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genode/repos/base-sel4/src/core/platform.cc
Norman Feske 9e6f3be806 sel4: update to version 2.1 
This patch updates seL4 from the experimental branch of one year ago to
the master branch of version 2.1. The transition has the following
implications.

In contrast to the experimental branch, the master branch has no way to
manually define the allocation of kernel objects within untyped memory
ranges. Instead, the kernel maintains a built-in allocation policy. This
policy rules out the deallocation of once-used parts of untyped memory.
The only way to reuse memory is to revoke the entire untyped memory
range. Consequently, we cannot share a large untyped memory range for
kernel objects of different protection domains. In order to reuse memory
at a reasonably fine granularity, we need to split the initial untyped
memory ranges into small chunks that can be individually revoked. Those
chunks are called "untyped pages". An untyped page is a 4 KiB untyped
memory region.

The bootstrapping of core has to employ a two-stage allocation approach
now. For creating the initial kernel objects for core, which remain
static during the entire lifetime of the system, kernel objects are
created directly out of the initial untyped memory regions as reported
by the kernel. The so-called "initial untyped pool" keeps track of the
consumption of those untyped memory ranges by mimicking the kernel's
internal allocation policy. Kernel objects created this way can be of
any size. For example the phys CNode, which is used to store page-frame
capabilities is 16 MiB in size. Also, core's CSpace uses a relatively
large CNode.

After the initial setup phase, all remaining untyped memory is turned
into untyped pages. From this point on, new created kernel objects
cannot exceed 4 KiB in size because one kernel object cannot span
multiple untyped memory regions. The capability selectors for untyped
pages are organized similarly to those of page-frame capabilities. There
is a new 2nd-level CNode (UNTYPED_CORE_CNODE) that is dimensioned
according to the maximum amount of physical memory (1M entries, each
entry representing 4 KiB). The CNode is organized such that an index
into the CNode directly corresponds to the physical frame number of the
underlying memory. This way, we can easily determine a untyped page
selector for any physical addresses, i.e., for revoking the kernel
objects allocated at a specific physical page. The downside is the need
for another 16 MiB chunk of meta data. Also, we need to keep in mind
that this approach won't scale to 64-bit systems. We will eventually
need to replace the PHYS_CORE_CNODE and UNTYPED_CORE_CNODE by CNode
hierarchies to model a sparsely populated CNode.

The size constrain of kernel objects has the immediate implication that
the VM CSpaces of protection domains must be organized via several
levels of CNodes. I.e., as the top-level CNode of core has a size of
2^12, the remaining 20 PD-specific CSpace address bits are organized as
a 2nd-level 2^4 padding CNode, a 3rd-level 2^8 CNode, and several
4th-level 2^8 leaf CNodes. The latter contain the actual selectors for
the page tables and page-table entries of the respective PD.

As another slight difference from the experimental branch, the master
branch requires the explicit assignment of page directories to an ASID
pool.

Besides the adjustment to the new seL4 version, the patch introduces a
dedicated type for capability selectors. Previously, we just used to
represent them as unsigned integer values, which became increasingly
confusing. The new type 'Cap_sel' is a PD-local capability selector. The
type 'Cnode_index' is an index into a CNode (which is not generally not
the entire CSpace of the PD).

