[PATCH v16 05/11] set_memory: allow querying whether set_direct_map_*() is actually enabled
From: Mike Rapoport <rppt@kernel.org>
Date: 2021-01-21 12:41:12
Also in:
linux-api, linux-arch, linux-fsdevel, linux-kselftest, linux-mm, linux-riscv, lkml, nvdimm
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
From: Mike Rapoport <redacted> On arm64, set_direct_map_*() functions may return 0 without actually changing the linear map. This behaviour can be controlled using kernel parameters, so we need a way to determine at runtime whether calls to set_direct_map_invalid_noflush() and set_direct_map_default_noflush() have any effect. Extend set_memory API with can_set_direct_map() function that allows checking if calling set_direct_map_*() will actually change the page table, replace several occurrences of open coded checks in arm64 with the new function and provide a generic stub for architectures that always modify page tables upon calls to set_direct_map APIs. Signed-off-by: Mike Rapoport <redacted> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: David Hildenbrand <redacted> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Christopher Lameter <redacted> Cc: Dan Williams <redacted> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Hagen Paul Pfeifer <redacted> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Bottomley <redacted> Cc: "Kirill A. Shutemov" <redacted> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Kerrisk <redacted> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Palmer Dabbelt <redacted> Cc: Paul Walmsley <redacted> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rick Edgecombe <rick.p.edgecombe@intel.com> Cc: Roman Gushchin <redacted> Cc: Shakeel Butt <redacted> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Gleixner <redacted> Cc: Tycho Andersen <redacted> Cc: Will Deacon <will@kernel.org> --- arch/arm64/include/asm/Kbuild | 1 - arch/arm64/include/asm/cacheflush.h | 6 ------ arch/arm64/include/asm/set_memory.h | 17 +++++++++++++++++ arch/arm64/kernel/machine_kexec.c | 1 + arch/arm64/mm/mmu.c | 6 +++--- arch/arm64/mm/pageattr.c | 13 +++++++++---- include/linux/set_memory.h | 12 ++++++++++++ 7 files changed, 42 insertions(+), 14 deletions(-) create mode 100644 arch/arm64/include/asm/set_memory.h
diff --git a/arch/arm64/include/asm/Kbuild b/arch/arm64/include/asm/Kbuild
index 07ac208edc89..73aa25843f65 100644
--- a/arch/arm64/include/asm/Kbuild
+++ b/arch/arm64/include/asm/Kbuild@@ -3,5 +3,4 @@ generic-y += early_ioremap.h generic-y += mcs_spinlock.h generic-y += qrwlock.h generic-y += qspinlock.h -generic-y += set_memory.h generic-y += user.h
diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
index d3598419a284..b1bdf83a73db 100644
--- a/arch/arm64/include/asm/cacheflush.h
+++ b/arch/arm64/include/asm/cacheflush.h@@ -136,12 +136,6 @@ static __always_inline void __flush_icache_all(void) dsb(ish); } -int set_memory_valid(unsigned long addr, int numpages, int enable); - -int set_direct_map_invalid_noflush(struct page *page, int numpages); -int set_direct_map_default_noflush(struct page *page, int numpages); -bool kernel_page_present(struct page *page); - #include <asm-generic/cacheflush.h> #endif /* __ASM_CACHEFLUSH_H */
diff --git a/arch/arm64/include/asm/set_memory.h b/arch/arm64/include/asm/set_memory.h
new file mode 100644
index 000000000000..ecb6b0f449ab
--- /dev/null
+++ b/arch/arm64/include/asm/set_memory.h@@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef _ASM_ARM64_SET_MEMORY_H +#define _ASM_ARM64_SET_MEMORY_H + +#include <asm-generic/set_memory.h> + +bool can_set_direct_map(void); +#define can_set_direct_map can_set_direct_map + +int set_memory_valid(unsigned long addr, int numpages, int enable); + +int set_direct_map_invalid_noflush(struct page *page, int numpages); +int set_direct_map_default_noflush(struct page *page, int numpages); +bool kernel_page_present(struct page *page); + +#endif /* _ASM_ARM64_SET_MEMORY_H */
