Merge branch kvm-arm64/nvhe-stacktrace into kvmarm-master/next

* kvm-arm64/nvhe-stacktrace: (27 commits)
  : .
  : Add an overflow stack to the nVHE EL2 code, allowing
  : the implementation of an unwinder, courtesy of
  : Kalesh Singh. From the cover letter (slightly edited):
  :
  : "nVHE has two modes of operation: protected (pKVM) and unprotected
  : (conventional nVHE). Depending on the mode, a slightly different approach
  : is used to dump the hypervisor stacktrace but the core unwinding logic
  : remains the same.
  :
  : * Protected nVHE (pKVM) stacktraces:
  :
  : In protected nVHE mode, the host cannot directly access hypervisor memory.
  :
  : The hypervisor stack unwinding happens in EL2 and is made accessible to
  : the host via a shared buffer. Symbolizing and printing the stacktrace
  : addresses is delegated to the host and happens in EL1.
  :
  : * Non-protected (Conventional) nVHE stacktraces:
  :
  : In non-protected mode, the host is able to directly access the hypervisor
  : stack pages.
  :
  : The hypervisor stack unwinding and dumping of the stacktrace is performed
  : by the host in EL1, as this avoids the memory overhead of setting up
  : shared buffers between the host and hypervisor."
  :
  : Additional patches from Oliver Upton and Marc Zyngier, tidying up
  : the initial series.
  : .
  arm64: Update 'unwinder howto'
  KVM: arm64: Don't open code ARRAY_SIZE()
  KVM: arm64: Move nVHE-only helpers into kvm/stacktrace.c
  KVM: arm64: Make unwind()/on_accessible_stack() per-unwinder functions
  KVM: arm64: Move nVHE stacktrace unwinding into its own compilation unit
  KVM: arm64: Move PROTECTED_NVHE_STACKTRACE around
  KVM: arm64: Introduce pkvm_dump_backtrace()
  KVM: arm64: Implement protected nVHE hyp stack unwinder
  KVM: arm64: Save protected-nVHE (pKVM) hyp stacktrace
  KVM: arm64: Stub implementation of pKVM HYP stack unwinder
  KVM: arm64: Allocate shared pKVM hyp stacktrace buffers
  KVM: arm64: Add PROTECTED_NVHE_STACKTRACE Kconfig
  KVM: arm64: Introduce hyp_dump_backtrace()
  KVM: arm64: Implement non-protected nVHE hyp stack unwinder
  KVM: arm64: Prepare non-protected nVHE hypervisor stacktrace
  KVM: arm64: Stub implementation of non-protected nVHE HYP stack unwinder
  KVM: arm64: On stack overflow switch to hyp overflow_stack
  arm64: stacktrace: Add description of stacktrace/common.h
  arm64: stacktrace: Factor out common unwind()
  arm64: stacktrace: Handle frame pointer from different address spaces
  ...

Signed-off-by: Marc Zyngier <maz@kernel.org>

9 files changed, 406 insertions, 10 deletions

diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 8a5fbbf084df..815cc118c675 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -56,4 +56,17 @@ config NVHE_EL2_DEBUG
 
 	  If unsure, say N.
 
+config PROTECTED_NVHE_STACKTRACE
+	bool "Protected KVM hypervisor stacktraces"
+	depends on NVHE_EL2_DEBUG
+	default n
+	help
+	  Say Y here to enable pKVM hypervisor stacktraces on hyp_panic()
+
+	  If using protected nVHE mode, but cannot afford the associated
+	  memory cost (less than 0.75 page per CPU) of pKVM stacktraces,
+	  say N.
+
+	  If unsure, or not using protected nVHE (pKVM), say N.
+
 endif # VIRTUALIZATION
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index aa127ae9f675..5e33c2d4645a 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -12,7 +12,7 @@ obj-$(CONFIG_KVM) += hyp/
 
 kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
 	 inject_fault.o va_layout.o handle_exit.o \
-	 guest.o debug.o reset.o sys_regs.o \
+	 guest.o debug.o reset.o sys_regs.o stacktrace.o \
 	 vgic-sys-reg-v3.o fpsimd.o pkvm.o \
 	 arch_timer.o trng.o vmid.o \
 	 vgic/vgic.o vgic/vgic-init.o \
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index b81f34800d3c..8fe73ee5fa84 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -49,7 +49,7 @@ DEFINE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
 
