# Copyright 2020 The Android KVM Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

##
## This is a GDB script with commands to easier debug KVM on arm64.
## Do not use this script directly. The calling script first replaces
## variables in the form "##VAR##" with real values.
##

set architecture aarch64

define virt_to_phys
	set $__addr = $arg0
	if ($__addr & $kern_va_lm_bit) == 0
		p/x (($__addr & (~$page_offset)) + $phys_offset)
	else
		p/x ($__addr - $kimage_voffset)
	end
end
document virt_to_phys
	Convert kernel VA to IPA and print the result.
	Usage: virt_to_phy <kernel_va>
end

define phys_to_virt
	set $__addr = $arg0
	p/x (($__addr - $phys_offset) | $page_offset)
end
document phys_to_virt
	Convert kernel IPA to linear-map VA and print the result.
	Usage: phys_to_virt <kernel_ipa>
end

define lm_alias
	virt_to_phys $arg0
	phys_to_virt $
end
document lm_alias
	Convert kernel VA to linear-map VA and print the result.
	Usage: lm_alias <kernel_va>
end

define kern_hyp_va
	set $__addr = $arg0
	p/x (($__addr & $hyp_va_mask) | $hyp_va_tag)
end
document kern_hyp_va
	Convert kernel VA to hyp VA and print the result.
	Usage: kern_hyp_va <kernel_va>
end

define sym_hyp_va
	set $__addr = (unsigned long)&$arg0
	lm_alias $__addr
	kern_hyp_va $
end
document sym_hyp_va
	Get hyp VA of an ELF symbol and print the result.
	Usage: sym_hyp_va <sym>
end

define break_nvhe
	sym_hyp_va __kvm_nvhe_$arg0
	b *$
end
define bn
	break_nvhe $arg0
end
document break_nvhe
	Set breakpoint at hyp VA of a given nVHE symbol name.
	Symbol name is provided without the "__kvm_nvhe_" prefix.
	Usage: break_nvhe <sym>
	       bn <sym>
end

file "##ELF_PATH##"

# Break after memory layout constants have been computed.
break apply_alternatives_all
commands
	# Cache kernel constants so they are available regardless
	# of CurrentEL.
	set $hyp_va_tag = (tag_val << tag_lsb)
	set $hyp_va_mask = va_mask
	set $kern_va_lm_bit = (1ul << (vabits_actual - 1))
	set $page_offset = (-(1ul << 48))
	set $phys_offset = memstart_addr
	set $kimage_voffset = kimage_voffset

	# Load the ELF again under hyp VA.
	# We use '_stext' here because 'add-symbol-file' expects address
	# of the '.text' section. '_text' corresponds to '.head.text'.
	sym_hyp_va _stext
	add-symbol-file "##ELF_PATH##" $

	# Unset this breakpoint.
	# Note: this deletes *all* breakpoints.
	delete breakpoint

	echo Protected KVM debug mode initialized\n
end

# Connect to QEMU emulating the kernel.
target remote :1234

# Boot the kernel up to the breakpoint above.
continue