selftests/bpf: Check that JMP32 pointer vs zero jumps are not predictedgrafted

Add jmp32_ptr_vs_zero_jne: the fall-through of the 32-bit compare, which
the verifier used to skip, contains an out of bounds map value access,
hence w/o the previous patch the program is accepted. See previous patch
for detailed description.

Reported-by: Nicholas Carlini <npc@anthropic.com>
Suggested-by: Nicholas Carlini <npc@anthropic.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260904083325.2083493-6-eddyz87@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/dcr.c b/arch/powerpc/sysdev/dcr.c
new file mode 100644
index 000000000..cb44a6995
--- /dev/null
+++ b/arch/powerpc/sysdev/dcr.c
@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ */
+
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/of_address.h>
+#include <asm/dcr.h>
+
+unsigned int dcr_resource_start(const struct device_node *np,
+				unsigned int index)
+{
+	unsigned int ds;
+	const u32 *dr = of_get_property(np, "dcr-reg", &ds);
+
+	if (dr == NULL || ds & 1 || index >= (ds / 8))
+		return 0;
+
+	return dr[index * 2];
+}
+EXPORT_SYMBOL_GPL(dcr_resource_start);
+
+unsigned int dcr_resource_len(const struct device_node *np, unsigned int index)
+{
+	unsigned int ds;
+	const u32 *dr = of_get_property(np, "dcr-reg", &ds);
+
+	if (dr == NULL || ds & 1 || index >= (ds / 8))
+		return 0;
+
+	return dr[index * 2 + 1];
+}
+EXPORT_SYMBOL_GPL(dcr_resource_len);
+
+DEFINE_SPINLOCK(dcr_ind_lock);
+EXPORT_SYMBOL_GPL(dcr_ind_lock);