| d7e6ab7a | 17-Apr-2025 |
Warner Losh <imp@FreeBSD.org> |
kboot: Add support for UEFI booting amd64
In an ideal world, we'd get systbl and efi memory map from
/sys/firmware/efi somewhere. They are currently not published,
but may be in the future.
The sys
kboot: Add support for UEFI booting amd64
In an ideal world, we'd get systbl and efi memory map from
/sys/firmware/efi somewhere. They are currently not published,
but may be in the future.
The systab comes from the first call to the EFI entry point and there's
no way to find it otherwise.
Memmap is obtained from BootServices which is long gone. And besides,
it's modified for the runtime entries for the call to
SetVirtualAddresses call in runtime services. Even though that's in
runtime services, it can be called only once.
kexec tools + Pandora (the kexec boot loader embedded in the Linux
kenrel) don't need this because pandora copyies this structure over when
the new kernel is a bzImage. Our current trampoline doesn't do that, so
we have to get it from the current kernel. Even so, we have to pass the
PAs for the memory map to the trampoline which copies this over (in part
so we can boot an modified kernel, otherwise we could put this into an
alternative entry point, but those are hard to manage).
So, we can sig out the PA of the memory map via this method, but some
care is needed. For the initial round, it suffices. However, Linux on
x86 does some odd things with EFI_RUNTIME that need to be preserved (so
this is a temporary measure until we get the /sys/firmware/efi code
working). The Linux kernel keeps this memory around, but it's not clear
how long. It stops referencing it after it converts it to the BIOS e820
memory map array it uses elsewhere. It seems to be OK to use since our
use case is an immediate boot to FreeBSD, not a boot after Linux runs a
while and had a chance to (maybe) overwrite this data.
Migrating to a proper interface that publishes the modified EFI
map in /sys/firmware/efi/memmap is in the future.
Update the trampoline to copy this data before jumping into the kernel.
We use the simple laucnhing interface instead of the bzImage interface
that kexec_file() uses, so there's no last-second chance to use the
boot params data.
Sponsored by: Netflix
Reviewed by: kevans
Differential Revision: https://reviews.freebsd.org/D49869
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| f3c0d74e | 17-Apr-2025 |
Warner Losh <imp@FreeBSD.org> |
kboot: Implement data_from_kernel to read kernel variables
Since the linux kernel doesn't expose enough of the EFI details to
userland via /sys/firmware/efi, write a routine to extract data from the
kboot: Implement data_from_kernel to read kernel variables
Since the linux kernel doesn't expose enough of the EFI details to
userland via /sys/firmware/efi, write a routine to extract data from the
kernel directly by parsing /proc/kproc and /proc/kallsyms.
Sponsored by: Netflix
Reviewed by: kevans, jhibbits
Differential Revision: https://reviews.freebsd.org/D49868
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| b7d1c3fd | 17-Apr-2025 |
Warner Losh <imp@FreeBSD.org> |
kboot/amd64: Use efi_bi_loadsmap in bi_loadsmap
For the EFI case, we just need to call efi_bi_loadsmap in bi_loadsmap.
If we need to do BIOS again, we'll revisit.
Sponsored by: Netflix
Reviewed by
kboot/amd64: Use efi_bi_loadsmap in bi_loadsmap
For the EFI case, we just need to call efi_bi_loadsmap in bi_loadsmap.
If we need to do BIOS again, we'll revisit.
Sponsored by: Netflix
Reviewed by: kevans, jhibbits
Differential Revision: https://reviews.freebsd.org/D49867
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| 50bc81e7 | 17-Apr-2025 |
Warner Losh <imp@FreeBSD.org> |
kboot/amd64: Use segs framework to find kernel location
Use the segs framework to find a place to land the kernel, with the same
super ugly defaults as aarch64.
Sponsored by: Netflix
Reviewed by:
kboot/amd64: Use segs framework to find kernel location
Use the segs framework to find a place to land the kernel, with the same
super ugly defaults as aarch64.
Sponsored by: Netflix
Reviewed by: kevans, jhibbits
Differential Revision: https://reviews.freebsd.org/D49866
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| 9acf6422 | 17-Apr-2025 |
Warner Losh <imp@FreeBSD.org> |
kboot/amd64: Use common routines for memory map parsing
Use populate_avail_from_iomem and efi_read_from_sysfs from the
refactored work rather than replicating them (imperfectly) here.
Note: memmap
kboot/amd64: Use common routines for memory map parsing
Use populate_avail_from_iomem and efi_read_from_sysfs from the
refactored work rather than replicating them (imperfectly) here.
Note: memmap might need to be revisited. EFI memory maps are complex on
x86 and we might need to reconstruct it from /sys/firmware/memmap as
well as using that for the BIOS case, should we ever want to support
that again (hardware makes no sense, but many VM hosting services use
that). For now, we're going all in on EFI, though, and will revisit what
to do about BIOS later. The zfsboot project suggests BIOS support isn't
really that hard (but is a distraction atm).
