Messages in this thread | | | Subject | Re: [PATCH v3 1/6] x86/alternatives: Teach text_poke_bp() to emulate instructions | From | Daniel Bristot de Oliveira <> | Date | Wed, 9 Oct 2019 14:03:16 +0200 |
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On 07/10/2019 10:17, Peter Zijlstra wrote: > In preparation for static_call and variable size jump_label support, > teach text_poke_bp() to emulate instructions, namely: > > JMP32, JMP8, CALL, NOP2, NOP_ATOMIC5, INT3 > > The current text_poke_bp() takes a @handler argument which is used as > a jump target when the temporary INT3 is hit by a different CPU. > > When patching CALL instructions, this doesn't work because we'd miss > the PUSH of the return address. Instead, teach poke_int3_handler() to > emulate an instruction, typically the instruction we're patching in. > > This fits almost all text_poke_bp() users, except > arch_unoptimize_kprobe() which restores random text, and for that site > we have to build an explicit emulate instruction. > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Daniel Bristot de Oliveira <bristot@redhat.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Thanks! -- Daniel
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