aboutsummaryrefslogtreecommitdiff
path: root/arch/sh
diff options
context:
space:
mode:
Diffstat (limited to 'arch/sh')
-rw-r--r--arch/sh/include/asm/dwarf.h22
-rw-r--r--arch/sh/kernel/dwarf.c201
2 files changed, 142 insertions, 81 deletions
diff --git a/arch/sh/include/asm/dwarf.h b/arch/sh/include/asm/dwarf.h
index 2fbe8720411..a22fbe98303 100644
--- a/arch/sh/include/asm/dwarf.h
+++ b/arch/sh/include/asm/dwarf.h
@@ -265,10 +265,7 @@ struct dwarf_frame {
unsigned long pc;
- struct dwarf_reg *regs;
- unsigned int num_regs; /* how many regs are allocated? */
-
- unsigned int depth; /* what level are we in the callstack? */
+ struct list_head reg_list;
unsigned long cfa;
@@ -292,22 +289,15 @@ struct dwarf_frame {
* @flags: Describes how to calculate the value of this register
*/
struct dwarf_reg {
+ struct list_head link;
+
+ unsigned int number;
+
unsigned long addr;
unsigned long flags;
#define DWARF_REG_OFFSET (1 << 0)
};
-/**
- * dwarf_stack - a DWARF stack contains a collection of DWARF frames
- * @depth: the number of frames in the stack
- * @level: an array of DWARF frames, indexed by stack level
- *
- */
-struct dwarf_stack {
- unsigned int depth;
- struct dwarf_frame **level;
-};
-
/*
* Call Frame instruction opcodes.
*/
@@ -372,7 +362,7 @@ static inline unsigned int DW_CFA_operand(unsigned long insn)
extern struct dwarf_frame *dwarf_unwind_stack(unsigned long,
struct dwarf_frame *);
-#endif /* __ASSEMBLY__ */
+#endif /* !__ASSEMBLY__ */
#define CFI_STARTPROC .cfi_startproc
#define CFI_ENDPROC .cfi_endproc
diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c
index d0652153f57..e4810375207 100644
--- a/arch/sh/kernel/dwarf.c
+++ b/arch/sh/kernel/dwarf.c
@@ -17,6 +17,7 @@
#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>
@@ -25,6 +26,17 @@
#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);
static DEFINE_SPINLOCK(dwarf_cie_lock);
@@ -33,33 +45,25 @@ 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
+ *
+ * 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.
*
- * Register numbers start at zero, therefore we need to allocate space
- * for "reg" + 1 registers.
+ * 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;
+ struct dwarf_reg *reg;
- 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;
-
- 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.
@@ -67,13 +71,44 @@ static void dwarf_frame_alloc_regs(struct dwarf_frame *frame,
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(&reg->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(&reg->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;
}
/**
@@ -347,6 +382,7 @@ static int dwarf_cfa_execute_insns(unsigned char *insn_start,
unsigned char insn;
unsigned char *current_insn;
unsigned int count, delta, reg, expr_len, offset;
+ struct dwarf_reg *regp;
current_insn = insn_start;
@@ -369,9 +405,9 @@ static int dwarf_cfa_execute_insns(unsigned char *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:
@@ -453,17 +489,18 @@ static int dwarf_cfa_execute_insns(unsigned char *insn_start,
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, &reg);
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_REG_OFFSET;
+ regp->addr = offset;
break;
case DW_CFA_GNU_args_size:
count = dwarf_read_uleb128(current_insn, &offset);
@@ -474,9 +511,10 @@ static int dwarf_cfa_execute_insns(unsigned char *insn_start,
current_insn += count;
count = dwarf_read_uleb128(current_insn, &offset);
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;
default:
pr_debug("unhandled DWARF instruction 0x%x\n", insn);
@@ -502,8 +540,8 @@ struct dwarf_frame *dwarf_unwind_stack(unsigned long pc,
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
@@ -516,11 +554,16 @@ struct dwarf_frame *dwarf_unwind_stack(unsigned long pc,
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");
+ BUG();
+ }
+ INIT_LIST_HEAD(&frame->reg_list);
+ frame->flags = 0;
frame->prev = prev;
+ frame->return_addr = 0;
fde = dwarf_lookup_fde(pc);
if (!fde) {
@@ -540,7 +583,7 @@ struct dwarf_frame *dwarf_unwind_stack(unsigned long pc,
* case above, which sucks because we could print a
* warning here.
*/
- return NULL;
+ goto bail;
}
cie = dwarf_lookup_cie(fde->cie_pointer);
@@ -560,10 +603,10 @@ struct dwarf_frame *dwarf_unwind_stack(unsigned long pc,
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);
+ BUG_ON(!reg);
- addr = prev->cfa;
- addr += prev->regs[frame->cfa_register].addr;
+ addr = prev->cfa + reg->addr;
frame->cfa = __raw_readl(addr);
} else {
@@ -584,23 +627,18 @@ struct dwarf_frame *dwarf_unwind_stack(unsigned long pc,
}
/* 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];
-
- if (!reg->flags)
- continue;
+ reg = dwarf_frame_reg(frame, DWARF_ARCH_RA_REG);
+ BUG_ON(!reg);
- offset = reg->addr;
- offset += frame->cfa;
- }
-
- 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,
@@ -770,14 +808,29 @@ static void dwarf_unwinder_dump(struct task_struct *task, struct pt_regs *regs,
unsigned long *sp,
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);
+
+ if (_frame) {
+ dwarf_frame_free_regs(_frame);
+ mempool_free(_frame, dwarf_frame_pool);
+ }
+
+ _frame = frame;
+
+ if (!frame || !frame->return_addr)
+ break;
- while (frame && frame->return_addr) {
- ops->address(data, frame->return_addr, 1);
- frame = frame->next;
+ return_addr = frame->return_addr;
+ ops->address(data, return_addr, 1);
}
+
}
static struct unwinder dwarf_unwinder = {
@@ -801,6 +854,9 @@ static void dwarf_unwinder_cleanup(void)
list_for_each_entry(fde, &dwarf_fde_list, link)
kfree(fde);
+
+ kmem_cache_destroy(dwarf_reg_cachep);
+ kmem_cache_destroy(dwarf_frame_cachep);
}
/**
@@ -827,6 +883,21 @@ static int __init dwarf_unwinder_init(void)
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",
+ sizeof(struct dwarf_reg), 0, SLAB_PANIC, 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;