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-rw-r--r--arch/sh/include/asm/bug.h25
-rw-r--r--arch/sh/include/asm/dwarf.h26
-rw-r--r--arch/sh/include/asm/system.h5
-rw-r--r--arch/sh/include/asm/unwinder.h6
-rw-r--r--arch/sh/kernel/cpu/sh3/entry.S2
-rw-r--r--arch/sh/kernel/debugtraps.S6
-rw-r--r--arch/sh/kernel/dwarf.c246
-rw-r--r--arch/sh/kernel/traps.c7
-rw-r--r--arch/sh/kernel/traps_32.c1
-rw-r--r--arch/sh/kernel/unwinder.c33
10 files changed, 252 insertions, 105 deletions
diff --git a/arch/sh/include/asm/bug.h b/arch/sh/include/asm/bug.h
index c017180..b7d9822 100644
--- a/arch/sh/include/asm/bug.h
+++ b/arch/sh/include/asm/bug.h
@@ -1,6 +1,7 @@
#ifndef __ASM_SH_BUG_H
#define __ASM_SH_BUG_H
+#define TRAPA_UNWINDER_BUG_OPCODE 0xc33b /* trapa #0x3b */
#define TRAPA_BUG_OPCODE 0xc33e /* trapa #0x3e */
#ifdef CONFIG_GENERIC_BUG
@@ -72,6 +73,30 @@ do { \
unlikely(__ret_warn_on); \
})
+#define UNWINDER_BUG() \
+do { \
+ __asm__ __volatile__ ( \
+ "1:\t.short %O0\n" \
+ _EMIT_BUG_ENTRY \
+ : \
+ : "n" (TRAPA_UNWINDER_BUG_OPCODE), \
+ "i" (__FILE__), \
+ "i" (__LINE__), "i" (0), \
+ "i" (sizeof(struct bug_entry))); \
+} while (0)
+
+#define UNWINDER_BUG_ON(x) ({ \
+ int __ret_unwinder_on = !!(x); \
+ if (__builtin_constant_p(__ret_unwinder_on)) { \
+ if (__ret_unwinder_on) \
+ UNWINDER_BUG(); \
+ } else { \
+ if (unlikely(__ret_unwinder_on)) \
+ UNWINDER_BUG(); \
+ } \
+ unlikely(__ret_unwinder_on); \
+})
+
#endif /* CONFIG_GENERIC_BUG */
#include <asm-generic/bug.h>
diff --git a/arch/sh/include/asm/dwarf.h b/arch/sh/include/asm/dwarf.h
index 2fbe872..c367ed3 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;
@@ -292,20 +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;
+#define DWARF_VAL_OFFSET (1 << 1)
+#define DWARF_UNDEFINED (1 << 2)
};
/*
@@ -372,13 +364,14 @@ 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
#define CFI_DEF_CFA .cfi_def_cfa
#define CFI_REGISTER .cfi_register
#define CFI_REL_OFFSET .cfi_rel_offset
+#define CFI_UNDEFINED .cfi_undefined
#else
@@ -392,6 +385,7 @@ extern struct dwarf_frame *dwarf_unwind_stack(unsigned long,
#define CFI_DEF_CFA CFI_IGNORE
#define CFI_REGISTER CFI_IGNORE
#define CFI_REL_OFFSET CFI_IGNORE
+#define CFI_UNDEFINED CFI_IGNORE
#ifndef __ASSEMBLY__
static inline void dwarf_unwinder_init(void)
diff --git a/arch/sh/include/asm/system.h b/arch/sh/include/asm/system.h
index ab79e1f..f9e2ceb 100644
--- a/arch/sh/include/asm/system.h
+++ b/arch/sh/include/asm/system.h
@@ -181,6 +181,11 @@ BUILD_TRAP_HANDLER(breakpoint);
BUILD_TRAP_HANDLER(singlestep);
BUILD_TRAP_HANDLER(fpu_error);
BUILD_TRAP_HANDLER(fpu_state_restore);
+BUILD_TRAP_HANDLER(unwinder);
+
+#ifdef CONFIG_BUG
+extern void handle_BUG(struct pt_regs *);
+#endif
#define arch_align_stack(x) (x)
diff --git a/arch/sh/include/asm/unwinder.h b/arch/sh/include/asm/unwinder.h
index 3dc5514..1e65c07 100644
--- a/arch/sh/include/asm/unwinder.h
+++ b/arch/sh/include/asm/unwinder.h
@@ -22,4 +22,10 @@ extern void stack_reader_dump(struct task_struct *, struct pt_regs *,
unsigned long *, const struct stacktrace_ops *,
void *);
+/*
+ * Used by fault handling code to signal to the unwinder code that it
+ * should switch to a different unwinder.
