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powerpc: Use a function for reading instructions

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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
This commit is contained in:
Jordan Niethe
2020-05-06 13:40:32 +10:00
committed by Michael Ellerman
parent 94afd069d9
commit f8faaffaa7
9 changed files with 33 additions and 26 deletions
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6
arch/powerpc/kernel/kprobes.c
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@@ -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);

2
arch/powerpc/kernel/mce_power.c
View File

@@ -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;

4
arch/powerpc/kernel/optprobes.c
View File

@@ -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;
}

4
arch/powerpc/kernel/trace/ftrace.c
View File

@@ -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);
}

2
arch/powerpc/kernel/uprobes.c
View File

@@ -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;