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powerpc/64s: Enable KFENCE on book3s64

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KFENCE support was added for ppc32 in commit 90cbac0e995d
("powerpc: Enable KFENCE for PPC32").
Enable KFENCE on ppc64 architecture with hash and radix MMUs.
It uses the same mechanism as debug pagealloc to
protect/unprotect pages. All KFENCE kunit tests pass on both
MMUs.

KFENCE memory is initially allocated using memblock but is
later marked as SLAB allocated. This necessitates the change
to __pud_free to ensure that the KFENCE pages are freed
appropriately.

Based on previous work by Christophe Leroy and Jordan Niethe.

Signed-off-by: Nicholas Miehlbradt <nicholas@linux.ibm.com>
Reviewed-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220926075726.2846-4-nicholas@linux.ibm.com
This commit is contained in:
Nicholas Miehlbradt 2022-09-26 07:57:26 +00:00 committed by Michael Ellerman
parent d7902d31cb
commit a5edf9815d
6 changed files with 30 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/powerpc/Kconfig
View File

@ -195,7 +195,7 @@ config PPC
select HAVE_ARCH_KASAN if PPC_RADIX_MMU select HAVE_ARCH_KASAN if PPC_RADIX_MMU
select HAVE_ARCH_KASAN if PPC_BOOK3E_64 select HAVE_ARCH_KASAN if PPC_BOOK3E_64
select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN
select HAVE_ARCH_KFENCE if PPC_BOOK3S_32 || PPC_8xx || 40x select HAVE_ARCH_KFENCE if ARCH_SUPPORTS_DEBUG_PAGEALLOC
select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET
select HAVE_ARCH_KGDB select HAVE_ARCH_KGDB
select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_BITS

6
arch/powerpc/include/asm/book3s/64/pgalloc.h
View File

@ -113,9 +113,11 @@ static inline void __pud_free(pud_t *pud)
/* /*
* Early pud pages allocated via memblock allocator * Early pud pages allocated via memblock allocator
* can't be directly freed to slab * can't be directly freed to slab. KFENCE pages have
* both reserved and slab flags set so need to be freed
* kmem_cache_free.
*/ */
if (PageReserved(page)) if (PageReserved(page) && !PageSlab(page))
free_reserved_page(page); free_reserved_page(page);
else else
kmem_cache_free(PGT_CACHE(PUD_CACHE_INDEX), pud); kmem_cache_free(PGT_CACHE(PUD_CACHE_INDEX), pud);

2
arch/powerpc/include/asm/book3s/64/pgtable.h
View File

@ -1106,7 +1106,7 @@ static inline void vmemmap_remove_mapping(unsigned long start,
} }
#endif #endif
#ifdef CONFIG_DEBUG_PAGEALLOC #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
static inline void __kernel_map_pages(struct page *page, int numpages, int enable) static inline void __kernel_map_pages(struct page *page, int numpages, int enable)
{ {
if (radix_enabled()) if (radix_enabled())

15
arch/powerpc/include/asm/kfence.h
View File

@ -11,11 +11,25 @@
#include <linux/mm.h> #include <linux/mm.h>
#include <asm/pgtable.h> #include <asm/pgtable.h>
#ifdef CONFIG_PPC64_ELF_ABI_V1
#define ARCH_FUNC_PREFIX "."
#endif
static inline bool arch_kfence_init_pool(void) static inline bool arch_kfence_init_pool(void)
{ {
return true; return true;
} }
#ifdef CONFIG_PPC64
static inline bool kfence_protect_page(unsigned long addr, bool protect)
{
struct page *page = virt_to_page(addr);
__kernel_map_pages(page, 1, !protect);
return true;
}
#else
static inline bool kfence_protect_page(unsigned long addr, bool protect) static inline bool kfence_protect_page(unsigned long addr, bool protect)
{ {
pte_t *kpte = virt_to_kpte(addr); pte_t *kpte = virt_to_kpte(addr);
@ -29,5 +43,6 @@ static inline bool kfence_protect_page(unsigned long addr, bool protect)
return true; return true;
} }
#endif
#endif /* __ASM_POWERPC_KFENCE_H */ #endif /* __ASM_POWERPC_KFENCE_H */