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index a0b144cfaea7..0cbc50c4fa5a 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c@@ -11,6 +11,7 @@ #include <linux/kernel.h> #include <linux/kexec.h> #include <linux/page-flags.h> +#include <linux/set_memory.h> #include <linux/smp.h> #include <asm/cacheflush.h>
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 30c6dd02e706..79604049fff5 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c@@ -22,6 +22,7 @@ #include <linux/io.h> #include <linux/mm.h> #include <linux/vmalloc.h> +#include <linux/set_memory.h> #include <asm/barrier.h> #include <asm/cputype.h>
@@ -492,7 +493,7 @@ static void __init map_mem(pgd_t *pgdp) int flags = 0; u64 i; - if (rodata_full || crash_mem_map || debug_pagealloc_enabled()) + if (can_set_direct_map() || crash_mem_map) flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; /*
@@ -1468,8 +1469,7 @@ int arch_add_memory(int nid, u64 start, u64 size, * KFENCE requires linear map to be mapped at page granularity, so that * it is possible to protect/unprotect single pages in the KFENCE pool. */ - if (rodata_full || debug_pagealloc_enabled() || - IS_ENABLED(CONFIG_KFENCE)) + if (can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE)) flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index b53ef37bf95a..d505172265b0 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c@@ -19,6 +19,11 @@ struct page_change_data { bool rodata_full __ro_after_init = IS_ENABLED(CONFIG_RODATA_FULL_DEFAULT_ENABLED); +bool can_set_direct_map(void) +{ + return rodata_full || debug_pagealloc_enabled(); +} + static int change_page_range(pte_t *ptep, unsigned long addr, void *data) { struct page_change_data *cdata = data;
@@ -156,7 +161,7 @@ int set_direct_map_invalid_noflush(struct page *page, int numpages) }; unsigned long size = PAGE_SIZE * numpages; - if (!debug_pagealloc_enabled() && !rodata_full) + if (!can_set_direct_map()) return 0; return apply_to_page_range(&init_mm,
@@ -172,7 +177,7 @@ int set_direct_map_default_noflush(struct page *page, int numpages) }; unsigned long size = PAGE_SIZE * numpages; - if (!debug_pagealloc_enabled() && !rodata_full) + if (!can_set_direct_map()) return 0; return apply_to_page_range(&init_mm,
@@ -183,7 +188,7 @@ int set_direct_map_default_noflush(struct page *page, int numpages) #ifdef CONFIG_DEBUG_PAGEALLOC void __kernel_map_pages(struct page *page, int numpages, int enable) { - if (!debug_pagealloc_enabled() && !rodata_full) + if (!can_set_direct_map()) return; set_memory_valid((unsigned long)page_address(page), numpages, enable);
@@ -208,7 +213,7 @@ bool kernel_page_present(struct page *page) pte_t *ptep; unsigned long addr = (unsigned long)page_address(page); - if (!debug_pagealloc_enabled() && !rodata_full) + if (!can_set_direct_map()) return true; pgdp = pgd_offset_k(addr);
diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h
index c650f82db813..7b4b6626032d 100644
--- a/include/linux/set_memory.h
+++ b/include/linux/set_memory.h@@ -28,7 +28,19 @@ static inline bool kernel_page_present(struct page *page) { return true; } +#else /* CONFIG_ARCH_HAS_SET_DIRECT_MAP */ +/* + * Some architectures, e.g. ARM64 can disable direct map modifications at + * boot time. Let them overrive this query. + */ +#ifndef can_set_direct_map +static inline bool can_set_direct_map(void) +{ + return true; +} +#define can_set_direct_map can_set_direct_map #endif +#endif /* CONFIG_ARCH_HAS_SET_DIRECT_MAP */ #ifndef set_mce_nospec static inline int set_mce_nospec(unsigned long pfn, bool unmap)
--
2.28.0
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