On Mon, 2020-04-06 at 18:09 +1000, Jordan Niethe wrote: > 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 <jniet...@gmail.com> > --- > v4: New to series > v5: - Rename read_inst() -> probe_kernel_read_inst() > - No longer modify uprobe probe type in this patch > --- > arch/powerpc/include/asm/inst.h | 5 +++++ > arch/powerpc/kernel/kprobes.c | 11 ++++------ > arch/powerpc/kernel/mce_power.c | 2 +- > arch/powerpc/kernel/optprobes.c | 4 ++-- > arch/powerpc/kernel/trace/ftrace.c | 33 +++++++++++++++++++----------- > arch/powerpc/lib/code-patching.c | 23 ++++++++++----------- > arch/powerpc/lib/feature-fixups.c | 2 +- > arch/powerpc/xmon/xmon.c | 6 +++--- > 8 files changed, 48 insertions(+), 38 deletions(-) > > diff --git a/arch/powerpc/include/asm/inst.h > b/arch/powerpc/include/asm/inst.h > index a71decf5f871..369b35ce964c 100644 > --- a/arch/powerpc/include/asm/inst.h > +++ b/arch/powerpc/include/asm/inst.h > @@ -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 !memcmp(&x, &y, sizeof(struct ppc_inst)); > diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c > index 9ed996cb0589..ff53e5ef7e40 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"); > @@ -125,11 +125,8 @@ 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; > - flush_icache_range((unsigned long)p->ainsn.insn, > - (unsigned long)p->ainsn.insn + > sizeof(kprobe_opcode_t)); > + patch_instruction((struct ppc_inst *)p->ainsn.insn, insn); > + p->opcode = ppc_inst_val(insn);
This is a different change from this commit -- Bala > } > > p->ainsn.boostable = 0; > @@ -217,7 +214,7 @@ 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 7118b46a6543..859b602fa270 100644 > --- a/arch/powerpc/kernel/mce_power.c > +++ b/arch/powerpc/kernel/mce_power.c > @@ -374,7 +374,7 @@ 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 b61bbcee84f4..684640b8fa2e 100644 > --- a/arch/powerpc/kernel/optprobes.c > +++ b/arch/powerpc/kernel/optprobes.c > @@ -100,8 +100,8 @@ 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(*(struct ppc_inst *)p->ainsn.insn) && > - analyse_instr(&op, ®s, *(struct ppc_inst *)p- > >ainsn.insn) == 1) { > + if (!is_conditional_branch(ppc_inst_read((struct ppc_inst *)p- > >ainsn.insn)) && > + analyse_instr(&op, ®s, ppc_inst_read((struct > ppc_inst *)p->ainsn.insn)) == 1) { > emulate_update_regs(®s, &op); > nip = regs.nip; > } > diff --git a/arch/powerpc/kernel/trace/ftrace.c > b/arch/powerpc/kernel/trace/ftrace.c > index 442c62fb68ff..e78742613b36 100644 > --- a/arch/powerpc/kernel/trace/ftrace.c > +++ b/arch/powerpc/kernel/trace/ftrace.c > @@ -41,6 +41,12 @@ > #define NUM_FTRACE_TRAMPS 8 > static unsigned long ftrace_tramps[NUM_FTRACE_TRAMPS]; > > +static long > +probe_kernel_read_inst(struct ppc_inst *inst, const void *src) > +{ > + return probe_kernel_read((void *)inst, src, MCOUNT_INSN_SIZE); > +} > + > static struct ppc_inst > ftrace_call_replace(unsigned long ip, unsigned long addr, int link) > { > @@ -68,7 +74,7 @@ ftrace_modify_code(unsigned long ip, struct ppc_inst old, > struct ppc_inst new) > */ > > /* read the text we want to modify */ > - if (probe_kernel_read(&replaced, (void *)ip, MCOUNT_INSN_SIZE)) > + if (probe_kernel_read_inst(&replaced, (void *)ip)) > return -EFAULT; > > /* Make sure it is what we expect it to be */ > @@ -130,7 +136,7 @@ __ftrace_make_nop(struct module *mod, > struct ppc_inst op, pop; > > /* read where this goes */ > - if (probe_kernel_read(&op, (void *)ip, sizeof(int))) { > + if (probe_kernel_read_inst(&op, (void *)ip)) { > pr_err("Fetching opcode failed.