x86/entry: Align entry text section to PMD boundary

CVE-2017-5754

The (irq)entry text must be visible in the user space page tables. To allow
simple PMD based sharing, make the entry text PMD aligned.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.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: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.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
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(cherry picked from commit 2f7412ba9c6af5ab16bdbb4a3fdb1dcd2b4fd3c2)
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 423aa36f0150b4ec59c6bed009338901db83f89e..f505d8dbdccf2d630a169d99c1a711a40c7098de 100644 (file)
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -60,11 +60,17 @@ jiffies_64 = jiffies;
                . = ALIGN(HPAGE_SIZE);                          \
                __end_rodata_hpage_align = .;
 
+#define ALIGN_ENTRY_TEXT_BEGIN . = ALIGN(PMD_SIZE);
+#define ALIGN_ENTRY_TEXT_END   . = ALIGN(PMD_SIZE);
+
 #else
 
 #define X64_ALIGN_RODATA_BEGIN
 #define X64_ALIGN_RODATA_END
 
+#define ALIGN_ENTRY_TEXT_BEGIN
+#define ALIGN_ENTRY_TEXT_END
+
 #endif
 
 PHDRS {
@@ -101,8 +107,10 @@ SECTIONS
                CPUIDLE_TEXT
                LOCK_TEXT
                KPROBES_TEXT
+               ALIGN_ENTRY_TEXT_BEGIN
                ENTRY_TEXT
                IRQENTRY_TEXT
+               ALIGN_ENTRY_TEXT_END
                SOFTIRQENTRY_TEXT
                *(.fixup)
                *(.gnu.warning)