Commit 7a8818e0 authored by Jordan Niethe's avatar Jordan Niethe Committed by Michael Ellerman
Browse files

powerpc/optprobes: Add register argument to patch_imm64_load_insns() 



Currently patch_imm32_load_insns() is used to load an instruction to
r4 to be emulated by emulate_step(). For prefixed instructions we
would like to be able to load a 64bit immediate to r4. To prepare for
this make patch_imm64_load_insns() take an argument that decides which
register to load an immediate to - rather than hardcoding r3.

Signed-off-by: default avatarJordan Niethe <jniethe5@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200516115449.4168796-1-mpe@ellerman.id.au
parent b691505e

arch/powerpc/kernel/optprobes.c

+17 −17
Original line number Diff line number Diff line
@@ -162,38 +162,38 @@ void patch_imm32_load_insns(unsigned int val, kprobe_opcode_t *addr) 


/*

 * Generate instructions to load provided immediate 64-bit value

 * to register 'r3' and patch these instructions at 'addr'.

 * to register 'reg' and patch these instructions at 'addr'.

 */

void patch_imm64_load_insns(unsigned long val, kprobe_opcode_t *addr)

void patch_imm64_load_insns(unsigned long val, int reg, kprobe_opcode_t *addr)

{

	/* lis r3,(op)@highest */

	/* lis reg,(op)@highest */

	patch_instruction((struct ppc_inst *)addr,

			  ppc_inst(PPC_INST_ADDIS | ___PPC_RT(3) |

			  ppc_inst(PPC_INST_ADDIS | ___PPC_RT(reg) |

				   ((val >> 48) & 0xffff)));

	addr++;



	/* ori r3,r3,(op)@higher */

	/* ori reg,reg,(op)@higher */

	patch_instruction((struct ppc_inst *)addr,

			  ppc_inst(PPC_INST_ORI | ___PPC_RA(3) |

				   ___PPC_RS(3) | ((val >> 32) & 0xffff)));

			  ppc_inst(PPC_INST_ORI | ___PPC_RA(reg) |

				   ___PPC_RS(reg) | ((val >> 32) & 0xffff)));

	addr++;



	/* rldicr r3,r3,32,31 */

	/* rldicr reg,reg,32,31 */

	patch_instruction((struct ppc_inst *)addr,

			  ppc_inst(PPC_INST_RLDICR | ___PPC_RA(3) |

				   ___PPC_RS(3) | __PPC_SH64(32) | __PPC_ME64(31)));

			  ppc_inst(PPC_INST_RLDICR | ___PPC_RA(reg) |

				   ___PPC_RS(reg) | __PPC_SH64(32) | __PPC_ME64(31)));

	addr++;



	/* oris r3,r3,(op)@h */

	/* oris reg,reg,(op)@h */

	patch_instruction((struct ppc_inst *)addr,

			  ppc_inst(PPC_INST_ORIS | ___PPC_RA(3) |

				   ___PPC_RS(3) | ((val >> 16) & 0xffff)));

			  ppc_inst(PPC_INST_ORIS | ___PPC_RA(reg) |

				   ___PPC_RS(reg) | ((val >> 16) & 0xffff)));

	addr++;



	/* ori r3,r3,(op)@l */

	/* ori reg,reg,(op)@l */

	patch_instruction((struct ppc_inst *)addr,

			  ppc_inst(PPC_INST_ORI | ___PPC_RA(3) |

				   ___PPC_RS(3) | (val & 0xffff)));

			  ppc_inst(PPC_INST_ORI | ___PPC_RA(reg) |

				   ___PPC_RS(reg) | (val & 0xffff)));

}



int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
@@ -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()