linux-kernel - [PATCH rfc v2 08/10] loongarch: mm: cleanup __do_page

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Date:   Mon, 21 Aug 2023 20:30:54 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Andrew Morton <akpm@...ux-foundation.org>, <linux-mm@...ck.org>
CC:     <surenb@...gle.com>, <willy@...radead.org>,
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Huacai Chen <chenhuacai@...nel.org>,
        WANG Xuerui <kernel@...0n.name>,
        Michael Ellerman <mpe@...erman.id.au>,
        Nicholas Piggin <npiggin@...il.com>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Gerald Schaefer <gerald.schaefer@...ux.ibm.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Sven Schnelle <svens@...ux.ibm.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        <x86@...nel.org>, "H . Peter Anvin" <hpa@...or.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <loongarch@...ts.linux.dev>,
        <linuxppc-dev@...ts.ozlabs.org>, <linux-riscv@...ts.infradead.org>,
        <linux-s390@...r.kernel.org>,
        Kefeng Wang <wangkefeng.wang@...wei.com>
Subject: [PATCH rfc v2 08/10] loongarch: mm: cleanup __do_page_fault()

Cleanup __do_page_fault() by reuse bad_area_nosemaphore and
bad_area label.

Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
---
 arch/loongarch/mm/fault.c | 48 +++++++++++++--------------------------
 1 file changed, 16 insertions(+), 32 deletions(-)

diff --git a/arch/loongarch/mm/fault.c b/arch/loongarch/mm/fault.c
index e6376e3dce86..5d4c742c4bc5 100644
--- a/arch/loongarch/mm/fault.c
+++ b/arch/loongarch/mm/fault.c
@@ -157,18 +157,15 @@ static void __kprobes __do_page_fault(struct pt_regs *regs,
 		if (!user_mode(regs))
 			no_context(regs, write, address);
 		else
-			do_sigsegv(regs, write, address, si_code);
-		return;
+			goto bad_area_nosemaphore;
 	}
 
 	/*
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (faulthandler_disabled() || !mm) {
-		do_sigsegv(regs, write, address, si_code);
-		return;
-	}
+	if (faulthandler_disabled() || !mm)
+		goto bad_area_nosemaphore;
 
 	if (user_mode(regs))
 		flags |= FAULT_FLAG_USER;
@@ -178,23 +175,7 @@ static void __kprobes __do_page_fault(struct pt_regs *regs,
 	vma = lock_mm_and_find_vma(mm, address, regs);
 	if (unlikely(!vma))
 		goto bad_area_nosemaphore;
-	goto good_area;
-
-/*
- * 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);
-bad_area_nosemaphore:
-	do_sigsegv(regs, write, address, si_code);
-	return;
 
-/*
- * Ok, we have a good vm_area for this memory access, so
- * we can handle it..
- */
-good_area:
 	si_code = SEGV_ACCERR;
 
 	if (write) {
@@ -235,22 +216,25 @@ static void __kprobes __do_page_fault(struct pt_regs *regs,
 		 */
 		goto retry;
 	}
+
+	mmap_read_unlock(mm);
+
 	if (unlikely(fault & VM_FAULT_ERROR)) {
-		mmap_read_unlock(mm);
-		if (fault & VM_FAULT_OOM) {
+		if (fault & VM_FAULT_OOM)
 			do_out_of_memory(regs, write, address);
-			return;
-		} else if (fault & VM_FAULT_SIGSEGV) {
-			do_sigsegv(regs, write, address, si_code);
-			return;
-		} else if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {
+		else if (fault & VM_FAULT_SIGSEGV)
+			goto bad_area_nosemaphore;
+		else if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE))
 			do_sigbus(regs, write, address, si_code);
-			return;
-		}
-		BUG();
+		else
+			BUG();
 	}
 
+	return;
+bad_area:
 	mmap_read_unlock(mm);
+bad_area_nosemaphore:
+	do_sigsegv(regs, write, address, si_code);
 }
 
 asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
-- 
2.27.0