Kernel/aarch64: Perform an ISB after setting TTBR*_EL1

[spholz]

Changes to ARM system registers are not guaranteed to be visible until a context synchronization event, like performing an ISB.

[spholz]

@implicitfield does this also fix your page fault issue when running with hvf?

[implicitfield]

Yes, this does fix the page faults, and now the system appears to boot fine. Unfortunately, nothing appears on the framebuffer, and qemu itself crashes a few seconds after the system has finished starting up, as it hits this assertion. I found a somewhat similar issue on the qemu bug tracker, so could it be that we're not accessing some MMIO region properly somewhere?

Kernel log

[Kernel]: No early framebuffer console available, initializing dummy console [Kernel]: Starting SerenityOS... [Kernel]: DeviceTree: Attached device "timer" to driver ARMv8TimerDriver [Kernel]: DeviceTree: Attached device "intc@8000000" to driver GICDriver [Kernel]: TimeManagement: System timer: ARMv8 Timer 0.000 [Kernel]: KernelRng: Using bad entropy source TimeManagement 0.000 [#0 Kernel]: VFSRootContext(0): Root ("/") FileSystemID 1, Mounting RAMFS at inode 1:1 with flags 0 0.000 [#0 Kernel]: VFSRootContext(0): Context is artificially made, detach from global list 0.000 [#0 colonel(0:0)]: Scheduler[0]: idle loop running 0.237 [init_stage2(1:1)]: PCI [0000:00:00:00] PCI::HardwareID [1b36:0008] 0.237 [init_stage2(1:1)]: PCI [0000:00:01:00] PCI::HardwareID [8086:244e] 0.242 [init_stage2(1:1)]: PCI [0000:01:00:00] PCI::HardwareID [1b36:0010] 0.242 [init_stage2(1:1)]: PCI [0000:00:02:00] PCI::HardwareID [1234:1111] 0.310 [#0 init_stage2(1:1)]: Framebuffer Console: taking 3145728 bytes 0.314 [#0 init_stage2(1:1)]: Framebuffer Console: taking 3145728 bytes 0.314 [#0 init_stage2(1:1)]: VC 0: Resized to 113 x 48 0.314 [#0 init_stage2(1:1)]: VC 1: Resized to 113 x 48 0.314 [#0 init_stage2(1:1)]: VC 2: Resized to 113 x 48 0.314 [#0 init_stage2(1:1)]: VC 3: Resized to 113 x 48 0.314 [#0 init_stage2(1:1)]: VC 4: Resized to 113 x 48 0.314 [#0 init_stage2(1:1)]: VC 5: Resized to 113 x 48 0.320 [#0 init_stage2(1:1)]: AudioManagement: no audio controller was initialized. 0.324 [#0 VFS Sync Task(4:4)]: VFS SyncTask is running 2.322 [#0 init_stage2(1:1)]: GUIDPartitionTable: bad signature 0x00000000 0x00000000 2.322 [#0 init_stage2(1:1)]: VFSRootContext(1): Root ("/") FileSystemID 2, Mounting RAMFS at inode 2:1 with flags 0 2.322 [init_stage2(1:1)]: Ext2FS: Mount successful, setting superblock to error state. 2.326 [#0 init_stage2(1:1)]: VirtualFileSystem: Unmounting file system 2 for the last time... 2.326 [#0 init_stage2(1:1)]: VirtualFileSystem: Unmounting file system 2... 2.326 [#0 init_stage2(1:1)]: VFSRootContext(1): Root mount set to FileSystemID 3, Mounting Ext2FS at inode 3:2 with flags 0 2.326 [init_stage2(1:1)]: Write-protected kernel symbols after init. 2.326 [init_stage2(1:1)]: Unmapped 272 KiB of kernel text after init! :^) 2.326 [init_stage2(1:1)]: Running first user process: /init 2.326 [init_stage2(1:1)]: Init (first) process args: [ ] 2.342 [Network Task(7:7)]: NetworkTask: LoopbackAdapter network adapter found: hw={13:55:02:09:55:aa} 2.354 init(6): Spawning mount -a to mount all filesystems. 