Commit f8faaffa authored by Jordan Niethe's avatar Jordan Niethe Committed by Michael Ellerman
Browse files

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: default avatarJordan Niethe <jniethe5@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Reviewed-by: default avatarAlistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-13-jniethe5@gmail.com
parent 94afd069

arch/powerpc/include/asm/inst.h

+5 −0
Original line number Diff line number Diff line
@@ -27,6 +27,11 @@ static inline struct ppc_inst ppc_inst_swab(struct ppc_inst x) 
	return ppc_inst(swab32(ppc_inst_val(x)));

}



static inline struct ppc_inst ppc_inst_read(const struct ppc_inst *ptr)

{

	return *ptr;

}



static inline bool ppc_inst_equal(struct ppc_inst x, struct ppc_inst y)

{

	return ppc_inst_val(x) == ppc_inst_val(y);

arch/powerpc/kernel/kprobes.c

+3 −3
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/kernel/mce_power.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

arch/powerpc/kernel/optprobes.c

+2 −2
Original line number Diff line number Diff line
@@ -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;

	}

arch/powerpc/kernel/trace/ftrace.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

	}