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x86/mm: Tabulate the page table encoding definitions
authorIngo Molnar <mingo@kernel.org>
Wed, 20 Nov 2019 16:38:39 +0000 (17:38 +0100)
committerIngo Molnar <mingo@kernel.org>
Tue, 10 Dec 2019 09:12:55 +0000 (10:12 +0100)
I got lost in trying to figure out which bits were enabled
in one of the PTE masks, so let's make it pretty
obvious at the definition site already:

 #define PAGE_NONE            __pg(   0|   0|   0|___A|   0|   0|   0|___G)
 #define PAGE_SHARED          __pg(__PP|__RW|_USR|___A|__NX|   0|   0|   0)
 #define PAGE_SHARED_EXEC     __pg(__PP|__RW|_USR|___A|   0|   0|   0|   0)
 #define PAGE_COPY_NOEXEC     __pg(__PP|   0|_USR|___A|__NX|   0|   0|   0)
 #define PAGE_COPY_EXEC       __pg(__PP|   0|_USR|___A|   0|   0|   0|   0)
 #define PAGE_COPY            __pg(__PP|   0|_USR|___A|__NX|   0|   0|   0)
 #define PAGE_READONLY        __pg(__PP|   0|_USR|___A|__NX|   0|   0|   0)
 #define PAGE_READONLY_EXEC   __pg(__PP|   0|_USR|___A|   0|   0|   0|   0)

 #define __PAGE_KERNEL            (__PP|__RW|   0|___A|__NX|___D|   0|___G)
 #define __PAGE_KERNEL_EXEC       (__PP|__RW|   0|___A|   0|___D|   0|___G)
 #define _KERNPG_TABLE_NOENC      (__PP|__RW|   0|___A|   0|___D|   0|   0)
 #define _KERNPG_TABLE            (__PP|__RW|   0|___A|   0|___D|   0|   0| _ENC)
 #define _PAGE_TABLE_NOENC        (__PP|__RW|_USR|___A|   0|___D|   0|   0)
 #define _PAGE_TABLE              (__PP|__RW|_USR|___A|   0|___D|   0|   0| _ENC)
 #define __PAGE_KERNEL_RO         (__PP|   0|   0|___A|__NX|___D|   0|___G)
 #define __PAGE_KERNEL_RX         (__PP|   0|   0|___A|   0|___D|   0|___G)
 #define __PAGE_KERNEL_NOCACHE    (__PP|__RW|   0|___A|__NX|___D|   0|___G| __NC)
 #define __PAGE_KERNEL_VVAR       (__PP|   0|_USR|___A|__NX|___D|   0|___G)
 #define __PAGE_KERNEL_LARGE      (__PP|__RW|   0|___A|__NX|___D|_PSE|___G)
 #define __PAGE_KERNEL_LARGE_EXEC (__PP|__RW|   0|___A|   0|___D|_PSE|___G)
 #define __PAGE_KERNEL_WP         (__PP|__RW|   0|___A|__NX|___D|   0|___G| __WP)

Especially security relevant bits like 'NX' or coherence related bits like 'G'
are now super easy to read based on a single grep.

We do the underscore gymnastics to not pollute the kernel's symbol namespace,
and the longest line still fits into 80 columns, so this should be readable
for everyone.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/include/asm/pgtable_types.h patch | blob | history

diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index b5e49e6bac6352e5f5ca792250a478c4875d8e4e..ea7400726d7a7c15bccbb4fd7e96287da40958ef 100644 (file)
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -110,11 +110,6 @@
 
 #define _PAGE_PROTNONE (_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE)
 
