From: Dave Hansen <dave.han...@linux.intel.com>

local_flush_tlb() does a CR3 write.  But, that kind of TLB flush is
not guaranteed to invalidate global pages.  The entire kernel is
mapped with global pages.

Also, now that we have PCIDs, local_flush_tlb() will only flush the
*current* PCID.  It would not flush the entries for all PCIDs.
At the moment, this is a moot point because all kernel pages are
_PAGE_GLOBAL which do not really *have* a particular PCID.

Use the stronger __flush_tlb_all() which does flush global pages.

This was found because of a warning I added to __native_flush_tlb()
to look for calls to it when PCIDs are enabled.  This patch does
not fix any bug known to be hit in practice.

Signed-off-by: Dave Hansen <dave.han...@linux.intel.com>
Cc: x...@kernel.org
Cc: Andy Lutomirski <l...@kernel.org>
---

 b/arch/x86/kernel/alternative.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff -puN arch/x86/kernel/alternative.c~x86-mm-text-poke-misses-global-pages 
arch/x86/kernel/alternative.c
--- a/arch/x86/kernel/alternative.c~x86-mm-text-poke-misses-global-pages        
2017-10-31 10:28:44.306557256 -0700
+++ b/arch/x86/kernel/alternative.c     2017-10-31 10:28:44.309557393 -0700
@@ -722,7 +722,8 @@ void *text_poke(void *addr, const void *
        clear_fixmap(FIX_TEXT_POKE0);
        if (pages[1])
                clear_fixmap(FIX_TEXT_POKE1);
-       local_flush_tlb();
+       /* Make sure to flush Global pages: */
+       __flush_tlb_all();
        sync_core();
        /* Could also do a CLFLUSH here to speed up CPU recovery; but
           that causes hangs on some VIA CPUs. */
_

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