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Message-Id: <20190813205225.12032-17-yu-cheng.yu@intel.com>
Date: Tue, 13 Aug 2019 13:52:14 -0700
From: Yu-cheng Yu <yu-cheng.yu@...el.com>
To: x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
linux-doc@...r.kernel.org, linux-mm@...ck.org,
linux-arch@...r.kernel.org, linux-api@...r.kernel.org,
Arnd Bergmann <arnd@...db.de>,
Andy Lutomirski <luto@...capital.net>,
Balbir Singh <bsingharora@...il.com>,
Borislav Petkov <bp@...en8.de>,
Cyrill Gorcunov <gorcunov@...il.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Eugene Syromiatnikov <esyr@...hat.com>,
Florian Weimer <fweimer@...hat.com>,
"H.J. Lu" <hjl.tools@...il.com>, Jann Horn <jannh@...gle.com>,
Jonathan Corbet <corbet@....net>,
Kees Cook <keescook@...omium.org>,
Mike Kravetz <mike.kravetz@...cle.com>,
Nadav Amit <nadav.amit@...il.com>,
Oleg Nesterov <oleg@...hat.com>, Pavel Machek <pavel@....cz>,
Peter Zijlstra <peterz@...radead.org>,
Randy Dunlap <rdunlap@...radead.org>,
"Ravi V. Shankar" <ravi.v.shankar@...el.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@...el.com>,
Dave Martin <Dave.Martin@....com>
Cc: Yu-cheng Yu <yu-cheng.yu@...el.com>
Subject: [PATCH v8 16/27] mm: Handle THP/HugeTLB shadow stack page fault
This patch implements THP shadow stack (SHSTK) copying in the same
way as in the previous patch for regular PTE.
In copy_huge_pmd(), clear the dirty bit from the PMD to cause a page
fault upon the next SHSTK access to the PMD. At that time, fix the
PMD and copy/re-use the page.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@...el.com>
---
arch/x86/mm/pgtable.c | 8 ++++++++
include/asm-generic/pgtable.h | 6 ++++++
mm/huge_memory.c | 4 ++++
3 files changed, 18 insertions(+)
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 0c10d0c5e329..6f3959ca2a08 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -886,6 +886,14 @@ inline pte_t pte_set_vma_features(pte_t pte, struct vm_area_struct *vma)
return pte;
}
+inline pmd_t pmd_set_vma_features(pmd_t pmd, struct vm_area_struct *vma)
+{
+ if (vma->vm_flags & VM_SHSTK)
+ return pmd_mkdirty_shstk(pmd);
+ else
+ return pmd;
+}
+
inline bool arch_copy_pte_mapping(vm_flags_t vm_flags)
{
return (vm_flags & VM_SHSTK);
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 89b0fa132f1f..438ce73b57ea 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -1194,12 +1194,18 @@ static inline pte_t pte_set_vma_features(pte_t pte, struct vm_area_struct *vma)
return pte;
}
+static inline pmd_t pmd_set_vma_features(pmd_t pmd, struct vm_area_struct *vma)
+{
+ return pmd;
+}
+
static inline bool arch_copy_pte_mapping(vm_flags_t vm_flags)
{
return false;
}
#else
pte_t pte_set_vma_features(pte_t pte, struct vm_area_struct *vma);
+pmd_t pmd_set_vma_features(pmd_t pmd, struct vm_area_struct *vma);
bool arch_copy_pte_mapping(vm_flags_t vm_flags);
#endif
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1334ede667a8..39d66c628121 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -611,6 +611,7 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
entry = mk_huge_pmd(page, vma->vm_page_prot);
entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
+ entry = pmd_set_vma_features(entry, vma);
page_add_new_anon_rmap(page, vma, haddr, true);
mem_cgroup_commit_charge(page, memcg, false, true);
lru_cache_add_active_or_unevictable(page, vma);
@@ -1253,6 +1254,7 @@ static vm_fault_t do_huge_pmd_wp_page_fallback(struct vm_fault *vmf,
pte_t entry;
entry = mk_pte(pages[i], vma->vm_page_prot);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+ entry = pte_set_vma_features(entry, vma);
memcg = (void *)page_private(pages[i]);
set_page_private(pages[i], 0);
page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false);
@@ -1335,6 +1337,7 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
pmd_t entry;
entry = pmd_mkyoung(orig_pmd);
entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
+ entry = pmd_set_vma_features(entry, vma);
if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1))
update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
ret |= VM_FAULT_WRITE;
@@ -1407,6 +1410,7 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
pmd_t entry;
entry = mk_huge_pmd(new_page, vma->vm_page_prot);
entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
+ entry = pmd_set_vma_features(entry, vma);
pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd);
page_add_new_anon_rmap(new_page, vma, haddr, true);
mem_cgroup_commit_charge(new_page, memcg, false, true);
--
2.17.1
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