diff options
Diffstat (limited to 'trapasm.S')
| -rw-r--r-- | trapasm.S | 150 |
1 files changed, 127 insertions, 23 deletions
@@ -1,32 +1,136 @@ +#include "param.h" +#include "x86.h" #include "mmu.h" - - # vectors.S sends all traps here. + +# vectors.S sends all traps here. .globl alltraps alltraps: # Build trap frame. - pushl %ds - pushl %es - pushl %fs - pushl %gs - pushal - - # Set up data segments. - movw $(SEG_KDATA<<3), %ax - movw %ax, %ds - movw %ax, %es + push %r15 + push %r14 + push %r13 + push %r12 + push %r11 + push %r10 + push %r9 + push %r8 + push %rdi + push %rsi + push %rbp + push %rdx + push %rcx + push %rbx + push %rax - # Call trap(tf), where tf=%esp - pushl %esp + cmpw $KCSEG, 32(%rsp) # compare to saved cs + jz 1f + swapgs + +1:mov %rsp, %rdi # frame in arg1 call trap - addl $4, %esp - # Return falls through to trapret... +# Return falls through to trapret... .globl trapret trapret: - popal - popl %gs - popl %fs - popl %es - popl %ds - addl $0x8, %esp # trapno and errcode - iret + cli + cmpw $KCSEG, 32(%rsp) # compare to saved cs + jz 1f + swapgs + +1:pop %rax + pop %rbx + pop %rcx + pop %rdx + pop %rbp + pop %rsi + pop %rdi + pop %r8 + pop %r9 + pop %r10 + pop %r11 + pop %r12 + pop %r13 + pop %r14 + pop %r15 + + add $16, %rsp # discard trapnum and errorcode + iretq +#PAGEBREAK! + +# syscall_entry jumps here after syscall instruction +.globl sysentry +sysentry: # Build trap frame. + // load kernel stack address + swapgs + movq %rax, %gs:0 // save %rax in syscallno of cpu entry + movq %rsp, %gs:8 // user sp + movq %gs:16, %rax // proc entry + + movq %ss:0(%rax), %rax // load kstack from proc + addq $(KSTACKSIZE), %rax + + movq %rax, %rsp + movq %gs:0, %rax // restore rax + + // push usp + push $0 + push %gs:8 + // safe eflags and eip + push %r11 + push $UCSEG + push %rcx + // push errno and trapno to make stack look like a trap + push $0 + push $64 + + // push values on kernel stack + push %r15 + push %r14 + push %r13 + push %r12 + push %r11 + push %r10 + push %r9 + push %r8 + push %rdi + push %rsi + push %rbp + push %rdx + push %rcx + push %rbx + push %rax + + mov %rsp, %rdi # frame in arg1 + + call trap +#PAGEBREAK! + +# Return falls through to trapret... +.globl sysexit +sysexit: + # to make sure we don't get any interrupts on the user stack while in + # supervisor mode. insufficient? (see vunerability reports for sysret) + cli + + pop %rax + pop %rbx + pop %rcx + pop %rdx + pop %rbp + pop %rsi + pop %rdi + pop %r8 + pop %r9 + pop %r10 + pop %r11 + pop %r12 + pop %r13 + pop %r14 + pop %r15 + + add $(5*8), %rsp # discard trapnum, errorcode, rip, cs and rflags + mov (%rsp),%rsp # switch to the user stack + swapgs + + sysretq + |