From: Dave Hansen <dave.han...@linux.intel.com>
Part of the global bit _setting_ patches also includes clearing the
Global bit when we do not want it. That is done with
set_memory_nonglobal(), which uses change_page_attr_clear() in
pageattr.c under the covers.
The TLB flushing code inside pageattr.c has has checks like
BUG_ON(irqs_disabled()), looking for interrupt disabling that might
cause deadlocks. But, these also trip in early boot on certain
preempt configurations. Just copy the existing BUG_ON() sequence from
cpa_flush_range() to the other two sites and check for early boot.
Signed-off-by: Dave Hansen <dave.han...@linux.intel.com>
Fixes: 39114b7a7 (x86/pti: Never implicitly clear _PAGE_GLOBAL for kernel image)
Reported-by: Mariusz Ceier <mce...@gmail.com>
Reported-by: Aaro Koskinen <aaro.koski...@nokia.com>
Cc: Andrea Arcangeli <aarca...@redhat.com>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Arjan van de Ven <ar...@linux.intel.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: David Woodhouse <dw...@infradead.org>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Cc: Hugh Dickins <hu...@google.com>
Cc: Josh Poimboeuf <jpoim...@redhat.com>
Cc: Juergen Gross <jgr...@suse.com>
Cc: Kees Cook <keesc...@google.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Nadav Amit <na...@vmware.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: linux...@kvack.org
---
b/arch/x86/mm/pageattr.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN arch/x86/mm/pageattr.c~pti-glb-boot-problem-fix arch/x86/mm/pageattr.c
--- a/arch/x86/mm/pageattr.c~pti-glb-boot-problem-fix 2018-04-20
14:10:01.086749169 -0700
+++ b/arch/x86/mm/pageattr.c 2018-04-20 14:10:01.090749169 -0700
@@ -172,7 +172,7 @@ static void __cpa_flush_all(void *arg)
static void cpa_flush_all(unsigned long cache)
{
- BUG_ON(irqs_disabled());
+ BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);
on_each_cpu(__cpa_flush_all, (void *) cache, 1);
}
@@ -236,7 +236,7 @@ static void cpa_flush_array(unsigned lon
unsigned long do_wbinvd = cache && numpages >= 1024; /* 4M threshold */
#endif
- BUG_ON(irqs_disabled());
+ BUG_ON(irqs_disabled() && !early_boot_irqs_disabled);
on_each_cpu(__cpa_flush_all, (void *) do_wbinvd, 1);
_
