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SubjectRe: [PATCH] riscv: Get rid of MAX_EARLY_MAPPING_SIZE
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Le 2/22/21 à 12:40 AM, Alex Ghiti a écrit :
> Hi Dmitry,
>
> Le 2/21/21 à 10:38 AM, Dmitry Vyukov a écrit :
>> On Sun, Feb 21, 2021 at 3:22 PM Alexandre Ghiti <alex@ghiti.fr> wrote:
>>>
>>> At early boot stage, we have a whole PGDIR to map the kernel, so there
>>> is no need to restrict the early mapping size to 128MB. Removing this
>>> define also allows us to simplify some compile time logic.
>>>
>>> This fixes large kernel mappings with a size greater than 128MB, as it
>>> is the case for syzbot kernels whose size was just ~130MB.
>>>
>>> Note that on rv64, for now, we are then limited to PGDIR size for early
>>> mapping as we can't use PGD mappings (see [1]). That should be enough
>>> given the relative small size of syzbot kernels compared to PGDIR_SIZE
>>> which is 1GB.
>>>
>>> [1] https://lore.kernel.org/lkml/20200603153608.30056-1-alex@ghiti.fr/
>>
>> I've applied this patch to (as it contains the HEAD fix):
>>
>> commit f49815047c1a3e3644a0ba38f3825c5cde8a0922 (HEAD, riscv/for-next)
>> Author: Tobias Klauser <tklauser@distanz.ch>
>> Date:   Tue Feb 16 18:33:05 2021 +0100
>>      riscv: Disable KSAN_SANITIZE for vDSO
>>
>> and the kernel started booting with my large config.
>> It quickly crashed (see below), but at least it started booting, so
>> it's an improvement.
>>
>> Tested-by: Dmitry Vyukov <dvyukov@google.com>
>
> Thanks for that.
>
>>
>> Linux version 5.11.0-rc2-00069-gf49815047c1a-dirty
>> (dvyukov@dvyukov-desk.muc.corp.google.com) (riscv64-linux-gnu-gcc
>> (Debian 10.2.1-6+build1) 10.2.1 20210110, GNU ld (GNU Binutils for
>> Debian) 2.35.1) #34 SMP PREEMPT Sun Feb 21 15:51:40 CET 2021
>> OF: fdt: Ignoring memory range 0x80000000 - 0x80200000
>> Machine model: riscv-virtio,qemu
>> earlycon: ns16550a0 at MMIO 0x0000000010000000 (options '')
>> printk: bootconsole [ns16550a0] enabled
>> efi: UEFI not found.
>> cma: Reserved 16 MiB at 0x00000000fec00000
>> Zone ranges:
>>    DMA32    [mem 0x0000000080200000-0x00000000ffffffff]
>>    Normal   empty
>> Movable zone start for each node
>> Early memory node ranges
>>    node   0: [mem 0x0000000080200000-0x00000000ffffffff]
>> Zeroed struct page in unavailable ranges: 512 pages
>> Initmem setup node 0 [mem 0x0000000080200000-0x00000000ffffffff]
>> SBI specification v0.2 detected
>> SBI implementation ID=0x1 Version=0x8
>> SBI v0.2 TIME extension detected
>> SBI v0.2 IPI extension detected
>> SBI v0.2 RFENCE extension detected
>> software IO TLB: mapped [mem 0x00000000f7c00000-0x00000000fbc00000]
>> (64MB)
>> ------------[ cut here ]------------
>> DEBUG_LOCKS_WARN_ON(early_boot_irqs_disabled)
>> WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:4085
>> lockdep_hardirqs_on_prepare+0x384/0x388 kernel/locking/lockdep.c:4085
>> Modules linked in:
>> CPU: 0 PID: 0 Comm: swapper Not tainted
>> 5.11.0-rc2-00069-gf49815047c1a-dirty #34
>> Hardware name: riscv-virtio,qemu (DT)
>> epc : lockdep_hardirqs_on_prepare+0x384/0x388
>> kernel/locking/lockdep.c:4085
>>   ra : lockdep_hardirqs_on_prepare+0x384/0x388
>> kernel/locking/lockdep.c:4085
>> epc : ffffffe0000c125a ra : ffffffe0000c125a sp : ffffffe006603ce0
>>   gp : ffffffe006c338f0 tp : ffffffe006689e00 t0 : ffffffe00669a9a8
>>   t1 : ffffffc400cc0738 t2 : 0000000000000000 s0 : ffffffe006603d20
>>   s1 : ffffffe006689e00 a0 : 000000000000002d a1 : 00000000000f0000
