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RISC-V: Initial support for CONFIG_BUILD_KERNEL
This implements initial support for kernel build (address environments, page allocator) for RISC-V. This is done a bit differently compared to the ARMV7 implementation: - Support implemented for Sv39 MMU, however the implementation should be extensible for other MMU types also. - Instead of preserving and moving the L1 references around, a canonical approach is used instead, where the page table base address register is switched upon context switch. - To preserve a bit of memory, only a single L1/L2 table is supported, this gives access to 1GiB of virtual memory for each process, which should be more than enough. Some things worth noting: - Assumes page pool is mapped with vaddr=paddr mappings - The CONFIG_ARCH_XXXX_VBASE and CONFIG_ARCH_XXXX_NPAGES values are ignored, with the exception of CONFIG_ARCH_DATA_VBASE which is used for ARCH_DATA_RESERVE - ARCH_DATA_RESERVE is placed at the beginning of the userspace task's address environment
This commit is contained in:
Ville Juven
Xiang Xiao
@@ -111,6 +111,8 @@ config ARCH_CHIP_MPFS
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select ARCH_HAVE_MPU
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select ARCH_HAVE_MMU
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select ARCH_MMU_TYPE_SV39
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select ARCH_HAVE_ADDRENV
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select ARCH_NEED_ADDRENV_MAPPING
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select ARCH_HAVE_RESET
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select ARCH_HAVE_SPI_CS_CONTROL
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select ARCH_HAVE_PWM_MULTICHAN
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@@ -33,6 +33,7 @@
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#ifndef __ASSEMBLY__
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# include <stdint.h>
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# include <stddef.h>
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#endif
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/****************************************************************************
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@@ -70,6 +71,18 @@
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#define STACK_ALIGNMENT 16
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#define STACK_FRAME_SIZE __XSTR(STACK_ALIGNMENT)
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/* Provide the maximum amount of page table levels per MMU type */
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#ifdef CONFIG_ARCH_MMU_TYPE_SV39
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# define ARCH_PGT_MAX_LEVELS (3)
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#endif
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/* Amount of static page tables allocated for an address environment */
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#ifdef CONFIG_ARCH_ADDRENV
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# define ARCH_SPGTS (ARCH_PGT_MAX_LEVELS - 1)
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#endif
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/****************************************************************************
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* Inline functions
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****************************************************************************/
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@@ -97,6 +110,60 @@ static inline uintptr_t up_getsp(void)
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* Public Types
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****************************************************************************/
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#ifdef CONFIG_ARCH_ADDRENV
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#ifndef __ASSEMBLY__
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/* A task group must have its L1 table in memory always, and the rest can
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* be dynamically committed to memory (and even swapped).
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*
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* In this implementation every level tables besides the final level N are
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* kept in memory always, while the level N tables are dynamically allocated.
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*
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* The implications ? They depend on the MMU type.
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*
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* For Sv39 this means that:
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* - A task can not have more than 1GB of memory allocated. This should be
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* plenty enough...
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* - The minimum amount of memory needed for page tables per task is 12K,
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* which gives access to 2MB of memory. This is plenty for many tasks.
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*/
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struct group_addrenv_s
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{
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/* Pointers to MAX_LEVELS-1 tables here, one of each are allocated for the
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* task when it is created.
