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comment the sfences

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This commit is contained in:
Robert Morris 2022-08-24 13:47:47 -04:00
parent 581bc4cbd1
commit ed101befee
1 changed files with 9 additions and 1 deletions
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10
kernel/trampoline.S
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@ -80,10 +80,18 @@ uservec:
# load the address of usertrap(), from p->trapframe->kernel_trap # load the address of usertrap(), from p->trapframe->kernel_trap
ld t0, 16(a0) ld t0, 16(a0)
# load the kernel page table, from p->trapframe->kernel_satp
# fetch the kernel page table address, from p->trapframe->kernel_satp.
ld t1, 0(a0) ld t1, 0(a0)
# wait for any previous memory operations to complete, so that
# they use the user page table.
sfence.vma zero, zero sfence.vma zero, zero
# install the kernel page table.
csrw satp, t1 csrw satp, t1
# flush now-stale user entries from the TLB.
sfence.vma zero, zero sfence.vma zero, zero
# jump to usertrap(), which does not return # jump to usertrap(), which does not return