>>   a2 : 0000000000000002 a3 : ffffffe0000d2718 a4 : 0000000000000000
>>   a5 : 0000000000000000 a6 : 0000000000f00000 a7 : ffffffe0066039c7
>>   s2 : ffffffe004a337c0 s3 : ffffffe0076fa1b8 s4 : 0000000000000000
>>   s5 : ffffffe006689e00 s6 : 0000000000000001 s7 : ffffffe07fcfc000
>>   s8 : ffffffe07fcfd000 s9 : ffffffe006c3c0d0 s10: fffffffffffff000
>>   s11: ffffffe004a1fbb8 t3 : 000000002d2d2d2d t4 : ffffffc400cc0737
>>   t5 : ffffffc400cc0739 t6 : ffffffe0066039c8
>> status: 0000000000000100 badaddr: 0000000000000000 cause:
>> 0000000000000003
>> Call Trace:
>> [<ffffffe0000c125a>] lockdep_hardirqs_on_prepare+0x384/0x388
>> kernel/locking/lockdep.c:4085
>> [<ffffffe0001b7dc0>] trace_hardirqs_on+0x116/0x174
>> kernel/trace/trace_preemptirq.c:49
>> [<ffffffe00000550a>] _save_context+0xa2/0xe2
>> [<ffffffe004807908>] local_flush_tlb_all
>> arch/riscv/include/asm/tlbflush.h:16 [inline]
>> [<ffffffe004807908>] populate arch/riscv/mm/kasan_init.c:95 [inline]
>> [<ffffffe004807908>] kasan_init+0x23e/0x31a
>> arch/riscv/mm/kasan_init.c:157
>> irq event stamp: 0
>> hardirqs last  enabled at (0): [<0000000000000000>] 0x0
>> hardirqs last disabled at (0): [<0000000000000000>] 0x0
>> softirqs last  enabled at (0): [<0000000000000000>] 0x0
>> softirqs last disabled at (0): [<0000000000000000>] 0x0
>> random: get_random_bytes called from init_oops_id kernel/panic.c:546
>> [inline] with crng_init=0
>> random: get_random_bytes called from init_oops_id kernel/panic.c:543
>> [inline] with crng_init=0
>> random: get_random_bytes called from print_oops_end_marker
>> kernel/panic.c:556 [inline] with crng_init=0
>> random: get_random_bytes called from __warn+0x1be/0x20a
>> kernel/panic.c:613 with crng_init=0
>> ---[ end trace 0000000000000000 ]---
>> Unable to handle kernel paging request at virtual address
>> dfffffc810040000
>> Oops [#1]
>> Modules linked in:
>> CPU: 0 PID: 0 Comm: swapper Tainted: G        W
>> 5.11.0-rc2-00069-gf49815047c1a-dirty #34
>> Hardware name: riscv-virtio,qemu (DT)
>> epc : __memset+0x60/0xfc arch/riscv/lib/memset.S:67
>>   ra : populate arch/riscv/mm/kasan_init.c:96 [inline]
>>   ra : kasan_init+0x256/0x31a arch/riscv/mm/kasan_init.c:157
>> epc : ffffffe001791cf0 ra : ffffffe004807920 sp : ffffffe006603e80
>>   gp : ffffffe006c338f0 tp : ffffffe006689e00 t0 : dfffffc810040000
>>   t1 : ffffffe004a1fc80 t2 : 0000000000000000 s0 : ffffffe006603f30
>>   s1 : 0000000000000001 a0 : dfffffc810040000 a1 : 0000000000000000
>>   a2 : 000000000ffc0000 a3 : dfffffc820000000 a4 : 0000000000000000
>>   a5 : dfffffc820000000 a6 : 0000000000f00000 a7 : ffffffe004a1fcaf
>>   s2 : dfffffc810040000 s3 : 000000000000ffc0 s4 : dfffffc800000000
>>   s5 : ffffffe006c46908 s6 : 0000000000000001 s7 : ffffffe07fcfc000
>>   s8 : ffffffe07fcfd000 s9 : ffffffe006c3c0d0 s10: fffffffffffff000
>>   s11: ffffffe004a1fbb8 t3 : 0000000000000000 t4 : 0000000000000001
>>   t5 : ffffffc400943f96 t6 : ffffffe006603b98
>> status: 0000000000000100 badaddr: dfffffc810040000 cause:
>> 000000000000000f
>> Call Trace:
>> [<ffffffe001791cf0>] __memset+0x60/0xfc arch/riscv/lib/memset.S:65
>> [<ffffffe004805e7a>] setup_arch+0x6c4/0x6f2 arch/riscv/kernel/setup.c:271
>> [<ffffffe0048010ea>] start_kernel+0xca/0x5d6 init/main.c:871
>> ---[ end trace f68728a0d3053b52 ]---
>>
>>
>
> Ok this issue lies in for-next as I had no problem getting to init on
> both master and my sv48 patchset, I'm taking a look at that !
>
> Thanks,
>
> Alex
>

