1 files changed, 67 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/vdso/getrandom.h b/arch/powerpc/include/asm/vdso/getrandom.h
new file mode 100644
index 000000000000..067a5396aac6
--- /dev/null
+++ b/arch/powerpc/include/asm/vdso/getrandom.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2024 Christophe Leroy <christophe.leroy@csgroup.eu>, CS GROUP France
+ */
+#ifndef _ASM_POWERPC_VDSO_GETRANDOM_H
+#define _ASM_POWERPC_VDSO_GETRANDOM_H
+
+#ifndef __ASSEMBLY__
+
+#include <asm/vdso_datapage.h>
+
+static __always_inline int do_syscall_3(const unsigned long _r0, const unsigned long _r3,
+					const unsigned long _r4, const unsigned long _r5)
+{
+	register long r0 asm("r0") = _r0;
+	register unsigned long r3 asm("r3") = _r3;
+	register unsigned long r4 asm("r4") = _r4;
+	register unsigned long r5 asm("r5") = _r5;
+	register int ret asm ("r3");
+
+	asm volatile(
+		"       sc\n"
+		"	bns+	1f\n"
+		"	neg	%0, %0\n"
+		"1:\n"
+	: "=r" (ret), "+r" (r4), "+r" (r5), "+r" (r0)
+	: "r" (r3)
+	: "memory", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "cr0", "ctr");
+
+	return ret;
+}
+
+/**
+ * getrandom_syscall - Invoke the getrandom() syscall.
+ * @buffer:	Destination buffer to fill with random bytes.
+ * @len:	Size of @buffer in bytes.
+ * @flags:	Zero or more GRND_* flags.
+ * Returns:	The number of bytes written to @buffer, or a negative value indicating an error.
+ */
+static __always_inline ssize_t getrandom_syscall(void *buffer, size_t len, unsigned int flags)
+{
+	return do_syscall_3(__NR_getrandom, (unsigned long)buffer,
+			    (unsigned long)len, (unsigned long)flags);
+}
+
+static __always_inline const struct vdso_rng_data *__arch_get_vdso_u_rng_data(void)
+{
+	struct vdso_rng_data *data;
+
+	asm (
+		"	bcl	20, 31, .+4 ;"
+		"0:	mflr	%0 ;"
+		"	addis	%0, %0, (vdso_u_rng_data - 0b)@ha ;"
+		"	addi	%0, %0, (vdso_u_rng_data - 0b)@l  ;"
+		: "=r" (data) : : "lr"
+	);
+
+	return data;
+}
+#define __arch_get_vdso_u_rng_data __arch_get_vdso_u_rng_data
+
+ssize_t __c_kernel_getrandom(void *buffer, size_t len, unsigned int flags, void *opaque_state,
+			     size_t opaque_len);
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* _ASM_POWERPC_VDSO_GETRANDOM_H */