 DECLARE_KVM_HYP_PER_CPU(unsigned long, kvm_hyp_vector);
 
-static DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
+DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
 unsigned long kvm_arm_hyp_percpu_base[NR_CPUS];
 DECLARE_KVM_NVHE_PER_CPU(struct kvm_nvhe_init_params, kvm_init_params);
 
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c
index cb0bc77c16f9..bbe5b393d689 100644
--- a/arch/arm64/kvm/handle_exit.c
+++ b/arch/arm64/kvm/handle_exit.c
@@ -17,6 +17,7 @@
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_mmu.h>
 #include <asm/debug-monitors.h>
+#include <asm/stacktrace/nvhe.h>
 #include <asm/traps.h>
 
 #include <kvm/arm_hypercalls.h>
@@ -353,6 +354,9 @@ void __noreturn __cold nvhe_hyp_panic_handler(u64 esr, u64 spsr,
 				(void *)(panic_addr + kaslr_offset()));
 	}
 
+	/* Dump the nVHE hypervisor backtrace */
+	kvm_nvhe_dump_backtrace(hyp_offset);
+
 	/*
 	 * Hyp has panicked and we're going to handle that by panicking the
 	 * kernel. The kernel offset will be revealed in the panic so we're
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index a2b0d043dddf..ed5d222e2826 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -14,7 +14,7 @@ lib-objs := $(addprefix ../../../lib/, $(lib-objs))
 
 hyp-obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o \
 	 hyp-main.o hyp-smp.o psci-relay.o early_alloc.o page_alloc.o \
-	 cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o
+	 cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o stacktrace.o
 hyp-obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \
 	 ../fpsimd.o ../hyp-entry.o ../exception.o ../pgtable.o
 hyp-obj-$(CONFIG_DEBUG_LIST) += list_debug.o
diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S
index ea6a397b64a6..b6c0188c4b35 100644
--- a/arch/arm64/kvm/hyp/nvhe/host.S
+++ b/arch/arm64/kvm/hyp/nvhe/host.S
@@ -177,13 +177,8 @@ SYM_FUNC_END(__host_hvc)
 	b	hyp_panic
 
 .L__hyp_sp_overflow\@:
-	/*
-	 * Reset SP to the top of the stack, to allow handling the hyp_panic.
-	 * This corrupts the stack but is ok, since we won't be attempting
-	 * any unwinding here.
-	 */
-	ldr_this_cpu	x0, kvm_init_params + NVHE_INIT_STACK_HYP_VA, x1
-	mov	sp, x0
+	/* Switch to the overflow stack */
+	adr_this_cpu sp, overflow_stack + OVERFLOW_STACK_SIZE, x0
 