\n"); > return -EFAULT; > } > @@ -164,7 +170,7 @@ __ftrace_make_nop(struct module *mod, > /* When using -mkernel_profile there is no load to jump over */ > pop = ppc_inst(PPC_INST_NOP); > > - if (probe_kernel_read(&op, (void *)(ip - 4), 4)) { > + if (probe_kernel_read_inst(&op, (void *)(ip - 4))) { > pr_err("Fetching instruction at %lx failed.\n", ip - 4); > return -EFAULT; > } > @@ -196,7 +202,7 @@ __ftrace_make_nop(struct module *mod, > * Check what is in the next instruction. We can see ld r2,40(r1), but > * on first pass after boot we will see mflr r0. > */ > - if (probe_kernel_read(&op, (void *)(ip+4), MCOUNT_INSN_SIZE)) { > + if (probe_kernel_read_inst(&op, (void *)(ip+4))) { > pr_err("Fetching op failed.\n"); > return -EFAULT; > } > @@ -348,7 +354,7 @@ static int setup_mcount_compiler_tramp(unsigned long > tramp) > return -1; > > /* New trampoline -- read where this goes */ > - if (probe_kernel_read(&op, (void *)tramp, sizeof(int))) { > + if (probe_kernel_read_inst(&op, (void *)tramp)) { > pr_debug("Fetching opcode failed.\n"); > return -1; > } > @@ -398,7 +404,7 @@ static int __ftrace_make_nop_kernel(struct dyn_ftrace > *rec, unsigned long addr) > struct ppc_inst op; > > /* Read where this goes */ > - if (probe_kernel_read(&op, (void *)ip, sizeof(int))) { > + if (probe_kernel_read_inst(&op, (void *)ip)) { > pr_err("Fetching opcode failed.\n"); > return -EFAULT; > } > @@ -524,7 +530,10 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long > addr) > struct module *mod = rec->arch.mod; > > /* read where this goes */ > - if (probe_kernel_read(op, ip, sizeof(op))) > + if (probe_kernel_read_inst(op, ip)) > + return -EFAULT; > + > + if (probe_kernel_read_inst(op + 1, ip + 4)) > return -EFAULT; > > if (!expected_nop_sequence(ip, op[0], op[1])) { > @@ -587,7 +596,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long > addr) > unsigned long ip = rec->ip; > > /* read where this goes */ > - if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE)) > + if (probe_kernel_read_inst(&op, (void *)ip)) > return -EFAULT; > > /* It should be pointing to a nop */ > @@ -643,7 +652,7 @@ static int __ftrace_make_call_kernel(struct dyn_ftrace > *rec, unsigned long addr) > } > > /* Make sure we have a nop */ > - if (probe_kernel_read(&op, ip, sizeof(op))) { > + if (probe_kernel_read_inst(&op, ip)) { > pr_err("Unable to read ftrace location %p\n", ip); > return -EFAULT; > } > @@ -721,7 +730,7 @@ __ftrace_modify_call(struct dyn_ftrace *rec, unsigned > long old_addr, > } > > /* read where this goes */ > - if (probe_kernel_read(&op, (void *)ip, sizeof(int))) { > + if (probe_kernel_read_inst(&op, (void *)ip)) { > pr_err("Fetching opcode failed.\n"); > return -EFAULT; > } > @@ -846,7 +855,7 @@ 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); > > @@ -854,7 +863,7 @@ 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/lib/code-patching.c b/arch/powerpc/lib/code- > patching.c > index 91be4a0b51cb..ba08f3815d00 100644 > --- a/arch/powerpc/lib/code-patching.c > +++ b/arch/powerpc/lib/code-patching.c > @@ -349,9 +349,9 @@ static unsigned long branch_bform_target(const struct > ppc_inst *instr) > > unsigned long branch_target(const struct ppc_inst *instr) > { > - if (instr_is_branch_iform(*instr)) > + if (instr_is_branch_iform(ppc_inst_read(instr))) > return branch_iform_target(instr); > - else if (instr_is_branch_bform(*instr)) > + else if (instr_is_branch_bform(ppc_inst_read(instr))) > return branch_bform_target(instr); > > return 0; > @@ -359,7 +359,7 @@ unsigned long branch_target(const struct ppc_inst *instr) > > int instr_is_branch_to_addr(const struct ppc_inst *instr, unsigned long > addr) > { > - if (instr_is_branch_iform(*instr) || instr_is_branch_bform(*instr)) > + if (instr_is_branch_iform(ppc_inst_read(instr)) || > instr_is_branch_bform(ppc_inst_read(instr))) > return branch_target(instr) == addr; > > return 