[PATCH 1/1] iommu/vt-d: Fix build error of pasid_enable_wpe() with !X86

[Lu Baolu]

Commit f68c7f539b6e9 ("iommu/vt-d: Enable write protect for supervisor
SVM") added pasid_enable_wpe() which hit below compile error with !X86.

../drivers/iommu/intel/pasid.c: In function 'pasid_enable_wpe':
../drivers/iommu/intel/pasid.c:554:22: error: implicit declaration of function 'read_cr0' [-Werror=implicit-function-declaration]
  554 |  unsigned long cr0 = read_cr0();
      |                      ^~~~~~~~
In file included from ../include/linux/build_bug.h:5,
                 from ../include/linux/bits.h:22,
                 from ../include/linux/bitops.h:6,
                 from ../drivers/iommu/intel/pasid.c:12:
../drivers/iommu/intel/pasid.c:557:23: error: 'X86_CR0_WP' undeclared (first use in this function)
  557 |  if (unlikely(!(cr0 & X86_CR0_WP))) {
      |                       ^~~~~~~~~~
../include/linux/compiler.h:78:42: note: in definition of macro 'unlikely'
   78 | # define unlikely(x) __builtin_expect(!!(x), 0)
      |                                          ^
../drivers/iommu/intel/pasid.c:557:23: note: each undeclared identifier is reported only once for each function it appears in
  557 |  if (unlikely(!(cr0 & X86_CR0_WP))) {
      |                       ^~~~~~~~~~
../include/linux/compiler.h:78:42: note: in definition of macro 'unlikely'
   78 | # define unlikely(x) __builtin_expect(!!(x), 0)
      |

Add the missing dependency.

Cc: Sanjay Kumar <sanjay.k.kumar@xxxxxxxxx>
Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Fixes: f68c7f539b6e9 ("iommu/vt-d: Enable write protect for supervisor SVM")
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
---
 drivers/iommu/intel/pasid.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 477b2e1d303c..72646bafc52f 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -551,6 +551,7 @@ static void pasid_flush_caches(struct intel_iommu *iommu,
 
 static inline int pasid_enable_wpe(struct pasid_entry *pte)
 {
+#ifdef CONFIG_X86
 	unsigned long cr0 = read_cr0();
 
 	/* CR0.WP is normally set but just to be sure */
@@ -558,6 +559,7 @@ static inline int pasid_enable_wpe(struct pasid_entry *pte)
 		pr_err_ratelimited("No CPU write protect!\n");
 		return -EINVAL;
 	}
+#endif
 	pasid_set_wpe(pte);
 
 	return 0;
-- 
2.25.1