3 files changed, 143 insertions, 0 deletions
diff --git a/arch/riscv/kernel/pi/Makefile b/arch/riscv/kernel/pi/Makefile
new file mode 100644
index 0000000000..07915dc927
--- /dev/null
+++ b/arch/riscv/kernel/pi/Makefile
@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: GPL-2.0
+# This file was copied from arm64/kernel/pi/Makefile.
+
+KBUILD_CFLAGS	:= $(subst $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) -fpie \
+		   -Os -DDISABLE_BRANCH_PROFILING $(DISABLE_STACKLEAK_PLUGIN) \
+		   $(call cc-option,-mbranch-protection=none) \
+		   -I$(srctree)/scripts/dtc/libfdt -fno-stack-protector \
+		   -D__DISABLE_EXPORTS -ffreestanding \
+		   -fno-asynchronous-unwind-tables -fno-unwind-tables \
+		   $(call cc-option,-fno-addrsig)
+
+KBUILD_CFLAGS	+= -mcmodel=medany
+
+CFLAGS_cmdline_early.o += -D__NO_FORTIFY
+CFLAGS_lib-fdt_ro.o += -D__NO_FORTIFY
+
+GCOV_PROFILE	:= n
+KASAN_SANITIZE	:= n
+KCSAN_SANITIZE	:= n
+UBSAN_SANITIZE	:= n
+KCOV_INSTRUMENT	:= n
+
+$(obj)/%.pi.o: OBJCOPYFLAGS := --prefix-symbols=__pi_ \
+			       --remove-section=.note.gnu.property \
+			       --prefix-alloc-sections=.init.pi
+$(obj)/%.pi.o: $(obj)/%.o FORCE
+	$(call if_changed,objcopy)
+
+$(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
+	$(call if_changed_rule,cc_o_c)
+
+$(obj)/string.o: $(srctree)/lib/string.c FORCE
+	$(call if_changed_rule,cc_o_c)
+
+$(obj)/ctype.o: $(srctree)/lib/ctype.c FORCE
+	$(call if_changed_rule,cc_o_c)
+
+obj-y		:= cmdline_early.pi.o fdt_early.pi.o string.pi.o ctype.pi.o lib-fdt.pi.o lib-fdt_ro.pi.o
+extra-y		:= $(patsubst %.pi.o,%.o,$(obj-y))
diff --git a/arch/riscv/kernel/pi/cmdline_early.c b/arch/riscv/kernel/pi/cmdline_early.c
new file mode 100644
index 0000000000..f6d4dedffb
--- /dev/null
+++ b/arch/riscv/kernel/pi/cmdline_early.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/libfdt.h>
+#include <linux/string.h>
+#include <asm/pgtable.h>
+#include <asm/setup.h>
+
+static char early_cmdline[COMMAND_LINE_SIZE];
+
+/*
+ * Declare the functions that are exported (but prefixed) here so that LLVM
+ * does not complain it lacks the 'static' keyword (which, if added, makes
+ * LLVM complain because the function is actually unused in this file).
+ */
+u64 set_satp_mode_from_cmdline(uintptr_t dtb_pa);
+bool set_nokaslr_from_cmdline(uintptr_t dtb_pa);
+
+static char *get_early_cmdline(uintptr_t dtb_pa)
+{
+	const char *fdt_cmdline = NULL;
+	unsigned int fdt_cmdline_size = 0;
+	int chosen_node;
+
+	if (!IS_ENABLED(CONFIG_CMDLINE_FORCE)) {
+		chosen_node = fdt_path_offset((void *)dtb_pa, "/chosen");
+		if (chosen_node >= 0) {
+			fdt_cmdline = fdt_getprop((void *)dtb_pa, chosen_node,
+						  "bootargs", NULL);
+			if (fdt_cmdline) {
+				fdt_cmdline_size = strlen(fdt_cmdline);
+				strscpy(early_cmdline, fdt_cmdline,
+					COMMAND_LINE_SIZE);
+			}
+		}
+	}
+
+	if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
+	    IS_ENABLED(CONFIG_CMDLINE_FORCE) ||
+	    fdt_cmdline_size == 0 /* CONFIG_CMDLINE_FALLBACK */) {
+		strlcat(early_cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+	}
+
+	return early_cmdline;
+}
+
+static u64 match_noXlvl(char *cmdline)
+{
+	if (strstr(cmdline, "no4lvl"))
+		return SATP_MODE_48;
+	else if (strstr(cmdline, "no5lvl"))
+		return SATP_MODE_57;
+
+	return 0;
+}
+
+u64 set_satp_mode_from_cmdline(uintptr_t dtb_pa)
+{
+	char *cmdline = get_early_cmdline(dtb_pa);
+
+	return match_noXlvl(cmdline);
+}
+
+static bool match_nokaslr(char *cmdline)
+{
+	return strstr(cmdline, "nokaslr");
+}
+
+bool set_nokaslr_from_cmdline(uintptr_t dtb_pa)
+{
+	char *cmdline = get_early_cmdline(dtb_pa);
+
+	return match_nokaslr(cmdline);
+}
diff --git a/arch/riscv/kernel/pi/fdt_early.c b/arch/riscv/kernel/pi/fdt_early.c
new file mode 100644
index 0000000000..899610e042
--- /dev/null
+++ b/arch/riscv/kernel/pi/fdt_early.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/libfdt.h>
+
+/*
+ * Declare the functions that are exported (but prefixed) here so that LLVM
+ * does not complain it lacks the 'static' keyword (which, if added, makes
+ * LLVM complain because the function is actually unused in this file).
+ */
+u64 get_kaslr_seed(uintptr_t dtb_pa);
+
+u64 get_kaslr_seed(uintptr_t dtb_pa)
+{
+	int node, len;
+	fdt64_t *prop;
+	u64 ret;
+
+	node = fdt_path_offset((void *)dtb_pa, "/chosen");
+	if (node < 0)
+		return 0;
+
+	prop = fdt_getprop_w((void *)dtb_pa, node, "kaslr-seed", &len);
+	if (!prop || len != sizeof(u64))
+		return 0;
+
+	ret = fdt64_to_cpu(*prop);
+	*prop = 0;
+	return ret;
+}