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From: Pekka Enberg <penberg@gmail.com>
To: linux-riscv@lists.infradead.org
Cc: Pekka Enberg <penberg@kernel.org>, palmer@dabbelt.com
Subject: [PATCH 2/8] riscv/mm/fault: Move bad area handling to bad_area()
Date: Tue, 25 Aug 2020 21:39:01 +0300	[thread overview]
Message-ID: <20200825183907.275950-3-penberg@gmail.com> (raw)
In-Reply-To: <20200825183907.275950-1-penberg@gmail.com>

From: Pekka Enberg <penberg@kernel.org>

This patch moves the bad area handling in do_page_fault() to bad_area()
function and converts gotos to calls to the new function.
---
 arch/riscv/mm/fault.c | 67 ++++++++++++++++++++++++++-----------------
 1 file changed, 40 insertions(+), 27 deletions(-)

diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index 1612552478c5..ac9a99255365 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -37,6 +37,22 @@ static inline void no_context(struct pt_regs *regs, unsigned long addr)
 	do_exit(SIGKILL);
 }
 
+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);
+}
+
 /*
  * This routine handles page faults.  It determines the address and the
  * problem, and then passes it off to one of the appropriate routines.
@@ -90,14 +106,20 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
 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
@@ -108,16 +130,22 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
 
 	switch (cause) {
 	case EXC_INST_PAGE_FAULT:
-		if (!(vma->vm_flags & VM_EXEC))
-			goto bad_area;
+		if (!(vma->vm_flags & VM_EXEC)) {
+			bad_area(regs, mm, code, addr);
+			return;
+		}
 		break;
 	case EXC_LOAD_PAGE_FAULT:
-		if (!(vma->vm_flags & VM_READ))
-			goto bad_area;
+		if (!(vma->vm_flags & VM_READ)) {
+			bad_area(regs, mm, code, addr);
+			return;
+		}
 		break;
 	case EXC_STORE_PAGE_FAULT:
-		if (!(vma->vm_flags & VM_WRITE))
-			goto bad_area;
+		if (!(vma->vm_flags & VM_WRITE)) {
+			bad_area(regs, mm, code, addr);
+			return;
+		}
 		flags |= FAULT_FLAG_WRITE;
 		break;
 	default:
@@ -161,21 +189,6 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
 	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);
-		return;
-	}
-
-	no_context(regs, addr);
-	return;
-
 	/*
 	 * 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).
-- 
2.26.2


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  parent reply	other threads:[~2020-08-25 18:39 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-25 18:38 [PATCH 0/8] riscv/mm/fault: Page fault handler cleanups Pekka Enberg
2020-08-25 18:39 ` [PATCH 1/8] riscv/mm/fault: Move no context handling to no_context() Pekka Enberg
2020-08-25 18:39 ` Pekka Enberg [this message]
2020-08-25 18:39 ` [PATCH 3/8] riscv/mm/fault: Move vmalloc fault handling to vmalloc_fault() Pekka Enberg
2020-08-25 18:39 ` [PATCH 4/8] riscv/mm/fault: Simplify fault error handling Pekka Enberg
2020-08-25 18:39 ` [PATCH 5/8] riscv/mm/fault: Move fault error handling to mm_fault_error() Pekka Enberg
2020-08-25 18:39 ` [PATCH 6/8] riscv/mm/fault: Simplify mm_fault_error() Pekka Enberg
2020-08-25 18:39 ` [PATCH 7/8] riscv/mm/fault: Move FAULT_FLAG_WRITE handling in do_page_fault() Pekka Enberg
2020-08-25 18:39 ` [PATCH 8/8] riscv/mm/fault: Move access error check to function Pekka Enberg
2020-08-25 19:08 ` [PATCH 0/8] riscv/mm/fault: Page fault handler cleanups Pekka Enberg
2020-09-04 17:37 ` Palmer Dabbelt

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