2 files changed, 101 insertions, 0 deletions

diff --git a/arch/arm64/kernel/patching.c b/arch/arm64/kernel/patching.c
index b4835f6d594b..255534930368 100644
--- a/arch/arm64/kernel/patching.c
+++ b/arch/arm64/kernel/patching.c
@@ -105,6 +105,81 @@ noinstr int aarch64_insn_write_literal_u64(void *addr, u64 val)
 	return ret;
 }
 
+typedef void text_poke_f(void *dst, void *src, size_t patched, size_t len);
+
+static void *__text_poke(text_poke_f func, void *addr, void *src, size_t len)
+{
+	unsigned long flags;
+	size_t patched = 0;
+	size_t size;
+	void *waddr;
+	void *ptr;
+
+	raw_spin_lock_irqsave(&patch_lock, flags);
+
+	while (patched < len) {
+		ptr = addr + patched;
+		size = min_t(size_t, PAGE_SIZE - offset_in_page(ptr),
+			     len - patched);
+
+		waddr = patch_map(ptr, FIX_TEXT_POKE0);
+		func(waddr, src, patched, size);
+		patch_unmap(FIX_TEXT_POKE0);
+
+		patched += size;
+	}
+	raw_spin_unlock_irqrestore(&patch_lock, flags);
+
+	flush_icache_range((uintptr_t)addr, (uintptr_t)addr + len);
+
+	return addr;
+}
+
+static void text_poke_memcpy(void *dst, void *src, size_t patched, size_t len)
+{
+	copy_to_kernel_nofault(dst, src + patched, len);
+}
+
+static void text_poke_memset(void *dst, void *src, size_t patched, size_t len)
+{
+	u32 c = *(u32 *)src;
+
+	memset32(dst, c, len / 4);
+}
+
+/**
+ * aarch64_insn_copy - Copy instructions into (an unused part of) RX memory
+ * @dst: address to modify
+ * @src: source of the copy
+ * @len: length to copy
+ *
+ * Useful for JITs to dump new code blocks into unused regions of RX memory.
+ */
+noinstr void *aarch64_insn_copy(void *dst, void *src, size_t len)
+{
+	/* A64 instructions must be word aligned */
+	if ((uintptr_t)dst & 0x3)
+		return NULL;
+
+	return __text_poke(text_poke_memcpy, dst, src, len);
+}
+
+/**
+ * aarch64_insn_set - memset for RX memory regions.
+ * @dst: address to modify
+ * @insn: value to set
+ * @len: length of memory region.
+ *
+ * Useful for JITs to fill regions of RX memory with illegal instructions.
+ */
+noinstr void *aarch64_insn_set(void *dst, u32 insn, size_t len)
+{
+	if ((uintptr_t)dst & 0x3)
+		return NULL;
+
+	return __text_poke(text_poke_memset, dst, &insn, len);
+}
+
 int __kprobes aarch64_insn_patch_text_nosync(void *addr, u32 insn)
 {
 	u32 *tp = addr;
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index b2a60e0bcfd2..684c26511696 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -7,6 +7,7 @@
 #include <linux/kernel.h>
 #include <linux/efi.h>
 #include <linux/export.h>
+#include <linux/filter.h>
 #include <linux/ftrace.h>
 #include <linux/kprobes.h>
 #include <linux/sched.h>
@@ -266,6 +267,31 @@ noinline noinstr void arch_stack_walk(stack_trace_consume_fn consume_entry,
 	kunwind_stack_walk(arch_kunwind_consume_entry, &data, task, regs);
 }
 
+struct bpf_unwind_consume_entry_data {
+	bool (*consume_entry)(void *cookie, u64 ip, u64 sp, u64 fp);
+	void *cookie;
+};
+
+static bool
+arch_bpf_unwind_consume_entry(const struct kunwind_state *state, void *cookie)
+{
+	struct bpf_unwind_consume_entry_data *data = cookie;
+
+	return data->consume_entry(data->cookie, state->common.pc, 0,
+				   state->common.fp);
+}
+
+noinline noinstr void arch_bpf_stack_walk(bool (*consume_entry)(void *cookie, u64 ip, u64 sp,
+								u64 fp), void *cookie)
+{
+	struct bpf_unwind_consume_entry_data data = {
+		.consume_entry = consume_entry,
+		.cookie = cookie,
+	};
+
+	kunwind_stack_walk(arch_bpf_unwind_consume_entry, &data, current, NULL);
+}
+
 static bool dump_backtrace_entry(void *arg, unsigned long where)
 {
 	char *loglvl = arg;