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    Subject[PATCH v6 1/2] riscv: move sbi_init() earlier before jump_label_init()
    Date
    We call jump_label_init() in setup_arch() is to use static key
    mechanism earlier, but riscv jump label relies on the sbi functions,
    If we enable static key before sbi_init(), the code path looks like:
    static_branch_enable()
    ..
    arch_jump_label_transform()
    patch_text_nosync()
    flush_icache_range()
    flush_icache_all()
    sbi_remote_fence_i() for CONFIG_RISCV_SBI case
    __sbi_rfence()

    Since sbi isn't initialized, so NULL deference! Here is a typical
    panic log:

    [ 0.000000] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
    [ 0.000000] Oops [#1]
    [ 0.000000] Modules linked in:
    [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.18.0-rc7+ #79
    [ 0.000000] Hardware name: riscv-virtio,qemu (DT)
    [ 0.000000] epc : 0x0
    [ 0.000000] ra : sbi_remote_fence_i+0x1e/0x26
    [ 0.000000] epc : 0000000000000000 ra : ffffffff80005826 sp : ffffffff80c03d50
    [ 0.000000] gp : ffffffff80ca6178 tp : ffffffff80c0ad80 t0 : 6200000000000000
    [ 0.000000] t1 : 0000000000000000 t2 : 62203a6b746e6972 s0 : ffffffff80c03d60
    [ 0.000000] s1 : ffffffff80001af6 a0 : 0000000000000000 a1 : 0000000000000000
    [ 0.000000] a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000
    [ 0.000000] a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000000080200
    [ 0.000000] s2 : ffffffff808b3e48 s3 : ffffffff808bf698 s4 : ffffffff80cb2818
    [ 0.000000] s5 : 0000000000000001 s6 : ffffffff80c9c345 s7 : ffffffff80895aa0
    [ 0.000000] s8 : 0000000000000001 s9 : 000000000000007f s10: 0000000000000000
    [ 0.000000] s11: 0000000000000000 t3 : ffffffff80824d08 t4 : 0000000000000022
    [ 0.000000] t5 : 000000000000003d t6 : 0000000000000000
    [ 0.000000] status: 0000000000000100 badaddr: 0000000000000000 cause: 000000000000000c
    [ 0.000000] ---[ end trace 0000000000000000 ]---
    [ 0.000000] Kernel panic - not syncing: Attempted to kill the idle task!
    [ 0.000000] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---

    Fix this issue by moving sbi_init() earlier before jump_label_init()

    Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
    Reviewed-by: Anup Patel <anup@brainfault.org>
    Reviewed-by: Atish Patra <atishp@rivosinc.com>
    ---
    arch/riscv/kernel/setup.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
    index f0f36a4a0e9b..f5762f7b982d 100644
    --- a/arch/riscv/kernel/setup.c
    +++ b/arch/riscv/kernel/setup.c
    @@ -269,6 +269,7 @@ void __init setup_arch(char **cmdline_p)
    *cmdline_p = boot_command_line;

    early_ioremap_setup();
    + sbi_init();
    jump_label_init();
    parse_early_param();

    @@ -285,7 +286,6 @@ void __init setup_arch(char **cmdline_p)
    misc_mem_init();

    init_resources();
    - sbi_init();

    #ifdef CONFIG_KASAN
    kasan_init();
    --
    2.34.1
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