From d2479a30499d93377d3ab10b7822bc5f10ed7f22 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Fri, 20 Apr 2018 15:20:19 -0700 Subject: [PATCH] x86/pti: Fix boot problems from Global-bit setting commit 16dce603adc9de4237b7bf2ff5c5290f34373e7b Part of the global bit _setting_ patches also includes clearing the Global bit when it should not be enabled. 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. Fixes: 39114b7a7 (x86/pti: Never implicitly clear _PAGE_GLOBAL for kernel image) Reported-by: Mariusz Ceier Reported-by: Aaro Koskinen Signed-off-by: Dave Hansen Signed-off-by: Thomas Gleixner Tested-by: Aaro Koskinen Acked-by: Ingo Molnar Cc: Andrea Arcangeli Cc: Juergen Gross Cc: Nadav Amit Cc: Kees Cook Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: David Woodhouse Cc: Hugh Dickins Cc: linux-mm@kvack.org Cc: Linus Torvalds Cc: Andy Lutomirski Cc: Greg Kroah-Hartman Cc: Borislav Petkov Cc: Dan Williams Cc: Arjan van de Ven Link: https://lkml.kernel.org/r/20180420222019.20C4A410@viggo.jf.intel.com --- arch/x86/mm/pageattr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 0f3d50f4c48c..4fadfd2b7017 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -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 long *start, int numpages, int cache, 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); -- 2.20.1