From: Andy Lutomirski <luto@kernel.org>
Date: Sun, 28 May 2017 10:00:16 -0700
Subject: x86/mm: Be more consistent wrt PAGE_SHIFT vs PAGE_SIZE in tlb flush
code
Git-commit: be4ffc0d787fafb22b89a2f29e71fea3b119205e
Patch-mainline: v4.13-rc1
References: bsc#1068032 CVE-2017-5754
Nadav pointed out that some code used PAGE_SIZE and other code used
PAGE_SHIFT. Use PAGE_SHIFT instead of multiplying or dividing by
PAGE_SIZE.
Requested-by: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Borislav Petkov <bp@suse.de>
---
arch/x86/mm/tlb.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -223,8 +223,7 @@ static void flush_tlb_func_common(const
trace_tlb_flush(reason, TLB_FLUSH_ALL);
} else {
unsigned long addr;
- unsigned long nr_pages =
- (f->end - f->start) / PAGE_SIZE;
+ unsigned long nr_pages = (f->end - f->start) >> PAGE_SHIFT;
addr = f->start;
while (addr < f->end) {
__flush_tlb_single(addr);
@@ -359,7 +358,7 @@ void flush_tlb_kernel_range(unsigned lon
/* Balance as user space task's flush, a bit conservative */
if (end == TLB_FLUSH_ALL ||
- (end - start) > tlb_single_page_flush_ceiling * PAGE_SIZE) {
+ (end - start) > tlb_single_page_flush_ceiling << PAGE_SHIFT) {
on_each_cpu(do_flush_tlb_all, NULL, 1);
} else {
struct flush_tlb_info info;