2.358 mount(8): Mounting all filesystems... 2.358 mount(8): Skipping mounting root 2.358 mount(8): Mounting /bin (bind) on /bin 2.358 [#0 mount(8:8)]: VFSRootContext(1): Bind-mounting inode 3:115272 at inode 3:115272 2.362 mount(8): Mounting /etc (bind) on /etc 2.362 [#0 mount(8:8)]: VFSRootContext(1): Bind-mounting inode 3:119379 at inode 3:119379 2.362 mount(8): Mounting /home (bind) on /home 2.362 [#0 mount(8:8)]: VFSRootContext(1): Bind-mounting inode 3:12290 at inode 3:12290 2.362 mount(8): Mounting /root (bind) on /root 2.362 [#0 mount(8:8)]: VFSRootContext(1): Bind-mounting inode 3:33364 at inode 3:33364 2.362 mount(8): Mounting /var (bind) on /var 2.362 [#0 mount(8:8)]: VFSRootContext(1): Bind-mounting inode 3:102996 at inode 3:102996 2.362 mount(8): Mounting /www (bind) on /www 2.362 [#0 mount(8:8)]: VFSRootContext(1): Bind-mounting inode 3:90708 at inode 3:90708 2.362 mount(8): Mounting /usr/Tests (bind) on /usr/Tests 2.362 [#0 mount(8:8)]: VFSRootContext(1): Bind-mounting inode 3:33092 at inode 3:33092 2.362 mount(8): Mounting /usr/local (bind) on /usr/local 2.362 [#0 mount(8:8)]: VFSRootContext(1): Bind-mounting inode 3:41304 at inode 3:41304 2.362 mount(8): Mounting /usr/Ports (bind) on /usr/Ports 2.362 [#0 mount(8:8)]: VFSRootContext(1): Bind-mounting inode 3:127325 at inode 3:127325 2.366 [#0 init(6:6)]: VirtualFileSystem: Remounting inode 3:2 2.366 [#0 init(6:6)]: VFSRootContext(1): FileSystemID 4, Mounting ProcFS at inode 3:8193 with flags 4 2.366 [#0 init(6:6)]: VFSRootContext(1): FileSystemID 5, Mounting SysFS at inode 3:86612 with flags 0 2.366 [#0 init(6:6)]: VFSRootContext(1): FileSystemID 6, Mounting RAMFS at inode 3:53844 with flags 262 2.366 [#0 init(6:6)]: VFSRootContext(1): FileSystemID 7, Mounting RAMFS at inode 3:119380 with flags 5 2.366 init(6): Creating /tmp/system/devicemap directory 2.366 [#0 init(6:6)]: VFSRootContext(1): FileSystemID 8, Mounting RAMFS at inode 7:3 with flags 7 2.374 [#0 init(6:6)]: VFSRootContext(1): FileSystemID 9, Mounting DevPtsFS at inode 6:10 with flags 0 2.374 [#0 init(6:6)]: VFSRootContext(1): FileSystemID 10, Mounting DevLoopFS at inode 6:11 with flags 0 2.378 init(6): Creating /tmp/coredump directory 2.378 init(6): Setting /tmp/coredump as the coredump directory 2.378 init(6): Creating /tmp/semaphore directory 2.395 SystemServer(6): Read system_mode: text 2.399 SystemServer(6): No such file or directory (errno=2) 2.399 SystemServer(6): No such file or directory (errno=2) 2.399 SystemServer(6): No such file or directory (errno=2) 2.399 SystemServer(6): Activating 4 services... 2.455 LookupServer(11): Using network config file at /etc/LookupServer.ini 2.476 NetworkServer(12): Interfaces to configure: [ ep1s0 ] 2.480 SystemServer(6): Service NetworkServer has exited with exit code 0 Assertion failed: (isv), function hvf_vcpu_exec, file hvf.c, line 1230.