These files are mostly based on the score port, but as all the non-stub
functions are very ISA specific they've been heavily modified.
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxx>
---
arch/riscv/mm/Makefile | 1 +
arch/riscv/mm/extable.c | 37 +++++++
arch/riscv/mm/fault.c | 280 ++++++++++++++++++++++++++++++++++++++++++++++++
arch/riscv/mm/init.c | 72 +++++++++++++
arch/riscv/mm/ioremap.c | 93 ++++++++++++++++
5 files changed, 483 insertions(+)
create mode 100644 arch/riscv/mm/Makefile
create mode 100644 arch/riscv/mm/extable.c
create mode 100644 arch/riscv/mm/fault.c
create mode 100644 arch/riscv/mm/init.c
create mode 100644 arch/riscv/mm/ioremap.c
diff --git a/arch/riscv/mm/Makefile b/arch/riscv/mm/Makefile
new file mode 100644
index 000000000000..36ebe6feb5d6
--- /dev/null
+++ b/arch/riscv/mm/Makefile
@@ -0,0 +1 @@
+obj-y := init.o fault.o extable.o ioremap.o
diff --git a/arch/riscv/mm/extable.c b/arch/riscv/mm/extable.c
new file mode 100644
index 000000000000..11bb9417123b
--- /dev/null
+++ b/arch/riscv/mm/extable.c
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
+ * Lennox Wu <lennox.wu@xxxxxxxxxxxxx>
+ * Chen Liqin <liqin.chen@xxxxxxxxxxxxx>
+ * Copyright (C) 2013 Regents of the University of California
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see the file COPYING, or write
+ * to the Free Software Foundation, Inc.,
+ */
+
+
+#include <linux/extable.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+
+int fixup_exception(struct pt_regs *regs)
+{
+ const struct exception_table_entry *fixup;
+
+ fixup = search_exception_tables(regs->sepc);
+ if (fixup) {
+ regs->sepc = fixup->fixup;
+ return 1;
+ }
+ return 0;
+}
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
new file mode 100644
index 000000000000..b2a431c7f233
--- /dev/null
+++ b/arch/riscv/mm/fault.c
@@ -0,0 +1,280 @@
+/*
+ * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
+ * Lennox Wu <lennox.wu@xxxxxxxxxxxxx>
+ * Chen Liqin <liqin.chen@xxxxxxxxxxxxx>
+ * Copyright (C) 2012 Regents of the University of California
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see the file COPYING, or write
+ * to the Free Software Foundation, Inc.,
+ */
+
+
+#include <linux/mm.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/perf_event.h>
+#include <linux/signal.h>
+#include <linux/uaccess.h>
+
+#include <asm/pgalloc.h>
+#include <asm/ptrace.h>
+#include <asm/uaccess.h>
+
+/*
+ * This routine handles page faults. It determines the address and the
+ * problem, and then passes it off to one of the appropriate routines.
+ */
+asmlinkage void do_page_fault(struct pt_regs *regs)
+{
+ struct task_struct *tsk;
+ struct vm_area_struct *vma;
+ struct mm_struct *mm;
+ unsigned long addr, cause;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+ int fault, code = SEGV_MAPERR;
+
+ cause = regs->scause;
+ addr = regs->sbadaddr;
+
+ tsk = current;
+ mm = tsk->mm;
+
+ /*
+ * Fault-in kernel-space virtual memory on-demand.
+ * The 'reference' page table is init_mm.pgd.
+ *
+ * NOTE! We MUST NOT take any locks for this case. We may
+ * be in an interrupt or a critical region, and should
+ * only copy the information from the master page table,
+ * nothing more.
+ */
+ if (unlikely((addr >= VMALLOC_START) && (addr <= VMALLOC_END)))
+ goto vmalloc_fault;
+
+ /* Enable interrupts if they were enabled in the parent context. */
+ if (likely(regs->sstatus & SR_PIE))
+ local_irq_enable();
+
+ /*
+ * If we're in an interrupt, have no user context, or are running
+ * in an atomic region, then we must not take the fault.
