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Message-ID: <66e9a8e0-5764-2eea-4070-bad3fb7ee48e@ghiti.fr>
Date: Fri, 23 Apr 2021 04:34:02 -0400
From: Alex Ghiti <alex@...ti.fr>
To: Anup Patel <anup@...infault.org>
Cc: Jonathan Corbet <corbet@....net>,
Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
Arnd Bergmann <arnd@...db.de>,
Andrey Ryabinin <aryabinin@...tuozzo.com>,
Alexander Potapenko <glider@...gle.com>,
Dmitry Vyukov <dvyukov@...gle.com>, linux-doc@...r.kernel.org,
linux-riscv <linux-riscv@...ts.infradead.org>,
"linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org>,
kasan-dev@...glegroups.com,
linux-arch <linux-arch@...r.kernel.org>,
Linux Memory Management List <linux-mm@...ck.org>
Subject: Re: [PATCH] riscv: Fix 32b kernel caused by 64b kernel mapping moving
outside linear mapping
Le 4/20/21 à 12:18 AM, Anup Patel a écrit :
> On Sat, Apr 17, 2021 at 10:52 PM Alexandre Ghiti <alex@...ti.fr> wrote:
>>
>> Fix multiple leftovers when moving the kernel mapping outside the linear
>> mapping for 64b kernel that left the 32b kernel unusable.
>>
>> Fixes: 4b67f48da707 ("riscv: Move kernel mapping outside of linear mapping")
>> Signed-off-by: Alexandre Ghiti <alex@...ti.fr>
>
> Quite a few #ifdef but I don't see any better way at the moment. Maybe we can
> clean this later. Otherwise looks good to me.
>
> Reviewed-by: Anup Patel <anup@...infault.org>
Thanks Anup!
@Palmer: This is not on for-next yet and then rv32 is broken. This does
not apply immediately on top of for-next though, so if you need a new
version, I can do that. But this squashes nicely with the patch it fixes
if you prefer.
Let me know, I can do that very quickly.
Alex
>
> Regards,
> Anup
>
>> ---
>> arch/riscv/include/asm/page.h | 9 +++++++++
>> arch/riscv/include/asm/pgtable.h | 16 ++++++++++++----
>> arch/riscv/mm/init.c | 25 ++++++++++++++++++++++++-
>> 3 files changed, 45 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
>> index 22cfb2be60dc..f64b61296c0c 100644
>> --- a/arch/riscv/include/asm/page.h
>> +++ b/arch/riscv/include/asm/page.h
>> @@ -90,15 +90,20 @@ typedef struct page *pgtable_t;
>>
>> #ifdef CONFIG_MMU
>> extern unsigned long va_pa_offset;
>> +#ifdef CONFIG_64BIT
>> extern unsigned long va_kernel_pa_offset;
>> +#endif
>> extern unsigned long pfn_base;
>> #define ARCH_PFN_OFFSET (pfn_base)
>> #else
>> #define va_pa_offset 0
>> +#ifdef CONFIG_64BIT
>> #define va_kernel_pa_offset 0
>> +#endif
>> #define ARCH_PFN_OFFSET (PAGE_OFFSET >> PAGE_SHIFT)
>> #endif /* CONFIG_MMU */
>>
>> +#ifdef CONFIG_64BIT
>> extern unsigned long kernel_virt_addr;
>>
>> #define linear_mapping_pa_to_va(x) ((void *)((unsigned long)(x) + va_pa_offset))
>> @@ -112,6 +117,10 @@ extern unsigned long kernel_virt_addr;
>> (_x < kernel_virt_addr) ? \
>> linear_mapping_va_to_pa(_x) : kernel_mapping_va_to_pa(_x); \
>> })
>> +#else
>> +#define __pa_to_va_nodebug(x) ((void *)((unsigned long) (x) + va_pa_offset))
>> +#define __va_to_pa_nodebug(x) ((unsigned long)(x) - va_pa_offset)
>> +#endif
>>
>> #ifdef CONFIG_DEBUG_VIRTUAL
>> extern phys_addr_t __virt_to_phys(unsigned long x);
>> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
>> index 80e63a93e903..5afda75cc2c3 100644
>> --- a/arch/riscv/include/asm/pgtable.h
>> +++ b/arch/riscv/include/asm/pgtable.h
>> @@ -16,19 +16,27 @@
>> #else
>>
>> #define ADDRESS_SPACE_END (UL(-1))
>> -/*
>> - * Leave 2GB for kernel and BPF at the end of the address space
>> - */
>> +
>> +#ifdef CONFIG_64BIT
>> +/* Leave 2GB for kernel and BPF at the end of the address space */
>> #define KERNEL_LINK_ADDR (ADDRESS_SPACE_END - SZ_2G + 1)
>> +#else
>> +#define KERNEL_LINK_ADDR PAGE_OFFSET
>> +#endif
>>
