powerpc: Don't use 'struct ppc_inst' to reference instruction location

'struct ppc_inst' is an internal representation of an instruction, but
in-memory instructions are and will remain a table of 'u32' forever.

Replace all 'struct ppc_inst *' used for locating an instruction in
memory by 'u32 *'. This removes a lot of undue casts to 'struct
ppc_inst *'.

It also helps locating ab-use of 'struct ppc_inst' dereference.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Fix ppc_inst_next(), use u32 instead of unsigned int]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7062722b087228e42cbd896e39bfdf526d6a340a.1621516826.git.christophe.leroy@csgroup.eu

1 files changed, 18 insertions, 27 deletions

diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c
index a370190cd02a..88e205775ded 100644
--- a/arch/powerpc/kernel/optprobes.c
+++ b/arch/powerpc/kernel/optprobes.c
@@ -89,9 +89,8 @@ static unsigned long can_optimize(struct kprobe *p)
 	 * Ensure that the instruction is not a conditional branch,
 	 * and that can be emulated.
 	 */
-	if (!is_conditional_branch(ppc_inst_read((struct ppc_inst *)p->ainsn.insn)) &&
-	    analyse_instr(&op, &regs,
-			  ppc_inst_read((struct ppc_inst *)p->ainsn.insn)) == 1) {
+	if (!is_conditional_branch(ppc_inst_read(p->ainsn.insn)) &&
+	    analyse_instr(&op, &regs, ppc_inst_read(p->ainsn.insn)) == 1) {
 		emulate_update_regs(&regs, &op);
 		nip = regs.nip;
 	}
@@ -132,12 +131,10 @@ void arch_remove_optimized_kprobe(struct optimized_kprobe *op)
 
 static void patch_imm32_load_insns(unsigned long val, int reg, kprobe_opcode_t *addr)
 {
-	patch_instruction((struct ppc_inst *)addr,
-			  ppc_inst(PPC_RAW_LIS(reg, IMM_H(val))));
+	patch_instruction(addr, ppc_inst(PPC_RAW_LIS(reg, IMM_H(val))));
 	addr++;
 
-	patch_instruction((struct ppc_inst *)addr,
-			  ppc_inst(PPC_RAW_ORI(reg, reg, IMM_L(val))));
+	patch_instruction(addr, ppc_inst(PPC_RAW_ORI(reg, reg, IMM_L(val))));
 }
 
 /*
@@ -147,31 +144,31 @@ static void patch_imm32_load_insns(unsigned long val, int reg, kprobe_opcode_t *
 static void patch_imm64_load_insns(unsigned long long val, int reg, kprobe_opcode_t *addr)
 {
 	/* lis reg,(op)@highest */
-	patch_instruction((struct ppc_inst *)addr,
+	patch_instruction(addr,
 			  ppc_inst(PPC_INST_ADDIS | ___PPC_RT(reg) |
 				   ((val >> 48) & 0xffff)));
 	addr++;
 
 	/* ori reg,reg,(op)@higher */
-	patch_instruction((struct ppc_inst *)addr,
+	patch_instruction(addr,
 			  ppc_inst(PPC_INST_ORI | ___PPC_RA(reg) |
 				   ___PPC_RS(reg) | ((val >> 32) & 0xffff)));
 	addr++;
 
 	/* rldicr reg,reg,32,31 */
-	patch_instruction((struct ppc_inst *)addr,
+	patch_instruction(addr,
 			  ppc_inst(PPC_INST_RLDICR | ___PPC_RA(reg) |
 				   ___PPC_RS(reg) | __PPC_SH64(32) | __PPC_ME64(31)));
 	addr++;
 
 	/* oris reg,reg,(op)@h */
-	patch_instruction((struct ppc_inst *)addr,
+	patch_instruction(addr,
 			  ppc_inst(PPC_INST_ORIS | ___PPC_RA(reg) |
 				   ___PPC_RS(reg) | ((val >> 16) & 0xffff)));
 	addr++;
 
 	/* ori reg,reg,(op)@l */
-	patch_instruction((struct ppc_inst *)addr,
+	patch_instruction(addr,
 			  ppc_inst(PPC_INST_ORI | ___PPC_RA(reg) |
 				   ___PPC_RS(reg) | (val & 0xffff)));
 }
@@ -225,8 +222,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
 	size = (TMPL_END_IDX * sizeof(kprobe_opcode_t)) / sizeof(int);
 	pr_devel("Copying template to %p, size %lu\n", buff, size);
 	for (i = 0; i < size; i++) {
-		rc = patch_instruction((struct ppc_inst *)(buff + i),
-				       ppc_inst(*(optprobe_template_entry + i)));
+		rc = patch_instruction(buff + i, ppc_inst(*(optprobe_template_entry + i)));
 		if (rc < 0)
 			goto error;
 	}
@@ -247,34 +243,30 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
 		goto error;
 	}
 
-	rc = create_branch(&branch_op_callback,
-			   (struct ppc_inst *)(buff + TMPL_CALL_HDLR_IDX),
+	rc = create_branch(&branch_op_callback, buff + TMPL_CALL_HDLR_IDX,
 			   (unsigned long)op_callback_addr,
 			   BRANCH_SET_LINK);
 
-	rc |= create_branch(&branch_emulate_step,
-			    (struct ppc_inst *)(buff + TMPL_EMULATE_IDX),
+	rc |= create_branch(&branch_emulate_step, buff + TMPL_EMULATE_IDX,
 			    (unsigned long)emulate_step_addr,
 			    BRANCH_SET_LINK);
 
 	if (rc)
 		goto error;
 
-	patch_instruction((struct ppc_inst *)(buff + TMPL_CALL_HDLR_IDX),
-			  branch_op_callback);
-	patch_instruction((struct ppc_inst *)(buff + TMPL_EMULATE_IDX),
-			  branch_emulate_step);
+	patch_instruction(buff + TMPL_CALL_HDLR_IDX, branch_op_callback);
+	patch_instruction(buff + TMPL_EMULATE_IDX, branch_emulate_step);
 
 	/*
 	 * 3. load instruction to be emulated into relevant register, and
 	 */
-	temp = ppc_inst_read((struct ppc_inst *)p->ainsn.insn);
+	temp = ppc_inst_read(p->ainsn.insn);
 	patch_imm_load_insns(ppc_inst_as_ulong(temp), 4, buff + TMPL_INSN_IDX);
 
 	/*
 	 * 4. branch back from trampoline
 	 */
-	patch_branch((struct ppc_inst *)(buff + TMPL_RET_IDX), (unsigned long)nip, 0);
+	patch_branch(buff + TMPL_RET_IDX, nip, 0);
 
 	flush_icache_range((unsigned long)buff,
 			   (unsigned long)(&buff[TMPL_END_IDX]));
@@ -317,10 +309,9 @@ void arch_optimize_kprobes(struct list_head *oplist)
 		 */
 		memcpy(op->optinsn.copied_insn, op->kp.addr,
 					       RELATIVEJUMP_SIZE);
-		create_branch(&instr,
-			      (struct ppc_inst *)op->kp.addr,
+		create_branch(&instr, op->kp.addr,
 			      (unsigned long)op->optinsn.insn, 0);
-		patch_instruction((struct ppc_inst *)op->kp.addr, instr);
+		patch_instruction(op->kp.addr, instr);
 		list_del_init(&op->list);
 	}
 }