Fixes #1887
2016-02-26 11:36:55 +01:00

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/*
* \brief Platform interface implementation
* \author Norman Feske
* \date 2015-05-01
*/
/*
* Copyright (C) 2015 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
/* Genode includes */
#include <base/printf.h>
#include <base/sleep.h>
#include <base/thread.h>
/* core includes */
#include <core_parent.h>
#include <platform.h>
#include <map_local.h>
#include <cnode.h>
#include <untyped_memory.h>
using namespace Genode;
static bool const verbose_boot_info = true;
/*
* Memory-layout information provided by the linker script
*/
/* virtual address range consumed by core's program image */
extern unsigned _prog_img_beg, _prog_img_end;
/******************
** Boot modules **
******************/
struct Boot_module_header
{
char const *name; /* physical address of null-terminated string */
addr_t const base; /* physical address of module data */
size_t const size; /* size of module data in bytes */
};
extern Boot_module_header _boot_modules_headers_begin;
extern Boot_module_header _boot_modules_headers_end;
extern int _boot_modules_binaries_begin;
extern int _boot_modules_binaries_end;
/****************************************
** Support for core memory management **
****************************************/
bool Mapped_mem_allocator::_map_local(addr_t virt_addr, addr_t phys_addr,
unsigned size)
{
size_t const num_pages = size / get_page_size();
Untyped_memory::convert_to_page_frames(phys_addr, num_pages);
return map_local(phys_addr, virt_addr, num_pages);
}
bool Mapped_mem_allocator::_unmap_local(addr_t virt_addr, unsigned size)
{
return unmap_local(virt_addr, size / get_page_size());
}
/************************
** Platform interface **
************************/
void Platform::_init_unused_phys_alloc()
{
_unused_phys_alloc.add_range(0, ~0UL);
}
static inline void init_sel4_ipc_buffer()
{
asm volatile ("movl %0, %%gs" :: "r"(IPCBUF_GDT_SELECTOR) : "memory");
}
void Platform::_init_allocators()
{
/* interrupt allocator */
_irq_alloc.add_range(0, 255);
/*
* XXX allocate intermediate CNodes for organizing the untyped pages here
*/
/* register remaining untyped memory to physical memory allocator */
auto add_phys_range = [&] (Initial_untyped_pool::Range const &range) {
addr_t const page_aligned_offset =
align_addr(range.free_offset, get_page_size_log2());
if (page_aligned_offset >= range.size)
return;
addr_t const base = range.phys + page_aligned_offset;
size_t const size = range.size - page_aligned_offset;
PDBG("register phys mem range 0x%lx size=0x%zx", base, size);
_core_mem_alloc.phys_alloc()->add_range(base, size);
_unused_phys_alloc.remove_range(base, size);
};
_initial_untyped_pool.for_each_range(add_phys_range);
/* turn remaining untyped memory ranges into untyped pages */
_initial_untyped_pool.turn_remainder_into_untyped_pages();
/*
* From this point on, we can no longer create kernel objects from the
* '_initial_untyped_pool' because the pool is empty.
*/
/* I/O memory ranges */
// init_allocator(_io_mem_alloc, _unused_phys_alloc,
// bi, bi.deviceUntyped.start,
// bi.deviceUntyped.end - bi.deviceUntyped.start);
/* core's virtual memory */
_core_mem_alloc.virt_alloc()->add_range(_vm_base, _vm_size);
/* remove core image from core's virtual address allocator */
/*
* XXX Why do we need to skip a few KiB after the end of core?
* When allocating a PTE immediately after _prog_img_end, the
* kernel would complain "Mapping already present" on the
* attempt to map a page frame.
*/
addr_t const core_virt_beg = trunc_page((addr_t)&_prog_img_beg),
core_virt_end = round_page((addr_t)&_boot_modules_binaries_end)
+ 64*1024;
size_t const core_size = core_virt_end - core_virt_beg;
_core_mem_alloc.virt_alloc()->remove_range(core_virt_beg, core_size);
if (verbose_boot_info) {
printf("core image:\n");
printf(" virtual address range [%08lx,%08lx) size=0x%zx\n",
core_virt_beg, core_virt_end, core_size);
}
/* preserve context area in core's virtual address space */
_core_mem_alloc.virt_alloc()->remove_range(Native_config::context_area_virtual_base(),
Native_config::context_area_virtual_size());
