diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index b85492c42ccb8f0b785b4e8e26711b9ffed4475e..babc8a0d3d2e11f74166a202c332a9578fbca6dd 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -26,14 +26,14 @@ config RISCV
select GENERIC_IRQ_SHOW
select GENERIC_PCI_IOMAP
select GENERIC_SCHED_CLOCK
- select GENERIC_STRNCPY_FROM_USER
- select GENERIC_STRNLEN_USER
+ select GENERIC_STRNCPY_FROM_USER if MMU
+ select GENERIC_STRNLEN_USER if MMU
select GENERIC_SMP_IDLE_THREAD
select GENERIC_ATOMIC64 if !64BIT
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ASM_MODVERSIONS
select HAVE_MEMBLOCK_NODE_MAP
- select HAVE_DMA_CONTIGUOUS
+ select HAVE_DMA_CONTIGUOUS if MMU
select HAVE_FUTEX_CMPXCHG if FUTEX
select HAVE_PERF_EVENTS
select HAVE_PERF_REGS
@@ -50,6 +50,7 @@ config RISCV
select PCI_DOMAINS_GENERIC if PCI
select PCI_MSI if PCI
select RISCV_TIMER
+ select UACCESS_MEMCPY if !MMU
select GENERIC_IRQ_MULTI_HANDLER
select GENERIC_ARCH_TOPOLOGY if SMP
select ARCH_HAS_PTE_SPECIAL
@@ -60,7 +61,7 @@ config RISCV
select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
select SPARSEMEM_STATIC if 32BIT
select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
- select HAVE_ARCH_MMAP_RND_BITS
+ select HAVE_ARCH_MMAP_RND_BITS if MMU
config ARCH_MMAP_RND_BITS_MIN
default 18 if 64BIT
@@ -75,6 +76,7 @@ config ARCH_MMAP_RND_BITS_MAX
# set if we run in machine mode, cleared if we run in supervisor mode
config RISCV_M_MODE
bool
+ default !MMU
# set if we are running in S-mode and can use SBI calls
config RISCV_SBI
@@ -83,7 +85,11 @@ config RISCV_SBI
default y
config MMU
- def_bool y
+ bool "MMU-based Paged Memory Management Support"
+ default y
+ help
+ Select if you want MMU-based virtualised addressing space
+ support by paged memory management. If unsure, say 'Y'.
config ZONE_DMA32
bool
@@ -102,6 +108,7 @@ config PA_BITS
config PAGE_OFFSET
hex
default 0xC0000000 if 32BIT && MAXPHYSMEM_2GB
+ default 0x80000000 if 64BIT && !MMU
default 0xffffffff80000000 if 64BIT && MAXPHYSMEM_2GB
default 0xffffffe000000000 if 64BIT && MAXPHYSMEM_128GB
@@ -145,7 +152,7 @@ config GENERIC_HWEIGHT
def_bool y
config FIX_EARLYCON_MEM
- def_bool y
+ def_bool CONFIG_MMU
config PGTABLE_LEVELS
int
@@ -170,6 +177,7 @@ config ARCH_RV32I
select GENERIC_LIB_ASHRDI3
select GENERIC_LIB_LSHRDI3
select GENERIC_LIB_UCMPDI2
+ select MMU
config ARCH_RV64I
bool "RV64I"
@@ -178,9 +186,9 @@ config ARCH_RV64I
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FTRACE_MCOUNT_RECORD
- select HAVE_DYNAMIC_FTRACE
- select HAVE_DYNAMIC_FTRACE_WITH_REGS
- select SWIOTLB
+ select HAVE_DYNAMIC_FTRACE if MMU
+ select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
+ select SWIOTLB if MMU
endchoice
diff --git a/arch/riscv/configs/nommu_virt_defconfig b/arch/riscv/configs/nommu_virt_defconfig
new file mode 100644
index 0000000000000000000000000000000000000000..cf74e179bf90e4ffc76827e97b771d79c53be8ff
--- /dev/null
+++ b/arch/riscv/configs/nommu_virt_defconfig
