1 files changed, 265 insertions, 0 deletions
diff --git a/roms/opensbi/lib/utils/fdt/fdt_fixup.c b/roms/opensbi/lib/utils/fdt/fdt_fixup.c
new file mode 100644
index 000000000..eea450d80
--- /dev/null
+++ b/roms/opensbi/lib/utils/fdt/fdt_fixup.c
@@ -0,0 +1,265 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * fdt_fixup.c - Flat Device Tree parsing helper routines
+ * Implement helper routines to parse FDT nodes on top of
+ * libfdt for OpenSBI usage
+ *
+ * Copyright (C) 2020 Bin Meng <bmeng.cn@gmail.com>
+ */
+
+#include <libfdt.h>
+#include <sbi/sbi_console.h>
+#include <sbi/sbi_domain.h>
+#include <sbi/sbi_math.h>
+#include <sbi/sbi_hart.h>
+#include <sbi/sbi_scratch.h>
+#include <sbi/sbi_string.h>
+#include <sbi_utils/fdt/fdt_fixup.h>
+#include <sbi_utils/fdt/fdt_helper.h>
+
+void fdt_cpu_fixup(void *fdt)
+{
+	struct sbi_domain *dom = sbi_domain_thishart_ptr();
+	int err, cpu_offset, cpus_offset, len;
+	const char *mmu_type;
+	u32 hartid;
+
+	err = fdt_open_into(fdt, fdt, fdt_totalsize(fdt) + 32);
+	if (err < 0)
+		return;
+
+	cpus_offset = fdt_path_offset(fdt, "/cpus");
+	if (cpus_offset < 0)
+		return;
+
+	fdt_for_each_subnode(cpu_offset, fdt, cpus_offset) {
+		err = fdt_parse_hart_id(fdt, cpu_offset, &hartid);
+		if (err)
+			continue;
+
+		/*
+		 * Disable a HART DT node if one of the following is true:
+		 * 1. The HART is not assigned to the current domain
+		 * 2. MMU is not available for the HART
+		 */
+
+		mmu_type = fdt_getprop(fdt, cpu_offset, "mmu-type", &len);
+		if (!sbi_domain_is_assigned_hart(dom, hartid) ||
+		    !mmu_type || !len)
+			fdt_setprop_string(fdt, cpu_offset, "status",
+					   "disabled");
+	}
+}
+
+void fdt_plic_fixup(void *fdt, const char *compat)
+{
+	u32 *cells;
+	int i, cells_count;
+	int plic_off;
+
+	plic_off = fdt_node_offset_by_compatible(fdt, 0, compat);
+	if (plic_off < 0)
+		return;
+
+	cells = (u32 *)fdt_getprop(fdt, plic_off,
+				   "interrupts-extended", &cells_count);
+	if (!cells)
+		return;
+
+	cells_count = cells_count / sizeof(u32);
+	if (!cells_count)
+		return;
+
+	for (i = 0; i < (cells_count / 2); i++) {
+		if (fdt32_to_cpu(cells[2 * i + 1]) == IRQ_M_EXT)
+			cells[2 * i + 1] = cpu_to_fdt32(0xffffffff);
+	}
+}
+
+static int fdt_resv_memory_update_node(void *fdt, unsigned long addr,
+				       unsigned long size, int index,
+				       int parent, bool no_map)
+{
+	int na = fdt_address_cells(fdt, 0);
+	int ns = fdt_size_cells(fdt, 0);
+	fdt32_t addr_high, addr_low;
+	fdt32_t size_high, size_low;
+	int subnode, err;
+	fdt32_t reg[4];
+	fdt32_t *val;
+	char name[32];
+
+	addr_high = (u64)addr >> 32;
+	addr_low = addr;
+	size_high = (u64)size >> 32;
+	size_low = size;
+
+	if (na > 1 && addr_high)
+		sbi_snprintf(name, sizeof(name),
+			     "mmode_resv%d@%x,%x", index,
+			     addr_high, addr_low);
+	else
+		sbi_snprintf(name, sizeof(name),
+			     "mmode_resv%d@%x", index,
+			     addr_low);
+
+	subnode = fdt_add_subnode(fdt, parent, name);
+	if (subnode < 0)
+		return subnode;
+
+	if (no_map) {
+		/*
+		 * Tell operating system not to create a virtual
+		 * mapping of the region as part of its standard
+		 * mapping of system memory.
