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| author | Jordan Niethe <jniethe5@gmail.com> | 2022-07-12 10:46:24 +1000 |
|---|---|---|
| committer | Alexey Kardashevskiy <aik@ozlabs.ru> | 2022-07-19 12:54:08 +1000 |
| commit | b3f699c06ac03909d4af11806f3450092cde60ee (patch) | |
| tree | 231cb5c023145802d31a5b9c0c2900e834a9f549 | |
| parent | 5b4c5acdcd552a4e1796aeca6bb700f6cbb0282d (diff) | |
| download | qemu-SLOF-b3f699c06ac03909d4af11806f3450092cde60ee.tar.gz | |
OF: Add a separate direct kernel loading word
Currently, go-64 is used for booting a kernel from qemu (i.e. -kernel).
However, there is an expectation from users that this should be able to
boot not just vmlinux kernels but things like Zimages too.
The bootwrapper of a BE zImage is a 32-bit ELF. Attempting to load that
with go-64 means that it will be ran with MSR_SF set (64-bit mode). This
crashes early in boot (usually due to what should be 32-bit operations
being done with 64-bit registers eventually leading to an incorrect
address being generated and branched to).
Note that our 64-bit payloads are prepared to enter with MSR_SF cleared
and set it themselves very early.
Add a new word named go-direct that will execute any simple payload
in-place and will enter with MSR_SF cleared. This allows booting a BE
zImage from qemu with -machine kernel-addr=0.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
| -rw-r--r-- | board-qemu/slof/OF.fs | 5 | ||||
| -rw-r--r-- | slof/fs/boot.fs | 6 |
2 files changed, 8 insertions, 3 deletions
diff --git a/board-qemu/slof/OF.fs b/board-qemu/slof/OF.fs index f0fc9c6..3bcb2af 100644 --- a/board-qemu/slof/OF.fs +++ b/board-qemu/slof/OF.fs @@ -303,10 +303,9 @@ set-default-console : (boot-ram) direct-ram-boot-size 0<> IF ." Booting from memory..." cr - s" go-args 2@ " evaluate - direct-ram-boot-base 0 + s" direct-ram-boot-base to go-entry" evaluate s" true state-valid ! " evaluate - s" disable-watchdog go-64" evaluate + s" disable-watchdog go-direct" evaluate THEN ; diff --git a/slof/fs/boot.fs b/slof/fs/boot.fs index 6d16c54..a6dfdf3 100644 --- a/slof/fs/boot.fs +++ b/slof/fs/boot.fs @@ -112,6 +112,12 @@ defer go ( -- ) claim-list elf-release 0 to claim-list ; +: go-direct ( -- ) + 0 ciregs >r3 ! 0 ciregs >r4 ! 0 ciregs >r2 ! + msr@ 7fffffffffffffff and 2000 or ciregs >srr1 ! + go-args 2@ go-entry call-client +; + : set-le ( -- ) 1 ciregs >r13 ! ; |