From: Pekka Enberg <penberg@gmail.com>
To: linux-riscv@lists.infradead.org
Cc: Pekka Enberg <penberg@kernel.org>, palmer@dabbelt.com
Subject: [PATCH 3/8] riscv/mm/fault: Move vmalloc fault handling to vmalloc_fault()
Date: Tue, 25 Aug 2020 21:39:02 +0300 [thread overview]
Message-ID: <20200825183907.275950-4-penberg@gmail.com> (raw)
In-Reply-To: <20200825183907.275950-1-penberg@gmail.com>
From: Pekka Enberg <penberg@kernel.org>
This patch moves the vmalloc fault handling in do_page_fault() to
vmalloc_fault() function and converts gotos to calls to the new
function.
---
arch/riscv/mm/fault.c | 164 +++++++++++++++++++++---------------------
1 file changed, 82 insertions(+), 82 deletions(-)
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index ac9a99255365..460ea1d6c24e 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -53,6 +53,84 @@ static inline void bad_area(struct pt_regs *regs, struct mm_struct *mm, int code
no_context(regs, addr);
}
+static void inline 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;
+
+ /* 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)) {
+ 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);
+}
+
/*
* This routine handles page faults. It determines the address and the
* problem, and then passes it off to one of the appropriate routines.
@@ -82,8 +160,10 @@ 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))
@@ -211,84 +291,4 @@ asmlinkage void do_page_fault(struct pt_regs *regs)
}
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)) {
- 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);
-
- return;
- }
}
--
2.26.2
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next prev 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 ` [PATCH 2/8] riscv/mm/fault: Move bad area handling to bad_area() Pekka Enberg
2020-08-25 18:39 ` Pekka Enberg [this message]
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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