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    SubjectRe: [PATCH] riscv: Correct the MODULES_VADDR
    Hi Song,

    On Tue, Aug 1, 2023 at 1:10 PM Song Shuai <suagrfillet@gmail.com> wrote:
    >
    > As Documentation/riscv/vm-layout.rst describes, the 2G-sized "modules, BPF"
    > area should lie right before the "kernel" area. But the current definition
    > of MODULES_VADDR isn't consistent with that, so correct it.
    >
    > Before this patch, the size of "modules" from print_vm_layout() is not 2G.
    >
    > [ 0.000000] modules : 0xffffffff2ff2f000 - 0xffffffffae600000 (2022 MB)
    > [ 0.000000] lowmem : 0xff60000000000000 - 0xff60000040000000 (1024 MB)
    > [ 0.000000] kernel : 0xffffffffae600000 - 0xffffffffffffffff (1305 MB)
    >
    > After this patch, the size is 2G.
    >
    > [ 0.000000] modules : 0xffffffff3a000000 - 0xffffffffba000000 (2048 MB)
    > [ 0.000000] lowmem : 0xff60000000000000 - 0xff60000040000000 (1024 MB)
    > [ 0.000000] kernel : 0xffffffffba000000 - 0xffffffffffffffff (1119 MB)
    >
    > Signed-off-by: Song Shuai <suagrfillet@gmail.com>
    > ---
    > arch/riscv/include/asm/pgtable.h | 2 +-
    > 1 file changed, 1 insertion(+), 1 deletion(-)
    >
    > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
    > index 75970ee2bda2..7c57e17fc758 100644
    > --- a/arch/riscv/include/asm/pgtable.h
    > +++ b/arch/riscv/include/asm/pgtable.h
    > @@ -53,8 +53,8 @@
    > #ifdef CONFIG_64BIT
    > /* This is used to define the end of the KASAN shadow region */
    > #define MODULES_LOWEST_VADDR (KERNEL_LINK_ADDR - SZ_2G)
    > -#define MODULES_VADDR (PFN_ALIGN((unsigned long)&_end) - SZ_2G)
    > #define MODULES_END (PFN_ALIGN((unsigned long)&_start))
    > +#define MODULES_VADDR (MODULES_END - SZ_2G)
    > #endif
    >
    > /*
    > --
    > 2.20.1
    >

    The documentation is approximative, the modules must stay within a 2GB
    window to *all* the kernel symbols, hence the __end - 2G, not __start.

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