x86/mm/cpa: Add set_direct_map_*() functions

Add two new functions set_direct_map_default_noflush() and
set_direct_map_invalid_noflush() for setting the direct map alias for the
page to its default valid permissions and to an invalid state that cannot
be cached in a TLB, respectively. These functions do not flush the TLB.

Note, __kernel_map_pages() does something similar but flushes the TLB and
doesn't reset the permission bits to default on all architectures.

Also add an ARCH config ARCH_HAS_SET_DIRECT_MAP for specifying whether
these have an actual implementation or a default empty one.

Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-15-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/Kconfig b/arch/Kconfig
index 33687dddd86a7e04dfa7e7829788b4a0442ae61a..88e5a92a9e58773978a1cb6908f4a59e64341e4a 100644 (file)
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -249,6 +249,10 @@ config ARCH_HAS_FORTIFY_SOURCE
 config ARCH_HAS_SET_MEMORY
        bool
 
+# Select if arch has all set_direct_map_invalid/default() functions
+config ARCH_HAS_SET_DIRECT_MAP
+       bool
+
 # Select if arch init_task must go in the __init_task_data section
 config ARCH_TASK_STRUCT_ON_STACK
        bool

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index bd6f93ce063321d7f657cefebf1a04b134b03b7a..cee3f22ce8d1966a3403f7f1595e9b448d118c73 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -65,6 +65,7 @@ config X86
        select ARCH_HAS_UACCESS_FLUSHCACHE      if X86_64
        select ARCH_HAS_UACCESS_MCSAFE          if X86_64 && X86_MCE
        select ARCH_HAS_SET_MEMORY
+       select ARCH_HAS_SET_DIRECT_MAP
        select ARCH_HAS_STRICT_KERNEL_RWX
        select ARCH_HAS_STRICT_MODULE_RWX
        select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE

diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h
index 07a25753e85c5cd53b2613a71db91862fa31684f..ae7b909dc242d17f0bc1be10130a42d08c3785ae 100644 (file)
--- a/arch/x86/include/asm/set_memory.h
+++ b/arch/x86/include/asm/set_memory.h
@@ -85,6 +85,9 @@ int set_pages_nx(struct page *page, int numpages);
 int set_pages_ro(struct page *page, int numpages);
 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);
+
 extern int kernel_set_to_readonly;
 void set_kernel_text_rw(void);
 void set_kernel_text_ro(void);

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 4c570612e24eea5bee9dd837bd12baa8dc1e5ad2..3574550192c6070a0c83349520ffc4e5befd4750 100644 (file)
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -2209,8 +2209,6 @@ int set_pages_rw(struct page *page, int numpages)
        return set_memory_rw(addr, numpages);
 }
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
-
 static int __set_pages_p(struct page *page, int numpages)
 {
        unsigned long tempaddr = (unsigned long) page_address(page);
@@ -2249,6 +2247,17 @@ static int __set_pages_np(struct page *page, int numpages)
        return __change_page_attr_set_clr(&cpa, 0);
 }
 
+int set_direct_map_invalid_noflush(struct page *page)
+{
+       return __set_pages_np(page, 1);
+}
+
+int set_direct_map_default_noflush(struct page *page)
+{
+       return __set_pages_p(page, 1);
+}
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
 void __kernel_map_pages(struct page *page, int numpages, int enable)
 {
        if (PageHighMem(page))
@@ -2282,7 +2291,6 @@ void __kernel_map_pages(struct page *page, int numpages, int enable)
 }
 
 #ifdef CONFIG_HIBERNATION
-
 bool kernel_page_present(struct page *page)
 {
        unsigned int level;

diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h
index 2a986d282a975b5bb5b244efad5419334f74cfaa..b5071497b8cbe224af1e09b5ffa7d3c0e7abb4a2 100644 (file)
--- a/include/linux/set_memory.h
+++ b/include/linux/set_memory.h
@@ -17,6 +17,17 @@ static inline int set_memory_x(unsigned long addr,  int numpages) { return 0; }
 static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; }
 #endif
 
+#ifndef CONFIG_ARCH_HAS_SET_DIRECT_MAP
+static inline int set_direct_map_invalid_noflush(struct page *page)
+{
+       return 0;
+}
+static inline int set_direct_map_default_noflush(struct page *page)
+{
+       return 0;
+}
+#endif
+
 #ifndef set_mce_nospec
 static inline int set_mce_nospec(unsigned long pfn)
 {