@@ -0,0 +1,78 @@
+# CONFIG_CPU_ISOLATION is not set
+CONFIG_LOG_BUF_SHIFT=16
+CONFIG_PRINTK_SAFE_LOG_BUF_SHIFT=12
+CONFIG_BLK_DEV_INITRD=y
+# CONFIG_RD_BZIP2 is not set
+# CONFIG_RD_LZMA is not set
+# CONFIG_RD_XZ is not set
+# CONFIG_RD_LZO is not set
+# CONFIG_RD_LZ4 is not set
+CONFIG_CC_OPTIMIZE_FOR_SIZE=y
+CONFIG_EXPERT=y
+# CONFIG_SYSFS_SYSCALL is not set
+# CONFIG_FHANDLE is not set
+# CONFIG_BASE_FULL is not set
+# CONFIG_EPOLL is not set
+# CONFIG_SIGNALFD is not set
+# CONFIG_TIMERFD is not set
+# CONFIG_EVENTFD is not set
+# CONFIG_AIO is not set
+# CONFIG_IO_URING is not set
+# CONFIG_ADVISE_SYSCALLS is not set
+# CONFIG_MEMBARRIER is not set
+# CONFIG_KALLSYMS is not set
+# CONFIG_VM_EVENT_COUNTERS is not set
+# CONFIG_COMPAT_BRK is not set
+CONFIG_SLOB=y
+# CONFIG_SLAB_MERGE_DEFAULT is not set
+# CONFIG_MMU is not set
+CONFIG_MAXPHYSMEM_2GB=y
+CONFIG_SMP=y
+CONFIG_CMDLINE="root=/dev/vda rw earlycon=uart8250,mmio,0x10000000,115200n8 console=ttyS0"
+CONFIG_CMDLINE_FORCE=y
+# CONFIG_BLK_DEV_BSG is not set
+CONFIG_PARTITION_ADVANCED=y
+# CONFIG_MSDOS_PARTITION is not set
+# CONFIG_EFI_PARTITION is not set
+# CONFIG_MQ_IOSCHED_DEADLINE is not set
+# CONFIG_MQ_IOSCHED_KYBER is not set
+CONFIG_BINFMT_FLAT=y
+# CONFIG_COREDUMP is not set
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y
+# CONFIG_FW_LOADER is not set
+# CONFIG_ALLOW_DEV_COREDUMP is not set
+CONFIG_VIRTIO_BLK=y
+# CONFIG_INPUT_KEYBOARD is not set
+# CONFIG_INPUT_MOUSE is not set
+# CONFIG_SERIO is not set
+# CONFIG_LEGACY_PTYS is not set
+# CONFIG_LDISC_AUTOLOAD is not set
+# CONFIG_DEVMEM is not set
+CONFIG_SERIAL_8250=y
+# CONFIG_SERIAL_8250_DEPRECATED_OPTIONS is not set
+CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_SERIAL_8250_NR_UARTS=1
+CONFIG_SERIAL_8250_RUNTIME_UARTS=1
+CONFIG_SERIAL_OF_PLATFORM=y
+# CONFIG_HW_RANDOM is not set
+# CONFIG_HWMON is not set
+# CONFIG_LCD_CLASS_DEVICE is not set
+# CONFIG_BACKLIGHT_CLASS_DEVICE is not set
+# CONFIG_VGA_CONSOLE is not set
+# CONFIG_HID is not set
+# CONFIG_USB_SUPPORT is not set
+CONFIG_VIRTIO_MMIO=y
+CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES=y
+CONFIG_SIFIVE_PLIC=y
+# CONFIG_VALIDATE_FS_PARSER is not set
+CONFIG_EXT2_FS=y
+# CONFIG_DNOTIFY is not set
+# CONFIG_INOTIFY_USER is not set
+# CONFIG_MISC_FILESYSTEMS is not set
+CONFIG_LSM="[]"
+CONFIG_PRINTK_TIME=y
+# CONFIG_SCHED_DEBUG is not set
+# CONFIG_RCU_TRACE is not set
+# CONFIG_FTRACE is not set
+# CONFIG_RUNTIME_TESTING_MENU is not set
diff --git a/arch/riscv/include/asm/cache.h b/arch/riscv/include/asm/cache.h
index bfd523e8f0b2949f696af93ece3515ba33a84f6a..9b58b104559ee8c535d99a9ce63a93a29c09cfa9 100644
--- a/arch/riscv/include/asm/cache.h
+++ b/arch/riscv/include/asm/cache.h
@@ -11,4 +11,12 @@
#define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT)
+/*
+ * RISC-V requires the stack pointer to be 16-byte aligned, so ensure that
+ * the flat loader aligns it accordingly.