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*/
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uintptr_t spgtables[ARCH_SPGTS];
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/* For convenience store the text base here */
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uintptr_t textvbase;
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/* For convenience store the data base here */
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uintptr_t datavbase;
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/* For convenience store the heap base and initial size here */
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uintptr_t heapvbase;
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size_t heapsize;
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/* For convenience store the satp value here */
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uintptr_t satp;
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};
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typedef struct group_addrenv_s group_addrenv_t;
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/* If an address environment needs to be saved, saving the satp register
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* will suffice. The register width is architecture dependent
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*/
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typedef uintptr_t save_addrenv_t;
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#endif /* __ASSEMBLY__ */
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#endif /* CONFIG_ARCH_ADDRENV */
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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File diff suppressed because it is too large
Load Diff
@@ -26,6 +26,10 @@
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#define RV_MMU_PAGE_SHIFT (12)
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#define RV_MMU_PAGE_SIZE (1 << RV_MMU_PAGE_SHIFT) /* 4K pages */
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/* Entries per PGT */
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#define RV_MMU_PAGE_ENTRIES (RV_MMU_PAGE_SIZE / sizeof(uintptr_t))
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/* Supervisor Address Translation and Protection (satp) */
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#define SATP_PPN_SHIFT (0)
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@@ -90,10 +94,10 @@
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#ifdef CONFIG_ARCH_MMU_TYPE_SV39
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#define RV_MMU_PTE_PADDR_SHIFT (10)
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#define RV_MMU_PTE_PPN_MASK ((1 << RV_MMU_PTE_PADDR_SHIFT) - 1)
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#define RV_MMU_PTE_PPN_MASK (((1ul << 44) - 1) << RV_MMU_PTE_PADDR_SHIFT)
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#define RV_MMU_PTE_PPN_SHIFT (2)
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#define RV_MMU_VPN_WIDTH (9)
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#define RV_MMU_VPN_MASK ((1 << RV_MMU_VPN_WIDTH) - 1)
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#define RV_MMU_VPN_MASK ((1ul << RV_MMU_VPN_WIDTH) - 1)
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#define RV_MMU_PT_LEVELS (3)
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#define RV_MMU_VADDR_SHIFT(_n) (RV_MMU_PAGE_SHIFT + RV_MMU_VPN_WIDTH * \
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(RV_MMU_PT_LEVELS - (_n)))
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@@ -244,6 +248,28 @@ static inline void mmu_enable(uintptr_t pgbase, uint16_t asid)
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mmu_write_satp(reg);
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}
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/****************************************************************************
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* Name: mmu_pte_to_paddr
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*
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* Description:
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* Extract physical address from PTE
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*
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* Input Parameters:
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* pte - Page table entry
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*
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* Returned Value:
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* Physical address from PTE
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*
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****************************************************************************/
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static inline uintptr_t mmu_pte_to_paddr(uintptr_t pte)
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{
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uintptr_t paddr = pte;
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paddr &= RV_MMU_PTE_PPN_MASK; /* Remove flags */
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paddr <<= RV_MMU_PTE_PPN_SHIFT; /* Move to correct position */
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return paddr;
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}
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/****************************************************************************
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* Name: mmu_ln_setentry
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*
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@@ -279,6 +305,7 @@ void mmu_ln_setentry(uint32_t ptlevel, uintptr_t lnvaddr, uintptr_t paddr,
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* level n
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* vaddr - The virtual address to get pte for. Must be aligned to a PPN
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* address boundary which is dependent on the level of the entry
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*
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****************************************************************************/
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uintptr_t mmu_ln_getentry(uint32_t ptlevel, uintptr_t lnvaddr,
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@@ -0,0 +1,222 @@
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/****************************************************************************
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* arch/risc-v/src/common/riscv_pgalloc.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <string.h>
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#include <assert.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include <nuttx/addrenv.h>
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#include <nuttx/irq.h>
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#include <nuttx/pgalloc.h>
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#include <nuttx/sched.h>
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#include <arch/barriers.h>
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#include "riscv_mmu.h"
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#ifdef CONFIG_BUILD_KERNEL
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Last PGT level */
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#define PGT_LAST (RV_MMU_PT_LEVELS)
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: wipe_page
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*
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* Description:
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* Wipe a page of physical memory, first mapping it into virtual memory.