}
void Platform::_switch_to_core_cspace()
{
Cnode_base const initial_cspace(Cap_sel(seL4_CapInitThreadCNode), 32);
/* copy initial selectors to core's CNode */
_core_cnode.copy(initial_cspace, Cnode_index(seL4_CapInitThreadTCB));
_core_cnode.copy(initial_cspace, Cnode_index(seL4_CapInitThreadVSpace));
_core_cnode.move(initial_cspace, Cnode_index(seL4_CapIRQControl)); /* cannot be copied */
_core_cnode.copy(initial_cspace, Cnode_index(seL4_CapASIDControl));
_core_cnode.copy(initial_cspace, Cnode_index(seL4_CapInitThreadASIDPool));
_core_cnode.copy(initial_cspace, Cnode_index(seL4_CapIOPort));
_core_cnode.copy(initial_cspace, Cnode_index(seL4_CapBootInfoFrame));
_core_cnode.copy(initial_cspace, Cnode_index(seL4_CapInitThreadIPCBuffer));
_core_cnode.copy(initial_cspace, Cnode_index(seL4_CapDomain));
/* replace seL4_CapInitThreadCNode with new top-level CNode */
_core_cnode.copy(initial_cspace, Cnode_index(Core_cspace::TOP_CNODE_SEL),
Cnode_index(seL4_CapInitThreadCNode));
/* copy untyped memory selectors to core's CNode */
seL4_BootInfo const &bi = sel4_boot_info();
/*
* We have to move (not copy) the selectors for the initial untyped ranges
* because some of them are already populated with kernel objects allocated
* via '_initial_untyped_pool'. For such an untyped memory range, the
* attempt to copy its selector would result in the following error:
*
* <<seL4: Error deriving cap for CNode Copy operation.>>
*/
for (unsigned sel = bi.untyped.start; sel < bi.untyped.end; sel++)
_core_cnode.move(initial_cspace, Cnode_index(sel));
// for (unsigned sel = bi.deviceUntyped.start; sel < bi.deviceUntyped.end; sel++)
// _core_cnode.copy(initial_cspace, sel);
for (unsigned sel = bi.userImageFrames.start; sel < bi.userImageFrames.end; sel++)
_core_cnode.copy(initial_cspace, Cnode_index(sel));
/* copy statically created CNode selectors to core's CNode */
_core_cnode.copy(initial_cspace, Cnode_index(Core_cspace::TOP_CNODE_SEL));
_core_cnode.copy(initial_cspace, Cnode_index(Core_cspace::CORE_PAD_CNODE_SEL));
_core_cnode.copy(initial_cspace, Cnode_index(Core_cspace::CORE_CNODE_SEL));
_core_cnode.copy(initial_cspace, Cnode_index(Core_cspace::PHYS_CNODE_SEL));
/*
* Construct CNode hierarchy of core's CSpace
*/
/* insert 3rd-level core CNode into 2nd-level core-pad CNode */
_core_pad_cnode.copy(initial_cspace, Cnode_index(Core_cspace::CORE_CNODE_SEL),
Cnode_index(0));
/* insert 2nd-level core-pad CNode into 1st-level CNode */
_top_cnode.copy(initial_cspace, Cnode_index(Core_cspace::CORE_PAD_CNODE_SEL),
Cnode_index(Core_cspace::TOP_CNODE_CORE_IDX));
/* insert 2nd-level phys-mem CNode into 1st-level CNode */
_top_cnode.copy(initial_cspace, Cnode_index(Core_cspace::PHYS_CNODE_SEL),
Cnode_index(Core_cspace::TOP_CNODE_PHYS_IDX));
/* insert 2nd-level untyped-pages CNode into 1st-level CNode */
_top_cnode.copy(initial_cspace, Cnode_index(Core_cspace::UNTYPED_CNODE_SEL),
Cnode_index(Core_cspace::TOP_CNODE_UNTYPED_IDX));
/* activate core's CSpace */
{
seL4_CapData_t null_data = { { 0 } };
int const ret = seL4_TCB_SetSpace(seL4_CapInitThreadTCB,
seL4_CapNull, /* fault_ep */
Core_cspace::TOP_CNODE_SEL, null_data,
seL4_CapInitThreadPD, null_data);
if (ret != 0) {
PERR("%s: seL4_TCB_SetSpace returned %d", __FUNCTION__, ret);
}
}
}
Cap_sel Platform::_init_asid_pool()
{
return Cap_sel(seL4_CapInitThreadASIDPool);
}
void Platform::_init_core_page_table_registry()
{
seL4_BootInfo const &bi = sel4_boot_info();
/*
* Register initial page tables
*/
addr_t virt_addr = (addr_t)(&_prog_img_beg);
for (unsigned sel = bi.userImagePTs.start; sel < bi.userImagePTs.end; sel++) {
_core_page_table_registry.insert_page_table(virt_addr, Cap_sel(sel));
/* one page table has 1024 entries */
virt_addr += 1024*get_page_size();
}
/*
* Register initial page frames
*/
virt_addr = (addr_t)(&_prog_img_beg);
for (unsigned sel = bi.userImageFrames.start; sel < bi.userImageFrames.end; sel++) {
_core_page_table_registry.insert_page_table_entry(virt_addr, sel);
virt_addr += get_page_size();
}
}
void Platform::_init_rom_modules()
{
seL4_BootInfo const &bi = sel4_boot_info();
/*
