From: Sami Tolvanen <samitolvanen@google.com>
Date: Fri, 13 Sep 2019 14:14:02 -0700
Subject: x86/mm: Use the correct function type for native_set_fixmap()
Git-commit: f53e2cd0b8ab7d9e390414470bdbd830f660133f
Patch-mainline: 5.5-rc1
References: git-fixes

We call native_set_fixmap indirectly through the function pointer
struct pv_mmu_ops::set_fixmap, which expects the first parameter to be
'unsigned' instead of 'enum fixed_addresses'. This patch changes the
function type for native_set_fixmap to match the pointer, which fixes
indirect call mismatches with Control-Flow Integrity (CFI) checking.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H . Peter Anvin <hpa@zytor.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190913211402.193018-1-samitolvanen@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 arch/x86/include/asm/fixmap.h |    2 +-
 arch/x86/mm/pgtable.c         |    4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -157,7 +157,7 @@ extern pte_t *kmap_pte;
 extern pte_t *pkmap_page_table;
 
 void __native_set_fixmap(enum fixed_addresses idx, pte_t pte);
-void native_set_fixmap(enum fixed_addresses idx,
+void native_set_fixmap(unsigned /* enum fixed_addresses */ idx,
 		       phys_addr_t phys, pgprot_t flags);
 
 #ifndef CONFIG_PARAVIRT
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -594,8 +594,8 @@ void __native_set_fixmap(enum fixed_addr
 	fixmaps_set++;
 }
 
-void native_set_fixmap(enum fixed_addresses idx, phys_addr_t phys,
-		       pgprot_t flags)
+void native_set_fixmap(unsigned /* enum fixed_addresses */ idx,
+		       phys_addr_t phys, pgprot_t flags)
 {
 	__native_set_fixmap(idx, pfn_pte(phys >> PAGE_SHIFT, flags));
 }