| 220,10 → 220,11 |
|---|
| .macro handler i n |
| |
| /* |
| * Choose between version with error code and version without error code. |
| * Both versions have to be of the same size. amd64 assembly is, however, |
| * a little bit tricky. For instance, subq $0x80, %rsp and subq $0x78, %rsp |
| * can result in two instructions with different op-code lengths. |
| * Choose between version with error code and version without error |
| * code. Both versions have to be of the same size. amd64 assembly is, |
| * however, a little bit tricky. For instance, subq $0x80, %rsp and |
| * subq $0x78, %rsp can result in two instructions with different |
| * op-code lengths. |
| * Therefore we align the interrupt handlers. |
| */ |
| |
| 269,34 → 270,53 |
|---|
| handler 0 IDT_ITEMS |
| h_end: |
| |
| |
| ## Low-level syscall handler |
| # |
| # Registers on entry: |
| # |
| # @param rcx Userspace return address. |
| # @param r11 Userspace RLFAGS. |
| # |
| # @param rax Syscall number. |
| # @param rdi 1st syscall argument. |
| # @param rsi 2nd syscall argument. |
| # @param rdx 3rd syscall argument. |
| # @param r10 4th syscall argument. Used instead of RCX because the |
| # SYSCALL instruction clobbers it. |
| # @param r8 5th syscall argument. |
| # @param r9 6th syscall argument. |
| # |
| # @return Return value is in rax. |
| # |
| syscall_entry: |
| # Switch to hidden gs |
| swapgs |
| # %gs:0 now points to pointer to stack page |
| mov %gs:0, %r10 # We have a ptr to stack page in r10 |
| addq $PAGE_SIZE-16, %r10 # We need some space to store old %sp |
| swapgs # Switch to hidden gs |
| # |
| # %gs:0 Scratch space for this thread's user RSP |
| # %gs:8 Address to be used as this thread's kernel RSP |
| # |
| movq %rsp, %gs:0 # Save this thread's user RSP |
| movq %gs:8, %rsp # Set this thread's kernel RSP |
| swapgs # Switch back to remain consistent |
| sti |
| |
| movq %rsp, 0(%r10) # Save old stack pointer to stack |
| movq %r10, %rsp # Change to new stack |
| pushq %rcx # Return address |
| pushq %r11 # Save flags |
| pushq %rcx |
| pushq %r11 |
| |
| # Switch back to remain consistent |
| swapgs |
| |
| sti |
| movq %r9, %rcx # Exchange last parameter as a third |
| |
| movq %r10, %rcx # Copy the 4th argument where it is expected |
| pushq %rax |
| call syscall_handler |
| cli # We will be touching stack pointer |
| addq $8, %rsp |
| |
| popq %r11 |
| popq %rcx |
| movq 0(%rsp), %rsp |
| |
| cli |
| swapgs |
| movq %gs:0, %rsp # Restore the user RSP |
| swapgs |
| |
| sysretq |
| |
| |
| |
| .data |
| .global interrupt_handler_size |
| |