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Message-ID: <795f6a7-bcca-cdf-ad2a-fbdaa232998c@google.com>
Date: Thu, 8 Jun 2023 12:15:16 -0700 (PDT)
From: Hugh Dickins <hughd@...gle.com>
To: Andrew Morton <akpm@...ux-foundation.org>
cc: Mike Kravetz <mike.kravetz@...cle.com>,
Mike Rapoport <rppt@...nel.org>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Matthew Wilcox <willy@...radead.org>,
David Hildenbrand <david@...hat.com>,
Suren Baghdasaryan <surenb@...gle.com>,
Qi Zheng <zhengqi.arch@...edance.com>,
Peter Zijlstra <peterz@...radead.org>,
Russell King <linux@...linux.org.uk>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
Greg Ungerer <gerg@...ux-m68k.org>,
Michal Simek <monstr@...str.eu>,
Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
Helge Deller <deller@....de>,
John David Anglin <dave.anglin@...l.net>,
"Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
Michael Ellerman <mpe@...erman.id.au>,
Alexandre Ghiti <alexghiti@...osinc.com>,
Palmer Dabbelt <palmer@...belt.com>,
Heiko Carstens <hca@...ux.ibm.com>,
Christian Borntraeger <borntraeger@...ux.ibm.com>,
Claudio Imbrenda <imbrenda@...ux.ibm.com>,
Alexander Gordeev <agordeev@...ux.ibm.com>,
John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>,
"David S. Miller" <davem@...emloft.net>,
Chris Zankel <chris@...kel.net>,
Max Filippov <jcmvbkbc@...il.com>, x86@...nel.org,
linux-arm-kernel@...ts.infradead.org, linux-ia64@...r.kernel.org,
linux-m68k@...ts.linux-m68k.org, linux-mips@...r.kernel.org,
linux-parisc@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
linux-riscv@...ts.infradead.org, linux-s390@...r.kernel.org,
linux-sh@...r.kernel.org, sparclinux@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH v2 05/23] m68k: allow pte_offset_map[_lock]() to fail
In rare transient cases, not yet made possible, pte_offset_map() and
pte_offset_map_lock() may not find a page table: handle appropriately.
Restructure cf_tlb_miss() with a pte_unmap() (previously omitted)
at label out, followed by one local_irq_restore() for all.
Signed-off-by: Hugh Dickins <hughd@...gle.com>
---
arch/m68k/include/asm/mmu_context.h | 6 ++--
arch/m68k/kernel/sys_m68k.c | 2 ++
arch/m68k/mm/mcfmmu.c | 52 ++++++++++++-----------------
3 files changed, 27 insertions(+), 33 deletions(-)
diff --git a/arch/m68k/include/asm/mmu_context.h b/arch/m68k/include/asm/mmu_context.h
index 8ed6ac14d99f..141bbdfad960 100644
--- a/arch/m68k/include/asm/mmu_context.h
+++ b/arch/m68k/include/asm/mmu_context.h
@@ -99,7 +99,7 @@ static inline void load_ksp_mmu(struct task_struct *task)
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
- pte_t *pte;
+ pte_t *pte = NULL;
unsigned long mmuar;
local_irq_save(flags);
@@ -139,7 +139,7 @@ static inline void load_ksp_mmu(struct task_struct *task)
pte = (mmuar >= PAGE_OFFSET) ? pte_offset_kernel(pmd, mmuar)
: pte_offset_map(pmd, mmuar);
- if (pte_none(*pte) || !pte_present(*pte))
+ if (!pte || pte_none(*pte) || !pte_present(*pte))
goto bug;
set_pte(pte, pte_mkyoung(*pte));
@@ -161,6 +161,8 @@ static inline void load_ksp_mmu(struct task_struct *task)
bug:
pr_info("ksp load failed: mm=0x%p ksp=0x08%lx\n", mm, mmuar);
end:
+ if (pte && mmuar < PAGE_OFFSET)
+ pte_unmap(pte);
local_irq_restore(flags);
}
diff --git a/arch/m68k/kernel/sys_m68k.c b/arch/m68k/kernel/sys_m68k.c
index bd0274c7592e..c586034d2a7a 100644
--- a/arch/m68k/kernel/sys_m68k.c
+++ b/arch/m68k/kernel/sys_m68k.c
@@ -488,6 +488,8 @@ sys_atomic_cmpxchg_32(unsigned long newval, int oldval, int d3, int d4, int d5,
if (!pmd_present(*pmd))
goto bad_access;
pte = pte_offset_map_lock(mm, pmd, (unsigned long)mem, &ptl);
+ if (!pte)
+ goto bad_access;
if (!pte_present(*pte) || !pte_dirty(*pte)
|| !pte_write(*pte)) {
pte_unmap_unlock(pte, ptl);
diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c
index 70aa0979e027..42f45abea37a 100644
--- a/arch/m68k/mm/mcfmmu.c
+++ b/arch/m68k/mm/mcfmmu.c
@@ -91,7 +91,8 @@ int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
- pte_t *pte;
+ pte_t *pte = NULL;
+ int ret = -1;
int asid;
local_irq_save(flags);
@@ -100,47 +101,33 @@ int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
regs->pc + (extension_word * sizeof(long));
mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm;
- if (!mm) {
- local_irq_restore(flags);
- return -1;
- }
+ if (!mm)
+ goto out;
pgd = pgd_offset(mm, mmuar);
- if (pgd_none(*pgd)) {
- local_irq_restore(flags);
- return -1;
- }
+ if (pgd_none(*pgd))
+ goto out;
p4d = p4d_offset(pgd, mmuar);
- if (p4d_none(*p4d)) {
- local_irq_restore(flags);
- return -1;
- }
+ if (p4d_none(*p4d))
+ goto out;
pud = pud_offset(p4d, mmuar);
- if (pud_none(*pud)) {
- local_irq_restore(flags);
- return -1;
- }
+ if (pud_none(*pud))
+ goto out;
pmd = pmd_offset(pud, mmuar);
- if (pmd_none(*pmd)) {
- local_irq_restore(flags);
- return -1;
- }
+ if (pmd_none(*pmd))
+ goto out;
pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar)
: pte_offset_map(pmd, mmuar);
- if (pte_none(*pte) || !pte_present(*pte)) {
- local_irq_restore(flags);
- return -1;
- }
+ if (!pte || pte_none(*pte) || !pte_present(*pte))
+ goto out;
if (write) {
- if (!pte_write(*pte)) {
- local_irq_restore(flags);
- return -1;
- }
+ if (!pte_write(*pte))
+ goto out;
set_pte(pte, pte_mkdirty(*pte));
}
@@ -161,9 +148,12 @@ int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);
else
mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA);
-
+ ret = 0;
+out:
+ if (pte && !KMAPAREA(mmuar))
+ pte_unmap(pte);
local_irq_restore(flags);
- return 0;
+ return ret;
}
void __init cf_bootmem_alloc(void)
--
2.35.3
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