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Pause syscall and int 0xee interrupt syscalls

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The syscall/sysret instructions don't swap stacks. This was bad but
passable until syscalls caused the scheduler to run, and scheduling a
task that paused due to interrupt.

Adding a new (hopefully temporary) syscall interrupt `int 0xee` to allow
me to test syscalls without stack issues before I tackle the
syscall/sysret issue.

Also implemented a basic `pause` syscall that causes the calling process
to become unready. Because nothing can wake a process yet, it never
returns.
This commit is contained in:
Justin C. Miller
2018-09-12 20:59:08 -07:00
parent c2f85ce61b
commit 62c559043d
13 changed files with 233 additions and 136 deletions
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34
src/kernel/scheduler.cpp
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@@ -3,6 +3,7 @@
#include "cpu.h"
#include "gdt.h"
#include "interrupts.h"
#include "io.h"
#include "log.h"
#include "page_manager.h"
#include "scheduler.h"
@@ -11,8 +12,8 @@
#include "kutil/assert.h"
scheduler scheduler::s_instance(nullptr);
//static const uint32_t quantum = 2000000;
static const uint32_t quantum = 20000000;
static const uint32_t quantum = 2000000;
//static const uint32_t quantum = 20000000;
const int stack_size = 0x1000;
const uint64_t rflags_noint = 0x002;
@@ -69,7 +70,7 @@ load_process(const void *image_start, size_t bytes, process *proc, cpu_state sta
size_t size = (header->vaddr + header->mem_size) - aligned;
size_t pages = page_manager::page_count(size);
log::debug(logs::task, " Loadable segment %02d: vaddr %016lx size %016lx",
log::debug(logs::task, " Loadable segment %02u: vaddr %016lx size %016lx",
i, header->vaddr, header->mem_size);
log::debug(logs::task, " - aligned to: vaddr %016lx pages %d",
@@ -89,7 +90,7 @@ load_process(const void *image_start, size_t bytes, process *proc, cpu_state sta
!bitfield_has(header->flags, elf::section_flags::alloc))
continue;
log::debug(logs::task, " Loadable section %u: vaddr %016lx size %016lx",
log::debug(logs::task, " Loadable section %02u: vaddr %016lx size %016lx",
i, header->addr, header->size);
void *dest = reinterpret_cast<void *>(header->addr);
@@ -100,12 +101,7 @@ load_process(const void *image_start, size_t bytes, process *proc, cpu_state sta
state.rip = image.entrypoint();
proc->flags &= ~process_flags::loading;
log::debug(logs::task, "Loaded! New process state:");
log::debug(logs::task, " CS: %d [%d]", state.cs >> 3, state.cs & 0x07);
log::debug(logs::task, " SS: %d [%d]", state.ss >> 3, state.ss & 0x07);
log::debug(logs::task, " RFLAGS: %08x", state.rflags);
log::debug(logs::task, " RIP: %016lx", state.rip);
log::debug(logs::task, " uRSP: %016lx", state.user_rsp);
log::debug(logs::task, " Loaded! New process rip: %016lx", state.rip);
}
void
@@ -166,13 +162,9 @@ scheduler::create_process(const char *name, const void *data, size_t size)
loader_state->rcx = reinterpret_cast<uint64_t>(proc);
log::debug(logs::task, "Creating process %s:", name);
log::debug(logs::task, " PID %d", pid);
log::debug(logs::task, " Pri %d", pid);
log::debug(logs::task, "Creating process %s: pid %d pri %d", name, proc->pid, proc->priority);
log::debug(logs::task, " RSP0 %016lx", state);
log::debug(logs::task, " RSP3 %016lx", state->user_rsp);
log::debug(logs::task, " PML4 %016lx", pml4);
log::debug(logs::task, " Loading %016lx [%d]", loader_state->rax, loader_state->rbx);
}
void
@@ -187,7 +179,11 @@ scheduler::schedule(addr_t rsp0)
{
m_current->rsp = rsp0;
m_runlists[m_current->priority].remove(m_current);
m_runlists[m_current->priority].push_back(m_current);
if (m_current->flags && process_flags::ready)
m_runlists[m_current->priority].push_back(m_current);
else
m_blocked.push_back(m_current);
uint8_t pri = 0;
while (m_runlists[pri].empty()) {
@@ -198,14 +194,18 @@ scheduler::schedule(addr_t rsp0)
m_current = m_runlists[pri].pop_front();
rsp0 = m_current->rsp;
static const uint64_t ia32_gs_base = 0xc0000101;
static const uint64_t ia32_kernel_gs_base = 0xc0000102;
// Set rsp0 to after the end of the about-to-be-popped cpu state
tss_set_stack(0, rsp0 + sizeof(cpu_state));
wrmsr(ia32_gs_base, rsp0);
// Swap page tables
page_table *pml4 = m_current->pml4;
page_manager::set_pml4(pml4);
bool loading = bitfield_has(m_current->flags, process_flags::loading);
bool loading = m_current->flags && process_flags::loading;
log::debug(logs::task, "Scheduler switched to process %d, priority %d%s.",
m_current->pid, m_current->priority, loading ? " (loading)" : "");