+		 */
+		err = fdt_setprop_empty(fdt, subnode, "no-map");
+		if (err < 0)
+			return err;
+	}
+
+	/* encode the <reg> property value */
+	val = reg;
+	if (na > 1)
+		*val++ = cpu_to_fdt32(addr_high);
+	*val++ = cpu_to_fdt32(addr_low);
+	if (ns > 1)
+		*val++ = cpu_to_fdt32(size_high);
+	*val++ = cpu_to_fdt32(size_low);
+
+	err = fdt_setprop(fdt, subnode, "reg", reg,
+			  (na + ns) * sizeof(fdt32_t));
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+/**
+ * We use PMP to protect OpenSBI firmware to safe-guard it from buggy S-mode
+ * software, see pmp_init() in lib/sbi/sbi_hart.c. The protected memory region
+ * information needs to be conveyed to S-mode software (e.g.: operating system)
+ * via some well-known method.
+ *
+ * With device tree, this can be done by inserting a child node of the reserved
+ * memory node which is used to specify one or more regions of reserved memory.
+ *
+ * For the reserved memory node bindings, see Linux kernel documentation at
+ * Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
+ *
+ * Some additional memory spaces may be protected by platform codes via PMP as
+ * well, and corresponding child nodes will be inserted.
+ */
+int fdt_reserved_memory_fixup(void *fdt)
+{
+	struct sbi_domain_memregion *reg;
+	struct sbi_domain *dom = sbi_domain_thishart_ptr();
+	struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
+	unsigned long addr, size;
+	int err, parent, i;
+	int na = fdt_address_cells(fdt, 0);
+	int ns = fdt_size_cells(fdt, 0);
+
+	/*
+	 * Expand the device tree to accommodate new node
+	 * by the following estimated size:
+	 *
+	 * Each PMP memory region entry occupies 64 bytes.
+	 * With 16 PMP memory regions we need 64 * 16 = 1024 bytes.
+	 */
+	err = fdt_open_into(fdt, fdt, fdt_totalsize(fdt) + 1024);
+	if (err < 0)
+		return err;
+
+	/* try to locate the reserved memory node */
+	parent = fdt_path_offset(fdt, "/reserved-memory");
+	if (parent < 0) {
+		/* if such node does not exist, create one */
+		parent = fdt_add_subnode(fdt, 0, "reserved-memory");
+		if (parent < 0)
+			return parent;
+
+		/*
+		 * reserved-memory node has 3 required properties:
+		 * - #address-cells: the same value as the root node
+		 * - #size-cells: the same value as the root node
+		 * - ranges: should be empty
+		 */
+
+		err = fdt_setprop_empty(fdt, parent, "ranges");
+		if (err < 0)
+			return err;
+
+		err = fdt_setprop_u32(fdt, parent, "#size-cells", ns);
+		if (err < 0)
+			return err;
+
+		err = fdt_setprop_u32(fdt, parent, "#address-cells", na);
+		if (err < 0)
+			return err;
+	}
+
+	/*
+	 * We assume the given device tree does not contain any memory region
+	 * child node protected by PMP. Normally PMP programming happens at
+	 * M-mode firmware. The memory space used by OpenSBI is protected.
+	 * Some additional memory spaces may be protected by domain memory
+	 * regions.
+	 *
+	 * With above assumption, we create child nodes directly.
+	 */
+
+	i = 0;
+	sbi_domain_for_each_memregion(dom, reg) {
+		/* Ignore MMIO or READABLE or WRITABLE or EXECUTABLE regions */
+		if (reg->flags & SBI_DOMAIN_MEMREGION_MMIO)
+			continue;
+		if (reg->flags & SBI_DOMAIN_MEMREGION_READABLE)
+			continue;
+		if (reg->flags & SBI_DOMAIN_MEMREGION_WRITEABLE)
+			continue;
+		if (reg->flags & SBI_DOMAIN_MEMREGION_EXECUTABLE)
+			continue;
+
+		addr = reg->base;
+		size = 1UL << reg->order;
+		fdt_resv_memory_update_node(fdt, addr, size, i, parent,
+			(sbi_hart_pmp_count(scratch)) ? false : true);
+		i++;
+	}
+
+	return 0;
+}
+
+int fdt_reserved_memory_nomap_fixup(void *fdt)
+{
+	int parent, subnode;
+	int err;
+
+	/* Locate the reserved memory node */
+	parent = fdt_path_offset(fdt, "/reserved-memory");
+	if (parent < 0)
+		return parent;
+
+	fdt_for_each_subnode(subnode, fdt, parent) {
+		/*
+		 * Tell operating system not to create a virtual
+		 * mapping of the region as part of its standard
+		 * mapping of system memory.
+		 */
+		err = fdt_setprop_empty(fdt, subnode, "no-map");
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+void fdt_fixups(void *fdt)
+{
+	fdt_plic_fixup(fdt, "riscv,plic0");
+
+	fdt_reserved_memory_fixup(fdt);
+}
+
+