arch/arm64: implement up_addrenv_va_to_pa().

up_addrenv_va_to_pa() is declared in include/nuttx/arch.h but implemented
only by armv7-a, so no arm64 port can map a virtual address to a physical
one. A driver whose device addresses memory physically has nothing to call.

The translation is asked of the MMU with AT S1E1R rather than walked in
software, so it answers for whatever is actually mapped: any granule size,
block or page, at any level, and it cannot drift from the tables in use.

PAR_EL1 is one register per CPU, so nothing may run between the translation
and reading the result. Interrupts are banked with it, so masking them
locally is sufficient and SMP needs nothing further.

Returns zero for an address that is not mapped for a privileged read, which
is what the declaration in arch.h specifies. Note this differs from the
armv7-a implementation, which returns the virtual address unchanged.

Signed-off-by: Royyan Zahir <royzah@gmail.com>

arch/arm64/src/common/CMakeLists.txt

@@ -73,6 +73,12 @@ endif()
 
 if(CONFIG_ARCH_HAVE_MMU)
   list(APPEND SRCS arm64_mmu.c)
+
+  # drivers/misc/addrenv.c defines the same entry points from a table.
+
+  if(NOT CONFIG_DEV_SIMPLE_ADDRENV)
+    list(APPEND SRCS arm64_physpgaddr.c)
+  endif()
 endif()
 
 if(CONFIG_ARM64_MTE)

arch/arm64/src/common/Make.defs

@@ -80,6 +80,12 @@ endif
 
 ifeq ($(CONFIG_ARCH_HAVE_MMU),y)
 CMN_CSRCS += arm64_mmu.c
+
+# drivers/misc/addrenv.c defines the same entry points from a table.
+
+ifneq ($(CONFIG_DEV_SIMPLE_ADDRENV),y)
+CMN_CSRCS += arm64_physpgaddr.c
+endif
 endif
 
 ifeq ($(CONFIG_ARM64_MTE),y)

arch/arm64/src/common/arm64_physpgaddr.c

@@ -0,0 +1,101 @@
+/****************************************************************************
+ * arch/arm64/src/common/arm64_physpgaddr.c
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+
+#include <nuttx/arch.h>
+#include <nuttx/irq.h>
+
+#include "arm64_arch.h"
+#include "arm64_internal.h"
+
+#ifndef CONFIG_DEV_SIMPLE_ADDRENV
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* PAR_EL1, Physical Address Register. Bit 0 reports a failed translation;
+ * on success bits [51:12] carry the physical frame.
+ */
+
+#define PAR_F                (1ull << 0)
+#define PAR_PA_MASK          (0x000ffffffffff000ull)
+#define VA_PAGE_OFFSET_MASK  (0xfffull)
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_addrenv_va_to_pa
+ *
+ * Description:
+ *   Map a virtual address to its physical address.
+ *
+ *   The translation is asked of the MMU rather than walked in software, so
+ *   it answers for whatever is actually mapped: any granule size, block or
+ *   page, at any level, and it cannot drift from the tables in use.
+ *
+ * Input Parameters:
+ *   va - The virtual address to be mapped.
+ *
+ * Returned Value:
+ *   Physical address on success; zero if the address is not mapped for a
+ *   privileged read.
+ *
+ ****************************************************************************/
+
+uintptr_t up_addrenv_va_to_pa(void *va)
+{
+  irqstate_t flags;
+  uint64_t par;
+
+  /* PAR_EL1 is a single register per CPU, so nothing may run between the
+   * translation and reading the result or it reads someone else's answer.
+   * Interrupts are banked with it, so masking them locally is enough.
+   */
+
+  flags = up_irq_save();
+
+  __asm__ volatile ("at s1e1r, %0" : : "r" (va) : "memory");
+  UP_ISB();
+  par = read_sysreg(par_el1);
+
+  up_irq_restore(flags);
+
+  if ((par & PAR_F) != 0)
+    {
+      return 0;
+    }
+
+  return (uintptr_t)((par & PAR_PA_MASK) |
+                     ((uintptr_t)va & VA_PAGE_OFFSET_MASK));
+}
+
+#endif /* CONFIG_DEV_SIMPLE_ADDRENV */