rb_node = &fde_root.rb_node;
+ struct rb_node *parent;
struct dwarf_fde *fde;
struct dwarf_cie *cie;
unsigned long flags;
/* Call frame instructions. */
fde->instructions = p;
- fde->end = start + len;
+ fde->end = end;
/* 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);
+
+ if (mod != NULL)
+ list_add_tail(&fde->link, &mod->arch.fde_list);
+
spin_unlock_irqrestore(&dwarf_fde_lock, flags);
return 0;
}
-static void dwarf_unwinder_dump(struct task_struct *task, struct pt_regs *regs,
+static void dwarf_unwinder_dump(struct task_struct *task,
+ struct pt_regs *regs,
unsigned long *sp,
- const struct stacktrace_ops *ops, void *data)
+ const struct stacktrace_ops *ops,
+ void *data)
{
- struct dwarf_frame *frame;
+ struct dwarf_frame *frame, *_frame;
+ unsigned long return_addr;
+
+ _frame = NULL;
+ return_addr = 0;
+
+ while (1) {
+ frame = dwarf_unwind_stack(return_addr, _frame);
+
+ if (_frame)
+ dwarf_free_frame(_frame);
- frame = dwarf_unwind_stack(0, NULL);
+ _frame = frame;
- while (frame && frame->return_addr) {
- ops->address(data, frame->return_addr, 1);
- frame = frame->next;
+ if (!frame || !frame->return_addr)
+ break;
+
+ return_addr = frame->return_addr;
+ ops->address(data, return_addr, 1);
}
+
+ if (frame)
+ dwarf_free_frame(frame);
}
static struct unwinder dwarf_unwinder = {
static void dwarf_unwinder_cleanup(void)
{
- struct dwarf_cie *cie, *m;
- struct dwarf_fde *fde, *n;
- unsigned long flags;
+ struct rb_node **fde_rb_node = &fde_root.rb_node;
+ struct rb_node **cie_rb_node = &cie_root.rb_node;
/*
* 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.
*/
- spin_lock_irqsave(&dwarf_cie_lock, flags);
- list_for_each_entry_safe(cie, m, &dwarf_cie_list, link)
- kfree(cie);
- spin_unlock_irqrestore(&dwarf_cie_lock, flags);
+ while (*fde_rb_node) {
+ struct dwarf_fde *fde;
- spin_lock_irqsave(&dwarf_fde_lock, flags);
- list_for_each_entry_safe(fde, n, &dwarf_fde_list, link)
+ fde = rb_entry(*fde_rb_node, struct dwarf_fde, node);
+ rb_erase(*fde_rb_node, &fde_root);
kfree(fde);
- spin_unlock_irqrestore(&dwarf_fde_lock, flags);
+ }
+
+ while (*cie_rb_node) {
+ struct dwarf_cie *cie;
+
+ cie = rb_entry(*cie_rb_node, struct dwarf_cie, node);
+ rb_erase(*cie_rb_node, &cie_root);
+ 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.
*/
-void 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;
- unsigned long len;
+ int count, err = 0;
+ 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;
- while ((char *)entry < __stop_eh_frame) {
+ while ((char *)entry < eh_frame_end) {
p = entry;
count = dwarf_entry_len(p, &len);
* entry and move to the next one because 'len'
* tells us where our next entry is.
*/
+ err = -EINVAL;
goto out;
} else
p += count;
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);
+ err = dwarf_parse_fde(entry, entry_type, p, len,
+ end, mod);
if (err < 0)
goto out;
else
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;
+
+ 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);
+
+ err = dwarf_parse_section(__start_eh_frame, __stop_eh_frame, NULL);
+ if (err)
+ goto out;
+
err = unwinder_register(&dwarf_unwinder);
if (err)
goto out;
- return;
+ return 0;
out:
printk(KERN_ERR "Failed to initialise DWARF unwinder: %d\n", err);
dwarf_unwinder_cleanup();
+ return -EINVAL;
}
+early_initcall(dwarf_unwinder_init);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff