On Mon, 24 May 2021 12:04:18 +0200 Marco Elver wrote: > > > +Cc Mark > > On Mon, 24 May 2021 at 11:26, Jisheng Zhang <Jisheng.Zhang@xxxxxxxxxxxxx> wrote: > > > > KFENCE requires linear map to be mapped at page granularity, so that > > it is possible to protect/unprotect single pages in the KFENCE pool. > > Currently if KFENCE is enabled, arm64 maps all pages at page > > granularity, it seems overkilled. In fact, we only need to map the > > pages in KFENCE pool itself at page granularity. We acchieve this goal > > by allocating KFENCE pool before paging_init() so we know the KFENCE > > pool address, then we take care to map the pool at page granularity > > during map_mem(). > > > > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@xxxxxxxxxxxxx> > > --- > > arch/arm64/kernel/setup.c | 3 +++ > > arch/arm64/mm/mmu.c | 27 +++++++++++++++++++-------- > > 2 files changed, 22 insertions(+), 8 deletions(-) > > > > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c > > index 61845c0821d9..51c0d6e8b67b 100644 > > --- a/arch/arm64/kernel/setup.c > > +++ b/arch/arm64/kernel/setup.c > > @@ -18,6 +18,7 @@ > > #include <linux/screen_info.h> > > #include <linux/init.h> > > #include <linux/kexec.h> > > +#include <linux/kfence.h> > > #include <linux/root_dev.h> > > #include <linux/cpu.h> > > #include <linux/interrupt.h> > > @@ -345,6 +346,8 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p) > > > > arm64_memblock_init(); > > > > + kfence_alloc_pool(); > > + > > paging_init(); > > > > acpi_table_upgrade(); > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > > index 89b66ef43a0f..12712d31a054 100644 > > --- a/arch/arm64/mm/mmu.c > > +++ b/arch/arm64/mm/mmu.c > > @@ -13,6 +13,7 @@ > > #include <linux/init.h> > > #include <linux/ioport.h> > > #include <linux/kexec.h> > > +#include <linux/kfence.h> > > #include <linux/libfdt.h> > > #include <linux/mman.h> > > #include <linux/nodemask.h> > > @@ -515,10 +516,16 @@ static void __init map_mem(pgd_t *pgdp) > > */ > > BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end)); > > > > - if (rodata_full || crash_mem_map || debug_pagealloc_enabled() || > > - IS_ENABLED(CONFIG_KFENCE)) > > + if (rodata_full || crash_mem_map || debug_pagealloc_enabled()) > > flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; > > > > + /* > > + * KFENCE requires linear map to be mapped at page granularity, so > > + * temporarily skip mapping for __kfence_pool in the following > > + * for-loop > > + */ > > + memblock_mark_nomap(__pa(__kfence_pool), KFENCE_POOL_SIZE); > > + > > Did you build this with CONFIG_KFENCE unset? I don't think it builds. > Oops, nice catch! I will fix it in v2 thanks for your review