+ */
+#ifndef CONFIG_MMU
+#define ARCH_SLAB_MINALIGN 16
+#endif
+
#endif /* _ASM_RISCV_CACHE_H */
diff --git a/arch/riscv/include/asm/elf.h b/arch/riscv/include/asm/elf.h
index ef04084bf0deef957d718b9f6fe3a36710c8b821..d83a4efd052bc0344a811d87f372a798107adc64 100644
--- a/arch/riscv/include/asm/elf.h
+++ b/arch/riscv/include/asm/elf.h
@@ -56,16 +56,16 @@ extern unsigned long elf_hwcap;
*/
#define ELF_PLATFORM (NULL)
+#ifdef CONFIG_MMU
#define ARCH_DLINFO \
do { \
NEW_AUX_ENT(AT_SYSINFO_EHDR, \
(elf_addr_t)current->mm->context.vdso); \
} while (0)
-
-
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES
struct linux_binprm;
extern int arch_setup_additional_pages(struct linux_binprm *bprm,
int uses_interp);
+#endif /* CONFIG_MMU */
#endif /* _ASM_RISCV_ELF_H */
diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h
index 161f28d04a07a2c1075076526e673aabb624d6cd..42d2c42f3cc946d2b3b9eabe6758eb9fcd64e4ea 100644
--- a/arch/riscv/include/asm/fixmap.h
+++ b/arch/riscv/include/asm/fixmap.h
@@ -11,6 +11,7 @@
#include <asm/page.h>
#include <asm/pgtable.h>
+#ifdef CONFIG_MMU
/*
* Here we define all the compile-time 'special' virtual addresses.
* The point is to have a constant address at compile time, but to
@@ -42,4 +43,5 @@ extern void __set_fixmap(enum fixed_addresses idx,
#include <asm-generic/fixmap.h>
+#endif /* CONFIG_MMU */
#endif /* _ASM_RISCV_FIXMAP_H */
diff --git a/arch/riscv/include/asm/futex.h b/arch/riscv/include/asm/futex.h
index 4ad6409c4647db4a4a613817c9abeaf57707f1df..418564b96dc4f1e5edfa97b340fe4ae228104787 100644
--- a/arch/riscv/include/asm/futex.h
+++ b/arch/riscv/include/asm/futex.h
@@ -12,6 +12,12 @@
#include <linux/errno.h>
#include <asm/asm.h>
+/* We don't even really need the extable code, but for now keep it simple */
+#ifndef CONFIG_MMU
+#define __enable_user_access() do { } while (0)
+#define __disable_user_access() do { } while (0)
+#endif
+
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
{ \
uintptr_t tmp; \
diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h
index d5af79cd89dba3b35476ca366c2b20c6b204356d..0f477206a4edbc16c7c100e4ec7ce50485954ab1 100644
--- a/arch/riscv/include/asm/io.h
+++ b/arch/riscv/include/asm/io.h
@@ -24,8 +24,10 @@
/*
* I/O port access constants.
