* Thread creation and switching is working fine, however threads do not yet
get interrupted because I've not implemented hardware interrupt handling
yet (I'll do that next).
* I've made some changes to struct iframe: I've removed the e/r prefixes
from the member names for both 32/64, so now they're just named ip, ax,
bp, etc. This makes it easier to write code that works with both 32/64
without having to deal with different iframe member names.
This has been done by adding typedefs in elf_common.h to the correct ELF
structures for the architecture, and changing all Elf32_* uses to those
types. I don't know whether image loading works as I cannot test it yet,
there may be some 64-bit safety issues around. However, symbol lookup for
the kernel is working correctly.
This was an interesting bug to find. Was getting spurious triple faults
in the slab allocator. The problem was that the boot paging setup code
was mapping all page tables it created into the virtual address space,
but in the kernel no areas were being created to cover them, so during
arch_vm_init_end() the pages for them ended up being freed and then
overwritten later on. Fixed by unmapping page tables after populating
them in long_mmu_init().
* mmu_get_virtual_mapping() should check that the page directory entry is
present rather than assuming there's a page table there. This was resulting
in some invalid mappings being created in the 64-bit virtual address space.
* arch_vm_init_end() should clear from KERNEL_LOAD_BASE to virtual_end, not
from KERNEL_BASE. On x86_64 this was causing it to loop through ~512GB of
address space, which obviously was taking quite a while.
* Uses 64-bit multiplication, special handling for CPUs clocked < 1 GHz
in system_time_nsecs() not required like on x86.
* Tested against a straight conversion of the x86 version, noticably
faster with a large number of system_time() calls.
* vm_init now runs up until create_preloaded_image_areas(), which needs
fixing to handle ELF64.
* Not completely tested. I know Map(), Unmap() and Query() work fine, the
other methods have not been tested as the kernel doesn't boot far enough
for any of them to be called yet. As far as I know they're correct, though.
* Not yet implemented the destructor for X86VMTranslationMap64Bit or Init()
for a user address space.
Will be merged with the x86 one later on. Requires -fno-omit-frame-pointer on
the kernel build flags, GCC defaults to not generating stack frames on x86_64.
* Wasn't storing the fixed virtual address of the PML4 in kernel_args.
* After switching to long mode, reload GDTR with the virtual address of
the GDT. This was working fine until now because the physical address
was identity mapped, but broke as soon as I removed the identity
mapping.
* typedef for jmp_buf was using int where it should be long.
* setjmp was clearing the buffer pointer rather than the signal mask before
calling sigsetjmp.
* KDL now works without crashing on x86_64.
Since x86_64 has such a large virtual address space all available physical
memory can be mapped in to it. The physical page mapper implementation for
x86_64 will use this mapping. Also changed the mapping code to map kernel
pages with the global flag.
* Added empty source files for all the 64-bit paging method code, and a
stub implementation of X86PagingMethod64Bit.
* arch_vm_translation_map.cpp has been modified to use X86PagingMethod64Bit
on x86_64.
* Some things are currently ifndef'd out completely for x86_64 because
they aren't implemented, there's a few other ifdef's to handle x86_64
differences but most of the code works unchanged.
* Renamed some i386_* functions to x86_*.
* Added a temporary method for setting the current thread on x86_64
(a global variable, not SMP safe). This will be changed to be done
via the GS segment but I've not implemented that yet.
I've split the 32-bit dependent IDT setup code and ASM interrupt handlers to
the 32 subdirectory, arch_int.cpp now contains only the generic hardware
interrupt handling code.
For now I've just put all the stub functions that are needed to link the
kernel into a file called stubs.cpp. I've not yet moved across the interrupt
handling code or the ELF64 relocation code to the x86 directory. Once those
have been moved I can get rid of the x86_64 headers/source directories.
Not many changes seeing as there's not much x86_64 stuff done yet. Small
differences are handled with ifdefs, large differences (descriptors.h,
struct iframe) have separate headers under arch/x86/32 and arch/x86/64.
Since x86 and x86_64 share a lot of common code, x86_64 kernel sources/headers
are going to reside under headers/private/kernel/arch/x86 and
src/system/kernel/arch/x86 along with the existing x86 code. This commit
changes the build system to handle this. A new variable, TARGET_KERNEL_ARCH,
has been added. This is the name of the kernel/boot architecture directory
name, set to x86 on both x86 and x86_64. This is now used in all places where
TARGET_ARCH was used to get to kernel arch sources/headers (I've changed
everything necessary as far as I can tell). Kernel won't build for x86_64
at the moment as the sources have not been merged, loader does.
The setup procedure is fairly simple: create a 64-bit GDT and 64-bit page
tables that include all kernel mappings from the 32-bit address space, but at
the correct 64-bit address, then go through kernel_args and changes all virtual
addresses to 64-bit addresses, and finally switch to long mode and jump to the
kernel.
* platform_allocate_elf_region() is removed, it is implemented in platform-
independent code now (ELF*Class::AllocateRegion). For ELF64 it is now
assumed that 64-bit addresses are mapped in the loader's 32-bit address space
as (address - KERNEL_BASE_64BIT + KERNEL_BASE).
