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Date: Tue, 20 Apr 2021 09:48:26 +0530
From: Anup Patel <anup@...infault.org>
To: Alexandre Ghiti <alex@...ti.fr>
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
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>
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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