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authorJordan Niethe <jniethe5@gmail.com>2022-07-12 10:46:24 +1000
committerAlexey Kardashevskiy <aik@ozlabs.ru>2022-07-19 12:54:08 +1000
commitb3f699c06ac03909d4af11806f3450092cde60ee (patch)
tree231cb5c023145802d31a5b9c0c2900e834a9f549 /slof/fs/boot.fs
parent5b4c5acdcd552a4e1796aeca6bb700f6cbb0282d (diff)
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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>
Diffstat (limited to 'slof/fs/boot.fs')
-rw-r--r--slof/fs/boot.fs6
1 files changed, 6 insertions, 0 deletions
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 !
;