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| author |   Peter Zijlstra <peterz@infradead.org> | 2022-03-08 16:30:31 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-03-15 10:32:37 +0100 |
| commit | e52fc2cf3f662828cc0d51c4b73bed73ad275fce (patch) | |
| tree | 66c13647656492fd38701ff5bf2adff25e6e4b20 /lib/errseq.c | |
| parent | x86/livepatch: Validate __fentry__ location (diff) | |
| download | linux-dev-e52fc2cf3f662828cc0d51c4b73bed73ad275fce.tar.xz linux-dev-e52fc2cf3f662828cc0d51c4b73bed73ad275fce.zip | |
x86/ibt,ftrace: Make function-graph play nice
Return trampoline must not use indirect branch to return; while this
preserves the RSB, it is fundamentally incompatible with IBT. Instead
use a retpoline like ROP gadget that defeats IBT while not unbalancing
the RSB.
And since ftrace_stub is no longer a plain RET, don't use it to copy
from. Since RET is a trivial instruction, poke it directly.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154318.347296408@infradead.org
Diffstat (limited to 'lib/errseq.c')
0 files changed, 0 insertions, 0 deletions