[PATCH 2/3] xtensa: extract vmalloc_fault code into a function

From: Max Filippov
Date: Wed Apr 13 2022 - 19:49:59 EST


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@xxxxxxxxx>
---
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