Re: [RFC PATCH] powerpc/book3e: KASAN Full support for 64bit

From: Daniel Axtens
Date: Mon Jun 03 2019 - 19:54:08 EST

Christophe Leroy <christophe.leroy@xxxxxx> writes:

> Hi,
>
> Ok, can you share your .config ?

Sure! This one is with kasan off as the last build I did was testing to
see if the code reorgisation was the cause of the issues. (it was not)

Attachment: .config
Description: .config


This was the kasan-enabled config that failed to boot:

Attachment: .config.old
Description: .config


Regards,
Daniel

>
> Christophe
>
> Le 31/05/2019 Ã 03:29, Daniel Axtens a ÃcritÂ:
>> Hi Christophe,
>>
>> I tried this on the t4240rdb and it fails to boot if KASAN is
>> enabled. It does boot with the patch applied but KASAN disabled, so that
>> narrows it down a little bit.
>>
>> I need to focus on 3s first so I'll just drop 3e from my patch set for
>> now.
>>
>> Regards,
>> Daniel
>>
>>> The KASAN shadow area is mapped into vmemmap space:
>>> 0x8000 0400 0000 0000 to 0x8000 0600 0000 0000.
>>> For this vmemmap has to be disabled.
>>>
>>> Cc: Daniel Axtens <dja@xxxxxxxxxx>
>>> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
>>> ---
>>> arch/powerpc/Kconfig | 1 +
>>> arch/powerpc/Kconfig.debug | 3 +-
>>> arch/powerpc/include/asm/kasan.h | 11 +++
>>> arch/powerpc/kernel/Makefile | 2 +
>>> arch/powerpc/kernel/head_64.S | 3 +
>>> arch/powerpc/kernel/setup_64.c | 20 +++---
>>> arch/powerpc/mm/kasan/Makefile | 1 +
>>> arch/powerpc/mm/kasan/kasan_init_64.c | 129 ++++++++++++++++++++++++++++++++++
>>> 8 files changed, 159 insertions(+), 11 deletions(-)
>>> create mode 100644 arch/powerpc/mm/kasan/kasan_init_64.c
>>>
>>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>>> index 1a2fb50126b2..e0b7c45e4dc7 100644
>>> --- a/arch/powerpc/Kconfig
>>> +++ b/arch/powerpc/Kconfig
>>> @@ -174,6 +174,7 @@ config PPC
>>> select HAVE_ARCH_AUDITSYSCALL
>>> select HAVE_ARCH_JUMP_LABEL
>>> select HAVE_ARCH_KASAN if PPC32
>>> + select HAVE_ARCH_KASAN if PPC_BOOK3E_64 && !SPARSEMEM_VMEMMAP
>>> select HAVE_ARCH_KGDB
>>> select HAVE_ARCH_MMAP_RND_BITS
>>> select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
>>> diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
>>> index 61febbbdd02b..b4140dd6b4e4 100644
>>> --- a/arch/powerpc/Kconfig.debug
>>> +++ b/arch/powerpc/Kconfig.debug
>>> @@ -370,4 +370,5 @@ config PPC_FAST_ENDIAN_SWITCH
>>> config KASAN_SHADOW_OFFSET
>>> hex
>>> depends on KASAN
>>> - default 0xe0000000
>>> + default 0xe0000000 if PPC32
>>> + default 0x6800040000000000 if PPC64
>>> diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
>>> index 296e51c2f066..756b3d58f921 100644
>>> --- a/arch/powerpc/include/asm/kasan.h
>>> +++ b/arch/powerpc/include/asm/kasan.h
>>> @@ -23,10 +23,21 @@
>>>
>>> #define KASAN_SHADOW_OFFSET ASM_CONST(CONFIG_KASAN_SHADOW_OFFSET)
>>>
>>> +#ifdef CONFIG_PPC32
>>> #define KASAN_SHADOW_END 0UL
>>>
>>> #define KASAN_SHADOW_SIZE (KASAN_SHADOW_END - KASAN_SHADOW_START)
>>>
>>> +#else
>>> +
>>> +#include <asm/pgtable.h>
>>> +
>>> +#define KASAN_SHADOW_SIZE (KERN_VIRT_SIZE >> KASAN_SHADOW_SCALE_SHIFT)
>>> +
>>> +#define KASAN_SHADOW_END (KASAN_SHADOW_START + KASAN_SHADOW_SIZE)
>>> +
>>> +#endif /* CONFIG_PPC32 */
>>> +
>>> #ifdef CONFIG_KASAN
>>> void kasan_early_init(void);
>>> void kasan_mmu_init(void);
>>> diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
>>> index 0ea6c4aa3a20..7f232c06f11d 100644
>>> --- a/arch/powerpc/kernel/Makefile