+ */
+ if (unlikely(faulthandler_disabled() || !mm))
+ goto no_context;
+
+ if (user_mode(regs))
+ flags |= FAULT_FLAG_USER;
+
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
+
+retry:
+ down_read(&mm->mmap_sem);
+ vma = find_vma(mm, addr);
+ if (unlikely(!vma))
+ goto bad_area;
+ if (likely(vma->vm_start <= addr))
+ goto good_area;
+ if (unlikely(!(vma->vm_flags & VM_GROWSDOWN)))
+ goto bad_area;
+ if (unlikely(expand_stack(vma, addr)))
+ goto bad_area;
+
+ /*
+ * Ok, we have a good vm_area for this memory access, so
+ * we can handle it.
+ */
+good_area:
+ code = SEGV_ACCERR;
+
+ switch (cause) {
+ case EXC_INST_PAGE_FAULT:
+ if (!(vma->vm_flags & VM_EXEC))
+ goto bad_area;
+ break;
+ case EXC_LOAD_PAGE_FAULT:
+ if (!(vma->vm_flags & VM_READ))
+ goto bad_area;
+ break;
+ case EXC_STORE_PAGE_FAULT:
+ if (!(vma->vm_flags & VM_WRITE))
+ goto bad_area;
+ flags |= FAULT_FLAG_WRITE;
+ break;
+ default:
+ panic("%s: unhandled cause %lu", __func__, cause);
+ }
+
+ /*
+ * If for any reason at all we could not handle the fault,
+ * make sure we exit gracefully rather than endlessly redo
+ * the fault.
+ */
+ fault = handle_mm_fault(vma, addr, flags);
+
+ /*
+ * If we need to retry but a fatal signal is pending, handle the
+ * signal first. We do not need to release the mmap_sem because it
+ * would already be released in __lock_page_or_retry in mm/filemap.c.
+ */
+ if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(tsk))
+ return;
+
+ if (unlikely(fault & VM_FAULT_ERROR)) {
+ if (fault & VM_FAULT_OOM)
+ goto out_of_memory;
+ else if (fault & VM_FAULT_SIGBUS)
+ goto do_sigbus;
+ BUG();
+ }
+
+ /*
+ * Major/minor page fault accounting is only done on the
+ * initial attempt. If we go through a retry, it is extremely
+ * likely that the page will be found in page cache at that point.
+ */
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (fault & VM_FAULT_MAJOR) {
+ tsk->maj_flt++;
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ,
+ 1, regs, addr);
+ } else {
+ tsk->min_flt++;
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN,
+ 1, regs, addr);
+ }
+ if (fault & VM_FAULT_RETRY) {
+ /*
+ * Clear FAULT_FLAG_ALLOW_RETRY to avoid any risk
+ * of starvation.
+ */
+ flags &= ~(FAULT_FLAG_ALLOW_RETRY);
+ flags |= FAULT_FLAG_TRIED;
+
+ /*
+ * No need to up_read(&mm->mmap_sem) as we would
+ * have already released it in __lock_page_or_retry
+ * in mm/filemap.c.
+ */
+ goto retry;
+ }
+ }
+
+ up_read(&mm->mmap_sem);
+ return;
+
+ /*
+ * Something tried to access memory that isn't in our memory map.
+ * Fix it, but check if it's kernel or user first.
+ */
+bad_area:
+ up_read(&mm->mmap_sem);
+ /* User mode accesses just cause a SIGSEGV */
+ if (user_mode(regs)) {
+ do_trap(regs, SIGSEGV, code, addr, tsk);
+ return;
+ }
+
+no_context:
+ /* Are we prepared to handle this kernel fault? */
+ if (fixup_exception(regs))
+ return;
+
+ /*
+ * Oops. The kernel tried to access some bad page. We'll have to
+ * terminate things with extreme prejudice.
