To aid with debugging, add details of the source of a panic from nVHE
hyp. This is done by having nVHE hyp exit to nvhe_hyp_panic_handler()
rather than directly to panic(). The handler will then add the extra
details for debugging before panicking the kernel.

If the panic was due to a BUG(), look up the metadata to log the file
and line, if available, otherwise log an address that can be looked up
in vmlinux. The hyp offset is also logged to allow other hyp VAs to be
converted, similar to how the kernel offset is logged during a panic.

__hyp_panic_string is now inlined since it no longer needs to be
referenced as a symbol and the message is free to diverge between VHE
and nVHE.

The following is an example of the logs generated by a BUG in nVHE hyp.

[   46.754840] kvm [307]: nVHE hyp BUG at: arch/arm64/kvm/hyp/nvhe/switch.c:242!
[   46.755357] kvm [307]: Hyp Offset: 0xfffea6c58e1e0000
[   46.755824] Kernel panic - not syncing: HYP panic:
[   46.755824] PS:400003c9 PC:0000d93a82c705ac ESR:f2000800
[   46.755824] FAR:0000000080080000 HPFAR:0000000000800800 PAR:0000000000000000
[   46.755824] VCPU:0000d93a880d0000
[   46.756960] CPU: 3 PID: 307 Comm: kvm-vcpu-0 Not tainted 5.12.0-rc3-00005-gc572b99cf65b-dirty #133
[   46.757459] Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
[   46.758366] Call trace:
[   46.758601]  dump_backtrace+0x0/0x1b0
[   46.758856]  show_stack+0x18/0x70
[   46.759057]  dump_stack+0xd0/0x12c
[   46.759236]  panic+0x16c/0x334
[   46.759426]  arm64_kernel_unmapped_at_el0+0x0/0x30
[   46.759661]  kvm_arch_vcpu_ioctl_run+0x134/0x750
[   46.759936]  kvm_vcpu_ioctl+0x2f0/0x970
[   46.760156]  __arm64_sys_ioctl+0xa8/0xec
[   46.760379]  el0_svc_common.constprop.0+0x60/0x120
[   46.760627]  do_el0_svc+0x24/0x90
[   46.760766]  el0_svc+0x2c/0x54
[   46.760915]  el0_sync_handler+0x1a4/0x1b0
[   46.761146]  el0_sync+0x170/0x180
[   46.761889] SMP: stopping secondary CPUs
[   46.762786] Kernel Offset: 0x3e1cd2820000 from 0xffff800010000000
[   46.763142] PHYS_OFFSET: 0xffffa9f680000000
[   46.763359] CPU features: 0x00240022,61806008
[   46.763651] Memory Limit: none
[   46.813867] ---[ end Kernel panic - not syncing: HYP panic:
[   46.813867] PS:400003c9 PC:0000d93a82c705ac ESR:f2000800
[   46.813867] FAR:0000000080080000 HPFAR:0000000000800800 PAR:0000000000000000
[   46.813867] VCPU:0000d93a880d0000 ]---
Signed-off-by: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210318143311.839894-6-ascull@google.com