Changeset a4bd537 in mainline for kernel/genarch/src/mm/as_pt.c

Timestamp:

2019-04-06T13:39:58Z (6 years ago)

Author:

Petr Pavlu <setup@…>

Children:

f7842ef

Parents:

0d073b8

git-author:

Petr Pavlu <setup@…> (2019-03-31 14:09:57)

git-committer:

Petr Pavlu <setup@…> (2019-04-06 13:39:58)

Message:

arm64: Add support for the architecture

This changeset adds basic support to run HelenOS on AArch64, targeting
the QEMU virt platform.

Boot:

• Boot relies on the EDK II firmware, GRUB2 for EFI and the HelenOS bootloader (UEFI application). EDK II loads GRUB2 from a CD, GRUB2 loads the HelenOS bootloader (via UEFI) which loads OS components.
• UEFI applications use the PE/COFF format and must be relocatable. The first problem is solved by manually having the PE/COFF headers and tables written in assembler. The relocatable requirement is addressed by compiling the code with -fpic and having the bootloader relocate itself at its startup.

Kernel:

• Kernel code for AArch64 consists mostly of stubbing out various architecture-specific hooks: virtual memory management, interrupt and exception handling, context switching (including FPU lazy switching), support for virtual timer, atomic sequences and barriers, cache and TLB maintenance, thread and process initialization.
• The patch adds a kernel driver for GICv2 (interrupt controller).
• The PL011 kernel driver is extended to allow userspace to take ownership of the console.
• The current code is not able to dynamically obtain information about available devices on the underlying machine. The port instead implements a machine-func interface similar to the one implemented by arm32. It defines a machine for the QEMU AArch64 virt platform. The configuration (device addresses and IRQ numbers) is then baked into the machine definition.

User space:

• Uspace code for AArch64 similarly mostly implements architecture-specific hooks: context saving/restoring, syscall support, TLS support.

The patchset allows to boot the system but user interaction with the OS
is not yet possible.

File:

• kernel/genarch/src/mm/as_pt.c (modified) (2 diffs)

kernel/genarch/src/mm/as_pt.c

@@ -76 +76 @@
             PA2KA(frame_alloc(PTL0_FRAMES, FRAME_LOWMEM, PTL0_SIZE - 1));
 
-        if (flags & FLAG_AS_KERNEL)
-                memsetb(dst_ptl0, PTL0_SIZE, 0);
-        else {
+        memsetb(dst_ptl0, PTL0_SIZE, 0);
+
+        if (!KERNEL_SEPARATE_PTL0 && !(flags & FLAG_AS_KERNEL)) {
                 /*
                  * Copy the kernel address space portion to new PTL0.
@@ -93 +93 @@
                     &dst_ptl0[PTL0_INDEX(KERNEL_ADDRESS_SPACE_START)];
 
-                memsetb(dst_ptl0, PTL0_SIZE, 0);
                 memcpy((void *) dst, (void *) src,
                     PTL0_SIZE - (src - (uintptr_t) src_ptl0));