*/
+#ifdef CONFIG_MMU
#define IO_SPACE_LIMIT (PCI_IO_SIZE - 1)
#define PCI_IOBASE ((void __iomem *)PCI_IO_START)
+#endif /* CONFIG_MMU */
/*
* Emulation routines for the port-mapped IO space used by some PCI drivers.
diff --git a/arch/riscv/include/asm/mmio.h b/arch/riscv/include/asm/mmio.h
index 308b98f85753939d027aee0e07ba0ceb7eeaa4bd..a297a835e402bff0226ee5c8022d566f15cc70e0 100644
--- a/arch/riscv/include/asm/mmio.h
+++ b/arch/riscv/include/asm/mmio.h
@@ -14,6 +14,7 @@
#include <linux/types.h>
#include <asm/mmiowb.h>
+#ifdef CONFIG_MMU
void __iomem *ioremap(phys_addr_t offset, unsigned long size);
/*
@@ -26,6 +27,9 @@ void __iomem *ioremap(phys_addr_t offset, unsigned long size);
#define ioremap_wt(addr, size) ioremap((addr), (size))
void iounmap(volatile void __iomem *addr);
+#else
+#define pgprot_noncached(x) (x)
+#endif /* CONFIG_MMU */
/* Generic IO read/write. These perform native-endian accesses. */
#define __raw_writeb __raw_writeb
diff --git a/arch/riscv/include/asm/mmu.h b/arch/riscv/include/asm/mmu.h
index 151476fb58cbd8c2a51a9eb39da7fca07f94f988..967eacb01ab578f1b5efe3358c306b33c8bd5508 100644
--- a/arch/riscv/include/asm/mmu.h
+++ b/arch/riscv/include/asm/mmu.h
@@ -10,6 +10,9 @@
#ifndef __ASSEMBLY__
typedef struct {
+#ifndef CONFIG_MMU
+ unsigned long end_brk;
+#endif
void *vdso;
#ifdef CONFIG_SMP
/* A local icache flush is needed before user execution can resume. */
diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
index 3db261c4810fc1b01750d3c5ca61fc73b55d681e..ac699246ae7e621986f5b45e340e5760a0fba234 100644
--- a/arch/riscv/include/asm/page.h
+++ b/arch/riscv/include/asm/page.h
@@ -88,8 +88,14 @@ typedef struct page *pgtable_t;
#define PTE_FMT "%08lx"
#endif
+#ifdef CONFIG_MMU
extern unsigned long va_pa_offset;
extern unsigned long pfn_base;
+#define ARCH_PFN_OFFSET (pfn_base)
+#else
+#define va_pa_offset 0
+#define ARCH_PFN_OFFSET (PAGE_OFFSET >> PAGE_SHIFT)
+#endif /* CONFIG_MMU */
extern unsigned long max_low_pfn;
extern unsigned long min_low_pfn;
@@ -112,11 +118,9 @@ extern unsigned long min_low_pfn;
#ifdef CONFIG_FLATMEM
#define pfn_valid(pfn) \
- (((pfn) >= pfn_base) && (((pfn)-pfn_base) < max_mapnr))
+ (((pfn) >= ARCH_PFN_OFFSET) && (((pfn) - ARCH_PFN_OFFSET) < max_mapnr))
#endif
-#define ARCH_PFN_OFFSET (pfn_base)
-
#endif /* __ASSEMBLY__ */
#define virt_addr_valid(vaddr) (pfn_valid(virt_to_pfn(vaddr)))
diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h
index d59ea92285ec2b36ba90abacce6d107415f6ef80..3f601ee8233fb7f8c92059ef2b06fee7d88a603e 100644
--- a/arch/riscv/include/asm/pgalloc.h
+++ b/arch/riscv/include/asm/pgalloc.h
@@ -10,6 +10,7 @@
#include <linux/mm.h>
#include <asm/tlb.h>
+#ifdef CONFIG_MMU
#include <asm-generic/pgalloc.h> /* for pte_{alloc,free}_one */
static inline void pmd_populate_kernel(struct mm_struct *mm,
@@ -81,5 +82,6 @@ do { \
pgtable_pte_page_dtor(pte); \
tlb_remove_page((tlb), pte); \
} while (0)
+#endif /* CONFIG_MMU */
#endif /* _ASM_RISCV_PGALLOC_H */
diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index d3221017194dd19bfe824683ecb700dee60d6e7b..beb5f0865e399a9fba132908cae11c065f544f9f 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -25,6 +25,7 @@
