lkml.org 
[lkml]   [2020]   [Jan]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip: x86/mm] x86/mm: Tabulate the page table encoding definitions
The following commit has been merged into the x86/mm branch of tip:

Commit-ID: 4efb56649132687b5093d90aa62887595e65a09d
Gitweb: https://git.kernel.org/tip/4efb56649132687b5093d90aa62887595e65a09d
Author: Ingo Molnar <mingo@kernel.org>
AuthorDate: Wed, 20 Nov 2019 17:38:39 +01:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 10 Dec 2019 10:12:55 +01:00

x86/mm: Tabulate the page table encoding definitions

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 | 143 +++++++++++++-------------
1 file changed, 74 insertions(+), 69 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index b5e49e6..ea74007 100644
--- 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];

\
 
 \ /
  Last update: 2020-01-10 19:00    [W:0.040 / U:7.732 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site