 	b	hyp_panic_bad_stack
 	ASM_BUG()
diff --git a/arch/arm64/kvm/hyp/nvhe/stacktrace.c b/arch/arm64/kvm/hyp/nvhe/stacktrace.c
new file mode 100644
index 000000000000..58f645ad66bc
--- /dev/null
+++ b/arch/arm64/kvm/hyp/nvhe/stacktrace.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * KVM nVHE hypervisor stack tracing support.
+ *
+ * Copyright (C) 2022 Google LLC
+ */
+#include <asm/kvm_asm.h>
+#include <asm/kvm_hyp.h>
+#include <asm/memory.h>
+#include <asm/percpu.h>
+
+DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack)
+	__aligned(16);
+
+DEFINE_PER_CPU(struct kvm_nvhe_stacktrace_info, kvm_stacktrace_info);
+
+/*
+ * hyp_prepare_backtrace - Prepare non-protected nVHE backtrace.
+ *
+ * @fp : frame pointer at which to start the unwinding.
+ * @pc : program counter at which to start the unwinding.
+ *
+ * Save the information needed by the host to unwind the non-protected
+ * nVHE hypervisor stack in EL1.
+ */
+static void hyp_prepare_backtrace(unsigned long fp, unsigned long pc)
+{
+	struct kvm_nvhe_stacktrace_info *stacktrace_info = this_cpu_ptr(&kvm_stacktrace_info);
+	struct kvm_nvhe_init_params *params = this_cpu_ptr(&kvm_init_params);
+
+	stacktrace_info->stack_base = (unsigned long)(params->stack_hyp_va - PAGE_SIZE);
+	stacktrace_info->overflow_stack_base = (unsigned long)this_cpu_ptr(overflow_stack);
+	stacktrace_info->fp = fp;
+	stacktrace_info->pc = pc;
+}
+
+#ifdef CONFIG_PROTECTED_NVHE_STACKTRACE
+#include <asm/stacktrace/nvhe.h>
+
+DEFINE_PER_CPU(unsigned long [NVHE_STACKTRACE_SIZE/sizeof(long)], pkvm_stacktrace);
+
+static bool on_overflow_stack(unsigned long sp, unsigned long size,
+			      struct stack_info *info)
+{
+	unsigned long low = (unsigned long)this_cpu_ptr(overflow_stack);
+	unsigned long high = low + OVERFLOW_STACK_SIZE;
+
+	return on_stack(sp, size, low, high, STACK_TYPE_OVERFLOW, info);
+}
+
+static bool on_hyp_stack(unsigned long sp, unsigned long size,
+			      struct stack_info *info)
+{
+	struct kvm_nvhe_init_params *params = this_cpu_ptr(&kvm_init_params);
+	unsigned long high = params->stack_hyp_va;
+	unsigned long low = high - PAGE_SIZE;
+
+	return on_stack(sp, size, low, high, STACK_TYPE_HYP, info);
+}
+
+static bool on_accessible_stack(const struct task_struct *tsk,
+				unsigned long sp, unsigned long size,
+				struct stack_info *info)
+{
+	if (info)
+		info->type = STACK_TYPE_UNKNOWN;
+
+	return (on_overflow_stack(sp, size, info) ||
+		on_hyp_stack(sp, size, info));
+}
+
+static int unwind_next(struct unwind_state *state)
+{
+	struct stack_info info;
+