+ */
+extern int unwinder_faulted;
+
#endif /* _LINUX_UNWINDER_H */
diff --git a/arch/sh/kernel/cpu/sh3/entry.S b/arch/sh/kernel/cpu/sh3/entry.S
index 67ad646..f89ec87 100644
--- a/arch/sh/kernel/cpu/sh3/entry.S
+++ b/arch/sh/kernel/cpu/sh3/entry.S
@@ -508,6 +508,8 @@ ENTRY(handle_interrupt)
bsr save_regs ! needs original pr value in k3
mov #-1, k2 ! default vector kept in k2
+ setup_frame_reg
+
! Setup return address and jump to do_IRQ
mov.l 4f, r9 ! fetch return address
lds r9, pr ! put return address in pr
diff --git a/arch/sh/kernel/debugtraps.S b/arch/sh/kernel/debugtraps.S
index 5917413..cb00e4a 100644
--- a/arch/sh/kernel/debugtraps.S
+++ b/arch/sh/kernel/debugtraps.S
@@ -21,6 +21,10 @@
#define sh_bios_handler debug_trap_handler
#endif
+#if !defined(CONFIG_DWARF_UNWINDER)
+#define unwinder_trap_handler debug_trap_handler
+#endif
+
.data
ENTRY(debug_trap_table)
@@ -35,7 +39,7 @@ ENTRY(debug_trap_table)
.long debug_trap_handler /* 0x38 */
.long debug_trap_handler /* 0x39 */
.long debug_trap_handler /* 0x3a */
- .long debug_trap_handler /* 0x3b */
+ .long unwinder_trap_handler /* 0x3b */
.long breakpoint_trap_handler /* 0x3c */
.long singlestep_trap_handler /* 0x3d */
.long bug_trap_handler /* 0x3e */
diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c
index d065215..577302f 100644
--- a/arch/sh/kernel/dwarf.c
+++ b/arch/sh/kernel/dwarf.c
@@ -11,12 +11,14 @@
*
* 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>
@@ -25,6 +27,17 @@
#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);
@@ -33,47 +46,70 @@ 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.
*/
- BUG();
+ UNWINDER_BUG();
+ }
+
+ 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;
- 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;
}
/**
@@ -196,7 +232,7 @@ static int dwarf_read_encoded_value(char *addr, unsigned long *val,
break;
default:
pr_debug("encoding=0x%x\n", (encoding & 0x70));
- BUG();
+ UNWINDER_BUG();
}
if ((encoding & 0x07) == 0x00)
@@ -211,7 +247,7 @@ static int dwarf_read_encoded_value(char *addr, unsigned long *val,
break;
default:
pr_debug("encoding=0x%x\n", encoding);
- BUG();
+ UNWINDER_BUG();
}
return count;
@@ -347,6 +383,7 @@ 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 +406,9 @@ 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:
@@ -415,6 +452,8 @@ static int dwarf_cfa_execute_insns(unsigned char *insn_start,
case DW_CFA_undefined:
count = dwarf_read_uleb128(current_insn, &reg);
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,
@@ -453,17 +492,18 @@ 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_VAL_OFFSET;
+ regp->addr = offset;
break;
case DW_CFA_GNU_args_size:
count = dwarf_read_uleb128(current_insn, &offset);
@@ -474,12 +514,14 @@ 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);
+ UNWINDER_BUG();
break;
}
}
@@ -496,14 +538,14 @@ 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;
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 +558,16 @@ 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");
+ 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) {
@@ -540,7 +587,7 @@ 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 +607,11 @@ 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);
+ 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 {
@@ -580,27 +628,30 @@ struct dwarf_frame *dwarf_unwind_stack(unsigned long pc,
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 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;
- if (!reg->flags)
- continue;
+ UNWINDER_BUG_ON(reg->flags != DWARF_REG_OFFSET);
- 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,
@@ -625,7 +676,7 @@ 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;
@@ -655,7 +706,7 @@ static int dwarf_parse_cie(void *entry, void *p, unsigned long len,
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++;
@@ -683,16 +734,16 @@ static int dwarf_parse_cie(void *entry, void *p, unsigned long len,
* 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;
}
}
