3 files changed, 44 insertions, 0 deletions
diff --git a/include/vdso/getrandom.h b/include/vdso/getrandom.h
index a8b7c14b0ae0..6ca4d6de9e46 100644
--- a/include/vdso/getrandom.h
+++ b/include/vdso/getrandom.h
@@ -43,4 +43,32 @@ struct vgetrandom_state {
 	bool 			in_use;
 };
 
+/**
+ * __arch_chacha20_blocks_nostack - Generate ChaCha20 stream without using the stack.
+ * @dst_bytes:	Destination buffer to hold @nblocks * 64 bytes of output.
+ * @key:	32-byte input key.
+ * @counter:	8-byte counter, read on input and updated on return.
+ * @nblocks:	Number of blocks to generate.
+ *
+ * Generates a given positive number of blocks of ChaCha20 output with nonce=0, and does not write
+ * to any stack or memory outside of the parameters passed to it, in order to mitigate stack data
+ * leaking into forked child processes.
+ */
+extern void __arch_chacha20_blocks_nostack(u8 *dst_bytes, const u32 *key, u32 *counter, size_t nblocks);
+
+/**
+ * __vdso_getrandom - Architecture-specific vDSO implementation of getrandom() syscall.
+ * @buffer:		Passed to __cvdso_getrandom().
+ * @len:		Passed to __cvdso_getrandom().
+ * @flags:		Passed to __cvdso_getrandom().
+ * @opaque_state:	Passed to __cvdso_getrandom().
+ * @opaque_len:		Passed to __cvdso_getrandom();
+ *
+ * This function is implemented by making a single call to to __cvdso_getrandom(), whose
+ * documentation may be consulted for more information.
+ *
+ * Returns:	The return value of __cvdso_getrandom().
+ */
+extern ssize_t __vdso_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state, size_t opaque_len);
+
 #endif /* _VDSO_GETRANDOM_H */
diff --git a/include/vdso/helpers.h b/include/vdso/helpers.h
index 73501149439d..3ddb03bb05cb 100644
--- a/include/vdso/helpers.h
+++ b/include/vdso/helpers.h
@@ -4,6 +4,7 @@
 
 #ifndef __ASSEMBLY__
 
+#include <asm/barrier.h>
 #include <vdso/datapage.h>
 
 static __always_inline u32 vdso_read_begin(const struct vdso_data *vd)
diff --git a/include/vdso/unaligned.h b/include/vdso/unaligned.h
new file mode 100644
index 000000000000..eee3d2a4dbe4
--- /dev/null
+++ b/include/vdso/unaligned.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_UNALIGNED_H
+#define __VDSO_UNALIGNED_H
+
+#define __get_unaligned_t(type, ptr) ({						\
+	const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);	\
+	__pptr->x;								\
+})
+
+#define __put_unaligned_t(type, val, ptr) do {					\
+	struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr);		\
+	__pptr->x = (val);							\
+} while (0)
+
+#endif /* __VDSO_UNALIGNED_H */