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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2018-05-18 14:30:28 +0300
committerThomas Gleixner <tglx@linutronix.de>2018-06-06 13:38:01 +0200
commit94d49eb30e854c84d1319095b5dd0405a7da9362 (patch)
tree0c2c2a712fae357f64de8e330c4956bda1215255 /arch/x86/Kconfig
parent046c0dbec0238c25b7526c26c9a9687664229ce2 (diff)
x86/mm: Decouple dynamic __PHYSICAL_MASK from AMD SME
AMD SME claims one bit from physical address to indicate whether the page is encrypted or not. To achieve that we clear out the bit from __PHYSICAL_MASK. The capability to adjust __PHYSICAL_MASK is required beyond AMD SME. For instance for upcoming Intel Multi-Key Total Memory Encryption. Factor it out into a separate feature with own Kconfig handle. It also helps with overhead of AMD SME. It saves more than 3k in .text on defconfig + AMD_MEM_ENCRYPT: add/remove: 3/2 grow/shrink: 5/110 up/down: 189/-3753 (-3564) We would need to return to this once we have infrastructure to patch constants in code. That's good candidate for it. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Cc: linux-mm@kvack.org Cc: "H. Peter Anvin" <hpa@zytor.com> Link: https://lkml.kernel.org/r/20180518113028.79825-1-kirill.shutemov@linux.intel.com
Diffstat (limited to 'arch/x86/Kconfig')
-rw-r--r--arch/x86/Kconfig4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c07f492b871a..43a8fc476296 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -337,6 +337,9 @@ config ARCH_SUPPORTS_UPROBES
config FIX_EARLYCON_MEM
def_bool y
+config DYNAMIC_PHYSICAL_MASK
+ bool
+
config PGTABLE_LEVELS
int
default 5 if X86_5LEVEL
@@ -1508,6 +1511,7 @@ config ARCH_HAS_MEM_ENCRYPT
config AMD_MEM_ENCRYPT
bool "AMD Secure Memory Encryption (SME) support"
depends on X86_64 && CPU_SUP_AMD
+ select DYNAMIC_PHYSICAL_MASK
---help---
Say yes to enable support for the encryption of system memory.
This requires an AMD processor that supports Secure Memory