>> #define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1)
>> #define VMALLOC_END (PAGE_OFFSET - 1)
>> #define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE)
>>
>> -/* KASLR should leave at least 128MB for BPF after the kernel */
>> #define BPF_JIT_REGION_SIZE (SZ_128M)
>> +#ifdef CONFIG_64BIT
>> +/* KASLR should leave at least 128MB for BPF after the kernel */
>> #define BPF_JIT_REGION_START PFN_ALIGN((unsigned long)&_end)
>> #define BPF_JIT_REGION_END (BPF_JIT_REGION_START + BPF_JIT_REGION_SIZE)
>> +#else
>> +#define BPF_JIT_REGION_START (PAGE_OFFSET - BPF_JIT_REGION_SIZE)
>> +#define BPF_JIT_REGION_END (VMALLOC_END)
>> +#endif
>>
>> /* Modules always live before the kernel */
>> #ifdef CONFIG_64BIT
>> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
>> index 093f3a96ecfc..dc9b988e0778 100644
>> --- a/arch/riscv/mm/init.c
>> +++ b/arch/riscv/mm/init.c
>> @@ -91,8 +91,10 @@ static void print_vm_layout(void)
>> (unsigned long)VMALLOC_END);
>> print_mlm("lowmem", (unsigned long)PAGE_OFFSET,
>> (unsigned long)high_memory);
>> +#ifdef CONFIG_64BIT
>> print_mlm("kernel", (unsigned long)KERNEL_LINK_ADDR,
>> (unsigned long)ADDRESS_SPACE_END);
>> +#endif
>> }
>> #else
>> static void print_vm_layout(void) { }
>> @@ -165,9 +167,11 @@ static struct pt_alloc_ops pt_ops;
>> /* Offset between linear mapping virtual address and kernel load address */
>> unsigned long va_pa_offset;
>> EXPORT_SYMBOL(va_pa_offset);
>> +#ifdef CONFIG_64BIT
>> /* Offset between kernel mapping virtual address and kernel load address */
>> unsigned long va_kernel_pa_offset;
>> EXPORT_SYMBOL(va_kernel_pa_offset);
>> +#endif
>> unsigned long pfn_base;
>> EXPORT_SYMBOL(pfn_base);
>>
>> @@ -410,7 +414,9 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>> load_sz = (uintptr_t)(&_end) - load_pa;
>>
>> va_pa_offset = PAGE_OFFSET - load_pa;
>> +#ifdef CONFIG_64BIT
>> va_kernel_pa_offset = kernel_virt_addr - load_pa;
>> +#endif
>>
>> pfn_base = PFN_DOWN(load_pa);
>>
>> @@ -469,12 +475,16 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>> pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL);
>> dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PMD_SIZE - 1));
>> #else /* CONFIG_BUILTIN_DTB */
>> +#ifdef CONFIG_64BIT
>> /*
>> * __va can't be used since it would return a linear mapping address
>> * whereas dtb_early_va will be used before setup_vm_final installs
>> * the linear mapping.
>> */
>> dtb_early_va = kernel_mapping_pa_to_va(dtb_pa);
>> +#else
>> + dtb_early_va = __va(dtb_pa);
>> +#endif /* CONFIG_64BIT */
>> #endif /* CONFIG_BUILTIN_DTB */
>> #else
>> #ifndef CONFIG_BUILTIN_DTB
>> @@ -486,7 +496,11 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
>> pa + PGDIR_SIZE, PGDIR_SIZE, PAGE_KERNEL);
>> dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PGDIR_SIZE - 1));
>> #else /* CONFIG_BUILTIN_DTB */
>> +#ifdef CONFIG_64BIT
>> dtb_early_va = kernel_mapping_pa_to_va(dtb_pa);
>> +#else
>> + dtb_early_va = __va(dtb_pa);
>> +#endif /* CONFIG_64BIT */
>> #endif /* CONFIG_BUILTIN_DTB */
>> #endif
>> dtb_early_pa = dtb_pa;
>> @@ -571,12 +585,21 @@ static void __init setup_vm_final(void)
>> for (pa = start; pa < end; pa += map_size) {
>> va = (uintptr_t)__va(pa);
>> create_pgd_mapping(swapper_pg_dir, va, pa,
>> - map_size, PAGE_KERNEL);
>> + map_size,
>> +#ifdef CONFIG_64BIT
>> + PAGE_KERNEL
>> +#else
>> + PAGE_KERNEL_EXEC
>> +#endif
>> + );
>> +
>> }
>> }
>>
>> +#ifdef CONFIG_64BIT
>> /* Map the kernel */
>> create_kernel_page_table(swapper_pg_dir, PMD_SIZE);
>> +#endif
>>
>> /* Clear fixmap PTE and PMD mappings */
>> clear_fixmap(FIX_PTE);
>> --
>> 2.20.1
>>
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