powerpc: Use a function for reading instructions

Prefixed instructions will mean there are instructions of different
length. As a result dereferencing a pointer to an instruction will not
necessarily give the desired result. Introduce a function for reading
instructions from memory into the instruction data type.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-13-jniethe5@gmail.com

5 files changed, 9 insertions, 9 deletions

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index a08ae5803622..f64312dca84f 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -106,7 +106,7 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset)
 int arch_prepare_kprobe(struct kprobe *p)
 {
 	int ret = 0;
-	struct ppc_inst insn = *(struct ppc_inst *)p->addr;
+	struct ppc_inst insn = ppc_inst_read((struct ppc_inst *)p->addr);
 
 	if ((unsigned long)p->addr & 0x03) {
 		printk("Attempt to register kprobe at an unaligned address\n");
@@ -127,7 +127,7 @@ int arch_prepare_kprobe(struct kprobe *p)
 	if (!ret) {
 		memcpy(p->ainsn.insn, p->addr,
 				MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
-		p->opcode = *p->addr;
+		p->opcode = ppc_inst_val(insn);
 		flush_icache_range((unsigned long)p->ainsn.insn,
 			(unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
 	}
@@ -217,7 +217,7 @@ NOKPROBE_SYMBOL(arch_prepare_kretprobe);
 static int try_to_emulate(struct kprobe *p, struct pt_regs *regs)
 {
 	int ret;
-	struct ppc_inst insn = *(struct ppc_inst *)p->ainsn.insn;
+	struct ppc_inst insn = ppc_inst_read((struct ppc_inst *)p->ainsn.insn);
 
 	/* regs->nip is also adjusted if emulate_step returns 1 */
 	ret = emulate_step(regs, insn);
diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c
index 08b355f80d9e..c32af49a5138 100644
--- a/arch/powerpc/kernel/mce_power.c
+++ b/arch/powerpc/kernel/mce_power.c
@@ -378,7 +378,7 @@ static int mce_find_instr_ea_and_phys(struct pt_regs *regs, uint64_t *addr,
 	pfn = addr_to_pfn(regs, regs->nip);
 	if (pfn != ULONG_MAX) {
 		instr_addr = (pfn << PAGE_SHIFT) + (regs->nip & ~PAGE_MASK);
-		instr = *(struct ppc_inst *)(instr_addr);
+		instr = ppc_inst_read((struct ppc_inst *)instr_addr);
 		if (!analyse_instr(&op, &tmp, instr)) {
 			pfn = addr_to_pfn(regs, op.ea);
 			*addr = op.ea;
diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c
index 5a71fef71c22..52c1ab3f85aa 100644
--- a/arch/powerpc/kernel/optprobes.c
+++ b/arch/powerpc/kernel/optprobes.c
@@ -100,9 +100,9 @@ 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(*(struct ppc_inst *)p->ainsn.insn) &&
+	if (!is_conditional_branch(ppc_inst_read((struct ppc_inst *)p->ainsn.insn)) &&
 	    analyse_instr(&op, &regs,
-			  *(struct ppc_inst *)p->ainsn.insn) == 1) {
+			  ppc_inst_read((struct ppc_inst *)p->ainsn.insn)) == 1) {
 		emulate_update_regs(&regs, &op);
 		nip = regs.nip;
 	}
diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c
index 3117ed675735..acd5b889815f 100644
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -848,7 +848,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
 	struct ppc_inst old, new;
 	int ret;
 
-	old = *(struct ppc_inst *)&ftrace_call;
+	old = ppc_inst_read((struct ppc_inst *)&ftrace_call);
 	new = ftrace_call_replace(ip, (unsigned long)func, 1);
 	ret = ftrace_modify_code(ip, old, new);
 
@@ -856,7 +856,7 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
 	/* Also update the regs callback function */
 	if (!ret) {
 		ip = (unsigned long)(&ftrace_regs_call);
-		old = *(struct ppc_inst *)&ftrace_regs_call;
+		old = ppc_inst_read((struct ppc_inst *)&ftrace_regs_call);
 		new = ftrace_call_replace(ip, (unsigned long)func, 1);
 		ret = ftrace_modify_code(ip, old, new);
 	}
diff --git a/arch/powerpc/kernel/uprobes.c b/arch/powerpc/kernel/uprobes.c
index 31c870287f2b..6893d40a48c5 100644
--- a/arch/powerpc/kernel/uprobes.c
+++ b/arch/powerpc/kernel/uprobes.c
@@ -174,7 +174,7 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
 	 * emulate_step() returns 1 if the insn was successfully emulated.
 	 * For all other cases, we need to single-step in hardware.
 	 */
-	ret = emulate_step(regs, auprobe->insn);
+	ret = emulate_step(regs, ppc_inst_read(&auprobe->insn));
 	if (ret > 0)
 		return true;