From 94d49eb30e854c84d1319095b5dd0405a7da9362 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Fri, 18 May 2018 14:30:28 +0300 Subject: 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 Signed-off-by: Thomas Gleixner Reviewed-by: Tom Lendacky Cc: linux-mm@kvack.org Cc: "H. Peter Anvin" Link: https://lkml.kernel.org/r/20180518113028.79825-1-kirill.shutemov@linux.intel.com --- arch/x86/Kconfig | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/x86/Kconfig') 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 -- cgit v1.2.3