+	return unwind_next_common(state, &info, on_accessible_stack, NULL);
+}
+
+static void notrace unwind(struct unwind_state *state,
+			   stack_trace_consume_fn consume_entry,
+			   void *cookie)
+{
+	while (1) {
+		int ret;
+
+		if (!consume_entry(cookie, state->pc))
+			break;
+		ret = unwind_next(state);
+		if (ret < 0)
+			break;
+	}
+}
+
+/*
+ * pkvm_save_backtrace_entry - Saves a protected nVHE HYP stacktrace entry
+ *
+ * @arg    : index of the entry in the stacktrace buffer
+ * @where  : the program counter corresponding to the stack frame
+ *
+ * Save the return address of a stack frame to the shared stacktrace buffer.
+ * The host can access this shared buffer from EL1 to dump the backtrace.
+ */
+static bool pkvm_save_backtrace_entry(void *arg, unsigned long where)
+{
+	unsigned long *stacktrace = this_cpu_ptr(pkvm_stacktrace);
+	int *idx = (int *)arg;
+
+	/*
+	 * Need 2 free slots: 1 for current entry and 1 for the
+	 * delimiter.
+	 */
+	if (*idx > ARRAY_SIZE(pkvm_stacktrace) - 2)
+		return false;
+
+	stacktrace[*idx] = where;
+	stacktrace[++*idx] = 0UL;
+
+	return true;
+}
+
+/*
+ * pkvm_save_backtrace - Saves the protected nVHE HYP stacktrace
+ *
+ * @fp : frame pointer at which to start the unwinding.
+ * @pc : program counter at which to start the unwinding.
+ *
+ * Save the unwinded stack addresses to the shared stacktrace buffer.
+ * The host can access this shared buffer from EL1 to dump the backtrace.
+ */
+static void pkvm_save_backtrace(unsigned long fp, unsigned long pc)
+{
+	struct unwind_state state;
+	int idx = 0;
+
+	kvm_nvhe_unwind_init(&state, fp, pc);
+
+	unwind(&state, pkvm_save_backtrace_entry, &idx);
+}
+#else /* !CONFIG_PROTECTED_NVHE_STACKTRACE */
+static void pkvm_save_backtrace(unsigned long fp, unsigned long pc)
+{
+}
+#endif /* CONFIG_PROTECTED_NVHE_STACKTRACE */
+
+/*
+ * kvm_nvhe_prepare_backtrace - prepare to dump the nVHE backtrace
+ *
+ * @fp : frame pointer at which to start the unwinding.
+ * @pc : program counter at which to start the unwinding.
+ *
+ * Saves the information needed by the host to dump the nVHE hypervisor
+ * backtrace.
+ */
+void kvm_nvhe_prepare_backtrace(unsigned long fp, unsigned long pc)
+{
+	if (is_protected_kvm_enabled())
+		pkvm_save_backtrace(fp, pc);
+	else
+		hyp_prepare_backtrace(fp, pc);
+}
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index ab0e19117dfe..9f6385702061 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -34,6 +34,8 @@ DEFINE_PER_CPU(struct kvm_host_data, kvm_host_data);
 DEFINE_PER_CPU(struct kvm_cpu_context, kvm_hyp_ctxt);
 DEFINE_PER_CPU(unsigned long, kvm_hyp_vector);
 