-#define _PAGE_TABLE_NOENC      (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER |\
-                                _PAGE_ACCESSED | _PAGE_DIRTY)
-#define _KERNPG_TABLE_NOENC    (_PAGE_PRESENT | _PAGE_RW |             \
-                                _PAGE_ACCESSED | _PAGE_DIRTY)
-
 /*
  * Set of bits not changed in pte_modify.  The pte's
  * protection key is treated like _PAGE_RW, for
@@ -136,80 +131,93 @@
  */
 #ifndef __ASSEMBLY__
 enum page_cache_mode {
-       _PAGE_CACHE_MODE_WB = 0,
-       _PAGE_CACHE_MODE_WC = 1,
+       _PAGE_CACHE_MODE_WB       = 0,
+       _PAGE_CACHE_MODE_WC       = 1,
        _PAGE_CACHE_MODE_UC_MINUS = 2,
-       _PAGE_CACHE_MODE_UC = 3,
-       _PAGE_CACHE_MODE_WT = 4,
-       _PAGE_CACHE_MODE_WP = 5,
-       _PAGE_CACHE_MODE_NUM = 8
+       _PAGE_CACHE_MODE_UC       = 3,
+       _PAGE_CACHE_MODE_WT       = 4,
+       _PAGE_CACHE_MODE_WP       = 5,
+
+       _PAGE_CACHE_MODE_NUM      = 8
 };
 #endif
 
-#define _PAGE_CACHE_MASK       (_PAGE_PAT | _PAGE_PCD | _PAGE_PWT)
-#define _PAGE_NOCACHE          (cachemode2protval(_PAGE_CACHE_MODE_UC))
-#define _PAGE_CACHE_WP         (cachemode2protval(_PAGE_CACHE_MODE_WP))
+#define _PAGE_ENC              (_AT(pteval_t, sme_me_mask))
 
-#define PAGE_NONE      __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
-#define PAGE_SHARED    __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \
-                                _PAGE_ACCESSED | _PAGE_NX)
-
-#define PAGE_SHARED_EXEC       __pgprot(_PAGE_PRESENT | _PAGE_RW |     \
-                                        _PAGE_USER | _PAGE_ACCESSED)
-#define PAGE_COPY_NOEXEC       __pgprot(_PAGE_PRESENT | _PAGE_USER |   \
-                                        _PAGE_ACCESSED | _PAGE_NX)
-#define PAGE_COPY_EXEC         __pgprot(_PAGE_PRESENT | _PAGE_USER |   \
-                                        _PAGE_ACCESSED)
-#define PAGE_COPY              PAGE_COPY_NOEXEC
-#define PAGE_READONLY          __pgprot(_PAGE_PRESENT | _PAGE_USER |   \
-                                        _PAGE_ACCESSED | _PAGE_NX)
-#define PAGE_READONLY_EXEC     __pgprot(_PAGE_PRESENT | _PAGE_USER |   \
-                                        _PAGE_ACCESSED)
-
-#define __PAGE_KERNEL_EXEC                                             \
-       (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_GLOBAL)
-#define __PAGE_KERNEL          (__PAGE_KERNEL_EXEC | _PAGE_NX)
-
-#define __PAGE_KERNEL_RO               (__PAGE_KERNEL & ~_PAGE_RW)
-#define __PAGE_KERNEL_RX               (__PAGE_KERNEL_EXEC & ~_PAGE_RW)
-#define __PAGE_KERNEL_NOCACHE          (__PAGE_KERNEL | _PAGE_NOCACHE)
-#define __PAGE_KERNEL_VVAR             (__PAGE_KERNEL_RO | _PAGE_USER)
-#define __PAGE_KERNEL_LARGE            (__PAGE_KERNEL | _PAGE_PSE)
-#define __PAGE_KERNEL_LARGE_EXEC       (__PAGE_KERNEL_EXEC | _PAGE_PSE)
-#define __PAGE_KERNEL_WP               (__PAGE_KERNEL | _PAGE_CACHE_WP)
-
-#define __PAGE_KERNEL_IO               (__PAGE_KERNEL)
-#define __PAGE_KERNEL_IO_NOCACHE       (__PAGE_KERNEL_NOCACHE)
+#define _PAGE_CACHE_MASK       (_PAGE_PWT | _PAGE_PCD | _PAGE_PAT)
 
-#ifndef __ASSEMBLY__
+#define _PAGE_NOCACHE          (cachemode2protval(_PAGE_CACHE_MODE_UC))
+#define _PAGE_CACHE_WP         (cachemode2protval(_PAGE_CACHE_MODE_WP))
 
