riscv/addrenv: Implement up_shmat/shmdt for RISC-V

These are great utility functions to create/destroy anonymous mappings

arch/risc-v/src/common/Make.defs

@@ -103,5 +103,5 @@ endif
 
 ifeq ($(CONFIG_ARCH_ADDRENV),y)
 CMN_CSRCS += riscv_addrenv.c riscv_pgalloc.c riscv_addrenv_perms.c
-CMN_CSRCS += riscv_addrenv_utils.c
+CMN_CSRCS += riscv_addrenv_utils.c riscv_addrenv_shm.c
 endif

arch/risc-v/src/common/riscv_addrenv_shm.c

@@ -0,0 +1,176 @@
+/****************************************************************************
+ * arch/risc-v/src/common/riscv_addrenv_shm.c
+ *
+ * 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 <errno.h>
+#include <assert.h>
+#include <debug.h>
+
+#include <nuttx/addrenv.h>
+#include <nuttx/arch.h>
+#include <nuttx/irq.h>
+#include <nuttx/pgalloc.h>
+
+#include <arch/barriers.h>
+
+#include "addrenv.h"
+#include "pgalloc.h"
+#include "riscv_mmu.h"
+
+#if defined(CONFIG_BUILD_KERNEL) && defined(CONFIG_MM_SHM)
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_shmat
+ *
+ * Description:
+ *   Attach, i.e, map, on shared memory region to a user virtual address
+ *
+ * Input Parameters:
+ *   pages - A pointer to the first element in a array of physical address,
+ *     each corresponding to one page of memory.
+ *   npages - The number of pages in the list of physical pages to be mapped.
+ *   vaddr - The virtual address corresponding to the beginning of the
+ *     (contiguous) virtual address region.
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is returned
+ *   on failure.
+ *
+ ****************************************************************************/
+
+int up_shmat(uintptr_t *pages, unsigned int npages, uintptr_t vaddr)
+{
+  struct tcb_s        *tcb = nxsched_self();
+  struct task_group_s *group;
+  uintptr_t            ptlast;
+  uintptr_t            ptlevel;
+  uintptr_t            paddr;
+
+  /* Sanity checks */
+
+  DEBUGASSERT(tcb && tcb->group);
+  DEBUGASSERT(pages != NULL && npages > 0);
+  DEBUGASSERT(vaddr >= CONFIG_ARCH_SHM_VBASE && vaddr < ARCH_SHM_VEND);
+  DEBUGASSERT(MM_ISALIGNED(vaddr));
+
+  group   = tcb->group;
+  ptlevel = RV_MMU_PT_LEVELS;
+
+  /* Add the references to pages[] into the caller's address environment */
+
+  for (; npages > 0; npages--)
+    {
+      /* Get the address of the last level page table */
+
+      ptlast = riscv_pgvaddr(riscv_get_pgtable(&group->tg_addrenv, vaddr));
+      if (!ptlast)
+        {
+          return -ENOMEM;
+        }
+
+      /* Then add the reference */
+
+      paddr = *pages++;
+      mmu_ln_setentry(ptlevel, ptlast, paddr, vaddr, MMU_UDATA_FLAGS);
+      vaddr += MM_PGSIZE;
+    }
+
+  /* Flush the data cache, so the changes are committed to memory */
+
+  __DMB();
+
+  return OK;
+}
+
+/****************************************************************************
+ * Name: up_shmdt
+ *
+ * Description:
+ *   Detach, i.e, unmap, on shared memory region from a user virtual address
+ *
+ * Input Parameters:
+ *   vaddr - The virtual address corresponding to the beginning of the
+ *     (contiguous) virtual address region.
+ *   npages - The number of pages to be unmapped
+ *
+ * Returned Value:
+ *   Zero (OK) is returned on success; a negated errno value is returned
+ *   on failure.
+ *
+ ****************************************************************************/
+
+int up_shmdt(uintptr_t vaddr, unsigned int npages)
+{
+  struct tcb_s        *tcb = nxsched_self();
+  struct task_group_s *group;
+  uintptr_t            ptlast;
+  uintptr_t            ptprev;
+  uintptr_t            ptlevel;
+  uintptr_t            paddr;
+
+  /* Sanity checks */
+
+  DEBUGASSERT(tcb && tcb->group);
+  DEBUGASSERT(npages > 0);
+  DEBUGASSERT(vaddr >= CONFIG_ARCH_SHM_VBASE && vaddr < ARCH_SHM_VEND);
+  DEBUGASSERT(MM_ISALIGNED(vaddr));
+
+  group   = tcb->group;
+  ptlevel = ARCH_SPGTS;
+  ptprev  = riscv_pgvaddr(group->tg_addrenv.spgtables[ARCH_SPGTS - 1]);
+  if (!ptprev)
+    {
+      /* Something is very wrong */
+
+      return -EFAULT;
+    }
+
+  /* Remove the references from the caller's address environment */
+
+  for (; npages > 0; npages--)
+    {
+      /* Get the current final level entry corresponding to this vaddr */
+
+      paddr = mmu_pte_to_paddr(mmu_ln_getentry(ptlevel, ptprev, vaddr));
+      ptlast = riscv_pgvaddr(paddr);
+
+      /* Then wipe the reference */
+
+      mmu_ln_clear(ptlevel + 1, ptlast, vaddr);
+      vaddr += MM_PGSIZE;
+    }
+
+  /* Flush the data cache, so the changes are committed to memory */
+
+  __DMB();
+
+  return OK;
+}
+
+#endif /* CONFIG_BUILD_KERNEL */