#include <asm/pgtable-32.h>
#endif /* CONFIG_64BIT */
+#ifdef CONFIG_MMU
/* Number of entries in the page global directory */
#define PTRS_PER_PGD (PAGE_SIZE / sizeof(pgd_t))
/* Number of entries in the page table */
@@ -32,7 +33,6 @@
/* Number of PGD entries that a user-mode program can use */
#define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
-#define FIRST_USER_ADDRESS 0
/* Page protection bits */
#define _PAGE_BASE (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_USER)
@@ -84,42 +84,6 @@ extern pgd_t swapper_pg_dir[];
#define __S110 PAGE_SHARED_EXEC
#define __S111 PAGE_SHARED_EXEC
-#define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1)
-#define VMALLOC_END (PAGE_OFFSET - 1)
-#define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE)
-#define PCI_IO_SIZE SZ_16M
-
-/*
- * Roughly size the vmemmap space to be large enough to fit enough
- * struct pages to map half the virtual address space. Then
- * position vmemmap directly below the VMALLOC region.
- */
-#define VMEMMAP_SHIFT \
- (CONFIG_VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT)
-#define VMEMMAP_SIZE BIT(VMEMMAP_SHIFT)
-#define VMEMMAP_END (VMALLOC_START - 1)
-#define VMEMMAP_START (VMALLOC_START - VMEMMAP_SIZE)
-
-#define vmemmap ((struct page *)VMEMMAP_START)
-
-#define PCI_IO_END VMEMMAP_START
-#define PCI_IO_START (PCI_IO_END - PCI_IO_SIZE)
-#define FIXADDR_TOP PCI_IO_START
-
-#ifdef CONFIG_64BIT
-#define FIXADDR_SIZE PMD_SIZE
-#else
-#define FIXADDR_SIZE PGDIR_SIZE
-#endif
-#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
-
-/*
- * ZERO_PAGE is a global shared page that is always zero,
- * used for zero-mapped memory areas, etc.
- */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
static inline int pmd_present(pmd_t pmd)
{
return (pmd_val(pmd) & (_PAGE_PRESENT | _PAGE_PROT_NONE));
@@ -430,11 +394,34 @@ static inline int ptep_clear_flush_young(struct vm_area_struct *vma,
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
-#define kern_addr_valid(addr) (1) /* FIXME */
+#define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1)
+#define VMALLOC_END (PAGE_OFFSET - 1)
+#define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE)
-extern void *dtb_early_va;
-extern void setup_bootmem(void);
-extern void paging_init(void);
+/*
+ * Roughly size the vmemmap space to be large enough to fit enough
+ * struct pages to map half the virtual address space. Then
+ * position vmemmap directly below the VMALLOC region.
+ */
+#define VMEMMAP_SHIFT \
+ (CONFIG_VA_BITS - PAGE_SHIFT - 1 + STRUCT_PAGE_MAX_SHIFT)
+#define VMEMMAP_SIZE BIT(VMEMMAP_SHIFT)
+#define VMEMMAP_END (VMALLOC_START - 1)
+#define VMEMMAP_START (VMALLOC_START - VMEMMAP_SIZE)
+
+#define vmemmap ((struct page *)VMEMMAP_START)
+
+#define PCI_IO_SIZE SZ_16M
+#define PCI_IO_END VMEMMAP_START
+#define PCI_IO_START (PCI_IO_END - PCI_IO_SIZE)
+
+#define FIXADDR_TOP PCI_IO_START
+#ifdef CONFIG_64BIT
+#define FIXADDR_SIZE PMD_SIZE
+#else
+#define FIXADDR_SIZE PGDIR_SIZE
+#endif
+#define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE)
/*
* Task size is 0x4000000000 for RV64 or 0x9fc00000 for RV32.
