tree 14fe70644fa274e11e14a8cf35c0b5c32c99233a
parent 8a35921f4f958944ff41ec625de415747dd41c11
author Andy Lutomirski <luto@amacapital.net> 1421954878 -0800
committer chrmhoffmann <chrmhoffmann@gmail.com> 1586074859 +0200

x86, tls, ldt: Stop checking lm in LDT_empty

commit e30ab185c490e9a9381385529e0fd32f0a399495 upstream.

32-bit programs don't have an lm bit in their ABI, so they can't
reliably cause LDT_empty to return true without resorting to memset.
They shouldn't need to do this.

This should fix a longstanding, if minor, issue in all 64-bit kernels
as well as a potential regression in the TLS hardening code.

Fixes: 41bdc78544b8 x86/tls: Validate TLS entries to protect espfix
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/72a059de55e86ad5e2935c80aa91880ddf19d07c.1421954363.git.luto@amacapital.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Zefan Li <lizefan@huawei.com>