diff mbox series

[v6,4/4] arch, mm: make kernel_page_present() always available

Message ID 20201109162415.13764-5-rppt@kernel.org
State New
Headers show
Series arch, mm: improve robustness of direct map manipulation | expand

Commit Message

Mike Rapoport Nov. 9, 2020, 4:24 p.m. UTC 
From: Mike Rapoport <rppt@linux.ibm.com>

For architectures that enable ARCH_HAS_SET_MEMORY having the ability to
verify that a page is mapped in the kernel direct map can be useful
regardless of hibernation.

Add RISC-V implementation of kernel_page_present(), update its forward
declarations and stubs to be a part of set_memory API and remove ugly
ifdefery in inlcude/linux/mm.h around current declarations of
kernel_page_present().

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/arm64/include/asm/cacheflush.h |  1 +
 arch/arm64/mm/pageattr.c            |  4 +---
 arch/riscv/include/asm/set_memory.h |  1 +
 arch/riscv/mm/pageattr.c            | 29 +++++++++++++++++++++++++++++
 arch/x86/include/asm/set_memory.h   |  1 +
 arch/x86/mm/pat/set_memory.c        |  4 +---
 include/linux/mm.h                  |  7 -------
 include/linux/set_memory.h          |  5 +++++
 8 files changed, 39 insertions(+), 13 deletions(-)
diff mbox series

Patch

diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
index 9384fd8fc13c..45217f21f1fe 100644
--- a/arch/arm64/include/asm/cacheflush.h
+++ b/arch/arm64/include/asm/cacheflush.h
@@ -140,6 +140,7 @@  int set_memory_valid(unsigned long addr, int numpages, int enable);
 
 int set_direct_map_invalid_noflush(struct page *page);
 int set_direct_map_default_noflush(struct page *page);
+bool kernel_page_present(struct page *page);
 
 #include <asm-generic/cacheflush.h>
 
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index 439325532be1..92eccaf595c8 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -186,8 +186,8 @@  void __kernel_map_pages(struct page *page, int numpages, int enable)
 
 	set_memory_valid((unsigned long)page_address(page), numpages, enable);
 }
+#endif /* CONFIG_DEBUG_PAGEALLOC */
 
-#ifdef CONFIG_HIBERNATION
 /*
  * This function is used to determine if a linear map page has been marked as
  * not-valid. Walk the page table and check the PTE_VALID bit. This is based
@@ -234,5 +234,3 @@  bool kernel_page_present(struct page *page)
 	ptep = pte_offset_kernel(pmdp, addr);
 	return pte_valid(READ_ONCE(*ptep));
 }
-#endif /* CONFIG_HIBERNATION */
-#endif /* CONFIG_DEBUG_PAGEALLOC */
diff --git a/arch/riscv/include/asm/set_memory.h b/arch/riscv/include/asm/set_memory.h
index 4c5bae7ca01c..d690b08dff2a 100644
--- a/arch/riscv/include/asm/set_memory.h
+++ b/arch/riscv/include/asm/set_memory.h
@@ -24,6 +24,7 @@  static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; }
 
 int set_direct_map_invalid_noflush(struct page *page);
 int set_direct_map_default_noflush(struct page *page);
+bool kernel_page_present(struct page *page);
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c
index 321b09d2e2ea..87ba5a68bbb8 100644
--- a/arch/riscv/mm/pageattr.c
+++ b/arch/riscv/mm/pageattr.c
@@ -198,3 +198,32 @@  void __kernel_map_pages(struct page *page, int numpages, int enable)
 			     __pgprot(0), __pgprot(_PAGE_PRESENT));
 }
 #endif
+
+bool kernel_page_present(struct page *page)
+{
+	unsigned long addr = (unsigned long)page_address(page);
+	pgd_t *pgd;
+	pud_t *pud;
+	p4d_t *p4d;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	pgd = pgd_offset_k(addr);
+	if (!pgd_present(*pgd))
+		return false;
+
+	p4d = p4d_offset(pgd, addr);
+	if (!p4d_present(*p4d))
+		return false;
+
+	pud = pud_offset(p4d, addr);
+	if (!pud_present(*pud))
+		return false;
+
+	pmd = pmd_offset(pud, addr);
+	if (!pmd_present(*pmd))
+		return false;
+
+	pte = pte_offset_kernel(pmd, addr);
+	return pte_present(*pte);
+}
diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h
index 5948218f35c5..4352f08bfbb5 100644
--- a/arch/x86/include/asm/set_memory.h
+++ b/arch/x86/include/asm/set_memory.h
@@ -82,6 +82,7 @@  int set_pages_rw(struct page *page, int numpages);
 
 int set_direct_map_invalid_noflush(struct page *page);
 int set_direct_map_default_noflush(struct page *page);
+bool kernel_page_present(struct page *page);
 
 extern int kernel_set_to_readonly;
 
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index bc9be96b777f..16f878c26667 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -2226,8 +2226,8 @@  void __kernel_map_pages(struct page *page, int numpages, int enable)
 
 	arch_flush_lazy_mmu_mode();
 }
+#endif /* CONFIG_DEBUG_PAGEALLOC */
 
-#ifdef CONFIG_HIBERNATION
 bool kernel_page_present(struct page *page)
 {
 	unsigned int level;
@@ -2239,8 +2239,6 @@  bool kernel_page_present(struct page *page)
 	pte = lookup_address((unsigned long)page_address(page), &level);
 	return (pte_val(*pte) & _PAGE_PRESENT);
 }
-#endif /* CONFIG_HIBERNATION */
-#endif /* CONFIG_DEBUG_PAGEALLOC */
 
 int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address,
 				   unsigned numpages, unsigned long page_flags)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 260113ba660a..fe9a8d35a6eb 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2942,16 +2942,9 @@  static inline void debug_pagealloc_unmap_pages(struct page *page, int numpages)
 	if (debug_pagealloc_enabled_static())
 		__kernel_map_pages(page, numpages, 0);
 }
-
-#ifdef CONFIG_HIBERNATION
-extern bool kernel_page_present(struct page *page);
-#endif	/* CONFIG_HIBERNATION */
 #else	/* CONFIG_DEBUG_PAGEALLOC */
 static inline void debug_pagealloc_map_pages(struct page *page, int numpages) {}
 static inline void debug_pagealloc_unmap_pages(struct page *page, int numpages) {}
-#ifdef CONFIG_HIBERNATION
-static inline bool kernel_page_present(struct page *page) { return true; }
-#endif	/* CONFIG_HIBERNATION */
 #endif	/* CONFIG_DEBUG_PAGEALLOC */
 
 #ifdef __HAVE_ARCH_GATE_AREA
diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h
index 860e0f843c12..fe1aa4e54680 100644
--- a/include/linux/set_memory.h
+++ b/include/linux/set_memory.h
@@ -23,6 +23,11 @@  static inline int set_direct_map_default_noflush(struct page *page)
 {
 	return 0;
 }
+
+static inline bool kernel_page_present(struct page *page)
+{
+	return true;
+}
 #endif
 
 #ifndef set_mce_nospec