From 9999e48639b3cecb08ffb37358bcba3b48161b29 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 08:50:17 +0000
Subject: [PATCH] add ax88772_rst
---
kernel/arch/riscv/mm/fault.c | 528 +++++++++++++++++++++++++++++-----------------------------
1 files changed, 267 insertions(+), 261 deletions(-)
diff --git a/kernel/arch/riscv/mm/fault.c b/kernel/arch/riscv/mm/fault.c
index 523dbfb..54b1294 100644
--- a/kernel/arch/riscv/mm/fault.c
+++ b/kernel/arch/riscv/mm/fault.c
@@ -1,22 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
* Lennox Wu <lennox.wu@sunplusct.com>
* Chen Liqin <liqin.chen@sunplusct.com>
* 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.,
*/
@@ -27,166 +14,13 @@
#include <linux/signal.h>
#include <linux/uaccess.h>
-#include <asm/pgalloc.h>
#include <asm/ptrace.h>
#include <asm/tlbflush.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)
+#include "../kernel/head.h"
+
+static inline void no_context(struct pt_regs *regs, unsigned long addr)
{
- 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 code = SEGV_MAPERR;
- vm_fault_t fault;
-
- 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_SPIE))
- 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;
@@ -200,100 +34,272 @@
(addr < PAGE_SIZE) ? "NULL pointer dereference" :
"paging request", addr);
die(regs, "Oops");
- do_exit(SIGKILL);
+ make_task_dead(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;
-
+static inline void mm_fault_error(struct pt_regs *regs, unsigned long addr, vm_fault_t fault)
+{
+ if (fault & VM_FAULT_OOM) {
/*
- * 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.
- *
- * Note: Use the old spbtr name instead of using the current
- * satp name to support binutils 2.29 which doesn't know about
- * the privileged ISA 1.10 yet.
+ * 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).
*/
- 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;
-
- /*
- * The kernel assumes that TLBs don't cache invalid
- * entries, but in RISC-V, SFENCE.VMA specifies an
- * ordering constraint, not a cache flush; it is
- * necessary even after writing invalid entries.
- * Relying on flush_tlb_fix_spurious_fault would
- * suffice, but the extra traps reduce
- * performance. So, eagerly SFENCE.VMA.
- */
- local_flush_tlb_page(addr);
-
+ if (!user_mode(regs)) {
+ no_context(regs, addr);
+ return;
+ }
+ pagefault_out_of_memory();
+ return;
+ } else if (fault & VM_FAULT_SIGBUS) {
+ /* Kernel mode? Handle exceptions or die */
+ if (!user_mode(regs)) {
+ no_context(regs, addr);
+ return;
+ }
+ do_trap(regs, SIGBUS, BUS_ADRERR, addr);
return;
}
+ BUG();
+}
+
+static inline void bad_area(struct pt_regs *regs, struct mm_struct *mm, int code, unsigned long addr)
+{
+ /*
+ * Something tried to access memory that isn't in our memory map.
+ * Fix it, but check if it's kernel or user first.
+ */
+ mmap_read_unlock(mm);
+ /* User mode accesses just cause a SIGSEGV */
+ if (user_mode(regs)) {
+ do_trap(regs, SIGSEGV, code, addr);
+ return;
+ }
+
+ no_context(regs, addr);
+}
+
+static inline void vmalloc_fault(struct pt_regs *regs, int code, unsigned long addr)
+{
+ 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;
+ unsigned long pfn;
+
+ /* User mode accesses just cause a SIGSEGV */
+ if (user_mode(regs))
+ return do_trap(regs, SIGSEGV, code, addr);
+
+ /*
+ * 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);
+ pfn = csr_read(CSR_SATP) & SATP_PPN;
+ pgd = (pgd_t *)pfn_to_virt(pfn) + index;
+ pgd_k = init_mm.pgd + index;
+
+ if (!pgd_present(*pgd_k)) {
+ no_context(regs, addr);
+ return;
+ }
+ set_pgd(pgd, *pgd_k);
+
+ p4d = p4d_offset(pgd, addr);
+ p4d_k = p4d_offset(pgd_k, addr);
+ if (!p4d_present(*p4d_k)) {
+ no_context(regs, addr);
+ return;
+ }
+
+ pud = pud_offset(p4d, addr);
+ pud_k = pud_offset(p4d_k, addr);
+ if (!pud_present(*pud_k)) {
+ no_context(regs, addr);
+ return;
+ }
+
+ /*
+ * 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)) {
+ no_context(regs, addr);
+ return;
+ }
+ 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)) {
+ no_context(regs, addr);
+ return;
+ }
+
+ /*
+ * The kernel assumes that TLBs don't cache invalid
+ * entries, but in RISC-V, SFENCE.VMA specifies an
+ * ordering constraint, not a cache flush; it is
+ * necessary even after writing invalid entries.
