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, 63 insertions, 0 deletions

diff --git a/drivers/misc/sram.h b/drivers/misc/sram.h
new file mode 100644
index 000000000..397205b8b
--- /dev/null
+++ b/drivers/misc/sram.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Defines for the SRAM driver
+ */
+#ifndef __SRAM_H
+#define __SRAM_H
+
+struct sram_config {
+	int (*init)(void);
+	bool map_only_reserved;
+};
+
+struct sram_partition {
+	void __iomem *base;
+
+	struct gen_pool *pool;
+	struct bin_attribute battr;
+	struct mutex lock;
+	struct list_head list;
+};
+
+struct sram_dev {
+	const struct sram_config *config;
+
+	struct device *dev;
+	void __iomem *virt_base;
+	bool no_memory_wc;
+
+	struct gen_pool *pool;
+
+	struct sram_partition *partition;
+	u32 partitions;
+};
+
+struct sram_reserve {
+	struct list_head list;
+	u32 start;
+	u32 size;
+	struct resource res;
+	bool export;
+	bool pool;
+	bool protect_exec;
+	const char *label;
+};
+
+#ifdef CONFIG_SRAM_EXEC
+int sram_check_protect_exec(struct sram_dev *sram, struct sram_reserve *block,
+			    struct sram_partition *part);
+int sram_add_protect_exec(struct sram_partition *part);
+#else
+static inline int sram_check_protect_exec(struct sram_dev *sram,
+					  struct sram_reserve *block,
+					  struct sram_partition *part)
+{
+	return -ENODEV;
+}
+
+static inline int sram_add_protect_exec(struct sram_partition *part)
+{
+	return -ENODEV;
+}
+#endif /* CONFIG_SRAM_EXEC */
+#endif /* __SRAM_H */