On Thu, Dec 03, 2020 at 03:36:10PM -0800, Andrew Morton wrote: > On Thu, 3 Dec 2020 08:29:43 +0200 Mike Rapoport <rppt@xxxxxxxxxx> wrote: > > > From: Mike Rapoport <rppt@xxxxxxxxxxxxx> > > > > On arm64, set_direct_map_*() functions may return 0 without actually > > changing the linear map. This behaviour can be controlled using kernel > > parameters, so we need a way to determine at runtime whether calls to > > set_direct_map_invalid_noflush() and set_direct_map_default_noflush() have > > any effect. > > > > Extend set_memory API with can_set_direct_map() function that allows > > checking if calling set_direct_map_*() will actually change the page table, > > replace several occurrences of open coded checks in arm64 with the new > > function and provide a generic stub for architectures that always modify > > page tables upon calls to set_direct_map APIs. > > > > ... > > > > --- a/arch/arm64/mm/mmu.c > > +++ b/arch/arm64/mm/mmu.c > > @@ -22,6 +22,7 @@ > > #include <linux/io.h> > > #include <linux/mm.h> > > #include <linux/vmalloc.h> > > +#include <linux/set_memory.h> > > > > #include <asm/barrier.h> > > #include <asm/cputype.h> > > @@ -477,7 +478,7 @@ static void __init map_mem(pgd_t *pgdp) > > int flags = 0; > > u64 i; > > > > - if (rodata_full || debug_pagealloc_enabled()) > > + if (can_set_direct_map()) > > flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; > > Changes in -next turned this into > > if (can_set_direct_map() || crash_mem_map) Thanks for updating! -- Sincerely yours, Mike.