+extern void kvm_nvhe_prepare_backtrace(unsigned long fp, unsigned long pc);
+
 static void __activate_traps(struct kvm_vcpu *vcpu)
 {
 	u64 val;
@@ -375,6 +377,10 @@ asmlinkage void __noreturn hyp_panic(void)
 		__sysreg_restore_state_nvhe(host_ctxt);
 	}
 
+	/* Prepare to dump kvm nvhe hyp stacktrace */
+	kvm_nvhe_prepare_backtrace((unsigned long)__builtin_frame_address(0),
+				   _THIS_IP_);
+
 	__hyp_do_panic(host_ctxt, spsr, elr, par);
 	unreachable();
 }
diff --git a/arch/arm64/kvm/stacktrace.c b/arch/arm64/kvm/stacktrace.c
new file mode 100644
index 000000000000..949d19d603fb
--- /dev/null
+++ b/arch/arm64/kvm/stacktrace.c
@@ -0,0 +1,218 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * KVM nVHE hypervisor stack tracing support.
+ *
+ * The unwinder implementation depends on the nVHE mode:
+ *
+ *   1) Non-protected nVHE mode - the host can directly access the
+ *      HYP stack pages and unwind the HYP stack in EL1. This saves having
+ *      to allocate shared buffers for the host to read the unwinded
+ *      stacktrace.
+ *
+ *   2) pKVM (protected nVHE) mode - the host cannot directly access
+ *      the HYP memory. The stack is unwinded in EL2 and dumped to a shared
+ *      buffer where the host can read and print the stacktrace.
+ *
+ * Copyright (C) 2022 Google LLC
+ */
+
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+
+#include <asm/stacktrace/nvhe.h>
+
+/*
+ * kvm_nvhe_stack_kern_va - Convert KVM nVHE HYP stack addresses to a kernel VAs
+ *
+ * The nVHE hypervisor stack is mapped in the flexible 'private' VA range, to
+ * allow for guard pages below the stack. Consequently, the fixed offset address
+ * translation macros won't work here.
+ *
+ * The kernel VA is calculated as an offset from the kernel VA of the hypervisor
+ * stack base.
+ *
+ * Returns true on success and updates @addr to its corresponding kernel VA;
+ * otherwise returns false.
+ */
+static bool kvm_nvhe_stack_kern_va(unsigned long *addr,
+				   enum stack_type type)
+{
+	struct kvm_nvhe_stacktrace_info *stacktrace_info;
+	unsigned long hyp_base, kern_base, hyp_offset;
+
+	stacktrace_info = this_cpu_ptr_nvhe_sym(kvm_stacktrace_info);
+
+	switch (type) {
+	case STACK_TYPE_HYP:
+		kern_base = (unsigned long)*this_cpu_ptr(&kvm_arm_hyp_stack_page);
+		hyp_base = (unsigned long)stacktrace_info->stack_base;
+		break;
+	case STACK_TYPE_OVERFLOW:
+		kern_base = (unsigned long)this_cpu_ptr_nvhe_sym(overflow_stack);
+		hyp_base = (unsigned long)stacktrace_info->overflow_stack_base;
+		break;
+	default:
+		return false;
+	}
+
+	hyp_offset = *addr - hyp_base;
+
+	*addr = kern_base + hyp_offset;
+
+	return true;
+}
+
+static bool on_overflow_stack(unsigned long sp, unsigned long size,
+			      struct stack_info *info)
+{
+	struct kvm_nvhe_stacktrace_info *stacktrace_info
+				= this_cpu_ptr_nvhe_sym(kvm_stacktrace_info);
+	unsigned long low = (unsigned long)stacktrace_info->overflow_stack_base;
+	unsigned long high = low + OVERFLOW_STACK_SIZE;
+
+	return on_stack(sp, size, low, high, STACK_TYPE_OVERFLOW, info);
+}
+
+static bool on_hyp_stack(unsigned long sp, unsigned long size,
+			 struct stack_info *info)
+{
+	struct kvm_nvhe_stacktrace_info *stacktrace_info
+				= this_cpu_ptr_nvhe_sym(kvm_stacktrace_info);
+	unsigned long low = (unsigned long)stacktrace_info->stack_base;
+	unsigned long high = low + PAGE_SIZE;
+
+	return on_stack(sp, size, low, high, STACK_TYPE_HYP, info);
+}
+
+static bool on_accessible_stack(const struct task_struct *tsk,
+				unsigned long sp, unsigned long size,
+				struct stack_info *info)
+{
+	if (info)
+		info->type = STACK_TYPE_UNKNOWN;
