linux-kernel - [PATCH 2/3] xtensa: extract vmalloc

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Date:   Wed, 13 Apr 2022 16:49:29 -0700
From:   Max Filippov <jcmvbkbc@...il.com>
To:     linux-xtensa@...ux-xtensa.org
Cc:     Chris Zankel <chris@...kel.net>, linux-kernel@...r.kernel.org,
        Max Filippov <jcmvbkbc@...il.com>
Subject: [PATCH 2/3] xtensa: extract vmalloc_fault code into a function

Move full MMU-specific code into a separate function to isolate it from
more generic do_page_fault code. No functional changes.

Signed-off-by: Max Filippov <jcmvbkbc@...il.com>
---
 arch/xtensa/mm/fault.c | 107 +++++++++++++++++++++--------------------
 1 file changed, 54 insertions(+), 53 deletions(-)

diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c
index 2a120c024334..01e66da4a6b0 100644
--- a/arch/xtensa/mm/fault.c
+++ b/arch/xtensa/mm/fault.c
@@ -23,6 +23,55 @@
 
 void bad_page_fault(struct pt_regs*, unsigned long, int);
 
+static void vmalloc_fault(struct pt_regs *regs, unsigned int address)
+{
+	/* Synchronize this task's top level page-table
+	 * with the 'reference' page table.
+	 */
+	struct mm_struct *act_mm = current->active_mm;
+	int index = pgd_index(address);
+	pgd_t *pgd, *pgd_k;
+	p4d_t *p4d, *p4d_k;
+	pud_t *pud, *pud_k;
+	pmd_t *pmd, *pmd_k;
+	pte_t *pte_k;
+
+	if (act_mm == NULL)
+		goto bad_page_fault;
+
+	pgd = act_mm->pgd + index;
+	pgd_k = init_mm.pgd + index;
+
+	if (!pgd_present(*pgd_k))
+		goto bad_page_fault;
+
+	pgd_val(*pgd) = pgd_val(*pgd_k);
+
+	p4d = p4d_offset(pgd, address);
+	p4d_k = p4d_offset(pgd_k, address);
+	if (!p4d_present(*p4d) || !p4d_present(*p4d_k))
+		goto bad_page_fault;
+
+	pud = pud_offset(p4d, address);
+	pud_k = pud_offset(p4d_k, address);
+	if (!pud_present(*pud) || !pud_present(*pud_k))
+		goto bad_page_fault;
+
+	pmd = pmd_offset(pud, address);
+	pmd_k = pmd_offset(pud_k, address);
+	if (!pmd_present(*pmd) || !pmd_present(*pmd_k))
+		goto bad_page_fault;
+
+	pmd_val(*pmd) = pmd_val(*pmd_k);
+	pte_k = pte_offset_kernel(pmd_k, address);
+
+	if (!pte_present(*pte_k))
+		goto bad_page_fault;
+	return;
+
+bad_page_fault:
+	bad_page_fault(regs, address, SIGKILL);
+}
 /*
  * This routine handles page faults.  It determines the address,
  * and the problem, and then passes it off to one of the appropriate
@@ -48,8 +97,10 @@ void do_page_fault(struct pt_regs *regs)
 	/* We fault-in kernel-space virtual memory on-demand. The
 	 * 'reference' page table is init_mm.pgd.
 	 */
-	if (address >= TASK_SIZE && !user_mode(regs))
-		goto vmalloc_fault;
+	if (address >= TASK_SIZE && !user_mode(regs)) {
+		vmalloc_fault(regs, address);
+		return;
+	}
 
 	/* If we're in an interrupt or have no user
 	 * context, we must not take the fault..
@@ -113,7 +164,7 @@ void do_page_fault(struct pt_regs *regs)
 
 	if (fault_signal_pending(fault, regs)) {
 		if (!user_mode(regs))
-			goto bad_page_fault;
+			bad_page_fault(regs, address, SIGKILL);
 		return;
 	}
 
@@ -180,56 +231,6 @@ void do_page_fault(struct pt_regs *regs)
 	if (!user_mode(regs))
 		bad_page_fault(regs, address, SIGBUS);
 	return;
-
-vmalloc_fault:
-	{
-		/* Synchronize this task's top level page-table
-		 * with the 'reference' page table.
-		 */
-		struct mm_struct *act_mm = current->active_mm;
-		int index = pgd_index(address);
-		pgd_t *pgd, *pgd_k;
-		p4d_t *p4d, *p4d_k;
-		pud_t *pud, *pud_k;
-		pmd_t *pmd, *pmd_k;
-		pte_t *pte_k;
-
-		if (act_mm == NULL)
-			goto bad_page_fault;
-
-		pgd = act_mm->pgd + index;
-		pgd_k = init_mm.pgd + index;
-
-		if (!pgd_present(*pgd_k))
-			goto bad_page_fault;
-
-		pgd_val(*pgd) = pgd_val(*pgd_k);
-
-		p4d = p4d_offset(pgd, address);
-		p4d_k = p4d_offset(pgd_k, address);
-		if (!p4d_present(*p4d) || !p4d_present(*p4d_k))
-			goto bad_page_fault;
-
-		pud = pud_offset(p4d, address);
-		pud_k = pud_offset(p4d_k, address);
-		if (!pud_present(*pud) || !pud_present(*pud_k))
-			goto bad_page_fault;
-
-		pmd = pmd_offset(pud, address);
-		pmd_k = pmd_offset(pud_k, address);
-		if (!pmd_present(*pmd) || !pmd_present(*pmd_k))
-			goto bad_page_fault;
-
-		pmd_val(*pmd) = pmd_val(*pmd_k);
-		pte_k = pte_offset_kernel(pmd_k, address);
-
-		if (!pte_present(*pte_k))
-			goto bad_page_fault;
-		return;
-	}
-bad_page_fault:
-	bad_page_fault(regs, address, SIGKILL);
-	return;
 }
 
 
-- 
2.30.2