[PATCH] x86/speculation/l1tf: Add assembly guard for xtensa/ia64

[PATCH] x86/speculation/l1tf: Add assembly guard for xtensa/ia64

[Andi Kleen]

From: Andi Kleen <ak@linux.intel.com>

The stable backport of the

x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings

patch for 4.4 and 4.9 put new C code for !__HAVE_ARCH_PFN_MODIFY_ALLOWED
code outside the assembler ifdef. This breaks the xtensa and ia64
build as reported by 0day which somehow include this file
into assembler.

Just add an #ifdef __ASSEMBLY__ around the new code to fix this.

This patch is only needed for 4.9 and 4.4 stable, the newer stables
don't have this problem.

Fixes: 7c5b42f82c13 ("x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings")
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 include/asm-generic/pgtable.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index a88ea9e37a25..abc2a1b15dd8 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -825,6 +825,7 @@ static inline int pmd_free_pte_page(pmd_t *pmd)
 #endif
 #endif
 
+#ifndef __ASSEMBLY__
 struct file;
 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
 			unsigned long size, pgprot_t *vma_prot);
@@ -839,6 +840,9 @@ static inline bool arch_has_pfn_modify_check(void)
 {
 	return false;
 }
+
+#endif
+
 #endif /* !_HAVE_ARCH_PFN_MODIFY_ALLOWED */
 
 #endif /* !__ASSEMBLY__ */
-- 
2.17.1

Re: [PATCH] x86/speculation/l1tf: Add assembly guard for xtensa/ia64

[Guenter Roeck]

On Wed, Aug 15, 2018 at 02:56:46PM -0700, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
> 
> The stable backport of the
> 
> x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings
> 
> patch for 4.4 and 4.9 put new C code for !__HAVE_ARCH_PFN_MODIFY_ALLOWED
> code outside the assembler ifdef. This breaks the xtensa and ia64
> build as reported by 0day which somehow include this file
> into assembler.
> 
> Just add an #ifdef __ASSEMBLY__ around the new code to fix this.
> 
> This patch is only needed for 4.9 and 4.4 stable, the newer stables
> don't have this problem.
> 
> Fixes: 7c5b42f82c13 ("x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings")
> Signed-off-by: Andi Kleen <ak@linux.intel.com>

This should be fixed in the final stable releases.
The problem was caused by a couple of missing backports.

Guenter