Merge patch series "Handoff bloblist from previous boot stage"

Raymond Mao <[email protected]> says:

This patch set adds/adapts a few bloblist APIs and implements Arm arch
custom function to retrieve the bloblist (aka. Transfer List) from
previous loader via boot arguments when BLOBLIST option is enabled and
all boot arguments are compliant to the register conventions defined
in the Firmware Handoff spec v0.9.

If an arch wishes to have different behaviors for loading bloblist
from the previous boot stage, it is required to implement the custom
function xferlist_from_boot_arg().

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_ */