Hello Max, I could reproduce the build failure with nommu_kc705_defconfig. On 7/6/22 03:44, Max Filippov wrote: > Don't define protection_map and don't use DECLARE_VM_GET_PAGE_PROT in > noMMU configs, because in that case the definition for vm_get_page_prot > is provided by the include/linux/mm.h Right, a fallback (!CONFIG_MMU) stub definition is provided there. > > Fixes: 61ab8053710f ("xtensa/mm: enable ARCH_HAS_VM_GET_PAGE_PROT") > Signed-off-by: Max Filippov <jcmvbkbc@xxxxxxxxx> > --- > arch/xtensa/mm/init.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c > index fb830ec8183c..b2587a1a7c46 100644 > --- a/arch/xtensa/mm/init.c > +++ b/arch/xtensa/mm/init.c > @@ -217,6 +217,7 @@ static int __init parse_memmap_opt(char *str) > } > early_param("memmap", parse_memmap_opt); > > +#ifdef CONFIG_MMU > static const pgprot_t protection_map[16] = { > [VM_NONE] = PAGE_NONE, > [VM_READ] = PAGE_READONLY, > @@ -236,3 +237,4 @@ static const pgprot_t protection_map[16] = { > [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED_EXEC > }; > DECLARE_VM_GET_PAGE_PROT > +#endif LGTM and fixes the build problem. Reviewed-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> Reviewing CONFIG_MMU dependency for other platforms .... * powerpc - No CONFIG_MMU found - config MMU - bool default y * sparc - No CONFIG_MMU found - config MMU - bool default y * arm64 - No CONFIG_MMU found - config MMU - bool default y * x86 - No CONFIG_MMU found - config MMU - bool default y * microblaze - No CONFIG_MMU found - config MMU - bool default y * loongarch - No CONFIG_MMU found - config MMU - bool default y * openrisc - No CONFIG_MMU found - config MMU - bool default y * xtensa - This fix here * hexagon - No CONFIG_MMU found - config MMU - bool default y * parisc - No CONFIG_MMU found - config MMU - bool default y * alpha - No CONFIG_MMU found - config MMU - bool default y * nios2 - No CONFIG_MMU found - config MMU - bool default y * riscv - Both protection_map[] and DECLARE_VM_GET_PAGE_PROT are inside CONFIG_MMU * csky - No CONFIG_MMU found - config MMU - bool default y * s390 - No CONFIG_MMU found - config MMU - bool default y * ia64 - No CONFIG_MMU found - config MMU - bool default y * mips - No CONFIG_MMU found - config MMU - bool default y * m68k - Both protection_map[] and DECLARE_VM_GET_PAGE_PROT are inside CONFIG_MMU (SUN3, MOTOROLA, COLDFIRE) * arc - No CONFIG_MMU found - config MMU - bool default y * arm - Both protection_map[] and DECLARE_VM_GET_PAGE_PROT are inside CONFIG_MMU * um - No CONFIG_MMU found - config MMU - bool default y * sh - Both protection_map[] and DECLARE_VM_GET_PAGE_PROT needs to be moved inside CONFIG_MMU, will send a patch soon. So apart from xtensa and sh, no other platform seems to have this CONFIG_MMU related build problem. But please do let me know if I might have missed something. - Anshuman