x86/ldt: Define LDT_END_ADDR

joergroedel · KAGA-KOKO · commit 8195d869d118 · 2018-07-20T01:11:47.000+02:00
It marks the end of the address-space range reserved for the LDT. The LDT-code will use it when unmapping the LDT for user-space. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Pavel Machek <pavel@ucw.cz> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: linux-mm@kvack.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Laight <David.Laight@aculab.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Eduardo Valentin <eduval@amazon.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Will Deacon <will.deacon@arm.com> Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Waiman Long <llong@redhat.com> Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca> Cc: joro@8bytes.org Link: https://lkml.kernel.org/r/1531906876-13451-35-git-send-email-joro@8bytes.org
diff --git a/arch/x86/include/asm/pgtable_32_types.h b/arch/x86/include/asm/pgtable_32_types.h
@@ -53,6 +53,8 @@ extern bool __vmalloc_start_set; /* set once high_memory is set */
 #define LDT_BASE_ADDR		\
 	((CPU_ENTRY_AREA_BASE - PAGE_SIZE) & PMD_MASK)
 
+#define LDT_END_ADDR		(LDT_BASE_ADDR + PMD_SIZE)
+
 #define PKMAP_BASE		\
 	((LDT_BASE_ADDR - PAGE_SIZE) & PMD_MASK)
 
diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
@@ -115,6 +115,7 @@ extern unsigned int ptrs_per_p4d;
 #define LDT_PGD_ENTRY_L5	-112UL
 #define LDT_PGD_ENTRY		(pgtable_l5_enabled() ? LDT_PGD_ENTRY_L5 : LDT_PGD_ENTRY_L4)
 #define LDT_BASE_ADDR		(LDT_PGD_ENTRY << PGDIR_SHIFT)
+#define LDT_END_ADDR		(LDT_BASE_ADDR + PGDIR_SIZE)
 
 #define __VMALLOC_BASE_L4	0xffffc90000000000UL
 #define __VMALLOC_BASE_L5 	0xffa0000000000000UL
diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
@@ -206,7 +206,7 @@ static void free_ldt_pgtables(struct mm_struct *mm)
 #ifdef CONFIG_PAGE_TABLE_ISOLATION
 	struct mmu_gather tlb;
 	unsigned long start = LDT_BASE_ADDR;
-	unsigned long end = start + (1UL << PGDIR_SHIFT);
+	unsigned long end = LDT_END_ADDR;
 
 	if (!static_cpu_has(X86_FEATURE_PTI))
 		return;
