*
* 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 <asm/dwarf.h>
#include <asm/unwinder.h>
#include <asm/dwarf.h>
#include <asm/stacktrace.h>
+/* 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_cie_list);
-DEFINE_SPINLOCK(dwarf_cie_lock);
+static DEFINE_SPINLOCK(dwarf_cie_lock);
static LIST_HEAD(dwarf_fde_list);
-DEFINE_SPINLOCK(dwarf_fde_lock);
+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);
+ struct dwarf_reg *reg;
- /* Fast path: don't allocate any regs if we've already got enough. */
- if (frame->num_regs >= num_regs)
- return;
-
- regs = kzalloc(new_size, GFP_ATOMIC);
- 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();
+ }
+
+ 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;
- if (frame->regs) {
- memcpy(regs, frame->regs, old_size);
- kfree(frame->regs);
+ 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;
}
/**
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 dwarf_cie *cie;
unsigned long flags;
spin_lock_irqsave(&dwarf_cie_lock, flags);
goto out;
}
- list_for_each_entry_safe(cie, n, &dwarf_cie_list, link) {
+ list_for_each_entry(cie, &dwarf_cie_list, link) {
if (cie->cie_pointer == cie_ptr) {
cached_cie = cie;
break;
*/
struct dwarf_fde *dwarf_lookup_fde(unsigned long pc)
{
+ struct dwarf_fde *fde;
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) {
+
+ list_for_each_entry(fde, &dwarf_fde_list, link) {
unsigned long start, end;
start = fde->initial_location;
* @fde: the FDE for this function
* @frame: the instructions calculate the CFA for this frame
* @pc: the program counter of the address we're interested in
- * @define_ra: keep executing insns until the return addr reg is defined?
*
* Execute the Call Frame instruction sequence starting at
* @insn_start and ending at @insn_end. The instructions describe
struct dwarf_cie *cie,
struct dwarf_fde *fde,
struct dwarf_frame *frame,
- unsigned long pc,
- bool define_ra)
+ unsigned long pc)
{
unsigned char insn;
unsigned char *current_insn;
unsigned int count, delta, reg, expr_len, offset;
- bool seen_ra_reg;
+ struct dwarf_reg *regp;
current_insn = insn_start;
- /*
- * If we're executing instructions for the dwarf_unwind_stack()
- * FDE we need to keep executing instructions until the value of
- * DWARF_ARCH_RA_REG is defined. See the comment in
- * dwarf_unwind_stack() for more details.
- */
- if (define_ra)
- seen_ra_reg = false;
- else
- seen_ra_reg = true;
-
- while (current_insn < insn_end && (frame->pc <= pc || !seen_ra_reg) ) {
+ while (current_insn < insn_end && frame->pc <= pc) {
insn = __raw_readb(current_insn++);
- if (!seen_ra_reg) {
- if (frame->num_regs >= DWARF_ARCH_RA_REG &&
- frame->regs[DWARF_ARCH_RA_REG].flags)
- seen_ra_reg = true;
- }
-
/*
* Firstly, handle the opcodes that embed their operands
* in the instructions.
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;
}
}
* 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;
struct dwarf_fde *fde;
+ struct dwarf_reg *reg;
unsigned long addr;
- int i, offset;
- bool define_ra = false;
/*
* 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.
*
- * Setting "define_ra" to true indictates that we want
- * dwarf_cfa_execute_insns() to continue executing instructions
- * until we know how to calculate the value of DWARF_ARCH_RA_REG
- * (which we need in order to kick off the whole unwinding
- * process).
- *
* 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;
- define_ra = true;
- }
+ if (!pc && !prev)
+ pc = (unsigned long)current_text_addr();
- frame = kzalloc(sizeof(*frame), GFP_ATOMIC);
- 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) {
* 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, false);
+ frame, pc);
/* FDE instructions */
dwarf_cfa_execute_insns(fde->instructions, fde->end, cie,
- fde, frame, pc, define_ra);
+ fde, frame, pc);
/* Calculate the CFA */
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 {
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);
+ reg = dwarf_frame_reg(frame, DWARF_ARCH_RA_REG);
- for (i = 0; i <= frame->num_regs; i++) {
- struct dwarf_reg *reg = &frame->regs[i];
-
- 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);
return frame;
+
+bail:
+ dwarf_frame_free_regs(frame);
+ mempool_free(frame, dwarf_frame_pool);
+ return NULL;
}
static int dwarf_parse_cie(void *entry, void *p, unsigned long len,
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;
}
}
}
static int dwarf_parse_fde(void *entry, u32 entry_type,
- void *start, unsigned long len)
+ void *start, unsigned long len,
+ unsigned char *end)
{
struct dwarf_fde *fde;
struct dwarf_cie *cie;
/* Call frame instructions. */
fde->instructions = p;
- fde->end = start + len;
+ fde->end = end;
/* Add to list. */
spin_lock_irqsave(&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;
- frame = dwarf_unwind_stack(0, NULL);
+ while (1) {
+ frame = dwarf_unwind_stack(return_addr, _frame);
- while (frame && frame->return_addr) {
- ops->address(data, frame->return_addr, 1);
- frame = frame->next;
+ if (_frame) {
+ dwarf_frame_free_regs(_frame);
+ mempool_free(_frame, dwarf_frame_pool);
+ }
+
+ _frame = frame;
+
+ if (!frame || !frame->return_addr)
+ break;
+
+ return_addr = frame->return_addr;
+ ops->address(data, return_addr, 1);
}
}
static void dwarf_unwinder_cleanup(void)
{
- struct dwarf_cie *cie, *m;
- struct dwarf_fde *fde, *n;
- unsigned long flags;
+ struct dwarf_cie *cie;
+ struct dwarf_fde *fde;
/*
* 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)
+ list_for_each_entry(cie, &dwarf_cie_list, link)
kfree(cie);
- spin_unlock_irqrestore(&dwarf_cie_lock, flags);
- spin_lock_irqsave(&dwarf_fde_lock, flags);
- list_for_each_entry_safe(fde, n, &dwarf_fde_list, link)
+ list_for_each_entry(fde, &dwarf_fde_list, link)
kfree(fde);
- spin_unlock_irqrestore(&dwarf_fde_lock, flags);
+
+ kmem_cache_destroy(dwarf_reg_cachep);
+ kmem_cache_destroy(dwarf_frame_cachep);
}
/**
* easy to lookup the FDE for a given PC, so we build a list of FDE
* and CIE entries that make it easier.
*/
-void dwarf_unwinder_init(void)
+static int __init dwarf_unwinder_init(void)
{
u32 entry_type;
void *p, *entry;
- int count, err;
+ int count, err = 0;
unsigned long len;
unsigned int c_entries, f_entries;
unsigned char *end;
f_entries = 0;
entry = &__start_eh_frame;
+ 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) {
p = entry;
else
c_entries++;
} else {
- err = dwarf_parse_fde(entry, entry_type, p, len);
+ err = dwarf_parse_fde(entry, entry_type, p, len, end);
if (err < 0)
goto out;
else
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.openpandora.org / pandora-kernel.git / blobdiff