* Slab allocator for allocating 'Rom_module' meta data.
*/
static long slab_block[4096];
static Tslab<Rom_module, sizeof(slab_block)>
rom_module_slab(core_mem_alloc(), (Genode::Slab_block *)slab_block);
/*
* Allocate unused range of phys CNode address space where to make the
* boot modules available.
*/
void *out_ptr = nullptr;
size_t const modules_size = (addr_t)&_boot_modules_binaries_end
- (addr_t)&_boot_modules_binaries_begin + 1;
Range_allocator::Alloc_return const alloc_ret =
_unused_phys_alloc.alloc_aligned(modules_size, &out_ptr, get_page_size_log2());
if (alloc_ret.is_error()) {
PERR("could not reserve phys CNode space for boot modules");
struct Init_rom_modules_failed { };
throw Init_rom_modules_failed();
}
/*
* Calculate frame frame selector used to back the boot modules
*/
addr_t const unused_range_start = (addr_t)out_ptr;
addr_t const unused_first_frame_sel = unused_range_start >> get_page_size_log2();
addr_t const modules_start = (addr_t)&_boot_modules_binaries_begin;
addr_t const modules_core_offset = modules_start
- (addr_t)&_prog_img_beg;
addr_t const modules_first_frame_sel = bi.userImageFrames.start
+ (modules_core_offset >> get_page_size_log2());
Boot_module_header const *header = &_boot_modules_headers_begin;
for (; header < &_boot_modules_headers_end; header++) {
/* offset relative to first module */
addr_t const module_offset = header->base - modules_start;
addr_t const module_offset_frames = module_offset >> get_page_size_log2();
size_t const module_size = round_page(header->size);
addr_t const module_frame_sel = modules_first_frame_sel
+ module_offset_frames;
size_t const module_num_frames = module_size >> get_page_size_log2();
/*
* Destination frame within phys CNode
*/
addr_t const dst_frame = unused_first_frame_sel + module_offset_frames;
/*
* Install the module's frame selectors into phys CNode
*/
Cnode_base const initial_cspace(Cap_sel(seL4_CapInitThreadCNode), 32);
for (unsigned i = 0; i < module_num_frames; i++)
_phys_cnode.copy(initial_cspace, Cnode_index(module_frame_sel + i),
Cnode_index(dst_frame + i));
PLOG("boot module '%s' (%zd bytes)", header->name, header->size);
/*
* Register ROM module, the base address refers to location of the
* ROM module within the phys CNode address space.
*/
Rom_module * rom_module = new (rom_module_slab)
Rom_module(dst_frame << get_page_size_log2(), header->size,
(const char*)header->name);
_rom_fs.insert(rom_module);
}
}
Platform::Platform()
:
_io_mem_alloc(core_mem_alloc()), _io_port_alloc(core_mem_alloc()),
_irq_alloc(core_mem_alloc()),
_unused_phys_alloc(core_mem_alloc()),
_init_unused_phys_alloc_done((_init_unused_phys_alloc(), true)),
_vm_base(0x2000), /* 2nd page is used as IPC buffer of main thread */
_vm_size(2*1024*1024*1024UL - _vm_base), /* use the lower 2GiB */
_init_sel4_ipc_buffer_done((init_sel4_ipc_buffer(), true)),
_switch_to_core_cspace_done((_switch_to_core_cspace(), true)),
_core_page_table_registry(*core_mem_alloc()),
_init_core_page_table_registry_done((_init_core_page_table_registry(), true)),
_init_allocators_done((_init_allocators(), true)),
_core_vm_space(Cap_sel(seL4_CapInitThreadPD),
_core_sel_alloc,
_phys_alloc,
_top_cnode,
_core_cnode,
_phys_cnode,
Core_cspace::CORE_VM_ID,
_core_page_table_registry)
{
/*
* Print statistics about allocator initialization
*/
printf("VM area at [%08lx,%08lx)\n", _vm_base, _vm_base + _vm_size);
if (verbose_boot_info) {
printf(":phys_alloc: "); (*_core_mem_alloc.phys_alloc())()->dump_addr_tree();
printf(":unused_phys_alloc:"); _unused_phys_alloc()->dump_addr_tree();
printf(":virt_alloc: "); (*_core_mem_alloc.virt_alloc())()->dump_addr_tree();
printf(":io_mem_alloc: "); _io_mem_alloc()->dump_addr_tree();
}
_init_rom_modules();
}
unsigned Platform::alloc_core_rcv_sel()
{
Cap_sel rcv_sel = _core_sel_alloc.alloc();
seL4_SetCapReceivePath(_core_cnode.sel().value(), rcv_sel.value(),
_core_cnode.size_log2());
return rcv_sel.value();
}
void Platform::reset_sel(unsigned sel)
{
_core_cnode.remove(Cap_sel(sel));
}
void Platform::wait_for_exit()
{
sleep_forever();
}
void Core_parent::exit(int exit_value) { }
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