+
+	return (on_overflow_stack(sp, size, info) ||
+		on_hyp_stack(sp, size, info));
+}
+
+static int unwind_next(struct unwind_state *state)
+{
+	struct stack_info info;
+
+	return unwind_next_common(state, &info, on_accessible_stack,
+				  kvm_nvhe_stack_kern_va);
+}
+
+static void unwind(struct unwind_state *state,
+		   stack_trace_consume_fn consume_entry, void *cookie)
+{
+	while (1) {
+		int ret;
+
+		if (!consume_entry(cookie, state->pc))
+			break;
+		ret = unwind_next(state);
+		if (ret < 0)
+			break;
+	}
+}
+
+/*
+ * kvm_nvhe_dump_backtrace_entry - Symbolize and print an nVHE backtrace entry
+ *
+ * @arg    : the hypervisor offset, used for address translation
+ * @where  : the program counter corresponding to the stack frame
+ */
+static bool kvm_nvhe_dump_backtrace_entry(void *arg, unsigned long where)
+{
+	unsigned long va_mask = GENMASK_ULL(vabits_actual - 1, 0);
+	unsigned long hyp_offset = (unsigned long)arg;
+
+	/* Mask tags and convert to kern addr */
+	where = (where & va_mask) + hyp_offset;
+	kvm_err(" [<%016lx>] %pB\n", where, (void *)(where + kaslr_offset()));
+
+	return true;
+}
+
+static void kvm_nvhe_dump_backtrace_start(void)
+{
+	kvm_err("nVHE call trace:\n");
+}
+
+static void kvm_nvhe_dump_backtrace_end(void)
+{
+	kvm_err("---[ end nVHE call trace ]---\n");
+}
+
+/*
+ * hyp_dump_backtrace - Dump the non-protected nVHE backtrace.
+ *
+ * @hyp_offset: hypervisor offset, used for address translation.
+ *
+ * The host can directly access HYP stack pages in non-protected
+ * mode, so the unwinding is done directly from EL1. This removes
+ * the need for shared buffers between host and hypervisor for
+ * the stacktrace.
+ */
+static void hyp_dump_backtrace(unsigned long hyp_offset)
+{
+	struct kvm_nvhe_stacktrace_info *stacktrace_info;
+	struct unwind_state state;
+
+	stacktrace_info = this_cpu_ptr_nvhe_sym(kvm_stacktrace_info);
+
+	kvm_nvhe_unwind_init(&state, stacktrace_info->fp, stacktrace_info->pc);
+
+	kvm_nvhe_dump_backtrace_start();
+	unwind(&state, kvm_nvhe_dump_backtrace_entry, (void *)hyp_offset);
+	kvm_nvhe_dump_backtrace_end();
+}
+
+#ifdef CONFIG_PROTECTED_NVHE_STACKTRACE
+DECLARE_KVM_NVHE_PER_CPU(unsigned long [NVHE_STACKTRACE_SIZE/sizeof(long)],
+			 pkvm_stacktrace);
+
+/*
+ * pkvm_dump_backtrace - Dump the protected nVHE HYP backtrace.
+ *
+ * @hyp_offset: hypervisor offset, used for address translation.
+ *
+ * Dumping of the pKVM HYP backtrace is done by reading the
+ * stack addresses from the shared stacktrace buffer, since the
+ * host cannot directly access hypervisor memory in protected
+ * mode.
+ */
+static void pkvm_dump_backtrace(unsigned long hyp_offset)
+{
+	unsigned long *stacktrace
+		= (unsigned long *) this_cpu_ptr_nvhe_sym(pkvm_stacktrace);
+	int i;
+
+	kvm_nvhe_dump_backtrace_start();
+	/* The saved stacktrace is terminated by a null entry */
+	for (i = 0;
+	     i < ARRAY_SIZE(kvm_nvhe_sym(pkvm_stacktrace)) && stacktrace[i];
+	     i++)
+		kvm_nvhe_dump_backtrace_entry((void *)hyp_offset, stacktrace[i]);
+	kvm_nvhe_dump_backtrace_end();
+}
+#else	/* !CONFIG_PROTECTED_NVHE_STACKTRACE */
+static void pkvm_dump_backtrace(unsigned long hyp_offset)
+{
+	kvm_err("Cannot dump pKVM nVHE stacktrace: !CONFIG_PROTECTED_NVHE_STACKTRACE\n");
+}
+#endif /* CONFIG_PROTECTED_NVHE_STACKTRACE */
+
+/*
+ * kvm_nvhe_dump_backtrace - Dump KVM nVHE hypervisor backtrace.
+ *
+ * @hyp_offset: hypervisor offset, used for address translation.
+ */
+void kvm_nvhe_dump_backtrace(unsigned long hyp_offset)
+{
+	if (is_protected_kvm_enabled())
+		pkvm_dump_backtrace(hyp_offset);
+	else
+		hyp_dump_backtrace(hyp_offset);
+}