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authorPeter Zijlstra <peterz@infradead.org>2022-03-18 21:24:38 +0100
committerPeter Zijlstra <peterz@infradead.org>2022-04-05 09:59:37 +0200
commit1cd5f059d956e6f614ba6666ecdbcf95db05d5f5 (patch)
tree67088bbdb10a57988b8cc323e65abb0cb20c865e /kernel/static_call_inline.c
parent3123109284176b1532874591f7c81f3837bbdc17 (diff)
x86,static_call: Fix __static_call_return0 for i386
Paolo reported that the instruction sequence that is used to replace: call __static_call_return0 namely: 66 66 48 31 c0 data16 data16 xor %rax,%rax decodes to something else on i386, namely: 66 66 48 data16 dec %ax 31 c0 xor %eax,%eax Which is a nonsensical sequence that happens to have the same outcome. *However* an important distinction is that it consists of 2 instructions which is a problem when the thing needs to be overwriten with a regular call instruction again. As such, replace the instruction with something that decodes the same on both i386 and x86_64. Fixes: 3f2a8fc4b15d ("static_call/x86: Add __static_call_return0()") Reported-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20220318204419.GT8939@worktop.programming.kicks-ass.net
Diffstat (limited to 'kernel/static_call_inline.c')
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