Commit-ID:  f3e48e546c42e31c0c095a6f917a4ad64668608c
Gitweb:     https://git.kernel.org/tip/f3e48e546c42e31c0c095a6f917a4ad64668608c
Author:     Joerg Roedel <jroe...@suse.de>
AuthorDate: Wed, 18 Jul 2018 11:41:10 +0200
Committer:  Thomas Gleixner <t...@linutronix.de>
CommitDate: Fri, 20 Jul 2018 01:11:47 +0200

x86/ldt: Reserve address-space range on 32 bit for the LDT

Reserve 2MB/4MB of address-space for mapping the LDT to user-space on 32
bit PTI kernels.

Signed-off-by: Joerg Roedel <jroe...@suse.de>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Tested-by: Pavel Machek <pa...@ucw.cz>
Cc: "H . Peter Anvin" <h...@zytor.com>
Cc: linux...@kvack.org
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Dave Hansen <dave.han...@intel.com>
Cc: Josh Poimboeuf <jpoim...@redhat.com>
Cc: Juergen Gross <jgr...@suse.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Jiri Kosina <jkos...@suse.cz>
Cc: Boris Ostrovsky <boris.ostrov...@oracle.com>
Cc: Brian Gerst <brge...@gmail.com>
Cc: David Laight <david.lai...@aculab.com>
Cc: Denys Vlasenko <dvlas...@redhat.com>
Cc: Eduardo Valentin <edu...@amazon.com>
Cc: Greg KH <gre...@linuxfoundation.org>
Cc: Will Deacon <will.dea...@arm.com>
Cc: aligu...@amazon.com
Cc: daniel.gr...@iaik.tugraz.at
Cc: hu...@google.com
Cc: keesc...@google.com
Cc: Andrea Arcangeli <aarca...@redhat.com>
Cc: Waiman Long <ll...@redhat.com>
Cc: "David H . Gutteridge" <dhgutteri...@sympatico.ca>
Cc: j...@8bytes.org
Link: 
https://lkml.kernel.org/r/1531906876-13451-34-git-send-email-j...@8bytes.org

---
 arch/x86/include/asm/pgtable_32_types.h | 7 +++++--
 arch/x86/mm/dump_pagetables.c           | 9 +++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/pgtable_32_types.h 
b/arch/x86/include/asm/pgtable_32_types.h
index d9a001a4a872..7297810747cf 100644
--- a/arch/x86/include/asm/pgtable_32_types.h
+++ b/arch/x86/include/asm/pgtable_32_types.h
@@ -50,13 +50,16 @@ extern bool __vmalloc_start_set; /* set once high_memory is 
set */
        ((FIXADDR_TOT_START - PAGE_SIZE * (CPU_ENTRY_AREA_PAGES + 1))   \
         & PMD_MASK)
 
-#define PKMAP_BASE             \
+#define LDT_BASE_ADDR          \
        ((CPU_ENTRY_AREA_BASE - PAGE_SIZE) & PMD_MASK)
 
+#define PKMAP_BASE             \
+       ((LDT_BASE_ADDR - PAGE_SIZE) & PMD_MASK)
+
 #ifdef CONFIG_HIGHMEM
 # define VMALLOC_END   (PKMAP_BASE - 2 * PAGE_SIZE)
 #else
-# define VMALLOC_END   (CPU_ENTRY_AREA_BASE - 2 * PAGE_SIZE)
+# define VMALLOC_END   (LDT_BASE_ADDR - 2 * PAGE_SIZE)
 #endif
 
 #define MODULES_VADDR  VMALLOC_START
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index e6fd0cdef9ad..ccd92c4da57c 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -122,6 +122,9 @@ enum address_markers_idx {
        VMALLOC_END_NR,
 #ifdef CONFIG_HIGHMEM
        PKMAP_BASE_NR,
+#endif
+#ifdef CONFIG_MODIFY_LDT_SYSCALL
+       LDT_NR,
 #endif
        CPU_ENTRY_AREA_NR,
        FIXADDR_START_NR,
@@ -135,6 +138,9 @@ static struct addr_marker address_markers[] = {
        [VMALLOC_END_NR]        = { 0UL,                "vmalloc() End" },
 #ifdef CONFIG_HIGHMEM
        [PKMAP_BASE_NR]         = { 0UL,                "Persistent kmap() 
Area" },
+#endif
+#ifdef CONFIG_MODIFY_LDT_SYSCALL
+       [LDT_NR]                = { 0UL,                "LDT remap" },
 #endif
        [CPU_ENTRY_AREA_NR]     = { 0UL,                "CPU entry area" },
        [FIXADDR_START_NR]      = { 0UL,                "Fixmap area" },
@@ -609,6 +615,9 @@ static int __init pt_dump_init(void)
 # endif
        address_markers[FIXADDR_START_NR].start_address = FIXADDR_START;
        address_markers[CPU_ENTRY_AREA_NR].start_address = CPU_ENTRY_AREA_BASE;
+# ifdef CONFIG_MODIFY_LDT_SYSCALL
+       address_markers[LDT_NR].start_address = LDT_BASE_ADDR;
+# endif
 #endif
        return 0;
 }

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