From: Mike Rapoport <redacted>

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 <redacted>
---
  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 --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 ab0ef6bd351d..44b82f22e76a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h

@@ -2937,16 +2937,9 @@ static inline void debug_pagealloc_map_pages(struct page *page,
  	if (debug_pagealloc_enabled_static())
  		__kernel_map_pages(page, numpages, enable);
  }
-
-#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, int enable) {}
-#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