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| author | Freya Murphy <freya@freyacat.org> | 2025-04-25 11:20:08 -0400 |
|---|---|---|
| committer | Freya Murphy <freya@freyacat.org> | 2025-04-25 11:20:08 -0400 |
| commit | 228366dcf517266097a77b846efe2c2364a10fa3 (patch) | |
| tree | 619fba7611f01326a51bf9cb874a8d5459ce51f1 | |
| parent | fix physalloc edge case (diff) | |
| download | comus-228366dcf517266097a77b846efe2c2364a10fa3.tar.gz comus-228366dcf517266097a77b846efe2c2364a10fa3.tar.bz2 comus-228366dcf517266097a77b846efe2c2364a10fa3.zip | |
syscall_return fn
| -rw-r--r-- | kernel/cpu/idt.S | 23 | ||||
| -rw-r--r-- | kernel/include/comus/cpu.h | 6 | ||||
| -rw-r--r-- | kernel/procs.c | 2 |
3 files changed, 23 insertions, 8 deletions
diff --git a/kernel/cpu/idt.S b/kernel/cpu/idt.S index 177d3b1..06c70a0 100644 --- a/kernel/cpu/idt.S +++ b/kernel/cpu/idt.S @@ -1,5 +1,5 @@ .global isr_stub_table - .global isr_restore + .global syscall_return .global awd .extern idt_exception_handler @@ -8,6 +8,7 @@ .extern idt_pic_mouse .extern idt_pic_eoi .extern syscall_handler + .extern current_pcb .macro PUSHALL pushq %rax @@ -88,7 +89,7 @@ isr_stub_\num: cld movq %rsp, %rdi # top of stack callq syscall_handler - jmp isr_restore + jmp syscall_return .endm .macro PICGeneric num @@ -419,12 +420,18 @@ isr_stub_table: .code64 # isr restore -isr_restore: - movw $(0x20 | 3), %ax - movw %ax, %ds - movw %ax, %es - movw %ax, %fs - movw %ax, %gs +syscall_return: + movq current_pcb, %rbx // return user stack + movq 0(%rbx), %rsp // esp + movq 8(%rbx), %rcx // pml4 + movq (%rcx), %rcx + movq %rcx, %cr3 + + movw $(0x20 | 3), %ax + movw %ax, %ds + movw %ax, %es + movw %ax, %fs + movw %ax, %gs POPALL iretq diff --git a/kernel/include/comus/cpu.h b/kernel/include/comus/cpu.h index ffc1782..8f485be 100644 --- a/kernel/include/comus/cpu.h +++ b/kernel/include/comus/cpu.h @@ -89,4 +89,10 @@ void cpu_feats(struct cpu_feat *feats); */ void cpu_print_regs(struct cpu_regs *regs); +/** + * Return from a syscall handler back into userspace + */ +__attribute__((noreturn)) +void syscall_return(void); + #endif /* cpu.h */ diff --git a/kernel/procs.c b/kernel/procs.c index 9cde22f..8cd44a4 100644 --- a/kernel/procs.c +++ b/kernel/procs.c @@ -472,4 +472,6 @@ void dispatch(void) // set the process up for success current_pcb->state = PROC_STATE_RUNNING; current_pcb->ticks = 3; // ticks per process + + syscall_return(); } |