Sponsored by: Netflix
Reviewed by: kevans, jhibbits
Differential Revision: https://reviews.freebsd.org/D49864
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| 92ad79ec | 17-Apr-2025 |
Warner Losh <imp@FreeBSD.org> |
kboot: Move common EFI stuff from aarch64 to libkboot
Move efi_read_from_pa, efi_set_systbl and efi_bi_loadsmap into efi.c
Move prototype for populate_avail_from_efi as well, though that arrived
pre
kboot: Move common EFI stuff from aarch64 to libkboot
Move efi_read_from_pa, efi_set_systbl and efi_bi_loadsmap into efi.c
Move prototype for populate_avail_from_efi as well, though that arrived
previously.
Move efi memory map variables into efi.c.
Add efi_read_from_sysfs, but if 0 it out. We'll want to use it if we can
get the proposed /sys/firmware/efi/memmap data published in the same
format and the code works, it's just that the current
/sys/firmware/efi/runtime-memmap isn't complete enough to use.
Sponsored by: Netflix
Reviewed by: kevans, jhibbits
Differential Revision: https://reviews.freebsd.org/D49863
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| 988ee1cc | 17-Apr-2025 |
Warner Losh <imp@FreeBSD.org> |
kboot: Method to populate the avail array from EFI map
If we can get an efi memory map, populate_avail_from_efi will create an
avail array. We only use the regiions marked as 'free' to find a place
kboot: Method to populate the avail array from EFI map
If we can get an efi memory map, populate_avail_from_efi will create an
avail array. We only use the regiions marked as 'free' to find a place
for the kernel to land. The other regions are also eligible, but usually
too small to materially affect where we'd put the kernel (not to worry,
the kernel will use that memory).
Sponsored by: Netflix
Reviewed by: kevans, jhibbits
Differential Revision: https://reviews.freebsd.org/D49862
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| 0c48531b | 17-Apr-2025 |
Warner Losh <imp@FreeBSD.org> |
kboot: Account for machine specific padding
AMD64 kernels have an extra 2MB of padding that we need to account
for. So make the padding proper on a per-architecture basis.
Sponsored by: Netflix
Re
kboot: Account for machine specific padding
AMD64 kernels have an extra 2MB of padding that we need to account
for. So make the padding proper on a per-architecture basis.
Sponsored by: Netflix
Reviewed by: kevans, jhibbits
Differential Revision: https://reviews.freebsd.org/D49861
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| f0f44cdb | 17-Apr-2025 |
Warner Losh <imp@FreeBSD.org> |
kboot: Save the upper limit of the call stack.
The location of argc argument is a fine limit for the extent of the
stack traceback. We could save the location of return address for the
call to _star
kboot: Save the upper limit of the call stack.
The location of argc argument is a fine limit for the extent of the
stack traceback. We could save the location of return address for the
call to _start_c, but we'd have to move that into MD assembler. While
not hard, it wouldn't improve the traces we can get. And the math to
find it is architecture dependent (though the same for both arm64 and
amd64).
Sponsored by: Netflix
Reviewed by: kevans, andrew, jhibbits
Differential Revision: https://reviews.freebsd.org/D49858
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| 5fb044c8 | 17-Apr-2025 |
Warner Losh <imp@FreeBSD.org> |
kboot: format nit
Deleting trailing newline.
Sponsored by: Netflix
Reviewed by: kevans, andrew, emaste, jhibbits
Differential Revision: https://reviews.freebsd.org/D49857 |
| 14acbf61 | 17-Apr-2025 |
Warner Losh <imp@FreeBSD.org> |
kboot: Add option to parse 32-bit quantity
The type that's exposed from sysfs' memory map is 32-bit and so is the
data-type of memory description.
Sponsored by: Netflix
Reviewed by: kevans, andre
kboot: Add option to parse 32-bit quantity
The type that's exposed from sysfs' memory map is 32-bit and so is the
data-type of memory description.
Sponsored by: Netflix
Reviewed by: kevans, andrew, jhibbits
Differential Revision: https://reviews.freebsd.org/D49856
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| 58c99df2 | 17-Apr-2025 |
Warner Losh <imp@FreeBSD.org> |
kboot: .note.GNU-stack is needed
Add '.section .note.GNU-stack,"",%progbits' to all assembler. Newer
versions of clang complain when this isn't present because executable
stacks are going away in th
kboot: .note.GNU-stack is needed
Add '.section .note.GNU-stack,"",%progbits' to all assembler. Newer
versions of clang complain when this isn't present because executable
stacks are going away in the future. We don't need an executable stack
anyway.
Sponsored by: Netflix
Reviewed by: kevans, andrew, emaste, jhibbits
Differential Revision: https://reviews.freebsd.org/D49855
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