From ace65b453151845bc361f21f3e5b651c35f9f126 Mon Sep 17 00:00:00 2001
From: Jon Santmyer <jon@jonsantmyer.com>
Date: Wed, 22 May 2024 13:00:41 -0400
Subject: massive refactor for mp and organization

---
 task/exrtab.c    | 19 +++++++++++++++++++
 task/init.c      | 22 ++++++++++++++++++++++
 task/stack.c     | 14 ++++++++++++++
 task/tasking.c   | 45 +++++++++++++++++++++++++++++++++++++++++++++
 task/umode_vma.c | 37 +++++++++++++++++++++++++++++++++++++
 5 files changed, 137 insertions(+)
 create mode 100644 task/exrtab.c
 create mode 100644 task/init.c
 create mode 100644 task/stack.c
 create mode 100644 task/tasking.c
 create mode 100644 task/umode_vma.c

(limited to 'task')

diff --git a/task/exrtab.c b/task/exrtab.c
new file mode 100644
index 0000000..82b9e29
--- /dev/null
+++ b/task/exrtab.c
@@ -0,0 +1,19 @@
+#include "arch/processor.h"
+#include "assert.h"
+
+void
+_exrtab_push(void *v)
+{
+    processor_t *proc = processor_current();
+    proc->exrtab[proc->ert_i++] = (uintptr_t)v;
+}
+
+void*
+_exrtab_pop(void)
+{
+    processor_t *proc = processor_current();
+    
+    assert(proc->ert_i != 0);
+    uintptr_t r = proc->exrtab[--proc->ert_i];
+    return (void*)r;
+}
diff --git a/task/init.c b/task/init.c
new file mode 100644
index 0000000..c4c8bad
--- /dev/null
+++ b/task/init.c
@@ -0,0 +1,22 @@
+#include "commandline.h"
+#include "jove.h"
+#include "initrd.h"
+#include "tasking.h"
+#include "arch/elf.h"
+
+__attribute__((noreturn)) void
+kinit(void)
+{
+    const char *init_filepath = cmdline_get("init");
+    if(init_filepath == NULL)
+        kpanic("init filepath not found in kernel commandline\n");
+
+    initrd_file_t *init_file = ird_getfile(init_filepath);
+    if(init_file == NULL)
+        kpanic("init file not found in initrd [filepath=\"%s\"]\n", init_filepath);
+
+    uintptr_t ip = elf_load(init_file->data, init_file->size);
+
+    kexec((void*)ip, 0, NULL, 0, NULL);
+    kpanic("Reached end of kinit\n");
+}
diff --git a/task/stack.c b/task/stack.c
new file mode 100644
index 0000000..396ab3e
--- /dev/null
+++ b/task/stack.c
@@ -0,0 +1,14 @@
+#include "tasking.h"
+#include "string.h"
+#include "assert.h"
+
+void 
+tcb_stack_push(tcb_t *tcb, void *data, size_t len)
+{
+    assert(tcb != NULL);
+    void *spo = (void*)(tcb->ksp - len);
+    assert(spo >= tcb->stack);
+
+    memcpy(spo, data, len);
+    tcb->ksp = (uintptr_t)spo;
+}
diff --git a/task/tasking.c b/task/tasking.c
new file mode 100644
index 0000000..ee57a13
--- /dev/null
+++ b/task/tasking.c
@@ -0,0 +1,45 @@
+#include "tasking.h"
+#include "slab.h"
+#include "klib/rbtree.h"
+#include "arch/processor.h"
+
+rbtree_t s_tcbs;
+tcbid_t s_tcb_nextid = 0;
+slab_cache_t s_kstack_slab;
+
+void
+tasking_setup(void)
+{
+    rbtree_new(&s_tcbs, tcb_t);
+    slabcache_new(&s_kstack_slab, "kernel stack", KERNEL_STACKW);
+
+    extern void kernel_stage2(void);
+    tcb_t *init_tcb = tcb_new((void*)kernel_stage2, pd_current());
+
+    tcb_switch(init_tcb);
+}
+
+tcb_t*
+tcb_new(void *ip, page_directory_t *pd)
+{
+    void *stack = slab_alloc(&s_kstack_slab);
+    tcb_t *tcb = rbtree_reserve(&s_tcbs, s_tcb_nextid);
+    *tcb = (tcb_t) {
+        .id = s_tcb_nextid++,
+        .stack = stack,
+        .ksp = ((uintptr_t)stack) + (KERNEL_STACKW - 1),
+        .pd = pd,
+        .state = TCB_RUNNING
+    };
+
+    tcb_prepare(tcb, ip);
+    return tcb;
+}
+
+void 
+tcb_kill(tcb_t *tcb, int code)
+{
+    if(tcb->id == 0) kpanic("init thread killed!\n");
+    tcb->state = TCB_DEAD;
+    tcb->exit_code = code;
+}
diff --git a/task/umode_vma.c b/task/umode_vma.c
new file mode 100644
index 0000000..880e047
--- /dev/null
+++ b/task/umode_vma.c
@@ -0,0 +1,37 @@
+#include "umode_vma.h"
+#include "arch/processor.h"
+#include "api/errno.h"
+#include "print.h"
+
+__attribute__((naked))
+int
+_umode_vma_fail(void)
+{
+    __asm__ volatile(" \
+    movq %%rbp, %%rsp; \
+    popq %%rbp; \
+    mov $1, %%eax; \
+    retq":::);
+}
+
+int
+user_vma_read(void *dest, const void *src, size_t w)
+{
+    if((uintptr_t)src > USERLAND_MEMORY_LIMIT) return -EACCESS;
+
+    _exrtab_push((void*)_umode_vma_fail);
+    for(size_t i = 0; i < w; i++) ((char*)dest)[i] = ((const char*)src)[i];
+    _exrtab_pop();
+    return 0;
+}
+
+int
+user_vma_write(void *dest, const void *src, size_t w)
+{
+    if((uintptr_t)dest > USERLAND_MEMORY_LIMIT) return -EACCESS;
+    
+    _exrtab_push((void*)_umode_vma_fail);
+    for(size_t i = 0; i < w; i++) ((char*)dest)[i] = ((const char*)src)[i];
+    _exrtab_pop();
+    return 0;
+}
-- 
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