5 files changed, 98 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
index 69e281b086a..7730a16e512 100644
--- a/arch/arm/cpu/armv7/start.S
+++ b/arch/arm/cpu/armv7/start.S
@@ -152,9 +152,38 @@ ENDPROC(c_runtime_cpu_setup)
  *
  *************************************************************************/
 WEAK(save_boot_params)
+#if (IS_ENABLED(CONFIG_BLOBLIST))
+	/* Calculate the PC-relative address of saved_args */
+	adr	r12, saved_args_offset
+	ldr	r13, saved_args_offset
+	add	r12, r12, r13
+
+	/*
+	 * Intentionally swapping r0 with r2 in order to simplify the C
+	 * function we use later.
+	 */
+	str	r2, [r12]
+	str	r1, [r12, #4]
+	str	r0, [r12, #8]
+	str	r3, [r12, #12]
+#endif
 	b	save_boot_params_ret		@ back to my caller
 ENDPROC(save_boot_params)
 
+#if (IS_ENABLED(CONFIG_BLOBLIST))
+saved_args_offset:
+	.long	saved_args - .	/* offset from current code to save_args */
+
+	.section .data
+	.align 2
+	.global saved_args
+saved_args:
+	.rept 4
+	.word 0
+	.endr
+END(saved_args)
+#endif
+
 #ifdef CONFIG_ARMV7_LPAE
 WEAK(switch_to_hypervisor)
 	b	switch_to_hypervisor_ret
diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S
index 6cc1d26e5e2..74612802617 100644
--- a/arch/arm/cpu/armv8/start.S
+++ b/arch/arm/cpu/armv8/start.S
@@ -370,5 +370,28 @@ ENTRY(c_runtime_cpu_setup)
 ENDPROC(c_runtime_cpu_setup)
 
 WEAK(save_boot_params)
+#if (IS_ENABLED(CONFIG_BLOBLIST))
+	/* Calculate the PC-relative address of saved_args */
+	adr	x9, saved_args_offset
+	ldr	w10, saved_args_offset
+	add	x9, x9, w10, sxtw
+
+	stp	x0, x1, [x9]
+	stp	x2, x3, [x9, #16]
+#endif
 	b	save_boot_params_ret	/* back to my caller */
 ENDPROC(save_boot_params)
+
+#if (IS_ENABLED(CONFIG_BLOBLIST))
+saved_args_offset:
+	.long	saved_args - .	/* offset from current code to save_args */
+
+	.section .data
+	.align 2
+	.global saved_args
+saved_args:
+	.rept 4
+	.dword 0
+	.endr
+END(saved_args)
+#endif
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index b1bcd374662..67275fba616 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -85,6 +85,8 @@ obj-y	+= psci-dt.o
 
 obj-$(CONFIG_DEBUG_LL)	+= debug.o
 
+obj-$(CONFIG_BLOBLIST)  += xferlist.o
+
 # For EABI conformant tool chains, provide eabi_compat()
 ifneq (,$(findstring -mabi=aapcs-linux,$(PLATFORM_CPPFLAGS)))
 extra-y	+= eabi_compat.o
diff --git a/arch/arm/lib/xferlist.c b/arch/arm/lib/xferlist.c
new file mode 100644
index 00000000000..f9c5d88bd47
--- /dev/null
+++ b/arch/arm/lib/xferlist.c
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2023 Linaro Limited
+ * Author: Raymond Mao <[email protected]>
+ */
+#include <linux/types.h>
+#include <errno.h>
+#include <bloblist.h>
+#include "xferlist.h"
+
+int xferlist_from_boot_arg(ulong addr, ulong size)
+{
+	int ret;
+
+	ret = bloblist_check(saved_args[3], size);
+	if (ret)
+		return ret;
+
+	ret = bloblist_check_reg_conv(saved_args[0], saved_args[2],
+				      saved_args[1]);
+	if (ret)
+		return ret;
+
+	return bloblist_reloc((void *)addr, size);
+}
diff --git a/arch/arm/lib/xferlist.h b/arch/arm/lib/xferlist.h
new file mode 100644
index 00000000000..60d79c1a8eb
--- /dev/null
+++ b/arch/arm/lib/xferlist.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0+ BSD-3-Clause */
+/*
+ * Copyright (C) 2023 Linaro Limited
+ * Author: Raymond Mao <[email protected]>
+ */
+
+#ifndef _XFERLIST_H_
+#define _XFERLIST_H_
+
+/*
+ * Boot parameters saved from start.S
+ * saved_args[0]: FDT base address
+ * saved_args[1]: Bloblist signature
+ * saved_args[2]: must be 0
+ * saved_args[3]: Bloblist base address
+ */
+extern unsigned long saved_args[];
+
+#endif /* _XFERLIST_H_ */