@@ -446,6 +433,31 @@ extern void paging_init(void);
#define TASK_SIZE FIXADDR_START
#endif
+#else /* CONFIG_MMU */
+
+#define PAGE_KERNEL __pgprot(0)
+#define swapper_pg_dir NULL
+#define VMALLOC_START 0
+
+#define TASK_SIZE 0xffffffffUL
+
+#endif /* !CONFIG_MMU */
+
+#define kern_addr_valid(addr) (1) /* FIXME */
+
+extern void *dtb_early_va;
+void setup_bootmem(void);
+void paging_init(void);
+
+#define FIRST_USER_ADDRESS 0
+
+/*
+ * ZERO_PAGE is a global shared page that is always zero,
+ * used for zero-mapped memory areas, etc.
+ */
+extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
+#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
+
#include <asm-generic/pgtable.h>
#endif /* !__ASSEMBLY__ */
diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
index f02188a5b0f41b4a193aa432014aaf68bf5cce28..394cfbccdcd90e08e4708d607bde6f523d416b15 100644
--- a/arch/riscv/include/asm/tlbflush.h
+++ b/arch/riscv/include/asm/tlbflush.h
@@ -10,6 +10,7 @@
#include <linux/mm_types.h>
#include <asm/smp.h>
+#ifdef CONFIG_MMU
static inline void local_flush_tlb_all(void)
{
__asm__ __volatile__ ("sfence.vma" : : : "memory");
@@ -20,14 +21,19 @@ static inline void local_flush_tlb_page(unsigned long addr)
{
__asm__ __volatile__ ("sfence.vma %0" : : "r" (addr) : "memory");
}
+#else /* CONFIG_MMU */
+#define local_flush_tlb_all() do { } while (0)
+#define local_flush_tlb_page(addr) do { } while (0)
+#endif /* CONFIG_MMU */
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) && defined(CONFIG_MMU)
void flush_tlb_all(void);
void flush_tlb_mm(struct mm_struct *mm);
void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr);
void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end);
-#else /* CONFIG_SMP */
+#else /* CONFIG_SMP && CONFIG_MMU */
+
#define flush_tlb_all() local_flush_tlb_all()
#define flush_tlb_page(vma, addr) local_flush_tlb_page(addr)
@@ -38,7 +44,7 @@ static inline void flush_tlb_range(struct vm_area_struct *vma,
}
#define flush_tlb_mm(mm) flush_tlb_all()
-#endif /* CONFIG_SMP */
+#endif /* !CONFIG_SMP || !CONFIG_MMU */
/* Flush a range of kernel pages */
static inline void flush_tlb_kernel_range(unsigned long start,
diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h
index e076437cfafecff41edf7c6833ad60e46482430b..f462a183a9c2343415ce933ce34d996f0ae0b4d0 100644
--- a/arch/riscv/include/asm/uaccess.h
+++ b/arch/riscv/include/asm/uaccess.h
@@ -11,6 +11,7 @@
/*
* User space memory access functions
*/
+#ifdef CONFIG_MMU
#include <linux/errno.h>
#include <linux/compiler.h>
#include <linux/thread_info.h>
@@ -475,4 +476,7 @@ unsigned long __must_check clear_user(void __user *to, unsigned long n)
__ret; \
})
+#else /* CONFIG_MMU */
+#include <asm-generic/uaccess.h>
+#endif /* CONFIG_MMU */
#endif /* _ASM_RISCV_UACCESS_H */
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 2dca51046899723b30e9ed8159d37713eeb5be9e..f40205cb9a2277c1583adfe10bd973c6cec261d9 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -25,9 +25,8 @@ obj-y += time.o
obj-y += traps.o
