1 files changed, 200 insertions, 158 deletions

diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index 716d64e36f83..3c8b9e433c67 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -19,6 +19,169 @@
 
 #include "../kernel/head.h"
 
+static inline void no_context(struct pt_regs *regs, unsigned long addr)
+{
+	/* 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);
+}
+
+static inline void mm_fault_error(struct pt_regs *regs, unsigned long addr, vm_fault_t fault)
+{
+	if (fault & VM_FAULT_OOM) {
+		/*
+		 * 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).
+		 */
+		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:
+		if (!(vma->vm_flags & VM_READ)) {
+			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.
@@ -48,8 +211,10 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
 	 * only copy the information from the master page table,
 	 * nothing more.
 	 */
-	if (unlikely((addr >= VMALLOC_START) && (addr <= VMALLOC_END)))
-		goto vmalloc_fault;
+	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))
@@ -59,25 +224,37 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
 	 * 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 (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))
-		goto bad_area;
+	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)))
-		goto bad_area;
-	if (unlikely(expand_stack(vma, addr)))
-		goto bad_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
@@ -86,22 +263,9 @@ retry:
 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 (unlikely(access_error(cause, vma))) {
+		bad_area(regs, mm, code, addr);
+		return;
 	}
 
 	/*
@@ -119,144 +283,22 @@ good_area:
 	if (fault_signal_pending(fault, regs))
 		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();
-	}
-
-	if (flags & FAULT_FLAG_ALLOW_RETRY) {
-		if (fault & VM_FAULT_RETRY) {
-			flags |= FAULT_FLAG_TRIED;
+	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;
-		}
+		/*
+		 * 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);
-	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:
-	mmap_read_unlock(mm);
-	/* User mode accesses just cause a SIGSEGV */
-	if (user_mode(regs)) {
-		do_trap(regs, SIGSEGV, code, addr);
+	if (unlikely(fault & VM_FAULT_ERROR)) {
+		mm_fault_error(regs, addr, fault);
 		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:
-	mmap_read_unlock(mm);
-	if (!user_mode(regs))
-		goto no_context;
-	pagefault_out_of_memory();
-	return;
-
-do_sigbus:
-	mmap_read_unlock(mm);
-	/* Kernel mode? Handle exceptions or die */
-	if (!user_mode(regs))
-		goto no_context;
-	do_trap(regs, SIGBUS, BUS_ADRERR, addr);
 	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;
-
-		/* 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);
-		pgd = (pgd_t *)pfn_to_virt(csr_read(CSR_SATP)) + 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.
-		 */
-		local_flush_tlb_page(addr);
-
-		return;
-	}
 }