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sfence.vma in trampoline as well

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This commit is contained in:
Robert Morris 2019-09-03 16:29:48 -04:00
parent 9b9e2dd0f2
commit 25e113138d
2 changed files with 7 additions and 5 deletions
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4
kernel/main.c
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@ -13,7 +13,9 @@ main()
if(cpuid() == 0){
consoleinit();
printfinit();
printf("hart %d starting\n", cpuid());
printf("\n");
printf("xv6 kernel is booting\n");
printf("\n");
kinit(); // physical page allocator
kvminit(); // create kernel page table
kvminithart(); // turn on paging

8
kernel/trampoline.S
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@ -75,8 +75,8 @@ uservec:
# restore kernel page table from p->tf->kernel_satp
ld t1, 0(a0)
sfence.vma zero, zero
csrw satp, t1
sfence.vma zero, zero
# a0 is no longer valid, since the kernel page
# table does not specially map p->td.
@ -89,12 +89,12 @@ userret:
# userret(TRAPFRAME, pagetable)
# switch from kernel to user.
# usertrapret() calls here.
# a0: TRAPFRAME, in user page table
# a0: TRAPFRAME, in user page table
# a1: user page table, for satp
# switch to the user page table.
sfence.vma zero, zero
# switch to the user page table.
csrw satp, a1
sfence.vma zero, zero
# put the saved user a0 in sscratch, so we
# can swap it with our a0 (TRAPFRAME) in the last step.