-#define _PAGE_ENC      (_AT(pteval_t, sme_me_mask))
+#define __PP _PAGE_PRESENT
+#define __RW _PAGE_RW
+#define _USR _PAGE_USER
+#define ___A _PAGE_ACCESSED
+#define ___D _PAGE_DIRTY
+#define ___G _PAGE_GLOBAL
+#define __NX _PAGE_NX
+
+#define _ENC _PAGE_ENC
+#define __WP _PAGE_CACHE_WP
+#define __NC _PAGE_NOCACHE
+#define _PSE _PAGE_PSE
+
+#define pgprot_val(x)          ((x).pgprot)
+#define __pgprot(x)            ((pgprot_t) { (x) } )
+#define __pg(x)                        __pgprot(x)
+
+#define _PAGE_PAT_LARGE                (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
+
+#define PAGE_NONE           __pg(   0|   0|   0|___A|   0|   0|   0|___G)
+#define PAGE_SHARED         __pg(__PP|__RW|_USR|___A|__NX|   0|   0|   0)
+#define PAGE_SHARED_EXEC     __pg(__PP|__RW|_USR|___A|   0|   0|   0|   0)
+#define PAGE_COPY_NOEXEC     __pg(__PP|   0|_USR|___A|__NX|   0|   0|   0)
+#define PAGE_COPY_EXEC      __pg(__PP|   0|_USR|___A|   0|   0|   0|   0)
+#define PAGE_COPY           __pg(__PP|   0|_USR|___A|__NX|   0|   0|   0)
+#define PAGE_READONLY       __pg(__PP|   0|_USR|___A|__NX|   0|   0|   0)
+#define PAGE_READONLY_EXEC   __pg(__PP|   0|_USR|___A|   0|   0|   0|   0)
+
+#define __PAGE_KERNEL           (__PP|__RW|   0|___A|__NX|___D|   0|___G)
+#define __PAGE_KERNEL_EXEC      (__PP|__RW|   0|___A|   0|___D|   0|___G)
+#define _KERNPG_TABLE_NOENC     (__PP|__RW|   0|___A|   0|___D|   0|   0)
+#define _KERNPG_TABLE           (__PP|__RW|   0|___A|   0|___D|   0|   0| _ENC)
+#define _PAGE_TABLE_NOENC       (__PP|__RW|_USR|___A|   0|___D|   0|   0)
+#define _PAGE_TABLE             (__PP|__RW|_USR|___A|   0|___D|   0|   0| _ENC)
+#define __PAGE_KERNEL_RO        (__PP|   0|   0|___A|__NX|___D|   0|___G)
+#define __PAGE_KERNEL_RX        (__PP|   0|   0|___A|   0|___D|   0|___G)
+#define __PAGE_KERNEL_NOCACHE   (__PP|__RW|   0|___A|__NX|___D|   0|___G| __NC)
+#define __PAGE_KERNEL_VVAR      (__PP|   0|_USR|___A|__NX|___D|   0|___G)
+#define __PAGE_KERNEL_LARGE     (__PP|__RW|   0|___A|__NX|___D|_PSE|___G)
+#define __PAGE_KERNEL_LARGE_EXEC (__PP|__RW|   0|___A|   0|___D|_PSE|___G)
+#define __PAGE_KERNEL_WP        (__PP|__RW|   0|___A|__NX|___D|   0|___G| __WP)
+
+
+#define __PAGE_KERNEL_IO               __PAGE_KERNEL
+#define __PAGE_KERNEL_IO_NOCACHE       __PAGE_KERNEL_NOCACHE
 
-#define _KERNPG_TABLE  (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED |    \
-                        _PAGE_DIRTY | _PAGE_ENC)
-#define _PAGE_TABLE    (_KERNPG_TABLE | _PAGE_USER)
 
-#define __PAGE_KERNEL_ENC      (__PAGE_KERNEL | _PAGE_ENC)
-#define __PAGE_KERNEL_ENC_WP   (__PAGE_KERNEL_WP | _PAGE_ENC)
+#ifndef __ASSEMBLY__
 
