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Fix fork() for new task switching model

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This commit is contained in:
Justin C. Miller
2019-04-03 10:08:26 -07:00
parent 8375870af6
commit c605793a9d
13 changed files with 172 additions and 97 deletions
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64
src/kernel/page_manager.cpp
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@@ -2,12 +2,14 @@
#include "kutil/assert.h"
#include "console.h"
#include "io.h"
#include "log.h"
#include "page_manager.h"
using memory::frame_size;
using memory::kernel_offset;
using memory::page_offset;
using memory::page_mappable;
extern kutil::frame_allocator g_frame_allocator;
extern kutil::address_manager g_kernel_address_manager;
@@ -68,28 +70,58 @@ page_manager::create_process_map()
uintptr_t
page_manager::copy_page(uintptr_t orig)
{
uintptr_t virt = m_addrs.allocate(2 * frame_size);
uintptr_t copy = 0;
bool paged_orig = false;
bool paged_copy = false;
uintptr_t orig_virt;
if (page_mappable(orig)) {
orig_virt = orig + page_offset;
} else {
orig_virt = m_addrs.allocate(frame_size);
page_in(get_pml4(), orig, orig_virt, 1);
paged_orig = true;
}
uintptr_t copy = 0;
uintptr_t copy_virt;
size_t n = m_frames.allocate(1, &copy);
kassert(n, "copy_page could not allocate page");
page_in(get_pml4(), orig, virt, 1);
page_in(get_pml4(), copy, virt + frame_size, 1);
if (page_mappable(copy)) {
copy_virt = copy + page_offset;
} else {
copy_virt = m_addrs.allocate(frame_size);
page_in(get_pml4(), copy, copy_virt, 1);
paged_copy = true;
}
if (paged_orig || paged_copy) {
set_pml4(get_pml4());
__sync_synchronize();
io_wait();
}
kutil::memcpy(
reinterpret_cast<void *>(virt + frame_size),
reinterpret_cast<void *>(virt),
reinterpret_cast<void *>(copy_virt),
reinterpret_cast<void *>(orig_virt),
frame_size);
page_out(get_pml4(), virt, 2);
if (paged_orig) {
page_out(get_pml4(), orig_virt, 1);
m_addrs.free(orig_virt);
}
if (paged_copy) {
page_out(get_pml4(), copy_virt, 1);
m_addrs.free(copy_virt);
}
m_addrs.free(virt);
return copy;
}
page_table *
page_manager::copy_table(page_table *from, page_table::level lvl)
page_manager::copy_table(page_table *from, page_table::level lvl, page_table_indices index)
{
page_table *to = get_table_page();
log::debug(logs::paging, "Page manager copying level %d table at %016lx to %016lx.", lvl, from, to);
@@ -105,12 +137,17 @@ page_manager::copy_table(page_table *from, page_table::level lvl)
512;
unsigned pages_copied = 0;
uintptr_t from_addr = 0;
uintptr_t to_addr = 0;
for (int i = 0; i < max; ++i) {
if (!from->is_present(i)) {
to->entries[i] = 0;
continue;
}
index[lvl] = i;
bool is_page =
lvl == page_table::level::pt ||
from->is_large_page(lvl, i);
@@ -119,17 +156,20 @@ page_manager::copy_table(page_table *from, page_table::level lvl)
uint16_t flags = from->entries[i] & 0xfffull;
uintptr_t orig = from->entries[i] & ~0xfffull;
to->entries[i] = copy_page(orig) | flags;
pages_copied++;
if (!pages_copied++)
from_addr = index.addr();
to_addr = index.addr();
} else {
uint16_t flags = 0;
page_table *next_from = from->get(i, &flags);
page_table *next_to = copy_table(next_from, page_table::deeper(lvl));
page_table *next_to = copy_table(next_from, page_table::deeper(lvl), index);
to->set(i, next_to, flags);
}
}
if (pages_copied)
log::debug(logs::paging, " copied %3u pages", pages_copied);
log::debug(logs::paging, " copied %3u pages %016lx - %016lx",
pages_copied, from_addr, to_addr + frame_size);
return to;
}