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*
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* Input Parameters:
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* paddr - Physical address of page
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*
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****************************************************************************/
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static inline void wipe_page(uintptr_t paddr)
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{
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uintptr_t vaddr = paddr;
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memset((void *)vaddr, 0, MM_PGSIZE);
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}
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/****************************************************************************
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* Name: get_pgtable
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*
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* Description:
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* Get the physical address of the last page table level corresponding to
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* 'vaddr'
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*
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****************************************************************************/
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static uintptr_t get_pgtable(group_addrenv_t *addrenv, uintptr_t vaddr)
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{
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uintptr_t paddr;
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uintptr_t ptprev;
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uint32_t ptlevel;
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/* Get the current level MAX_LEVELS-1 entry corresponding to this vaddr */
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ptlevel = ARCH_SPGTS;
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ptprev = addrenv->spgtables[ARCH_SPGTS - 1];
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paddr = mmu_pte_to_paddr(mmu_ln_getentry(ptlevel, ptprev, vaddr));
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if (!paddr)
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{
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/* No page table has been allocated... allocate one now */
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paddr = mm_pgalloc(1);
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if (paddr)
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{
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/* Wipe the page and assign it */
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wipe_page(paddr);
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mmu_ln_setentry(ptlevel, ptprev, paddr, vaddr, MMU_UPGT_FLAGS);
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}
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}
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/* Flush the data cache, so the changes are committed to memory */
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__DMB();
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return paddr;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: pgalloc
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*
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* Description:
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* If there is a page allocator in the configuration and if and MMU is
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* available to map physical addresses to virtual address, then function
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* must be provided by the platform-specific code. This is part of the
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* implementation of sbrk(). This function will allocate the requested
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* number of pages using the page allocator and map them into consecutive
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* virtual addresses beginning with 'brkaddr'
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*
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* NOTE: This function does not use the up_ naming standard because it
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* is indirectly callable from user-space code via a system trap.
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* Therefore, it is a system interface and follows a different naming
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* convention.
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*
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* Input Parameters:
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* brkaddr - The heap break address. The next page will be allocated and
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* mapped to this address. Must be page aligned. If the memory manager
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* has not yet been initialized and this is the first block requested for
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* the heap, then brkaddr should be zero. pgalloc will then assigned the
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* well-known virtual address of the beginning of the heap.
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* npages - The number of pages to allocate and map. Mapping of pages
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* will be contiguous beginning beginning at 'brkaddr'
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*
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* Returned Value:
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* The (virtual) base address of the mapped page will returned on success.
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* Normally this will be the same as the 'brkaddr' input. However, if
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* the 'brkaddr' input was zero, this will be the virtual address of the
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* beginning of the heap. Zero is returned on any failure.
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*
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****************************************************************************/
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uintptr_t pgalloc(uintptr_t brkaddr, unsigned int npages)
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{
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struct tcb_s *tcb = nxsched_self();
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struct task_group_s *group;
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uintptr_t ptlast;
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uintptr_t paddr;
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uintptr_t vaddr;
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DEBUGASSERT(tcb && tcb->group);
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group = tcb->group;
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/* The current implementation only supports extending the user heap
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* region as part of the implementation of user sbrk(). This function
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* needs to be expanded to also handle (1) extending the user stack
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* space and (2) extending the kernel memory regions as well.
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*/
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DEBUGASSERT((group->tg_flags & GROUP_FLAG_ADDRENV) != 0);
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/* brkaddr = 0 means that no heap has yet been allocated */
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if (!brkaddr)
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{
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brkaddr = group->tg_addrenv.heapvbase;
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}
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/* Start mapping from the old heap break address */
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vaddr = brkaddr;
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/* Sanity checks */
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DEBUGASSERT(brkaddr >= group->tg_addrenv.heapvbase);
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DEBUGASSERT(MM_ISALIGNED(brkaddr));
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for (; npages > 0; npages--)
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{
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/* Get the address of the last level page table */
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ptlast = get_pgtable(&group->tg_addrenv, vaddr);
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if (!ptlast)
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{
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return 0;
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}
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/* Allocate physical memory for the new heap */
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paddr = mm_pgalloc(1);
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if (!paddr)
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{
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return 0;
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}
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/* Wipe the memory */
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wipe_page(paddr);
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/* Then add the reference */
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mmu_ln_setentry(PGT_LAST, ptlast, paddr, vaddr, MMU_UDATA_FLAGS);
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vaddr += MM_PGSIZE;
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}
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/* Flush the data cache, so the changes are committed to memory */
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__DMB();
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return brkaddr;
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}
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#endif /* CONFIG_BUILD_KERNEL */
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@@ -32,6 +32,7 @@
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#include <syscall.h>
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#include <arch/irq.h>
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#include <nuttx/addrenv.h>
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#include <nuttx/sched.h>
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#include <nuttx/userspace.h>
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