I fixed that in my patch "riscv: Pass virtual addresses to
kasan_mem_to_shadow", it should hopefully be ok now, I was able to boot
correctly to userspace with this.

Thanks again,

Alex

>>
>>
>>
>>> Reported-by: Dmitry Vyukov <dvyukov@google.com>
>>> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
>>> ---
>>>   arch/riscv/mm/init.c | 21 +++++----------------
>>>   1 file changed, 5 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
>>> index f9f9568d689e..f81f813b9603 100644
>>> --- a/arch/riscv/mm/init.c
>>> +++ b/arch/riscv/mm/init.c
>>> @@ -226,8 +226,6 @@ pgd_t swapper_pg_dir[PTRS_PER_PGD]
>>> __page_aligned_bss;
>>>   pgd_t trampoline_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
>>>   pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
>>>
>>> -#define MAX_EARLY_MAPPING_SIZE SZ_128M
>>> -
>>>   pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
>>>
>>>   void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys,
>>> pgprot_t prot)
>>> @@ -302,13 +300,7 @@ static void __init create_pte_mapping(pte_t *ptep,
>>>
>>>   pmd_t trampoline_pmd[PTRS_PER_PMD] __page_aligned_bss;
>>>   pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
>>> -
>>> -#if MAX_EARLY_MAPPING_SIZE < PGDIR_SIZE
>>> -#define NUM_EARLY_PMDS         1UL
>>> -#else
>>> -#define NUM_EARLY_PMDS         (1UL + MAX_EARLY_MAPPING_SIZE /
>>> PGDIR_SIZE)
>>> -#endif
>>> -pmd_t early_pmd[PTRS_PER_PMD * NUM_EARLY_PMDS] __initdata
>>> __aligned(PAGE_SIZE);
>>> +pmd_t early_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
>>>   pmd_t early_dtb_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
>>>
>>>   static pmd_t *__init get_pmd_virt_early(phys_addr_t pa)
>>> @@ -330,11 +322,9 @@ static pmd_t *get_pmd_virt_late(phys_addr_t pa)
>>>
>>>   static phys_addr_t __init alloc_pmd_early(uintptr_t va)
>>>   {
>>> -       uintptr_t pmd_num;
>>> +       BUG_ON((va - PAGE_OFFSET) >> PGDIR_SHIFT);
>>>
>>> -       pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT;
>>> -       BUG_ON(pmd_num >= NUM_EARLY_PMDS);
>>> -       return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD];
>>> +       return (uintptr_t)early_pmd;
>>>   }
>>>
>>>   static phys_addr_t __init alloc_pmd_fixmap(uintptr_t va)
>>> @@ -452,7 +442,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>>          uintptr_t va, pa, end_va;
>>>          uintptr_t load_pa = (uintptr_t)(&_start);
>>>          uintptr_t load_sz = (uintptr_t)(&_end) - load_pa;
>>> -       uintptr_t map_size = best_map_size(load_pa,
>>> MAX_EARLY_MAPPING_SIZE);
>>> +       uintptr_t map_size;
>>>   #ifndef __PAGETABLE_PMD_FOLDED
>>>          pmd_t fix_bmap_spmd, fix_bmap_epmd;
>>>   #endif
>>> @@ -464,12 +454,11 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>>>           * Enforce boot alignment requirements of RV32 and
>>>           * RV64 by only allowing PMD or PGD mappings.
>>>           */
>>> -       BUG_ON(map_size == PAGE_SIZE);
>>> +       map_size = PMD_SIZE;
>>>
>>>          /* Sanity check alignment and size */
>>>          BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
>>>          BUG_ON((load_pa % map_size) != 0);
>>> -       BUG_ON(load_sz > MAX_EARLY_MAPPING_SIZE);
>>>
>>>          pt_ops.alloc_pte = alloc_pte_early;
>>>          pt_ops.get_pte_virt = get_pte_virt_early;
>>> --
>>> 2.20.1
>>>
>>
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>>

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