@@ -709,7 +760,8 @@ 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)
+ void *start, unsigned long len,
+ unsigned char *end)
{
struct dwarf_fde *fde;
struct dwarf_cie *cie;
@@ -756,7 +808,7 @@ static int dwarf_parse_fde(void *entry, u32 entry_type,
/* Call frame instructions. */
fde->instructions = p;
- fde->end = start + len;
+ fde->end = end;
/* Add to list. */
spin_lock_irqsave(&dwarf_fde_lock, flags);
@@ -766,17 +818,33 @@ static int dwarf_parse_fde(void *entry, u32 entry_type,
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 = dwarf_unwind_stack(0, NULL);
+ _frame = NULL;
+ return_addr = 0;
- while (frame && frame->return_addr) {
- ops->address(data, frame->return_addr, 1);
- frame = frame->next;
+ 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;
+
+ return_addr = frame->return_addr;
+ ops->address(data, return_addr, 1);
}
}
@@ -801,6 +869,9 @@ 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 +898,21 @@ 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;
@@ -856,7 +942,7 @@ static int __init dwarf_unwinder_init(void)
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
diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c
index b3e0067..881b9a3 100644
--- a/arch/sh/kernel/traps.c
+++ b/arch/sh/kernel/traps.c
@@ -8,7 +8,7 @@
#include <asm/system.h>
#ifdef CONFIG_BUG
-static void handle_BUG(struct pt_regs *regs)
+void handle_BUG(struct pt_regs *regs)
{
enum bug_trap_type tt;
tt = report_bug(regs->pc, regs);
@@ -29,7 +29,10 @@ int is_valid_bugaddr(unsigned long addr)
if (probe_kernel_address((insn_size_t *)addr, opcode))
return 0;
- return opcode == TRAPA_BUG_OPCODE;
+ if (opcode == TRAPA_BUG_OPCODE || opcode == TRAPA_UNWINDER_BUG_OPCODE)
+ return 1;
+
+ return 0;
}
#endif
diff --git a/arch/sh/kernel/traps_32.c b/arch/sh/kernel/traps_32.c
index 5634264..05a04b6 100644
--- a/arch/sh/kernel/traps_32.c
+++ b/arch/sh/kernel/traps_32.c
@@ -136,6 +136,7 @@ static void die_if_no_fixup(const char * str, struct pt_regs * regs, long err)
regs->pc = fixup->fixup;
return;
}
+
die(str, regs, err);
}
}
diff --git a/arch/sh/kernel/unwinder.c b/arch/sh/kernel/unwinder.c
index 5f56ff3..e83861d 100644
--- a/arch/sh/kernel/unwinder.c
+++ b/arch/sh/kernel/unwinder.c
@@ -54,8 +54,6 @@ static struct list_head unwinder_list = {
static DEFINE_SPINLOCK(unwinder_lock);
-static atomic_t unwinder_running = ATOMIC_INIT(0);
-
/**
* select_unwinder - Select the best registered stack unwinder.
*
@@ -123,6 +121,8 @@ int unwinder_register(struct unwinder *u)
return ret;
}
+int unwinder_faulted = 0;
+
/*
* Unwind the call stack and pass information to the stacktrace_ops
* functions. Also handle the case where we need to switch to a new
@@ -145,20 +145,41 @@ void unwind_stack(struct task_struct *task, struct pt_regs *regs,
* Hopefully this will give us a semi-reliable stacktrace so we
* can diagnose why curr_unwinder->dump() faulted.
*/
- if (atomic_inc_return(&unwinder_running) != 1) {
+ if (unwinder_faulted) {
spin_lock_irqsave(&unwinder_lock, flags);
- if (!list_is_singular(&unwinder_list)) {
+ /* Make sure no one beat us to changing the unwinder */
+ if (unwinder_faulted && !list_is_singular(&unwinder_list)) {
list_del(&curr_unwinder->list);
curr_unwinder = select_unwinder();
+
+ unwinder_faulted = 0;
}
spin_unlock_irqrestore(&unwinder_lock, flags);
- atomic_dec(&unwinder_running);
}
curr_unwinder->dump(task, regs, sp, ops, data);
+}
+
+/*
+ * Trap handler for UWINDER_BUG() statements. We must switch to the
+ * unwinder with the next highest rating.
+ */
+BUILD_TRAP_HANDLER(unwinder)
+{
+ insn_size_t insn;
+ TRAP_HANDLER_DECL;
+
+ /* Rewind */
+ regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
+ insn = *(insn_size_t *)instruction_pointer(regs);
+
+ /* Switch unwinders when unwind_stack() is called */
+ unwinder_faulted = 1;
- atomic_dec(&unwinder_running);
+#ifdef CONFIG_BUG
+ handle_BUG(regs);
+#endif
}
EXPORT_SYMBOL_GPL(unwind_stack);
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