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V" , Donet Tom , Pavithra Prakash , LKML , "Ritesh Harjani (IBM)" Subject: [PATCH v3 09/12] book3s64/hash: Add kfence functionality Date: Fri, 18 Oct 2024 22:59:50 +0530 Message-ID: <5c2b61941b344077a2b8654dab46efa0322af3af.1729271995.git.ritesh.list@gmail.com> X-Mailer: git-send-email 2.46.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Now that linear map functionality of debug_pagealloc is made generic, enable kfence to use this generic infrastructure. 1. Define kfence related linear map variables. - u8 *linear_map_kf_hash_slots; - unsigned long linear_map_kf_hash_count; - DEFINE_RAW_SPINLOCK(linear_map_kf_hash_lock); 2. The linear map size allocated in RMA region is quite small (KFENCE_POOL_SIZE >> PAGE_SHIFT) which is 512 bytes by default. 3. kfence pool memory is reserved using memblock_phys_alloc() which has can come from anywhere. (default 255 objects =3D> ((1+255) * 2) << PAGE_SHIFT =3D 32MB) 4. The hash slot information for kfence memory gets added in linear map in hash_linear_map_add_slot() (which also adds for debug_pagealloc). Reported-by: Pavithra Prakash Signed-off-by: Ritesh Harjani (IBM) --- arch/powerpc/include/asm/kfence.h | 5 - arch/powerpc/mm/book3s64/hash_utils.c | 162 +++++++++++++++++++++++--- 2 files changed, 149 insertions(+), 18 deletions(-) diff --git a/arch/powerpc/include/asm/kfence.h b/arch/powerpc/include/asm/k= fence.h index f3a9476a71b3..fab124ada1c7 100644 --- a/arch/powerpc/include/asm/kfence.h +++ b/arch/powerpc/include/asm/kfence.h @@ -10,7 +10,6 @@ =20 #include #include -#include =20 #ifdef CONFIG_PPC64_ELF_ABI_V1 #define ARCH_FUNC_PREFIX "." @@ -26,10 +25,6 @@ static inline void disable_kfence(void) =20 static inline bool arch_kfence_init_pool(void) { -#ifdef CONFIG_PPC64 - if (!radix_enabled()) - return false; -#endif return !kfence_disabled; } #endif diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s= 64/hash_utils.c index f51f2cd9bf22..558d6f5202b9 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -40,6 +40,7 @@ #include #include #include +#include =20 #include #include @@ -66,6 +67,7 @@ #include #include #include +#include =20 #include =20 @@ -271,7 +273,7 @@ void hash__tlbiel_all(unsigned int action) WARN(1, "%s called on pre-POWER7 CPU\n", __func__); } =20 -#ifdef CONFIG_DEBUG_PAGEALLOC +#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE) static void kernel_map_linear_page(unsigned long vaddr, unsigned long idx, u8 *slots, raw_spinlock_t *lock) { @@ -325,11 +327,13 @@ static void kernel_unmap_linear_page(unsigned long va= ddr, unsigned long idx, mmu_linear_psize, mmu_kernel_ssize, 0); } +#endif =20 +#ifdef CONFIG_DEBUG_PAGEALLOC static u8 *linear_map_hash_slots; static unsigned long linear_map_hash_count; static DEFINE_RAW_SPINLOCK(linear_map_hash_lock); -static inline void hash_debug_pagealloc_alloc_slots(void) +static void hash_debug_pagealloc_alloc_slots(void) { unsigned long max_hash_count =3D ppc64_rma_size / 4; =20 @@ -352,7 +356,8 @@ static inline void hash_debug_pagealloc_alloc_slots(voi= d) __func__, linear_map_hash_count, &ppc64_rma_size); } =20 -static inline void hash_debug_pagealloc_add_slot(phys_addr_t paddr, int sl= ot) +static inline void hash_debug_pagealloc_add_slot(phys_addr_t paddr, + int slot) { if (!debug_pagealloc_enabled() || !linear_map_hash_count) return; @@ -386,20 +391,148 @@ static int hash_debug_pagealloc_map_pages(struct pag= e *page, int numpages, return 0; } =20 -int hash__kernel_map_pages(struct page *page, int numpages, int enable) +#else /* CONFIG_DEBUG_PAGEALLOC */ +static inline void hash_debug_pagealloc_alloc_slots(void) {} +static inline void hash_debug_pagealloc_add_slot(phys_addr_t paddr, int sl= ot) {} +static int __maybe_unused +hash_debug_pagealloc_map_pages(struct page *page, int numpages, int enable) { - return hash_debug_pagealloc_map_pages(page, numpages, enable); + return 0; } +#endif /* CONFIG_DEBUG_PAGEALLOC */ =20 -#else /* CONFIG_DEBUG_PAGEALLOC */ -int hash__kernel_map_pages(struct page *page, int numpages, - int enable) +#ifdef CONFIG_KFENCE +static u8 *linear_map_kf_hash_slots; +static unsigned long linear_map_kf_hash_count; +static DEFINE_RAW_SPINLOCK(linear_map_kf_hash_lock); + +static phys_addr_t kfence_pool; + +static inline void hash_kfence_alloc_pool(void) +{ + + /* allocate linear map for kfence within RMA region */ + linear_map_kf_hash_count =3D KFENCE_POOL_SIZE >> PAGE_SHIFT; + linear_map_kf_hash_slots =3D memblock_alloc_try_nid( + linear_map_kf_hash_count, 1, + MEMBLOCK_LOW_LIMIT, ppc64_rma_size, + NUMA_NO_NODE); + if (!linear_map_kf_hash_slots) { + pr_err("%s: memblock for linear map (%lu) failed\n", __func__, + linear_map_kf_hash_count); + goto err; + } + + /* allocate kfence pool early */ + kfence_pool =3D memblock_phys_alloc_range(KFENCE_POOL_SIZE, PAGE_SIZE, + MEMBLOCK_LOW_LIMIT, MEMBLOCK_ALLOC_ANYWHERE); + if (!kfence_pool) { + pr_err("%s: memblock for kfence pool (%lu) failed\n", __func__, + KFENCE_POOL_SIZE); + memblock_free(linear_map_kf_hash_slots, + linear_map_kf_hash_count); + linear_map_kf_hash_count =3D 0; + goto err; + } + memblock_mark_nomap(kfence_pool, KFENCE_POOL_SIZE); + + return; +err: + pr_info("Disabling kfence\n"); + disable_kfence(); +} + +static inline void hash_kfence_map_pool(void) +{ + unsigned long kfence_pool_start, kfence_pool_end; + unsigned long prot =3D pgprot_val(PAGE_KERNEL); + + if (!kfence_pool) + return; + + kfence_pool_start =3D (unsigned long) __va(kfence_pool); + kfence_pool_end =3D kfence_pool_start + KFENCE_POOL_SIZE; + __kfence_pool =3D (char *) kfence_pool_start; + BUG_ON(htab_bolt_mapping(kfence_pool_start, kfence_pool_end, + kfence_pool, prot, mmu_linear_psize, + mmu_kernel_ssize)); + memblock_clear_nomap(kfence_pool, KFENCE_POOL_SIZE); +} + +static inline void hash_kfence_add_slot(phys_addr_t paddr, int slot) { + unsigned long vaddr =3D (unsigned long) __va(paddr); + unsigned long lmi =3D (vaddr - (unsigned long)__kfence_pool) + >> PAGE_SHIFT; + + if (!kfence_pool) + return; + BUG_ON(!is_kfence_address((void *)vaddr)); + BUG_ON(lmi >=3D linear_map_kf_hash_count); + linear_map_kf_hash_slots[lmi] =3D slot | 0x80; +} + +static int hash_kfence_map_pages(struct page *page, int numpages, int enab= le) +{ + unsigned long flags, vaddr, lmi; + int i; + + WARN_ON_ONCE(!linear_map_kf_hash_count); + local_irq_save(flags); + for (i =3D 0; i < numpages; i++, page++) { + vaddr =3D (unsigned long)page_address(page); + lmi =3D (vaddr - (unsigned long)__kfence_pool) >> PAGE_SHIFT; + + /* Ideally this should never happen */ + if (lmi >=3D linear_map_kf_hash_count) { + WARN_ON_ONCE(1); + continue; + } + + if (enable) + kernel_map_linear_page(vaddr, lmi, + linear_map_kf_hash_slots, + &linear_map_kf_hash_lock); + else + kernel_unmap_linear_page(vaddr, lmi, + linear_map_kf_hash_slots, + &linear_map_kf_hash_lock); + } + local_irq_restore(flags); return 0; } -static inline void hash_debug_pagealloc_alloc_slots(void) {} -static inline void hash_debug_pagealloc_add_slot(phys_addr_t paddr, int sl= ot) {} -#endif /* CONFIG_DEBUG_PAGEALLOC */ +#else +static inline void hash_kfence_alloc_pool(void) {} +static inline void hash_kfence_map_pool(void) {} +static inline void hash_kfence_add_slot(phys_addr_t paddr, int slot) {} +static int __maybe_unused +hash_kfence_map_pages(struct page *page, int numpages, int enable) +{ + return 0; +} +#endif + +#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE) +int hash__kernel_map_pages(struct page *page, int numpages, int enable) +{ + void *vaddr =3D page_address(page); + + if (is_kfence_address(vaddr)) + return hash_kfence_map_pages(page, numpages, enable); + else + return hash_debug_pagealloc_map_pages(page, numpages, enable); +} + +static void hash_linear_map_add_slot(phys_addr_t paddr, int slot) +{ + if (is_kfence_address(__va(paddr))) + hash_kfence_add_slot(paddr, slot); + else + hash_debug_pagealloc_add_slot(paddr, slot); +} +#else +static void hash_linear_map_add_slot(phys_addr_t paddr, int slot) {} +#endif =20 /* * 'R' and 'C' update notes: @@ -559,7 +692,8 @@ int htab_bolt_mapping(unsigned long vstart, unsigned lo= ng vend, break; =20 cond_resched(); - hash_debug_pagealloc_add_slot(paddr, ret); + /* add slot info in debug_pagealloc / kfence linear map */ + hash_linear_map_add_slot(paddr, ret); } return ret < 0 ? ret : 0; } @@ -940,7 +1074,7 @@ static void __init htab_init_page_sizes(void) bool aligned =3D true; init_hpte_page_sizes(); =20 - if (!debug_pagealloc_enabled()) { + if (!debug_pagealloc_enabled_or_kfence()) { /* * Pick a size for the linear mapping. Currently, we only * support 16M, 1M and 4K which is the default @@ -1261,6 +1395,7 @@ static void __init htab_initialize(void) prot =3D pgprot_val(PAGE_KERNEL); =20 hash_debug_pagealloc_alloc_slots(); + hash_kfence_alloc_pool(); /* create bolted the linear mapping in the hash table */ for_each_mem_range(i, &base, &end) { size =3D end - base; @@ -1277,6 +1412,7 @@ static void __init htab_initialize(void) BUG_ON(htab_bolt_mapping(base, base + size, __pa(base), prot, mmu_linear_psize, mmu_kernel_ssize)); } + hash_kfence_map_pool(); memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE); =20 /* --=20 2.46.0