>>> +++ b/arch/powerpc/kernel/Makefile
>>> @@ -35,6 +35,8 @@ KASAN_SANITIZE_early_32.o := n
>>> KASAN_SANITIZE_cputable.o := n
>>> KASAN_SANITIZE_prom_init.o := n
>>> KASAN_SANITIZE_btext.o := n
>>> +KASAN_SANITIZE_paca.o := n
>>> +KASAN_SANITIZE_setup_64.o := n
>>>
>>> ifdef CONFIG_KASAN
>>> CFLAGS_early_32.o += -DDISABLE_BRANCH_PROFILING
>>> diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
>>> index 3fad8d499767..80fbd8024fb2 100644
>>> --- a/arch/powerpc/kernel/head_64.S
>>> +++ b/arch/powerpc/kernel/head_64.S
>>> @@ -966,6 +966,9 @@ start_here_multiplatform:
>>> * and SLB setup before we turn on relocation.
>>> */
>>>
>>> +#ifdef CONFIG_KASAN
>>> + bl kasan_early_init
>>> +#endif
>>> /* Restore parameters passed from prom_init/kexec */
>>> mr r3,r31
>>> bl early_setup /* also sets r13 and SPRG_PACA */
>>> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
>>> index ba404dd9ce1d..d2bf860dd966 100644
>>> --- a/arch/powerpc/kernel/setup_64.c
>>> +++ b/arch/powerpc/kernel/setup_64.c
>>> @@ -311,6 +311,16 @@ void __init early_setup(unsigned long dt_ptr)
>>> DBG(" -> early_setup(), dt_ptr: 0x%lx\n", dt_ptr);
>>>
>>> /*
>>> + * Configure exception handlers. This include setting up trampolines
>>> + * if needed, setting exception endian mode, etc...
>>> + */
>>> + configure_exceptions();
>>> +
>>> + /* Apply all the dynamic patching */
>>> + apply_feature_fixups();
>>> + setup_feature_keys();
>>> +
>>> + /*
>>> * Do early initialization using the flattened device
>>> * tree, such as retrieving the physical memory map or
>>> * calculating/retrieving the hash table size.
>>> @@ -325,16 +335,6 @@ void __init early_setup(unsigned long dt_ptr)
>>> setup_paca(paca_ptrs[boot_cpuid]);
>>> fixup_boot_paca();
>>>
>>> - /*
>>> - * Configure exception handlers. This include setting up trampolines
>>> - * if needed, setting exception endian mode, etc...
>>> - */
>>> - configure_exceptions();
>>> -
>>> - /* Apply all the dynamic patching */
>>> - apply_feature_fixups();
>>> - setup_feature_keys();
>>> -
>>> /* Initialize the hash table or TLB handling */
>>> early_init_mmu();
>>>
>>> diff --git a/arch/powerpc/mm/kasan/Makefile b/arch/powerpc/mm/kasan/Makefile
>>> index 6577897673dd..0bfbe3892808 100644
>>> --- a/arch/powerpc/mm/kasan/Makefile
>>> +++ b/arch/powerpc/mm/kasan/Makefile
>>> @@ -3,3 +3,4 @@
>>> KASAN_SANITIZE := n
>>>
>>> obj-$(CONFIG_PPC32) += kasan_init_32.o
>>> +obj-$(CONFIG_PPC64) += kasan_init_64.o
>>> diff --git a/arch/powerpc/mm/kasan/kasan_init_64.c b/arch/powerpc/mm/kasan/kasan_init_64.c
>>> new file mode 100644
>>> index 000000000000..7fd71b8e883b
>>> --- /dev/null
>>> +++ b/arch/powerpc/mm/kasan/kasan_init_64.c
>>> @@ -0,0 +1,129 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +
>>> +#define DISABLE_BRANCH_PROFILING
>>> +
>>> +#include <linux/kasan.h>
>>> +#include <linux/printk.h>
>>> +#include <linux/memblock.h>
>>> +#include <linux/sched/task.h>
>>> +#include <asm/pgalloc.h>
>>> +
>>> +static void __init kasan_populate_pte(pte_t *ptep, pgprot_t prot)
>>> +{
>>> + unsigned long va = (unsigned long)kasan_early_shadow_page;
>>> + phys_addr_t pa = __pa(kasan_early_shadow_page);
>>> + int i;
>>> +
>>> + for (i = 0; i < PTRS_PER_PTE; i++, ptep++)
>>> + __set_pte_at(&init_mm, va, ptep, pfn_pte(PHYS_PFN(pa), prot), 0);
>>> +}
>>> +
>>> +static void __init kasan_populate_pmd(pmd_t *pmdp)
>>> +{
>>> + int i;
>>> +
>>> + for (i = 0; i < PTRS_PER_PMD; i++)
