[TODO] platform: Add xuantie_pmp_ext_cfg

Used to disable permissions in S/U mode.

The DTS configuration reference:
  pmp_ext@35000000 {
    compatible = "xuantie,pmp_ext";
    reg = <0x0 0x35000000 0x0 0x4000000>;
  };

Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>

Author: cp0613

lib/sbi/sbi_hart.c

@@ -374,6 +374,12 @@ static unsigned int sbi_hart_get_smepmp_flags(struct sbi_scratch *scratch,
 			pmp_flags |= PMP_W;
 		if (reg->flags & SBI_DOMAIN_MEMREGION_SU_EXECUTABLE)
 			pmp_flags |= PMP_X;
+	} else if (reg->flags & SBI_DOMAIN_MEMREGION_ENF_PERMISSIONS) {
+		/*
+		 * If permissions are to be enforced for all modes on
+		 * this region, the lock bit should be set.
+		 */
+		pmp_flags |= PMP_L;
 	}
 
 	return pmp_flags;

platform/generic/include/xuantie/xuantie_pmp_ext.h

@@ -0,0 +1,12 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#ifndef __RISCV_XUANTIE_PMP_EXT_H__
+#define __RISCV_XUANTIE_PMP_EXT_H__
+
+#include <sbi/sbi_types.h>
+
+int xuantie_pmp_ext_cfg(void);
+
+#endif /* __RISCV_XUANTIE_PMP_EXT_H__ */

platform/generic/include/xuantie/xuantie_quirk.h

@@ -5,8 +5,9 @@
 #ifndef __RISCV_XUANTIE_QUIRK_H__
 #define __RISCV_XUANTIE_QUIRK_H__
 
-#define QUIRK_XUANTIE_PMC  BIT(0)
-#define QUIRK_XUANTIE_LINK BIT(1)
+#define QUIRK_XUANTIE_PMC     BIT(0)
+#define QUIRK_XUANTIE_LINK    BIT(1)
+#define QUIRK_XUANTIE_PMP_EXT BIT(2)
 
 struct xuantie_generic_quirks {
 	u32 quirk;

platform/generic/xuantie/objects.mk

@@ -3,4 +3,4 @@
 #
 
 carray-platform_override_modules-$(CONFIG_PLATFORM_XUANTIE) += xuantie_dummy
-platform-objs-$(CONFIG_PLATFORM_XUANTIE) += xuantie/xuantie_dummy.o xuantie/xuantie_pmc.o xuantie/xuantie_link.o
+platform-objs-$(CONFIG_PLATFORM_XUANTIE) += xuantie/xuantie_dummy.o xuantie/xuantie_pmc.o xuantie/xuantie_link.o xuantie/xuantie_pmp_ext.o

platform/generic/xuantie/xuantie_dummy.c

@@ -13,9 +13,20 @@
 #include <xuantie/xuantie_quirk.h>
 #include <xuantie/xuantie_pmc.h>
 #include <xuantie/xuantie_link.h>
+#include <xuantie/xuantie_pmp_ext.h>
 
 static u32 gquirk = 0;
 
+int xuantie_early_init(bool cold_boot)
+{
+	if (cold_boot) {
+		if (gquirk & QUIRK_XUANTIE_PMP_EXT)
+			xuantie_pmp_ext_cfg();
+	}
+
+	return generic_early_init(cold_boot);
+}
+
 int xuantie_final_init(bool cold_boot)
 {
 	if (cold_boot) {
@@ -34,13 +45,14 @@ static int xuantie_dummy_platform_init(const void *fdt, int nodeoff,
 	const struct xuantie_generic_quirks *data = match->data;
 
 	gquirk = data->quirk;
+	generic_platform_ops.early_init = xuantie_early_init;
 	generic_platform_ops.final_init = xuantie_final_init;
 
 	return 0;
 }
 
 static const struct xuantie_generic_quirks xuantie_quirks = {
-	.quirk = QUIRK_XUANTIE_PMC | QUIRK_XUANTIE_LINK,
+	.quirk = QUIRK_XUANTIE_PMC | QUIRK_XUANTIE_LINK | QUIRK_XUANTIE_PMP_EXT,
 };
 
 static const struct xuantie_generic_quirks xuantie_pmc_quirks = {
@@ -51,10 +63,15 @@ static const struct xuantie_generic_quirks xuantie_link_quirks = {
 	.quirk = QUIRK_XUANTIE_LINK,
 };
 
+static const struct xuantie_generic_quirks xuantie_pmp_ext_quirks = {
+	.quirk = QUIRK_XUANTIE_PMP_EXT,
+};
+
 static const struct fdt_match xuantie_dummy_match[] = {
 	{ .compatible = "xuantie,dummy", .data = &xuantie_quirks },
 	{ .compatible = "xuantie,pmc", .data = &xuantie_pmc_quirks },
 	{ .compatible = "xuantie,link", .data = &xuantie_link_quirks },
+	{ .compatible = "riscv-virtio",  .data = &xuantie_pmp_ext_quirks }, // qemu debug
 	{ },
 };
 

platform/generic/xuantie/xuantie_pmp_ext.c

@@ -0,0 +1,35 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <libfdt.h>
+#include <sbi/sbi_error.h>
+#include <sbi/sbi_console.h>
+#include <sbi/riscv_io.h>
+#include <sbi_utils/fdt/fdt_fixup.h>
+#include <sbi_utils/fdt/fdt_helper.h>
+#include <xuantie/xuantie_pmp_ext.h>
+
+/*
+sbi_domain_root_add_memrange needs to be called before sbi_domain_finalize,
+because sbi_domain_finalize sets domain_finalized = true, causing subsequent
+additions to fail.
+*/
+int xuantie_pmp_ext_cfg(void)
+{
+	int nodeoffset, rc;
+	uint64_t addr, size;
+	void *fdt = fdt_get_address_rw();
+
+	nodeoffset = fdt_node_offset_by_compatible(fdt, -1, "xuantie,pmp_ext");
+	if (nodeoffset < 0)
+		return nodeoffset;
+
+	rc = fdt_get_node_addr_size(fdt, nodeoffset, 0, &addr, &size);
+	if (rc)
+		return SBI_ENODEV;
+
+	rc = sbi_domain_root_add_memrange(addr, size, size & (-size),
+						  SBI_DOMAIN_MEMREGION_ENF_PERMISSIONS);
+	return rc;
+}