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    SubjectRe: [RFC PATCH] powerpc/book3e: KASAN Full support for 64bit
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    On 06/03/2019 11:50 PM, Daniel Axtens wrote:
    > Christophe Leroy <christophe.leroy@c-s.fr> 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)
    >
    >
    >
    >
    > This was the kasan-enabled config that failed to boot:
    >
    >

    Same issue with your .config under QEMU:

    A go with gdb shows:

    Breakpoint 3, 0xc000000000027b6c in exc_0x700_common ()
    => 0xc000000000027b6c <exc_0x700_common+0>: f8 01 00 70 std r0,112(r1)
    (gdb) bt
    #0 0xc000000000027b6c in exc_0x700_common ()
    #1 0xc00000000136f80c in .udbg_init_memcons ()


    Without CONFIG_PPC_EARLY_DEBUG, it boots fine for me. Can you check on
    your side ?

    Deactivating KASAN for arch/powerpc/kernel/udbg.o and
    arch/powerpc/sysdev/udbg_memcons.o is not enough, we hit a call to
    strstr() in register_early_udbg_console(), and once we get rid of it (in
    the same way as in prom_init.c) the next issue is register_console() and
    I don't know what to do about that one.

    Christophe

    >
    >
    > Regards,
    > Daniel
    >
    >>
    >> Christophe
    >>
    >> Le 31/05/2019 à 03:29, Daniel Axtens a écrit :
    >>> 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@axtens.net>
    >>>> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
    >>>> ---
    >>>> 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
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