• Greentime Hu's avatar
    riscv: uaccess should be used in nommu mode · adccfb1a
    Greentime Hu authored
    It might have the unaligned access exception when trying to exchange data
    with user space program. In this case, it failed in tty_ioctl(). Therefore
    we should enable uaccess.S for NOMMU mode since the generic code doesn't
    handle the unaligned access cases.
    
       0x8013a212 <tty_ioctl+462>:  ld      a5,460(s1)
    
    [    0.115279] Oops - load address misaligned [#1]
    [    0.115284] CPU: 0 PID: 29 Comm: sh Not tainted 5.4.0-rc5-00020-gb4c27160d562-dirty #36
    [    0.115294] epc: 000000008013a212 ra : 000000008013a212 sp : 000000008f48dd50
    [    0.115303]  gp : 00000000801cac28 tp : 000000008fb80000 t0 : 00000000000000e8
    [    0.115312]  t1 : 000000008f58f108 t2 : 0000000000000009 s0 : 000000008f48ddf0
    [    0.115321]  s1 : 000000008f8c6220 a0 : 0000000000000001 a1 : 000000008f48dd28
    [    0.115330]  a2 : 000000008fb80000 a3 : 00000000801a7398 a4 : 0000000000000000
    [    0.115339]  a5 : 0000000000000000 a6 : 000000008f58f0c6 a7 : 000000000000001d
    [    0.115348]  s2 : 000000008f8c6308 s3 : 000000008f78b7c8 s4 : 000000008fb834c0
    [    0.115357]  s5 : 0000000000005413 s6 : 0000000000000000 s7 : 000000008f58f2b0
    [    0.115366]  s8 : 000000008f858008 s9 : 000000008f776818 s10: 000000008f776830
    [    0.115375]  s11: 000000008fb840a8 t3 : 1999999999999999 t4 : 000000008f78704c
    [    0.115384]  t5 : 0000000000000005 t6 : 0000000000000002
    [    0.115391] status: 0000000200001880 badaddr: 000000008f8c63ec cause: 0000000000000004
    [    0.115401] ---[ end trace 00d490c6a8b6c9ac ]---
    
    This failure could be fixed after this patch applied.
    
    [    0.002282] Run /init as init process
    Initializing random number generator... [    0.005573] random: dd: uninitialized urandom read (512 bytes read)
    done.
    
    Welcome to Buildroot
    buildroot login: root
    Password:
    Jan  1 00:00:00 login[62]: root login on 'ttySIF0'
    ~ #
    Signed-off-by: default avatarGreentime Hu <greentime.hu@sifive.com>
    Reviewed-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
    Signed-off-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
    adccfb1a
uaccess.h 13.4 KB