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-rw-r--r--arch/arm64/include/asm/ftrace.h11
-rw-r--r--arch/arm64/include/asm/pgalloc.h2
-rw-r--r--arch/arm64/include/asm/stacktrace.h6
-rw-r--r--arch/arm64/include/asm/uaccess.h48
-rw-r--r--arch/arm64/kernel/ftrace.c6
-rw-r--r--arch/arm64/kernel/stacktrace.c18
6 files changed, 64 insertions, 27 deletions
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index 347b0cc68f07..1494cfa8639b 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -12,6 +12,17 @@
#define HAVE_FUNCTION_GRAPH_FP_TEST
+/*
+ * HAVE_FUNCTION_GRAPH_RET_ADDR_PTR means that the architecture can provide a
+ * "return address pointer" which can be used to uniquely identify a return
+ * address which has been overwritten.
+ *
+ * On arm64 we use the address of the caller's frame record, which remains the
+ * same for the lifetime of the instrumented function, unlike the return
+ * address in the LR.
+ */
+#define HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
+
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
#define ARCH_SUPPORTS_FTRACE_OPS 1
#else
diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h
index 8433a2058eb1..237224484d0f 100644
--- a/arch/arm64/include/asm/pgalloc.h
+++ b/arch/arm64/include/asm/pgalloc.h
@@ -76,7 +76,7 @@ static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t ptep,
static inline void
pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *ptep)
{
- VM_BUG_ON(mm != &init_mm);
+ VM_BUG_ON(mm && mm != &init_mm);
__pmd_populate(pmdp, __pa(ptep), PMD_TYPE_TABLE | PMD_TABLE_UXN);
}
diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
index a4e046ef4568..6564a01cc085 100644
--- a/arch/arm64/include/asm/stacktrace.h
+++ b/arch/arm64/include/asm/stacktrace.h
@@ -47,9 +47,6 @@ struct stack_info {
* @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.
- *
- * @graph: When FUNCTION_GRAPH_TRACER is selected, holds the index of a
- * replacement lr value in the ftrace graph stack.
*/
struct stackframe {
unsigned long fp;
@@ -57,9 +54,6 @@ struct stackframe {
DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES);
unsigned long prev_fp;
enum stack_type prev_type;
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- int graph;
-#endif
#ifdef CONFIG_KRETPROBES
struct llist_node *kr_cur;
#endif
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 6e2e0b7031ab..3a5ff5e20586 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -281,12 +281,22 @@ do { \
(x) = (__force __typeof__(*(ptr)))__gu_val; \
} while (0)
+/*
+ * We must not call into the scheduler between uaccess_ttbr0_enable() and
+ * uaccess_ttbr0_disable(). As `x` and `ptr` could contain blocking functions,
+ * we must evaluate these outside of the critical section.
+ */
#define __raw_get_user(x, ptr, err) \
do { \
+ __typeof__(*(ptr)) __user *__rgu_ptr = (ptr); \
+ __typeof__(x) __rgu_val; \
__chk_user_ptr(ptr); \
+ \
uaccess_ttbr0_enable(); \
- __raw_get_mem("ldtr", x, ptr, err); \
+ __raw_get_mem("ldtr", __rgu_val, __rgu_ptr, err); \
uaccess_ttbr0_disable(); \
+ \
+ (x) = __rgu_val; \
} while (0)
#define __get_user_error(x, ptr, err) \
@@ -310,14 +320,22 @@ do { \
#define get_user __get_user
+/*
+ * We must not call into the scheduler between __uaccess_enable_tco_async() and
+ * __uaccess_disable_tco_async(). As `dst` and `src` may contain blocking
+ * functions, we must evaluate these outside of the critical section.
+ */
#define __get_kernel_nofault(dst, src, type, err_label) \
do { \
+ __typeof__(dst) __gkn_dst = (dst); \
+ __typeof__(src) __gkn_src = (src); \
int __gkn_err = 0; \
\
__uaccess_enable_tco_async(); \
- __raw_get_mem("ldr", *((type *)(dst)), \
- (__force type *)(src), __gkn_err); \
+ __raw_get_mem("ldr", *((type *)(__gkn_dst)), \
+ (__force type *)(__gkn_src), __gkn_err); \
__uaccess_disable_tco_async(); \
+ \
if (unlikely(__gkn_err)) \
goto err_label; \
} while (0)
@@ -351,11 +369,19 @@ do { \
} \
} while (0)
+/*
+ * We must not call into the scheduler between uaccess_ttbr0_enable() and
+ * uaccess_ttbr0_disable(). As `x` and `ptr` could contain blocking functions,
+ * we must evaluate these outside of the critical section.