obj-y += riscv_ksyms.o
obj-y += stacktrace.o
-obj-y += vdso.o
obj-y += cacheinfo.o
-obj-y += vdso/
+obj-$(CONFIG_MMU) += vdso.o vdso/
obj-$(CONFIG_RISCV_M_MODE) += clint.o
obj-$(CONFIG_FPU) += fpu.o
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index b84f8d7f4911d2c168ca99f1ef00cb91bbbdd022..89aecba63f496f1d2840b6cf8114e7ac6af0260a 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -398,6 +398,10 @@ ENTRY(__switch_to)
ret
ENDPROC(__switch_to)
+#ifndef CONFIG_MMU
+#define do_page_fault do_trap_unknown
+#endif
+
.section ".rodata"
/* Exception vector table */
ENTRY(excp_vect_table)
@@ -419,3 +423,10 @@ ENTRY(excp_vect_table)
RISCV_PTR do_page_fault /* store page fault */
excp_vect_table_end:
END(excp_vect_table)
+
+#ifndef CONFIG_MMU
+ENTRY(__user_rt_sigreturn)
+ li a7, __NR_rt_sigreturn
+ scall
+END(__user_rt_sigreturn)
+#endif
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index 64eb8beb228ee7884aeae462ee1939deabe296d5..84a6f0a4b120b4c8dbc0d171d9472fd17c862797 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -109,8 +109,10 @@ clear_bss_done:
la sp, init_thread_union + THREAD_SIZE
mv a0, s1
call setup_vm
+#ifdef CONFIG_MMU
la a0, early_pg_dir
call relocate
+#endif /* CONFIG_MMU */
/* Restore C environment */
la tp, init_task
@@ -121,6 +123,7 @@ clear_bss_done:
call parse_dtb
tail start_kernel
+#ifdef CONFIG_MMU
relocate:
/* Relocate return address */
li a1, PAGE_OFFSET
@@ -171,6 +174,7 @@ relocate:
sfence.vma
ret
+#endif /* CONFIG_MMU */
.Lsecondary_start:
#ifdef CONFIG_SMP
@@ -196,9 +200,11 @@ relocate:
beqz tp, .Lwait_for_cpu_up
fence
+#ifdef CONFIG_MMU
/* Enable virtual memory and relocate to virtual address */
la a0, swapper_pg_dir
call relocate
+#endif
tail smp_callin
#endif
diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c
index b7f9a5565c4bfc2ec37a8ba0020e58f306bfa0bb..17ba190e84a53df83a3b9a6c263724de3d757b12 100644
--- a/arch/riscv/kernel/signal.c
+++ b/arch/riscv/kernel/signal.c
@@ -17,11 +17,16 @@
#include <asm/switch_to.h>
#include <asm/csr.h>
+extern u32 __user_rt_sigreturn[2];
+
#define DEBUG_SIG 0
struct rt_sigframe {
struct siginfo info;
struct ucontext uc;
+#ifndef CONFIG_MMU
+ u32 sigreturn_code[2];
+#endif
};
#ifdef CONFIG_FPU
@@ -166,7 +171,6 @@ static inline void __user *get_sigframe(struct ksignal *ksig,
return (void __user *)sp;
}
-
static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
@@ -189,8 +193,19 @@ static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
return -EFAULT;
/* Set up to return from userspace. */
+#ifdef CONFIG_MMU
regs->ra = (unsigned long)VDSO_SYMBOL(
current->mm->context.vdso, rt_sigreturn);
+#else
+ /*
+ * For the nommu case we don't have a VDSO. Instead we push two
+ * instructions to call the rt_sigreturn syscall onto the user stack.
+ */
+ if (copy_to_user(&frame->sigreturn_code, __user_rt_sigreturn,
+ sizeof(frame->sigreturn_code)))
+ return -EFAULT;
+ regs->ra = (unsigned long)&frame->sigreturn_code;
+#endif /* CONFIG_MMU */
/*
* Set up registers for signal handler.