* mapped_delta field from preloaded_*_image removed, now handled compile-time
using the ELF*Class::Map method.
* Also link the kernel with -z max-page-size=0x1000, removes the need for
2MB alignment on the data segment (not going to map the kernel with large
pages for the time being).
The ELF loader now uses a new platform function, platform_allocate_elf_region,
which returns 2 addresses: the real load address and an address where the
region is mapped in the loader's address space. All of the ELF loading code
has been changed to access the load region through the mapped address rather
than the addresses contained in the ELF image. The ELF64 version of
platform_allocate_elf_region on x86 uses the existing MMU code, which maps
everything at 0x80000000, but returns the correct 64-bit address. The long
mode switch code will just set up the 64-bit address space with everything
remapped at the correct address.
After enabling BOOT_SUPPORT_ELF64 on x86 the x86 kernel could no longer be
booted because too many kernel_args allocations were taking place and filling
kernel_args_ranges. This was because for each image load it would check if
the image is ELF64, fail and fall back to ELF32 (each ELF64 check allocated
a preloaded_image). Changed elf_load_image() so that it only tries both when
loading the kernel image, and then for modules it will only try the same ELF
class as the kernel image.
The actual implementation of the ELF loading methods have been put into
an ELFLoader template class that takes a single template parameter, which
is a structure containing all the necessary ELF typedefs. It's a bit
verbose, but I thought it was a neater solution than using a bunch of
standalone functions with a huge number of template parameters. There is
no change to code outside of elf.cpp, the ELF32/ELF64 differences are
handled internally.
* There is now 2 structures, preloaded_elf32_image and preloaded_elf64_image,
which both inherit from preloaded_image.
* For now I've just hardcoded in use of preloaded_elf32_image, but the
bootloader ELF code will shortly be converted to use templates which use
the appropriate structure. The kernel will be changed later when I add
ELF64 support to it.
* All kernel_args data is now compatible between 32-bit and 64-bit kernels.
* Added a FixedWidthPointer template class which uses 64-bit storage to hold
a pointer. This is used in place of raw pointers in kernel_args.
* Added __attribute__((packed)) to kernel_args and all structures contained
within it. This is necessary due to different alignment behaviour for
32-bit and 64-bit compilation with GCC.
* With these changes, kernel_args will now come out the same size for both
the x86_64 kernel and the loader, excluding the preloaded_image structure
which has not yet been changed.
* Tested both an x86 GCC2 and GCC4 build, no problems caused by these changes.
I've tested this change on x86, causing no issues. I've checked over the code
for all other platforms and made the necessary changes and to the best of my
knowledge they should also still work, but I haven't actually built and
tested them. Once I've completed the kernel_args changes the other platforms
will need testing.
Pointers in kernel_args are going to be changed to unconditionally use 64-bit
storage (to make kernel_args compatible with both the x86 and x86_64 kernels).
KMessage stores a pointer to its buffer, however since KMessage is used
outside of the boot code it is undesirable to change it to use 64-bit storage
for the pointer as it may add additional overhead on 32-bit builds. Therefore,
only store the buffer address and size and then construct a KMessage from
those in the kernel.
* set_haiku_revision doesn't currently support ELF64, don't use a
revisioned kernel image on x86_64 for now.
* Don't try to build add-ons for x86_64 yet.
The whole kernel now builds and there are no undefined references when
linking, I just need to fix some strange relocation errors I'm getting
(probably a problem with the linker script) and then I'll have a kernel
image.
The red zone is a 128-byte area below the stack pointer specified by the
AMD64 ABI that can be used by leaf functions for their stack frame without
modifying the stack pointer. It is guaranteed not to be modified by signal
handlers. This cannot be used in kernel mode code, as an interrupt handler
could overwrite it, so stop GCC from generating code that uses it.
Since ICI arguments are used to send addresses in some places, uint32 is
not sufficient on x86_64. addr_t still refers to the same type as uint32
(unsigned long) on other platforms, so this change only really affects
x86_64.
* Most of this is incorrect printf format strings. Changed all strings
causing errors to use the B_PRI* format string definitions, which
means the strings should be correct across all platforms.
* Some other fixes for errors, casts required, etc.
* Based on the x86 one, changes made to match the default GCC x86_64 linker
script and correct kernel load address added.
* Not tested yet as the kernel doesn't fully compile.
* x86_64 is using the existing *_ia32 boot platforms.
* Special flags are required when compiling the loader to get GCC to compile
32-bit code. This adds a new set of rules for compiling boot code rather
than using the kernel rules, which compile using the necessary flags.
* Some x86_64 private headers have been stubbed by #include'ing the x86
versions. These will be replaced later.
This appears to be a problem with GCC's build system: it defaults to having
multilib enabled, but if it is explicitly enabled with --enable-multilib,
the build fails.
Signed-off-by: Ingo Weinhold <[email protected]>
Alex Smith