bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/arch/powerpc/boot/cuboot.c b/arch/powerpc/boot/cuboot.c
new file mode 100644
index 000000000..7f186658f
--- /dev/null
+++ b/arch/powerpc/boot/cuboot.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Compatibility for old (not device tree aware) U-Boot versions
+ *
+ * Author: Scott Wood <scottwood@freescale.com>
+ * Consolidated using macros by David Gibson <david@gibson.dropbear.id.au>
+ *
+ * Copyright 2007 David Gibson, IBM Corporation.
+ * Copyright (c) 2007 Freescale Semiconductor, Inc.
+ */
+
+#include "ops.h"
+#include "stdio.h"
+
+#include "ppcboot.h"
+
+void cuboot_init(unsigned long r4, unsigned long r5,
+		 unsigned long r6, unsigned long r7,
+		 unsigned long end_of_ram)
+{
+	unsigned long avail_ram = end_of_ram - (unsigned long)_end;
+
+	loader_info.initrd_addr = r4;
+	loader_info.initrd_size = r4 ? r5 - r4 : 0;
+	loader_info.cmdline = (char *)r6;
+	loader_info.cmdline_len = r7 - r6;
+
+	simple_alloc_init(_end, avail_ram - 1024*1024, 32, 64);
+}