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, 40 insertions, 0 deletions

diff --git a/arch/powerpc/boot/treeboot-bamboo.c b/arch/powerpc/boot/treeboot-bamboo.c
new file mode 100644
index 000000000..97b5b161d
--- /dev/null
+++ b/arch/powerpc/boot/treeboot-bamboo.c
@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright IBM Corporation, 2007
+ * Josh Boyer <jwboyer@linux.vnet.ibm.com>
+ *
+ * Based on ebony wrapper:
+ * Copyright 2007 David Gibson, IBM Corporation.
+ */
+#include "ops.h"
+#include "stdio.h"
+#include "44x.h"
+#include "stdlib.h"
+
+BSS_STACK(4096);
+
+#define PIBS_MAC0 0xfffc0400
+#define PIBS_MAC1 0xfffc0500
+char pibs_mac0[6];
+char pibs_mac1[6];
+
+static void read_pibs_mac(void)
+{
+	unsigned long long mac64;
+
+	mac64 = strtoull((char *)PIBS_MAC0, 0, 16);
+	memcpy(&pibs_mac0, (char *)&mac64+2, 6);
+
+	mac64 = strtoull((char *)PIBS_MAC1, 0, 16);
+	memcpy(&pibs_mac1, (char *)&mac64+2, 6);
+}
+
+void platform_init(void)
+{
+	unsigned long end_of_ram = 0x8000000;
+	unsigned long avail_ram = end_of_ram - (unsigned long)_end;
+
+	simple_alloc_init(_end, avail_ram, 32, 64);
+	read_pibs_mac();
+	bamboo_init((u8 *)&pibs_mac0, (u8 *)&pibs_mac1);
+}