Messages in this thread Patch in this message | | | Subject | [PATCH 1/5] x86, pti: fix boot problems from Global-bit setting | From | Dave Hansen <> | Date | Fri, 20 Apr 2018 15:20:19 -0700 |
| |
From: Dave Hansen <dave.hansen@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.hansen@linux.intel.com> Fixes: 39114b7a7 (x86/pti: Never implicitly clear _PAGE_GLOBAL for kernel image) Reported-by: Mariusz Ceier <mceier@gmail.com> Reported-by: Aaro Koskinen <aaro.koskinen@nokia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nadav Amit <namit@vmware.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@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); _
| |