[amd-pstate:superm1/lockdown-iommu 3/3] security/lockdown/lockdown.c:217:8: error: call to undeclared function 'iommu_is_available'; ISO C99 and later do not support implicit function declarations

[amd-pstate:superm1/lockdown-iommu 3/3] security/lockdown/lockdown.c:217:8: error: call to undeclared function 'iommu_is_available'; ISO C99 and later do not support implicit function declarations

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/superm1/linux.git superm1/lockdown-iommu
head:   74b0183524154e17897a7789da06a937eaf8b2b7
commit: 74b0183524154e17897a7789da06a937eaf8b2b7 [3/3] security: lockdown: Prevent boot with lockdown but no IOMMU
config: arm64-randconfig-1003-20261028 (https://download.01.org/0day-ci/archive/20261028/202610282110.ZVggpdqM-lkp@intel.com/config)
compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project 1da436a23e613c425fc9b868fc8deb979ede47a4)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261028/202610282110.ZVggpdqM-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202610282110.ZVggpdqM-lkp@intel.com/

All errors (new ones prefixed by >>):

>> security/lockdown/lockdown.c:217:8: error: call to undeclared function 'iommu_is_available'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     217 |                 if (!iommu_is_available()) {
         |                      ^
   security/lockdown/lockdown.c:217:8: note: did you mean 'slab_is_available'?
   include/linux/slab.h:283:6: note: 'slab_is_available' declared here
     283 | bool slab_is_available(void);
         |      ^
   1 error generated.


vim +/iommu_is_available +217 security/lockdown/lockdown.c

   197	
   198	/*
   199	 * Late init call to verify IOMMU availability when lockdown is active.
   200	 * This catches cases where:
   201	 *  - IOMMU hardware is absent on the platform
   202	 *  - IOMMU was disabled by driver initialization failure
   203	 *  - IOMMU was not detected (e.g. broken firmware, missing ACPI tables)
   204	 *
   205	 * On x86, we also check no_iommu here as a double-check. The early check
   206	 * in lockdown_lsm_init() catches 'iommu=off' from the cmdline before
   207	 * lockdown_lsm_init() runs, but this late check covers any missed cases.
   208	 */
   209	static int __init lockdown_check_iommu(void)
   210	{
   211		if (kernel_locked_down > LOCKDOWN_NONE) {
   212			/*
   213			 * Check generic IOMMU availability (all architectures).
   214			 * iommu_is_available() returns true if any IOMMU driver
   215			 * registered successfully.
   216			 */
 > 217			if (!iommu_is_available()) {

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