+ */
#define __raw_put_user(x, ptr, err) \
do { \
- __chk_user_ptr(ptr); \
+ __typeof__(*(ptr)) __user *__rpu_ptr = (ptr); \
+ __typeof__(*(ptr)) __rpu_val = (x); \
+ __chk_user_ptr(__rpu_ptr); \
+ \
uaccess_ttbr0_enable(); \
- __raw_put_mem("sttr", x, ptr, err); \
+ __raw_put_mem("sttr", __rpu_val, __rpu_ptr, err); \
uaccess_ttbr0_disable(); \
} while (0)
@@ -380,14 +406,22 @@ do { \
#define put_user __put_user
+/*
+ * We must not call into the scheduler between __uaccess_enable_tco_async() and
+ * __uaccess_disable_tco_async(). As `dst` and `src` may contain blocking
+ * functions, we must evaluate these outside of the critical section.
+ */
#define __put_kernel_nofault(dst, src, type, err_label) \
do { \
+ __typeof__(dst) __pkn_dst = (dst); \
+ __typeof__(src) __pkn_src = (src); \
int __pkn_err = 0; \
\
__uaccess_enable_tco_async(); \
- __raw_put_mem("str", *((type *)(src)), \
- (__force type *)(dst), __pkn_err); \
+ __raw_put_mem("str", *((type *)(__pkn_src)), \
+ (__force type *)(__pkn_dst), __pkn_err); \
__uaccess_disable_tco_async(); \
+ \
if (unlikely(__pkn_err)) \
goto err_label; \
} while(0)
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index fc62dfe73f93..4506c4a90ac1 100644
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -244,8 +244,6 @@ void arch_ftrace_update_code(int command)
* on the way back to parent. For this purpose, this function is called
* in _mcount() or ftrace_caller() to replace return address (*parent) on
* the call stack to return_to_handler.
- *
- * Note that @frame_pointer is used only for sanity check later.
*/
void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
unsigned long frame_pointer)
@@ -263,8 +261,10 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent,
*/
old = *parent;
- if (!function_graph_enter(old, self_addr, frame_pointer, NULL))
+ if (!function_graph_enter(old, self_addr, frame_pointer,
+ (void *)frame_pointer)) {
*parent = return_hooker;
+ }
}
#ifdef CONFIG_DYNAMIC_FTRACE
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index c30624fff6ac..94f83cd44e50 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -38,9 +38,6 @@ void start_backtrace(struct stackframe *frame, unsigned long fp,
{
frame->fp = fp;
frame->pc = pc;
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- frame->graph = 0;
-#endif
#ifdef CONFIG_KRETPROBES
frame->kr_cur = NULL;
#endif
@@ -116,20 +113,23 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
frame->prev_fp = fp;
frame->prev_type = info.type;
+ frame->pc = ptrauth_strip_insn_pac(frame->pc);
+
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if (tsk->ret_stack &&
- (ptrauth_strip_insn_pac(frame->pc) == (unsigned long)return_to_handler)) {
- struct ftrace_ret_stack *ret_stack;
+ (frame->pc == (unsigned long)return_to_handler)) {
+ unsigned long orig_pc;
/*
* This is a case where function graph tracer has
* modified a return address (LR) in a stack frame
* to hook a function return.
* So replace it to an original value.
*/
- ret_stack = ftrace_graph_get_ret_stack(tsk, frame->graph++);
- if (WARN_ON_ONCE(!ret_stack))
+ orig_pc = ftrace_graph_ret_addr(tsk, NULL, frame->pc,
+ (void *)frame->fp);
+ if (WARN_ON_ONCE(frame->pc == orig_pc))
return -EINVAL;
- frame->pc = ret_stack->ret;
+ frame->pc = orig_pc;
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
#ifdef CONFIG_KRETPROBES
@@ -137,8 +137,6 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
frame->pc = kretprobe_find_ret_addr(tsk, (void *)frame->fp, &frame->kr_cur);
#endif
- frame->pc = ptrauth_strip_insn_pac(frame->pc);
-
return 0;
}
NOKPROBE_SYMBOL(unwind_frame);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.