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I493SN:fix bugs introduced by I441IC

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This commit is contained in:
Wang Chen
2021-09-08 08:38:58 +08:00
parent d9f5e22e99
commit ca2629bebc
1 changed files with 9 additions and 7 deletions
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16
code/os/11-syscall/start.S
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@@ -30,14 +30,7 @@ _start:
add sp, sp, t0 # move the current hart stack pointer
# to its place in the stack space
# At the end of start_kernel, schedule() will call MRET to switch
# to the first task, so we parepare the mstatus here.
# Notice: default mstatus is 0
#ifdef CONFIG_SYSCALL
# Keep mstatus.MPP as 0, so we will run in User mode after MRET.
# Set mstatus.MPIE to 1, so MRET will enable the interrupt.
li t0, 1 << 7
# https://lore.kernel.org/qemu-devel/20201223192553.332508-1-atish.patra@wdc.com/
# For qemu version >= 6.0, exception would be raised if no PMP enty is
# configured. So just configure one entny, which allows all the whole
@@ -53,6 +46,15 @@ _start:
csrw pmpaddr0, t0
li t0, 0xf
csrw pmpcfg0, t0
#endif
# At the end of start_kernel, schedule() will call MRET to switch
# to the first task, so we parepare the mstatus here.
# Notice: default mstatus is 0
#ifdef CONFIG_SYSCALL
# Keep mstatus.MPP as 0, so we will run in User mode after MRET.
# Set mstatus.MPIE to 1, so MRET will enable the interrupt.
li t0, 1 << 7
#else
# Set mstatus.MPP to 3, so we still run in Machine mode after MRET.
# Set mstatus.MPIE to 1, so MRET will enable the interrupt.