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| author | Robert Morris <rtm@csail.mit.edu> | 2019-06-01 05:33:38 -0400 |
|---|---|---|
| committer | Robert Morris <rtm@csail.mit.edu> | 2019-06-01 05:33:38 -0400 |
| commit | 50cbc7510250a64674d619d13f5912edf08b767d (patch) | |
| tree | 874895d11adb72fed959619d85596b062260276f /trampoline.S | |
| parent | 7fd1f1eb0aab4d52852fc4f5e83eafc991f9a627 (diff) | |
| download | xv6-labs-50cbc7510250a64674d619d13f5912edf08b767d.tar.gz xv6-labs-50cbc7510250a64674d619d13f5912edf08b767d.tar.bz2 xv6-labs-50cbc7510250a64674d619d13f5912edf08b767d.zip | |
first shell prints $ prompt, though no console input yet
Diffstat (limited to 'trampoline.S')
| -rw-r--r-- | trampoline.S | 116 |
1 files changed, 71 insertions, 45 deletions
diff --git a/trampoline.S b/trampoline.S index 109dd93..5886942 100644 --- a/trampoline.S +++ b/trampoline.S @@ -5,14 +5,15 @@ # in user and kernel space so that it can switch # page tables. # - # kernel.ld causes trampstart to be aligned + # kernel.ld causes trampout to be aligned # to a page boundary. # .globl usertrap .section trampoline -.globl trampstart -trampstart: +.globl trampout +trampout: # switch from kernel to user. + # usertrapret() calls here. # a0: p->tf in user page table # a1: new value for satp, for user page table @@ -21,28 +22,40 @@ trampstart: # put the saved user a0 in sscratch, so we # can swap it with our a0 (p->tf) in the last step. - ld t0, 80(a0) + ld t0, 112(a0) csrw sscratch, t0 # restore all but a0 from p->tf - ld ra, 32(a0) - ld sp, 40(a0) - ld gp, 48(a0) - ld tp, 56(a0) - ld t0, 64(a0) - ld t1, 72(a0) - ld t2, 80(a0) - ld a1, 96(a0) - ld a2, 104(a0) - ld a3, 112(a0) - ld a4, 120(a0) - ld a5, 128(a0) - ld a6, 136(a0) - ld a7, 144(a0) - ld t3, 152(a0) - ld t4, 160(a0) - ld t5, 168(a0) - ld t6, 176(a0) + ld ra, 40(a0) + ld sp, 48(a0) + ld gp, 56(a0) + ld tp, 64(a0) + ld t0, 72(a0) + ld t1, 80(a0) + ld t2, 88(a0) + ld s0, 96(a0) + ld s1, 104(a0) + ld a1, 120(a0) + ld a2, 128(a0) + ld a3, 136(a0) + ld a4, 144(a0) + ld a5, 152(a0) + ld a6, 160(a0) + ld a7, 168(a0) + ld s2, 176(a0) + ld s3, 184(a0) + ld s4, 192(a0) + ld s5, 200(a0) + ld s6, 208(a0) + ld s7, 216(a0) + ld s8, 224(a0) + ld s9, 232(a0) + ld s10, 240(a0) + ld s11, 248(a0) + ld t3, 256(a0) + ld t4, 264(a0) + ld t5, 272(a0) + ld t6, 280(a0) # restore user a0, and save p->tf csrrw a0, sscratch, a0 @@ -51,45 +64,58 @@ trampstart: # caller has set up sstatus and sepc. sret +.align 4 +.globl trampin +trampin: # # trap.c set stvec to point here, so - # interrupts and exceptions start here, + # user interrupts and exceptions start here, # in supervisor mode, but with a # user page table. # # sscratch points to where the process's p->tf is # mapped into user space (TRAMPOLINE - 4096). # -.align 4 -.globl trampvec -trampvec: + # swap a0 and sscratch # so that a0 is p->tf csrrw a0, sscratch, a0 # save the user registers in p->tf - sd ra, 32(a0) - sd sp, 40(a0) - sd gp, 48(a0) - sd tp, 56(a0) - sd t0, 64(a0) - sd t1, 72(a0) - sd t2, 80(a0) - sd a1, 96(a0) - sd a2, 104(a0) - sd a3, 112(a0) - sd a4, 120(a0) - sd a5, 128(a0) - sd a6, 136(a0) - sd a7, 144(a0) - sd t3, 152(a0) - sd t4, 160(a0) - sd t5, 168(a0) - sd t6, 176(a0) + sd ra, 40(a0) + sd sp, 48(a0) + sd gp, 56(a0) + sd tp, 64(a0) + sd t0, 72(a0) + sd t1, 80(a0) + sd t2, 88(a0) + sd s0, 96(a0) + sd s1, 104(a0) + sd a1, 120(a0) + sd a2, 128(a0) + sd a3, 136(a0) + sd a4, 144(a0) + sd a5, 152(a0) + sd a6, 160(a0) + sd a7, 168(a0) + sd s2, 176(a0) + sd s3, 184(a0) + sd s4, 192(a0) + sd s5, 200(a0) + sd s6, 208(a0) + sd s7, 216(a0) + sd s8, 224(a0) + sd s9, 232(a0) + sd s10, 240(a0) + sd s11, 248(a0) + sd t3, 256(a0) + sd t4, 264(a0) + sd t5, 272(a0) + sd t6, 280(a0) # save the user a0 in p->tf->a0 csrr t0, sscratch - sd t0, 80(a0) + sd t0, 112(a0) # restore kernel stack pointer from p->tf->kernel_sp ld sp, 8(a0) |