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index 267feaa10f6ad2f3ad5a7b8bdf82a86ac434c7aa..47e7a82044608d1b1b81a981b1511ee3406cf68a 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -1,7 +1,6 @@
# SPDX-License-Identifier: GPL-2.0-only
-lib-y += delay.o
-lib-y += memcpy.o
-lib-y += memset.o
-lib-y += uaccess.o
-
-lib-$(CONFIG_64BIT) += tishift.o
+lib-y += delay.o
+lib-y += memcpy.o
+lib-y += memset.o
+lib-$(CONFIG_MMU) += uaccess.o
+lib-$(CONFIG_64BIT) += tishift.o
diff --git a/arch/riscv/mm/Makefile b/arch/riscv/mm/Makefile
index 9d9a173356868b6bcce2ca8657720bc26fd16527..44ab8f28c3fade77f78ff9c2faab5134555d4ad9 100644
--- a/arch/riscv/mm/Makefile
+++ b/arch/riscv/mm/Makefile
@@ -6,9 +6,8 @@ CFLAGS_REMOVE_init.o = -pg
endif
obj-y += init.o
-obj-y += fault.o
obj-y += extable.o
-obj-y += ioremap.o
+obj-$(CONFIG_MMU) += fault.o ioremap.o
obj-y += cacheflush.o
obj-y += context.o
obj-y += sifive_l2_cache.o
diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
index 794c9ab256ebadca4fd57b2643949ce67ed3c624..8f190068664059d3ed2bfc5e40b27e93c1d7bb88 100644
--- a/arch/riscv/mm/cacheflush.c
+++ b/arch/riscv/mm/cacheflush.c
@@ -78,6 +78,7 @@ void flush_icache_mm(struct mm_struct *mm, bool local)
#endif /* CONFIG_SMP */
+#ifdef CONFIG_MMU
void flush_icache_pte(pte_t pte)
{
struct page *page = pte_page(pte);
@@ -85,3 +86,4 @@ void flush_icache_pte(pte_t pte)
if (!test_and_set_bit(PG_dcache_clean, &page->flags))
flush_icache_all();
}
+#endif /* CONFIG_MMU */
diff --git a/arch/riscv/mm/context.c b/arch/riscv/mm/context.c
index ca66d44156b628d087fe1b2fc75c35f27f14e38f..613ec81a8979adc837390f3d676a56f78309563f 100644
--- a/arch/riscv/mm/context.c
+++ b/arch/riscv/mm/context.c
@@ -58,8 +58,10 @@ void switch_mm(struct mm_struct *prev, struct mm_struct *next,
cpumask_clear_cpu(cpu, mm_cpumask(prev));
cpumask_set_cpu(cpu, mm_cpumask(next));
+#ifdef CONFIG_MMU
csr_write(CSR_SATP, virt_to_pfn(next->pgd) | SATP_MODE);
local_flush_tlb_all();
+#endif
flush_icache_deferred(next);
}
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 573463d1c799a0425e550681507643a9e60fe1cb..6322ec82ec1d693270316fc91f713f9ac97fa8a3 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -26,6 +26,7 @@ unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
EXPORT_SYMBOL(empty_zero_page);
extern char _start[];
+void *dtb_early_va;
static void __init zone_sizes_init(void)
{
@@ -40,7 +41,7 @@ static void __init zone_sizes_init(void)
free_area_init_nodes(max_zone_pfns);
}
-void setup_zero_page(void)
+static void setup_zero_page(void)
{
memset((void *)empty_zero_page, 0, PAGE_SIZE);
}
@@ -142,12 +143,12 @@ void __init setup_bootmem(void)
}
}
+#ifdef CONFIG_MMU
unsigned long va_pa_offset;
EXPORT_SYMBOL(va_pa_offset);
unsigned long pfn_base;
EXPORT_SYMBOL(pfn_base);
-void *dtb_early_va;
pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
pgd_t trampoline_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
@@ -449,6 +450,16 @@ static void __init setup_vm_final(void)
csr_write(CSR_SATP, PFN_DOWN(__pa(swapper_pg_dir)) | SATP_MODE);
local_flush_tlb_all();
}
+#else
+asmlinkage void __init setup_vm(uintptr_t dtb_pa)
+{
+ dtb_early_va = (void *)dtb_pa;
+}
+
+static inline void setup_vm_final(void)
+{
+}
+#endif /* CONFIG_MMU */
void __init paging_init(void)
{