On Thursday, 14 May 2020 4:11:43 PM AEST Christophe Leroy wrote: > @@ -249,7 +249,7 @@ int arch_prepare_optimized_kprobe(struct > optimized_kprobe *op, struct kprobe *p) > > * Fixup the template with instructions to: > > * 1. load the address of the actual probepoint > > */ > > - patch_imm64_load_insns((unsigned long)op, buff + TMPL_OP_IDX); > > + patch_imm64_load_insns((unsigned long)op, 3, buff + TMPL_OP_IDX); > > > > /* > > * 2. branch to optimized_callback() and emulate_step() > > @@ -282,7 +282,11 @@ int arch_prepare_optimized_kprobe(struct > > optimized_kprobe *op, struct kprobe *p) /* > > * 3. load instruction to be emulated into relevant register, and > > */ > > - patch_imm32_load_insns(*p->ainsn.insn, buff + TMPL_INSN_IDX); > > + temp = ppc_inst_read((struct ppc_inst *)p->ainsn.insn); > > + patch_imm64_load_insns(ppc_inst_val(temp) | > > + ((u64)ppc_inst_suffix(temp) << 32), > > + 4, > > So now we are also using r4 ? Any explanation somewhere on the way it > works ? This change seems unrelated to this patch, nothing in the > description about it. Can we suddenly use a new register without problem ?
Unless I missed something there is no change in register usage here that I could see. patch_imm32_load_insns() was/is hardcoded to use register r4. - Alistair