>>> + pmd_populate_kernel(&init_mm, pmdp + i, kasan_early_shadow_pte);
>>> +}
>>> +
>>> +static void __init kasan_populate_pud(pud_t *pudp)
>>> +{
>>> + int i;
>>> +
>>> + for (i = 0; i < PTRS_PER_PUD; i++)
>>> + pud_populate(&init_mm, pudp + i, kasan_early_shadow_pmd);
>>> +}
>>> +
>>> +static void __init *kasan_alloc_pgtable(unsigned long size)
>>> +{
>>> + void *ptr = memblock_alloc_try_nid(size, size, MEMBLOCK_LOW_LIMIT,
>>> + __pa(MAX_DMA_ADDRESS), NUMA_NO_NODE);
>>> +
>>> + if (!ptr)
>>> + panic("%s: Failed to allocate %lu bytes align=0x%lx max_addr=%lx\n",
>>> + __func__, size, size, __pa(MAX_DMA_ADDRESS));
>>> +
>>> + return ptr;
>>> +}
>>> +
>>> +static int __init kasan_map_page(unsigned long va, unsigned long pa, pgprot_t prot)
>>> +{
>>> + pgd_t *pgdp = pgd_offset_k(va);
>>> + pud_t *pudp;
>>> + pmd_t *pmdp;
>>> + pte_t *ptep;
>>> +
>>> + if (pgd_none(*pgdp) || (void *)pgd_page_vaddr(*pgdp) == kasan_early_shadow_pud) {
>>> + pudp = kasan_alloc_pgtable(PUD_TABLE_SIZE);
>>> + kasan_populate_pud(pudp);
>>> + pgd_populate(&init_mm, pgdp, pudp);
>>> + }
>>> + pudp = pud_offset(pgdp, va);
>>> + if (pud_none(*pudp) || (void *)pud_page_vaddr(*pudp) == kasan_early_shadow_pmd) {
>>> + pmdp = kasan_alloc_pgtable(PMD_TABLE_SIZE);
>>> + kasan_populate_pmd(pmdp);
>>> + pud_populate(&init_mm, pudp, pmdp);
>>> + }
>>> + pmdp = pmd_offset(pudp, va);
>>> + if (!pmd_present(*pmdp) || (void *)pmd_page_vaddr(*pmdp) == kasan_early_shadow_pte) {
>>> + ptep = kasan_alloc_pgtable(PTE_TABLE_SIZE);
>>> + kasan_populate_pte(ptep, PAGE_KERNEL);
>>> + pmd_populate_kernel(&init_mm, pmdp, ptep);
>>> + }
>>> + ptep = pte_offset_kernel(pmdp, va);
>>> +
>>> + __set_pte_at(&init_mm, va, ptep, pfn_pte(pa >> PAGE_SHIFT, prot), 0);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static void __init kasan_init_region(struct memblock_region *reg)
>>> +{
>>> + void *start = __va(reg->base);
>>> + void *end = __va(reg->base + reg->size);
>>> + unsigned long k_start, k_end, k_cur;
>>> +
>>> + if (start >= end)
>>> + return;
>>> +
>>> + k_start = (unsigned long)kasan_mem_to_shadow(start);
>>> + k_end = (unsigned long)kasan_mem_to_shadow(end);
>>> +
>>> + for (k_cur = k_start; k_cur < k_end; k_cur += PAGE_SIZE) {
>>> + void *va = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
>>> +
>>> + kasan_map_page(k_cur, __pa(va), PAGE_KERNEL);
>>> + }
>>> + flush_tlb_kernel_range(k_start, k_end);
>>> +}
>>> +
>>> +void __init kasan_init(void)
>>> +{
>>> + struct memblock_region *reg;
>>> +
>>> + for_each_memblock(memory, reg)
>>> + kasan_init_region(reg);
>>> +
>>> + /* It's too early to use clear_page() ! */
>>> + memset(kasan_early_shadow_page, 0, sizeof(kasan_early_shadow_page));
>>> +
>>> + /* Enable error messages */
>>> + init_task.kasan_depth = 0;
>>> + pr_info("KASAN init done\n");
>>> +}
>>> +
>>> +/* The early shadow maps everything to a single page of zeroes */
>>> +asmlinkage void __init kasan_early_init(void)
>>> +{
>>> + unsigned long addr = KASAN_SHADOW_START;
>>> + unsigned long end = KASAN_SHADOW_END;
>>> + pgd_t *pgdp = pgd_offset_k(addr);
>>> +
>>> + kasan_populate_pte(kasan_early_shadow_pte, PAGE_KERNEL);
>>> + kasan_populate_pmd(kasan_early_shadow_pmd);
>>> + kasan_populate_pud(kasan_early_shadow_pud);
>>> +
>>> + do {
>>> + pgd_populate(&init_mm, pgdp, kasan_early_shadow_pud);
>>> + } while (pgdp++, addr = pgd_addr_end(addr, end), addr != end);
>>> +}
>>> --
>>> 2.13.3