Gave procs own kernel stack (TSS)

3 files changed, 31 insertions, 10 deletions

diff --git a/kernel/features/load.c b/kernel/features/load.c
index df01e04..02c02ae 100644
--- a/kernel/features/load.c
+++ b/kernel/features/load.c
@@ -145,7 +145,8 @@ res elf_load(const char *name, struct proc *proc)
 		/* } */
 
 		// Remap readonly sections
-		if (!(section.flags & ELF_SECTION_FLAG_WRITE)) {
+		if (!(section.flags & ELF_SECTION_FLAG_WRITE) && section.addr &&
+		    memory_is_user((void *)section.addr)) {
 			struct memory_range range =
 				memory_range_around(section.addr + rand_off, section.size);
 			virtual_remap_readonly(proc->page_dir, range);
@@ -158,14 +159,26 @@ res elf_load(const char *name, struct proc *proc)
 
 	stac();
 
-	// Allocate stack with readonly lower and upper page boundary
-	u32 stack = PAGE_SIZE + (u32)memory_alloc(proc->page_dir, PROC_STACK_SIZE + 2 * PAGE_SIZE,
-						  MEMORY_USER | MEMORY_CLEAR);
-	virtual_remap_readonly(proc->page_dir, memory_range(stack - PAGE_SIZE, PAGE_SIZE));
-	virtual_remap_readonly(proc->page_dir, memory_range(stack + PROC_STACK_SIZE, PAGE_SIZE));
-
-	proc->regs.ebp = stack + PROC_STACK_SIZE;
-	proc->regs.useresp = stack + PROC_STACK_SIZE;
+	// Allocate user stack with readonly lower and upper page boundary
+	u32 user_stack =
+		PAGE_SIZE + (u32)memory_alloc(proc->page_dir, PROC_STACK_SIZE + 2 * PAGE_SIZE,
+					      MEMORY_USER | MEMORY_CLEAR);
+	virtual_remap_readonly(proc->page_dir, memory_range(user_stack - PAGE_SIZE, PAGE_SIZE));
+	virtual_remap_readonly(proc->page_dir,
+			       memory_range(user_stack + PROC_STACK_SIZE, PAGE_SIZE));
+
+	// Allocate kernel stack with readonly lower and upper page boundary
+	u32 kernel_stack =
+		PAGE_SIZE +
+		(u32)memory_alloc(proc->page_dir, PROC_STACK_SIZE + 2 * PAGE_SIZE, MEMORY_CLEAR);
+	virtual_remap_readonly(proc->page_dir, memory_range(kernel_stack - PAGE_SIZE, PAGE_SIZE));
+	virtual_remap_readonly(proc->page_dir,
+			       memory_range(kernel_stack + PROC_STACK_SIZE, PAGE_SIZE));
+
+	proc->user_stack = user_stack + PROC_STACK_SIZE;
+	proc->kernel_stack = kernel_stack + PROC_STACK_SIZE;
+	proc->regs.ebp = proc->user_stack;
+	proc->regs.useresp = proc->user_stack;
 	proc->regs.eip = header.entry + rand_off;
 	proc->entry = header.entry + rand_off;
 
diff --git a/kernel/features/mm.c b/kernel/features/mm.c
index 466e448..0972ab3 100644
--- a/kernel/features/mm.c
+++ b/kernel/features/mm.c
@@ -677,8 +677,11 @@ void memory_user_hook(void)
 	}
 }
 
-CLEAR void memory_install(struct mem_info *mem_info, struct vid_info *vid_info)
+CLEAR void memory_install(struct boot_info *boot)
 {
+	struct mem_info *mem_info = boot->mem;
+	struct vid_info *vid_info = boot->vid;
+
 	for (struct mmap_boot *p = mem_info->start; (u32)(p - mem_info->start) < mem_info->size;
 	     p++) {
 		if (p->hbase || !p->acpi || !p->type)
@@ -731,6 +734,9 @@ CLEAR void memory_install(struct mem_info *mem_info, struct vid_info *vid_info)
 			    MEMORY_NONE);
 	fb_map_buffer(virtual_kernel_dir(), vid_info);
 
+	// Map TSS
+	memory_map_identity(&kernel_dir, memory_range_around(boot->tss, 0x1000), MEMORY_NONE);
+
 	// Unmap NULL byte/page
 	struct memory_range zero = memory_range(0, PAGE_SIZE);
 	virtual_free(&kernel_dir, zero);
diff --git a/kernel/features/proc.c b/kernel/features/proc.c
index 479427c..d5bf2e6 100644
--- a/kernel/features/proc.c
+++ b/kernel/features/proc.c
@@ -54,6 +54,7 @@ HOT FLATTEN void scheduler(struct regs *regs)
 		current = idle_proc;
 	}
 
+	tss_set_stack(0x10, PROC(current)->kernel_stack);
 	memory_switch_dir(PROC(current)->page_dir);
 	memcpy(regs, &PROC(current)->regs, sizeof(*regs));
 
@@ -581,6 +582,7 @@ NORETURN void proc_init(void)
 	// We'll shortly jump to usermode. Clear and protect every secret!
 	memory_user_hook();
 
+	tss_set_stack(0x10, init->kernel_stack);
 	memory_switch_dir(init->page_dir);
 	printf("Jumping to userspace!\n");