+ */
+ local_flush_tlb_page(addr);
+}
+
+static inline bool access_error(unsigned long cause, struct vm_area_struct *vma)
+{
+ switch (cause) {
+ case EXC_INST_PAGE_FAULT:
+ if (!(vma->vm_flags & VM_EXEC)) {
+ return true;
+ }
+ break;
+ case EXC_LOAD_PAGE_FAULT:
+ /* Write implies read */
+ if (!(vma->vm_flags & (VM_READ | VM_WRITE))) {
+ return true;
+ }
+ break;
+ case EXC_STORE_PAGE_FAULT:
+ if (!(vma->vm_flags & VM_WRITE)) {
+ return true;
+ }
+ break;
+ default:
+ panic("%s: unhandled cause %lu", __func__, cause);
+ }
+ return false;
+}
+
+/*
+ * 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_DEFAULT;
+ int code = SEGV_MAPERR;
+ vm_fault_t fault;
+
+ cause = regs->cause;
+ addr = regs->badaddr;
+
+ 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))) {
+ vmalloc_fault(regs, code, addr);
+ return;
+ }
+
+ /* Enable interrupts if they were enabled in the parent context. */
+ if (likely(regs->status & 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)) {
+ no_context(regs, addr);
+ return;
+ }
+
+ if (user_mode(regs))
+ flags |= FAULT_FLAG_USER;
+
+ perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
+
+ if (cause == EXC_STORE_PAGE_FAULT)
+ flags |= FAULT_FLAG_WRITE;
+ else if (cause == EXC_INST_PAGE_FAULT)
+ flags |= FAULT_FLAG_INSTRUCTION;
+retry:
+ mmap_read_lock(mm);
+ vma = find_vma(mm, addr);
+ if (unlikely(!vma)) {
+ bad_area(regs, mm, code, addr);
+ return;
+ }
+ if (likely(vma->vm_start <= addr))
+ goto good_area;
+ if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
+ bad_area(regs, mm, code, addr);
+ return;
+ }
+ if (unlikely(expand_stack(vma, addr))) {
+ bad_area(regs, mm, code, addr);
+ return;
+ }
+
+ /*
+ * Ok, we have a good vm_area for this memory access, so
+ * we can handle it.
+ */
+good_area:
+ code = SEGV_ACCERR;
+
+ if (unlikely(access_error(cause, vma))) {
+ bad_area(regs, mm, code, addr);
+ return;
+ }
+
+ /*
+ * 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, regs);
+
+ /*
+ * If we need to retry but a fatal signal is pending, handle the
+ * signal first. We do not need to release the mmap_lock because it
+ * would already be released in __lock_page_or_retry in mm/filemap.c.
+ */
+ if (fault_signal_pending(fault, regs))
+ return;
+
+ if (unlikely((fault & VM_FAULT_RETRY) && (flags & FAULT_FLAG_ALLOW_RETRY))) {
+ flags |= FAULT_FLAG_TRIED;
+
+ /*
+ * No need to mmap_read_unlock(mm) as we would
+ * have already released it in __lock_page_or_retry
+ * in mm/filemap.c.
+ */
+ goto retry;
+ }
+
+ mmap_read_unlock(mm);
+
+ if (unlikely(fault & VM_FAULT_ERROR)) {
+ mm_fault_error(regs, addr, fault);
+ return;
+ }
+ return;
}
--
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