arm64: stacktrace: factor out kernel unwind state

On arm64 we share some unwinding code between the regular kernel
unwinder and the KVM hyp unwinder. Some of this common code only matters
to the regular unwinder, e.g. the `kr_cur` and `task` fields in the
common struct unwind_state.

We're likely to add more state which only matters for regular kernel
unwinding (or only for hyp unwinding). In preparation for such changes,
this patch factors out the kernel-specific state into a new struct
kunwind_state, and updates the kernel unwind code accordingly.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Puranjay Mohan <puranjay12@gmail.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Puranjay Mohan <puranjay12@gmail.com>
Reviewed-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20231124110511.2795958-2-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

2 files changed, 2 insertions, 19 deletions

diff --git a/arch/arm64/include/asm/stacktrace/common.h b/arch/arm64/include/asm/stacktrace/common.h
index 508f734de46e..f63dc654e545 100644
--- a/arch/arm64/include/asm/stacktrace/common.h
+++ b/arch/arm64/include/asm/stacktrace/common.h
@@ -9,7 +9,6 @@
 #ifndef __ASM_STACKTRACE_COMMON_H
 #define __ASM_STACKTRACE_COMMON_H
 
-#include <linux/kprobes.h>
 #include <linux/types.h>
 
 struct stack_info {
@@ -23,12 +22,6 @@ struct stack_info {
  * @fp:          The fp value in the frame record (or the real fp)
  * @pc:          The lr value in the frame record (or the real lr)
  *
- * @kr_cur:      When KRETPROBES is selected, holds the kretprobe instance
- *               associated with the most recently encountered replacement lr
- *               value.
- *
- * @task:        The task being unwound.
- *
  * @stack:       The stack currently being unwound.
  * @stacks:      An array of stacks which can be unwound.
  * @nr_stacks:   The number of stacks in @stacks.
@@ -36,10 +29,6 @@ struct stack_info {
 struct unwind_state {
 	unsigned long fp;
 	unsigned long pc;
-#ifdef CONFIG_KRETPROBES
-	struct llist_node *kr_cur;
-#endif
-	struct task_struct *task;
 
 	struct stack_info stack;
 	struct stack_info *stacks;
@@ -66,14 +55,8 @@ static inline bool stackinfo_on_stack(const struct stack_info *info,
 	return true;
 }
 
-static inline void unwind_init_common(struct unwind_state *state,
-				      struct task_struct *task)
+static inline void unwind_init_common(struct unwind_state *state)
 {
-	state->task = task;
-#ifdef CONFIG_KRETPROBES
-	state->kr_cur = NULL;
-#endif
-
 	state->stack = stackinfo_get_unknown();
 }
 
diff --git a/arch/arm64/include/asm/stacktrace/nvhe.h b/arch/arm64/include/asm/stacktrace/nvhe.h
index 25ab83a315a7..44759281d0d4 100644
--- a/arch/arm64/include/asm/stacktrace/nvhe.h
+++ b/arch/arm64/include/asm/stacktrace/nvhe.h
@@ -31,7 +31,7 @@ static inline void kvm_nvhe_unwind_init(struct unwind_state *state,
 					unsigned long fp,
 					unsigned long pc)
 {
-	unwind_init_common(state, NULL);
+	unwind_init_common(state);
 
 	state->fp = fp;
 	state->pc = pc;