On 26/05/2026 19:58, Ard Biesheuvel wrote: > From: Ard Biesheuvel <[email protected]> > > Now that the map_mem() routines respect existing page mappings and > contiguous granule sized blocks with the contiguous bit cleared, there > is no longer a reason to play tricks with the memblock NOMAP attribute. > > Instead, the kfence pool can be allocated and mapped with page > granularity first, and this granularity will be respected when the rest > of DRAM is mapped later, even if block and contiguous mappings are > allowed for the remainder of those mappings. > > Signed-off-by: Ard Biesheuvel <[email protected]>
Reviewed-by: Kevin Brodsky <[email protected]> > --- > arch/arm64/mm/mmu.c | 25 ++++---------------- > 1 file changed, 5 insertions(+), 20 deletions(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index d7a6991e1844..55bb40348a47 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -1083,36 +1083,24 @@ static int __init parse_kfence_early_init(char *arg) > } > early_param("kfence.sample_interval", parse_kfence_early_init); > > -static phys_addr_t __init arm64_kfence_alloc_pool(void) > +static void __init arm64_kfence_map_pool(void) > { > phys_addr_t kfence_pool; > > if (!kfence_early_init) > - return 0; > + return; > > kfence_pool = memblock_phys_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); > if (!kfence_pool) { > pr_err("failed to allocate kfence pool\n"); > kfence_early_init = false; > - return 0; > - } > - > - /* Temporarily mark as NOMAP. */ > - memblock_mark_nomap(kfence_pool, KFENCE_POOL_SIZE); > - > - return kfence_pool; > -} > - > -static void __init arm64_kfence_map_pool(phys_addr_t kfence_pool) > -{ > - if (!kfence_pool) > return; > + } > > /* KFENCE pool needs page-level mapping. */ > __map_memblock(kfence_pool, kfence_pool + KFENCE_POOL_SIZE, > pgprot_tagged(PAGE_KERNEL), > NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); > - memblock_clear_nomap(kfence_pool, KFENCE_POOL_SIZE); > __kfence_pool = phys_to_virt(kfence_pool); > } > > @@ -1144,8 +1132,7 @@ bool arch_kfence_init_pool(void) > } > #else /* CONFIG_KFENCE */ > > -static inline phys_addr_t arm64_kfence_alloc_pool(void) { return 0; } > -static inline void arm64_kfence_map_pool(phys_addr_t kfence_pool) { } > +static inline void arm64_kfence_map_pool(void) { } > > #endif /* CONFIG_KFENCE */ > > @@ -1155,7 +1142,6 @@ static void __init map_mem(void) > phys_addr_t kernel_start = __pa_symbol(_text); > phys_addr_t kernel_end = __pa_symbol(__init_begin); > phys_addr_t start, end; > - phys_addr_t early_kfence_pool; > int flags = NO_EXEC_MAPPINGS; > u64 i; > > @@ -1172,7 +1158,7 @@ static void __init map_mem(void) > BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end) > && > pgd_index(_PAGE_OFFSET(VA_BITS_MIN)) != PTRS_PER_PGD - 1); > > - early_kfence_pool = arm64_kfence_alloc_pool(); > + arm64_kfence_map_pool(); > > linear_map_requires_bbml2 = !force_pte_mapping() && > can_set_direct_map(); > > @@ -1210,7 +1196,6 @@ static void __init map_mem(void) > */ > __map_memblock(kernel_start, kernel_end, PAGE_KERNEL, NO_CONT_MAPPINGS); > memblock_clear_nomap(kernel_start, kernel_end - kernel_start); > - arm64_kfence_map_pool(early_kfence_pool); > } > > void mark_rodata_ro(void)
