arm64: stacktrace: Add shared header for common stack unwinding code

In order to reuse the arm64 stack unwinding logic for the nVHE
hypervisor stack, move the common code to a shared header
(arch/arm64/include/asm/stacktrace/common.h).

The nVHE hypervisor cannot safely link against kernel code, so we
make use of the shared header to avoid duplicated logic later in
this series.

Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Fuad Tabba <tabba@google.com>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-2-kaleshsingh@google.com

diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
index aec9315bf15639a7d33c487adbdeb3e3768f8bf2..79f455b37c84df9472536b5168ec2e24c3ad7a87 100644 (file)
--- a/arch/arm64/include/asm/stacktrace.h
+++ b/arch/arm64/include/asm/stacktrace.h
@@ -8,52 +8,19 @@
 #include <linux/percpu.h>
 #include <linux/sched.h>
 #include <linux/sched/task_stack.h>
-#include <linux/types.h>
 #include <linux/llist.h>
 
 #include <asm/memory.h>
 #include <asm/ptrace.h>
 #include <asm/sdei.h>
 
-enum stack_type {
-       STACK_TYPE_UNKNOWN,
-       STACK_TYPE_TASK,
-       STACK_TYPE_IRQ,
-       STACK_TYPE_OVERFLOW,
-       STACK_TYPE_SDEI_NORMAL,
-       STACK_TYPE_SDEI_CRITICAL,
-       __NR_STACK_TYPES
-};
-
-struct stack_info {
-       unsigned long low;
-       unsigned long high;
-       enum stack_type type;
-};
+#include <asm/stacktrace/common.h>
 
 extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
                           const char *loglvl);
 
 DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
 
-static inline bool on_stack(unsigned long sp, unsigned long size,
-                           unsigned long low, unsigned long high,
-                           enum stack_type type, struct stack_info *info)
-{
-       if (!low)
-               return false;
-
-       if (sp < low || sp + size < sp || sp + size > high)
-               return false;
-
-       if (info) {
-               info->low = low;
-               info->high = high;
-               info->type = type;
-       }
-       return true;
-}
-
 static inline bool on_irq_stack(unsigned long sp, unsigned long size,
                                struct stack_info *info)
 {

diff --git a/arch/arm64/include/asm/stacktrace/common.h b/arch/arm64/include/asm/stacktrace/common.h
new file mode 100644 (file)
index 0000000..64ae4f6
--- /dev/null
+++ b/arch/arm64/include/asm/stacktrace/common.h
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Common arm64 stack unwinder code.
+ *
+ * Copyright (C) 2012 ARM Ltd.
+ */
+#ifndef __ASM_STACKTRACE_COMMON_H
+#define __ASM_STACKTRACE_COMMON_H
+
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/types.h>
+
+enum stack_type {
+       STACK_TYPE_UNKNOWN,
+       STACK_TYPE_TASK,
+       STACK_TYPE_IRQ,
+       STACK_TYPE_OVERFLOW,
+       STACK_TYPE_SDEI_NORMAL,
+       STACK_TYPE_SDEI_CRITICAL,
+       __NR_STACK_TYPES
+};
+
+struct stack_info {
+       unsigned long low;
+       unsigned long high;
+       enum stack_type type;
+};
+
+/*
+ * A snapshot of a frame record or fp/lr register values, along with some
+ * accounting information necessary for robust unwinding.
+ *
+ * @fp:          The fp value in the frame record (or the real fp)
+ * @pc:          The lr value in the frame record (or the real lr)
+ *
+ * @stacks_done: Stacks which have been entirely unwound, for which it is no
+ *               longer valid to unwind to.
+ *
+ * @prev_fp:     The fp that pointed to this frame record, or a synthetic value
+ *               of 0. This is used to ensure that within a stack, each
+ *               subsequent frame record is at an increasing address.
+ * @prev_type:   The type of stack this frame record was on, or a synthetic
+ *               value of STACK_TYPE_UNKNOWN. This is used to detect a
+ *               transition from one stack to another.
+ *
+ * @kr_cur:      When KRETPROBES is selected, holds the kretprobe instance
+ *               associated with the most recently encountered replacement lr
+ *               value.
+ *
+ * @task:        The task being unwound.
+ */
+struct unwind_state {
+       unsigned long fp;
+       unsigned long pc;
+       DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES);
+       unsigned long prev_fp;
+       enum stack_type prev_type;
+#ifdef CONFIG_KRETPROBES
+       struct llist_node *kr_cur;
+#endif
+       struct task_struct *task;
+};
+
+static inline bool on_stack(unsigned long sp, unsigned long size,
+                           unsigned long low, unsigned long high,
+                           enum stack_type type, struct stack_info *info)
+{
+       if (!low)
+               return false;
+
+       if (sp < low || sp + size < sp || sp + size > high)
+               return false;
+
+       if (info) {
+               info->low = low;
+               info->high = high;
+               info->type = type;
+       }
+       return true;
+}
+
+static inline void unwind_init_common(struct unwind_state *state,
+                                     struct task_struct *task)
+{
+       state->task = task;
+#ifdef CONFIG_KRETPROBES
+       state->kr_cur = NULL;
+#endif
+
+       /*
+        * Prime the first unwind.
+        *
+        * In unwind_next() we'll check that the FP points to a valid stack,
+        * which can't be STACK_TYPE_UNKNOWN, and the first unwind will be
+        * treated as a transition to whichever stack that happens to be. The
+        * prev_fp value won't be used, but we set it to 0 such that it is
+        * definitely not an accessible stack address.
+        */
+       bitmap_zero(state->stacks_done, __NR_STACK_TYPES);
+       state->prev_fp = 0;
+       state->prev_type = STACK_TYPE_UNKNOWN;
+}
+
+#endif /* __ASM_STACKTRACE_COMMON_H */

diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index fcaa151b81f19ff8cb8463805d04fc8814a04eaf..94a5dd2ab8fd38c0dc96889bcb06122660effb15 100644 (file)
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -18,63 +18,6 @@
 #include <asm/stack_pointer.h>
 #include <asm/stacktrace.h>
 
-/*
- * A snapshot of a frame record or fp/lr register values, along with some
- * accounting information necessary for robust unwinding.
- *
- * @fp:          The fp value in the frame record (or the real fp)
- * @pc:          The lr value in the frame record (or the real lr)
- *
- * @stacks_done: Stacks which have been entirely unwound, for which it is no
- *               longer valid to unwind to.
- *
- * @prev_fp:     The fp that pointed to this frame record, or a synthetic value
- *               of 0. This is used to ensure that within a stack, each
- *               subsequent frame record is at an increasing address.
- * @prev_type:   The type of stack this frame record was on, or a synthetic
- *               value of STACK_TYPE_UNKNOWN. This is used to detect a
- *               transition from one stack to another.
- *
- * @kr_cur:      When KRETPROBES is selected, holds the kretprobe instance
- *               associated with the most recently encountered replacement lr
- *               value.
- *
- * @task:        The task being unwound.
- */
-struct unwind_state {
-       unsigned long fp;
-       unsigned long pc;
-       DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES);
-       unsigned long prev_fp;
-       enum stack_type prev_type;
-#ifdef CONFIG_KRETPROBES
-       struct llist_node *kr_cur;
-#endif
-       struct task_struct *task;
-};
-
-static void unwind_init_common(struct unwind_state *state,
-                              struct task_struct *task)
-{
-       state->task = task;
-#ifdef CONFIG_KRETPROBES
-       state->kr_cur = NULL;
-#endif
-
-       /*
-        * Prime the first unwind.
-        *
-        * In unwind_next() we'll check that the FP points to a valid stack,
-        * which can't be STACK_TYPE_UNKNOWN, and the first unwind will be
-        * treated as a transition to whichever stack that happens to be. The
-        * prev_fp value won't be used, but we set it to 0 such that it is
-        * definitely not an accessible stack address.
-        */
-       bitmap_zero(state->stacks_done, __NR_STACK_TYPES);
-       state->prev_fp = 0;
-       state->prev_type = STACK_TYPE_UNKNOWN;
-}
-
 /*
  * Start an unwind from a pt_regs.
  *