+ */
+ bust_spinlocks(1);
+ pr_alert("Unable to handle kernel %s at virtual address " REG_FMT "\n",
+ (addr < PAGE_SIZE) ? "NULL pointer dereference" :
+ "paging request", addr);
+ die(regs, "Oops");
+ do_exit(SIGKILL);
+
+ /*
+ * We ran out of memory, call the OOM killer, and return the userspace
+ * (which will retry the fault, or kill us if we got oom-killed).
+ */
+out_of_memory:
+ up_read(&mm->mmap_sem);
+ if (!user_mode(regs))
+ goto no_context;
+ pagefault_out_of_memory();
+ return;
+
+do_sigbus:
+ up_read(&mm->mmap_sem);
+ /* Kernel mode? Handle exceptions or die */
+ if (!user_mode(regs))
+ goto no_context;
+ do_trap(regs, SIGBUS, BUS_ADRERR, addr, tsk);
+ return;
+
+vmalloc_fault:
+ {
+ pgd_t *pgd, *pgd_k;
+ pud_t *pud, *pud_k;
+ p4d_t *p4d, *p4d_k;
+ pmd_t *pmd, *pmd_k;
+ pte_t *pte_k;
+ int index;
+
+ if (user_mode(regs))
+ goto bad_area;
+
+ /*
+ * Synchronize this task's top level page-table
+ * with the 'reference' page table.
+ *
+ * Do _not_ use "tsk->active_mm->pgd" here.
+ * We might be inside an interrupt in the middle
+ * of a task switch.
+ */
+ index = pgd_index(addr);
+ pgd = (pgd_t *)pfn_to_virt(csr_read(sptbr)) + index;
+ pgd_k = init_mm.pgd + index;
+
+ if (!pgd_present(*pgd_k))
+ goto no_context;
+ set_pgd(pgd, *pgd_k);
+
+ p4d = p4d_offset(pgd, addr);
+ p4d_k = p4d_offset(pgd_k, addr);
+ if (!p4d_present(*p4d_k))
+ goto no_context;
+
+ pud = pud_offset(p4d, addr);
+ pud_k = pud_offset(p4d_k, addr);
+ if (!pud_present(*pud_k))
+ goto no_context;
+
+ /* Since the vmalloc area is global, it is unnecessary
+ * to copy individual PTEs
+ */
+ pmd = pmd_offset(pud, addr);
+ pmd_k = pmd_offset(pud_k, addr);
+ if (!pmd_present(*pmd_k))
+ goto no_context;
+ set_pmd(pmd, *pmd_k);
+
+ /* Make sure the actual PTE exists as well to
+ * catch kernel vmalloc-area accesses to non-mapped
+ * addresses. If we don't do this, this will just
+ * silently loop forever.
