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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 14:38:01 +0300
commit94d49eb30e854c84d1319095b5dd0405a7da9362 (patch)
tree0c2c2a712fae357f64de8e330c4956bda1215255 /arch/x86/boot
parent046c0dbec0238c25b7526c26c9a9687664229ce2 (diff)
downloadlinux-94d49eb30e854c84d1319095b5dd0405a7da9362.tar.xz
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/boot')
-rw-r--r--arch/x86/boot/compressed/kaslr_64.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/boot/compressed/kaslr_64.c b/arch/x86/boot/compressed/kaslr_64.c
index 522d11431433..748456c365f4 100644
--- a/arch/x86/boot/compressed/kaslr_64.c
+++ b/arch/x86/boot/compressed/kaslr_64.c
@@ -69,6 +69,8 @@ static struct alloc_pgt_data pgt_data;
/* The top level page table entry pointer. */
static unsigned long top_level_pgt;
+phys_addr_t physical_mask = (1ULL << __PHYSICAL_MASK_SHIFT) - 1;
+
/*
* Mapping information structure passed to kernel_ident_mapping_init().
* Due to relocation, pointers must be assigned at run time not build time.
@@ -81,6 +83,9 @@ void initialize_identity_maps(void)
/* If running as an SEV guest, the encryption mask is required. */
set_sev_encryption_mask();
+ /* Exclude the encryption mask from __PHYSICAL_MASK */
+ physical_mask &= ~sme_me_mask;
+
/* Init mapping_info with run-time function/buffer pointers. */
mapping_info.alloc_pgt_page = alloc_pgt_page;
mapping_info.context = &pgt_data;