-#define __PAGE_KERNEL_NOENC    (__PAGE_KERNEL)
-#define __PAGE_KERNEL_NOENC_WP (__PAGE_KERNEL_WP)
+#define __PAGE_KERNEL_ENC      (__PAGE_KERNEL    | _ENC)
+#define __PAGE_KERNEL_ENC_WP   (__PAGE_KERNEL_WP | _ENC)
+#define __PAGE_KERNEL_NOENC    (__PAGE_KERNEL    |    0)
+#define __PAGE_KERNEL_NOENC_WP (__PAGE_KERNEL_WP |    0)
 
-#define default_pgprot(x)      __pgprot((x) & __default_kernel_pte_mask)
+#define __pgprot_mask(x)       __pgprot((x) & __default_kernel_pte_mask)
 
-#define PAGE_KERNEL            default_pgprot(__PAGE_KERNEL | _PAGE_ENC)
-#define PAGE_KERNEL_NOENC      default_pgprot(__PAGE_KERNEL)
-#define PAGE_KERNEL_RO         default_pgprot(__PAGE_KERNEL_RO | _PAGE_ENC)
-#define PAGE_KERNEL_EXEC       default_pgprot(__PAGE_KERNEL_EXEC | _PAGE_ENC)
-#define PAGE_KERNEL_EXEC_NOENC default_pgprot(__PAGE_KERNEL_EXEC)
-#define PAGE_KERNEL_RX         default_pgprot(__PAGE_KERNEL_RX | _PAGE_ENC)
-#define PAGE_KERNEL_NOCACHE    default_pgprot(__PAGE_KERNEL_NOCACHE | _PAGE_ENC)
-#define PAGE_KERNEL_LARGE      default_pgprot(__PAGE_KERNEL_LARGE | _PAGE_ENC)
-#define PAGE_KERNEL_LARGE_EXEC default_pgprot(__PAGE_KERNEL_LARGE_EXEC | _PAGE_ENC)
-#define PAGE_KERNEL_VVAR       default_pgprot(__PAGE_KERNEL_VVAR | _PAGE_ENC)
+#define PAGE_KERNEL            __pgprot_mask(__PAGE_KERNEL            | _ENC)
+#define PAGE_KERNEL_NOENC      __pgprot_mask(__PAGE_KERNEL            |    0)
+#define PAGE_KERNEL_RO         __pgprot_mask(__PAGE_KERNEL_RO         | _ENC)
+#define PAGE_KERNEL_EXEC       __pgprot_mask(__PAGE_KERNEL_EXEC       | _ENC)
+#define PAGE_KERNEL_EXEC_NOENC __pgprot_mask(__PAGE_KERNEL_EXEC       |    0)
+#define PAGE_KERNEL_RX         __pgprot_mask(__PAGE_KERNEL_RX         | _ENC)
+#define PAGE_KERNEL_NOCACHE    __pgprot_mask(__PAGE_KERNEL_NOCACHE    | _ENC)
+#define PAGE_KERNEL_LARGE      __pgprot_mask(__PAGE_KERNEL_LARGE      | _ENC)
+#define PAGE_KERNEL_LARGE_EXEC __pgprot_mask(__PAGE_KERNEL_LARGE_EXEC | _ENC)
+#define PAGE_KERNEL_VVAR       __pgprot_mask(__PAGE_KERNEL_VVAR       | _ENC)
 
-#define PAGE_KERNEL_IO         default_pgprot(__PAGE_KERNEL_IO)
-#define PAGE_KERNEL_IO_NOCACHE default_pgprot(__PAGE_KERNEL_IO_NOCACHE)
+#define PAGE_KERNEL_IO         __pgprot_mask(__PAGE_KERNEL_IO)
+#define PAGE_KERNEL_IO_NOCACHE __pgprot_mask(__PAGE_KERNEL_IO_NOCACHE)
 
 #endif /* __ASSEMBLY__ */
 
@@ -449,9 +457,6 @@ static inline pteval_t pte_flags(pte_t pte)
        return native_pte_val(pte) & PTE_FLAGS_MASK;
 }
 
-#define pgprot_val(x)  ((x).pgprot)
-#define __pgprot(x)    ((pgprot_t) { (x) } )
-
 extern uint16_t __cachemode2pte_tbl[_PAGE_CACHE_MODE_NUM];
 extern uint8_t __pte2cachemode_tbl[8];
 
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