Fix loading large process images.

2MiB large pages were being used for any large page mapping, but the
page manager doesn't correctly handle them everywhere yet. Now only
allow them for offset pointers (eg MMIO space) that will never be
unmapped.

src/drivers/nulldrv/main.s

@@ -1,15 +1,22 @@
+section .bss
+mypid: resq 1
+mychild: resq 1
+
+section .text
 global _start
 _start:
 	xor rbp, rbp	; Sentinel rbp
 
 	mov rax, 5		; GETPID syscall
 	int 0xee
-	mov r12, rax	; save pid to r12
+	mov [mypid], rax
 
 	mov rax, 8		; FORK syscall
 	int 0xee
+	mov [mychild], rax
 
-	mov r10, rax
+	mov r12, [mypid]
+	mov r13, [mychild]
 	mov rax, 1		; DEBUG syscall
 	int 0xee
 
@@ -22,7 +29,7 @@ _start:
 	mov rbx, 20		; sleep timeout
 
 .loop:
-	mov rax, 2		; MESSAGE syscall
+	mov rax, 1		; MESSAGE syscall
 	;mov rax, 0		; NOOP syscall
 	;syscall
 	int 0xee

src/kernel/log.cpp

@@ -17,6 +17,7 @@ static const char *areas[] = {
 	"driver",
 	"file  ",
 	"task  ",
+	"paging",
 
 	nullptr
 };

src/kernel/log.h

@@ -14,6 +14,7 @@ enum class logs
 	driver,
 	fs,
 	task,
+	paging,
 
 	max
 };

src/kernel/main.cpp

@@ -38,13 +38,14 @@ init_console()
 	cons->puts(GIT_VERSION " booting...\n");
 
 	log::init(cons);
-	//log::enable(logs::apic, log::level::debug);
-	//log::enable(logs::device, log::level::info);
+	log::enable(logs::apic, log::level::info);
+	log::enable(logs::device, log::level::info);
 	log::enable(logs::driver, log::level::debug);
 	log::enable(logs::memory, log::level::debug);
 	log::enable(logs::fs, log::level::debug);
 	log::enable(logs::task, log::level::debug);
 	log::enable(logs::boot, log::level::debug);
+	log::enable(logs::paging, log::level::warn);
 }
 
 void

src/kernel/page_manager.cpp

@@ -92,7 +92,7 @@ page_table *
 page_manager::copy_table(page_table *from, page_table::level lvl)
 {
 	page_table *to = get_table_page();
-	log::debug(logs::memory, "Page manager copying level %d table at %016lx to %016lx.", lvl, from, to);
+	log::debug(logs::paging, "Page manager copying level %d table at %016lx to %016lx.", lvl, from, to);
 
 	if (lvl == page_table::level::pml4) {
 		to->entries[510] = m_kernel_pml4->entries[510];
@@ -129,7 +129,7 @@ page_manager::copy_table(page_table *from, page_table::level lvl)
 	}
 
 	if (pages_copied)
-		log::debug(logs::memory, "   copied %3u pages", pages_copied);
+		log::debug(logs::paging, "   copied %3u pages", pages_copied);
 
 	return to;
 }
@@ -147,8 +147,10 @@ page_manager::map_offset_pointer(void **pointer, size_t length)
 	uintptr_t v = *p + page_offset;
 	uintptr_t c = ((length - 1) / frame_size) + 1;
 
+	log::info(logs::paging, "Mapping offset pointer region at %016lx size 0x%lx", *pointer, length);
+
 	page_table *pml4 = get_pml4();
-	page_in(pml4, *p, v, c);
+	page_in(pml4, *p, v, c, false, true);
 	*p = v;
 }
 
@@ -179,7 +181,7 @@ page_manager::get_table_page()
 		}
 		reinterpret_cast<free_page_header *>(virt)->next = nullptr;
 
-		log::debug(logs::memory, "Mappd %d new page table pages at %lx", n, phys);
+		log::info(logs::paging, "Mappd %d new page table pages at %lx", n, phys);
 	}
 
 	free_page_header *page = m_page_cache;
@@ -210,7 +212,7 @@ page_manager::map_pages(uintptr_t address, size_t count, bool user, page_table *
 		uintptr_t phys = 0;
 		size_t n = m_frames.allocate(count, &phys);
 
-		log::debug(logs::memory, "Paging in %d pages at p:%016lx to v:%016lx into %016lx table",
+		log::info(logs::paging, "Paging in %d pages at p:%016lx to v:%016lx into %016lx table",
 				n, phys, address, pml4);
 
 		page_in(pml4, phys, address, n, user);
@@ -283,8 +285,11 @@ page_manager::check_needs_page(page_table *table, unsigned index, bool user)
 }
 
 void
-page_manager::page_in(page_table *pml4, uintptr_t phys_addr, uintptr_t virt_addr, size_t count, bool user)
+page_manager::page_in(page_table *pml4, uintptr_t phys_addr, uintptr_t virt_addr, size_t count, bool user, bool large)
 {
+	log::debug(logs::paging, "page_in for table %016lx p:%016lx v:%016lx c:%4d u:%d l:%d",
+			pml4, phys_addr, virt_addr, count, user, large);
+
 	page_table_indices idx{virt_addr};
 	page_table *tables[4] = {pml4, nullptr, nullptr, nullptr};
 
@@ -301,7 +306,8 @@ page_manager::page_in(page_table *pml4, uintptr_t phys_addr, uintptr_t virt_addr
 			tables[2] = tables[1]->get(idx[1]);
 
 			for (; idx[2] < 512; idx[2] += 1, idx[3] = 0) {
-				if (idx[3] == 0 &&
+				if (large &&
+					idx[3] == 0 &&
 					count >= 512 &&
 					tables[2]->get(idx[2]) == nullptr) {
 					// Do a 2MiB page instead

src/kernel/page_manager.h

@@ -136,13 +136,15 @@ private:
 	/// \arg phys_addr  The starting physical address of the pages to be mapped
 	/// \arg virt_addr  The starting virtual address ot the memory to be mapped
 	/// \arg count      The number of pages to map
-	/// \art user  True if this is a userspace mapping
+	/// \arg user       True if this is a userspace mapping
+	/// \arg large      Whether to allow large pages
 	void page_in(
 			page_table *pml4,
 			uintptr_t phys_addr,
 			uintptr_t virt_addr,
 			size_t count,
-			bool user = false);
+			bool user = false,
+			bool large = false);
 
 	/// Low-level routine for unmapping a number of pages from the given page table.
 	/// \arg pml4       The root page table for this mapping