+ */
+ pte_k = pte_offset_kernel(pmd_k, addr);
+ if (!pte_present(*pte_k))
+ goto no_context;
+ return;
+ }
+}
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
new file mode 100644
index 000000000000..8ad464ce4a4c
--- /dev/null
+++ b/arch/riscv/mm/init.c
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/bootmem.h>
+#include <linux/initrd.h>
+#include <linux/memblock.h>
+#include <linux/swap.h>
+
+#include <asm/tlbflush.h>
+#include <asm/sections.h>
+#include <asm/pgtable.h>
+#include <asm/io.h>
+
+static void __init zone_sizes_init(void)
+{
+ unsigned long zones_size[MAX_NR_ZONES];
+
+ memset(zones_size, 0, sizeof(zones_size));
+ zones_size[ZONE_NORMAL] = pfn_base + max_mapnr;
+ free_area_init_node(0, zones_size, pfn_base, NULL);
+}
+
+void setup_zero_page(void)
+{
+ memset((void *)empty_zero_page, 0, PAGE_SIZE);
+}
+
+void __init paging_init(void)
+{
+ init_mm.pgd = (pgd_t *)pfn_to_virt(csr_read(sptbr));
+
+ setup_zero_page();
+ local_flush_tlb_all();
+ zone_sizes_init();
+}
+
+void __init mem_init(void)
+{
+#ifdef CONFIG_FLATMEM
+ BUG_ON(!mem_map);
+#endif /* CONFIG_FLATMEM */
+
+ high_memory = (void *)(__va(PFN_PHYS(max_low_pfn)));
+ free_all_bootmem();
+
+ mem_init_print_info(NULL);
+}
+
+void free_initmem(void)
+{
+ free_initmem_default(0);
+}
+
+#ifdef CONFIG_BLK_DEV_INITRD
+void free_initrd_mem(unsigned long start, unsigned long end)
+{
+// free_reserved_area(start, end, 0, "initrd");
+}
+#endif /* CONFIG_BLK_DEV_INITRD */
+
diff --git a/arch/riscv/mm/ioremap.c b/arch/riscv/mm/ioremap.c
new file mode 100644
index 000000000000..c5cc0935096d
--- /dev/null
+++ b/arch/riscv/mm/ioremap.c
@@ -0,0 +1,93 @@
+/*
+ * (C) Copyright 1995 1996 Linus Torvalds
+ * (C) Copyright 2012 Regents of the University of California
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/io.h>
+
+#include <asm/pgtable.h>
+
+/*
+ * Remap an arbitrary physical address space into the kernel virtual
+ * address space. Needed when the kernel wants to access high addresses
+ * directly.
+ *
+ * NOTE! We need to allow non-page-aligned mappings too: we will obviously
+ * have to convert them into an offset in a page-aligned mapping, but the
+ * caller shouldn't need to know that small detail.
+ */
+static void __iomem *__ioremap_caller(phys_addr_t addr, size_t size,
+ pgprot_t prot, void *caller)
+{
+ phys_addr_t last_addr;
+ unsigned long offset, vaddr;
+ struct vm_struct *area;
+
+ /* Disallow wrap-around or zero size */
+ last_addr = addr + size - 1;
+ if (!size || last_addr < addr)
+ return NULL;
+
+ /* Page-align mappings */
+ offset = addr & (~PAGE_MASK);
+ addr &= PAGE_MASK;
+ size = PAGE_ALIGN(size + offset);
+
+ area = get_vm_area_caller(size, VM_IOREMAP, caller);
+ if (!area)
+ return NULL;
+ vaddr = (unsigned long)area->addr;
+
+ if (ioremap_page_range(vaddr, vaddr + size, addr, prot)) {
+ free_vm_area(area);
+ return NULL;
+ }
+
+ return (void __iomem *)(vaddr + offset);
+}
+
+/*
+ * ioremap - map bus memory into CPU space
+ * @offset: bus address of the memory
+ * @size: size of the resource to map
+ *
+ * ioremap performs a platform specific sequence of operations to
+ * make bus memory CPU accessible via the readb/readw/readl/writeb/
+ * writew/writel functions and the other mmio helpers. The returned
+ * address is not guaranteed to be usable directly as a virtual
+ * address.
+ *
+ * Must be freed with iounmap.
+ */
+void __iomem *ioremap(phys_addr_t offset, unsigned long size)
+{
+ return __ioremap_caller(offset, size, PAGE_KERNEL,
+ __builtin_return_address(0));
+}
+EXPORT_SYMBOL(ioremap);
+
+
+/**
+ * iounmap - Free a IO remapping
+ * @addr: virtual address from ioremap_*
+ *
+ * Caller must ensure there is only one unmapping for the same pointer.
+ */
+void iounmap(void __iomem *addr)
+{
+ vunmap((void *)((unsigned long)addr & PAGE_MASK));
+}
+EXPORT_SYMBOL(iounmap);
+
--
2.13.0
