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-rw-r--r--arch/sh/include/asm/bug.h25
-rw-r--r--arch/sh/include/asm/system.h5
-rw-r--r--arch/sh/include/asm/unwinder.h6
-rw-r--r--arch/sh/kernel/debugtraps.S6
-rw-r--r--arch/sh/kernel/dwarf.c38
-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
8 files changed, 95 insertions, 26 deletions
diff --git a/arch/sh/include/asm/bug.h b/arch/sh/include/asm/bug.h
index c01718040166..b7d9822fd6c2 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/system.h b/arch/sh/include/asm/system.h
index ab79e1f4fbe0..f9e2ceb94d9b 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 3dc551453e28..1e65c07b3e18 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/debugtraps.S b/arch/sh/kernel/debugtraps.S
index 591741383ee6..cb00e4a82d4d 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 d271d04adccd..606ece37eb42 100644
--- a/arch/sh/kernel/dwarf.c
+++ b/arch/sh/kernel/dwarf.c
@@ -69,7 +69,7 @@ static struct dwarf_reg *dwarf_frame_alloc_reg(struct dwarf_frame *frame,
* Let's just bomb hard here, we have no way to
* gracefully recover.
*/
- BUG();
+ UNWINDER_BUG();
}
reg->number = reg_num;
@@ -232,7 +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)
@@ -247,7 +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;
@@ -519,6 +519,7 @@ static int dwarf_cfa_execute_insns(unsigned char *insn_start,
break;
default:
pr_debug("unhandled DWARF instruction 0x%x\n", insn);
+ UNWINDER_BUG();
break;
}
}
@@ -535,8 +536,8 @@ 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;
@@ -558,7 +559,7 @@ struct dwarf_frame *dwarf_unwind_stack(unsigned long pc,
frame = mempool_alloc(dwarf_frame_pool, GFP_ATOMIC);
if (!frame) {
printk(KERN_ERR "Unable to allocate a dwarf frame\n");
- BUG();
+ UNWINDER_BUG();
}
INIT_LIST_HEAD(&frame->reg_list);
@@ -605,7 +606,8 @@ struct dwarf_frame *dwarf_unwind_stack(unsigned long pc,
case DWARF_FRAME_CFA_REG_OFFSET:
if (prev) {
reg = dwarf_frame_reg(prev, frame->cfa_register);
- BUG_ON(!reg);
+ UNWINDER_BUG_ON(!reg);
+ UNWINDER_BUG_ON(reg->flags != DWARF_REG_OFFSET);
addr = prev->cfa + reg->addr;
frame->cfa = __raw_readl(addr);
@@ -624,12 +626,13 @@ 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. */
reg = dwarf_frame_reg(frame, DWARF_ARCH_RA_REG);
- BUG_ON(!reg);
+ UNWINDER_BUG_ON(!reg);
+ UNWINDER_BUG_ON(reg->flags != DWARF_REG_OFFSET);
addr = frame->cfa + reg->addr;
frame->return_addr = __raw_readl(addr);
@@ -664,7 +667,7 @@ 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;
@@ -694,7 +697,7 @@ 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++;
@@ -722,16 +725,16 @@ 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;
}
}
@@ -805,9 +808,11 @@ 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, *_frame;
unsigned long return_addr;
@@ -831,7 +836,6 @@ static void dwarf_unwinder_dump(struct task_struct *task, struct pt_regs *regs,
return_addr = frame->return_addr;
ops->address(data, return_addr, 1);
}
-
}
static struct unwinder dwarf_unwinder = {
diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c
index b3e0067db358..881b9a32b7de 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 563426487c6b..05a04b6df844 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 2b30fa28b440..b9c122abe251 100644
--- a/arch/sh/kernel/unwinder.c
+++ b/arch/sh/kernel/unwinder.c
@@ -53,8 +53,6 @@ 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.
*
@@ -122,6 +120,8 @@ 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
@@ -144,19 +144,40 @@ 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
}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.