10
arch/powerpc/mm/book3s64/hash_utils.c
View File

@ -424,7 +424,7 @@ repeat:
break; break;
cond_resched(); cond_resched();
if (debug_pagealloc_enabled() && if (debug_pagealloc_enabled_or_kfence() &&
(paddr >> PAGE_SHIFT) < linear_map_hash_count) (paddr >> PAGE_SHIFT) < linear_map_hash_count)
linear_map_hash_slots[paddr >> PAGE_SHIFT] = ret | 0x80; linear_map_hash_slots[paddr >> PAGE_SHIFT] = ret | 0x80;
} }
@ -773,7 +773,7 @@ static void __init htab_init_page_sizes(void)
bool aligned = true; bool aligned = true;
init_hpte_page_sizes(); init_hpte_page_sizes();
if (!debug_pagealloc_enabled()) { if (!debug_pagealloc_enabled_or_kfence()) {
/* /*
* Pick a size for the linear mapping. Currently, we only * Pick a size for the linear mapping. Currently, we only
* support 16M, 1M and 4K which is the default * support 16M, 1M and 4K which is the default
@ -1061,7 +1061,7 @@ static void __init htab_initialize(void)
prot = pgprot_val(PAGE_KERNEL); prot = pgprot_val(PAGE_KERNEL);
if (debug_pagealloc_enabled()) { if (debug_pagealloc_enabled_or_kfence()) {
linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT; linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT;
linear_map_hash_slots = memblock_alloc_try_nid( linear_map_hash_slots = memblock_alloc_try_nid(
linear_map_hash_count, 1, MEMBLOCK_LOW_LIMIT, linear_map_hash_count, 1, MEMBLOCK_LOW_LIMIT,
@ -1980,7 +1980,7 @@ repeat:
return slot; return slot;
} }
#ifdef CONFIG_DEBUG_PAGEALLOC #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
static DEFINE_SPINLOCK(linear_map_hash_lock); static DEFINE_SPINLOCK(linear_map_hash_lock);
static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi) static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
@ -2053,7 +2053,7 @@ void hash__kernel_map_pages(struct page *page, int numpages, int enable)
} }
local_irq_restore(flags); local_irq_restore(flags);
} }
#endif /* CONFIG_DEBUG_PAGEALLOC */ #endif /* CONFIG_DEBUG_PAGEALLOC || CONFIG_KFENCE */
void hash__setup_initial_memory_limit(phys_addr_t first_memblock_base, void hash__setup_initial_memory_limit(phys_addr_t first_memblock_base,
phys_addr_t first_memblock_size) phys_addr_t first_memblock_size)

6
arch/powerpc/mm/book3s64/radix_pgtable.c
View File

@ -34,6 +34,8 @@
#include <trace/events/thp.h> #include <trace/events/thp.h>
#include <mm/mmu_decl.h>
unsigned int mmu_base_pid; unsigned int mmu_base_pid;
unsigned long radix_mem_block_size __ro_after_init; unsigned long radix_mem_block_size __ro_after_init;
@ -276,7 +278,7 @@ static int __meminit create_physical_mapping(unsigned long start,
int psize; int psize;
unsigned long max_mapping_size = radix_mem_block_size; unsigned long max_mapping_size = radix_mem_block_size;
if (debug_pagealloc_enabled()) if (debug_pagealloc_enabled_or_kfence())
max_mapping_size = PAGE_SIZE; max_mapping_size = PAGE_SIZE;
start = ALIGN(start, PAGE_SIZE); start = ALIGN(start, PAGE_SIZE);
@ -899,7 +901,7 @@ void __meminit radix__vmemmap_remove_mapping(unsigned long start, unsigned long
#endif #endif
#endif #endif
#ifdef CONFIG_DEBUG_PAGEALLOC #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
void radix__kernel_map_pages(struct page *page, int numpages, int enable) void radix__kernel_map_pages(struct page *page, int numpages, int enable)
{ {
unsigned long addr; unsigned long addr;