0; > @@ -368,13 +368,12 @@ int instr_is_branch_to_addr(const struct ppc_inst > *instr, unsigned long addr) > int translate_branch(struct ppc_inst *instr, const struct ppc_inst *dest, > const struct ppc_inst *src) > { > unsigned long target; > - > target = branch_target(src); > > - if (instr_is_branch_iform(*src)) > - return create_branch(instr, dest, target, ppc_inst_val(*src)); > - else if (instr_is_branch_bform(*src)) > - return create_cond_branch(instr, dest, target, > ppc_inst_val(*src)); > + if (instr_is_branch_iform(ppc_inst_read(src))) > + return create_branch(instr, dest, target, > ppc_inst_val(ppc_inst_read(src))); > + else if (instr_is_branch_bform(ppc_inst_read(src))) > + return create_cond_branch(instr, dest, target, > ppc_inst_val(ppc_inst_read(src))); > > return 1; > } > @@ -598,7 +597,7 @@ static void __init test_translate_branch(void) > patch_instruction(q, instr); > check(instr_is_branch_to_addr(p, addr)); > check(instr_is_branch_to_addr(q, addr)); > - check(ppc_inst_equal(*q, ppc_inst(0x4a000000))); > + check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x4a000000))); > > /* Maximum positive case, move x to x - 32 MB + 4 */ > p = buf + 0x2000000; > @@ -609,7 +608,7 @@ static void __init test_translate_branch(void) > patch_instruction(q, instr); > check(instr_is_branch_to_addr(p, addr)); > check(instr_is_branch_to_addr(q, addr)); > - check(ppc_inst_equal(*q, ppc_inst(0x49fffffc))); > + check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x49fffffc))); > > /* Jump to x + 16 MB moved to x + 20 MB */ > p = buf; > @@ -655,7 +654,7 @@ static void __init test_translate_branch(void) > patch_instruction(q, instr); > check(instr_is_branch_to_addr(p, addr)); > check(instr_is_branch_to_addr(q, addr)); > - check(ppc_inst_equal(*q, ppc_inst(0x43ff8000))); > + check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff8000))); > > /* Maximum positive case, move x to x - 32 KB + 4 */ > p = buf + 0x8000; > @@ -667,7 +666,7 @@ static void __init test_translate_branch(void) > patch_instruction(q, instr); > check(instr_is_branch_to_addr(p, addr)); > check(instr_is_branch_to_addr(q, addr)); > - check(ppc_inst_equal(*q, ppc_inst(0x43ff7ffc))); > + check(ppc_inst_equal(ppc_inst_read(q), ppc_inst(0x43ff7ffc))); > > /* Jump to x + 12 KB moved to x + 20 KB */ > p = buf; > diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature- > fixups.c > index 8c5d0db77013..f00dd13b1c3c 100644 > --- a/arch/powerpc/lib/feature-fixups.c > +++ b/arch/powerpc/lib/feature-fixups.c > @@ -48,7 +48,7 @@ static int patch_alt_instruction(struct ppc_inst *src, > struct ppc_inst *dest, > int err; > struct ppc_inst instr; > > - instr = *src; > + instr = ppc_inst_read(src); > > if (instr_is_relative_branch(*src)) { > struct ppc_inst *target = (struct ppc_inst > *)branch_target(src); > diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c > index e3d8e1b8ce01..5e3949322a6c 100644 > --- a/arch/powerpc/xmon/xmon.c > +++ b/arch/powerpc/xmon/xmon.c > @@ -705,13 +705,13 @@ static int xmon_core(struct pt_regs *regs, int fromipi) > if ((regs->msr & (MSR_IR|MSR_PR|MSR_64BIT)) == (MSR_IR|MSR_64BIT)) { > bp = at_breakpoint(regs->nip); > if (bp != NULL) { > - int stepped = emulate_step(regs, bp->instr[0]); > + int stepped = emulate_step(regs, ppc_inst_read(bp- > >instr)); > if (stepped == 0) { > regs->nip = (unsigned long) &bp->instr[0]; > atomic_inc(&bp->ref_count); > } else if (stepped < 0) { > printf("Couldn't single-step %s instruction\n", > - (IS_RFID(bp->instr[0])? "rfid": "mtmsrd")); > + IS_RFID(ppc_inst_read(bp->instr))? "rfid": > "mtmsrd"); > } > } > } > @@ -952,7 +952,7 @@ static void remove_bpts(void) > if (mread(bp->address, &instr, 4) == 4 > && ppc_inst_equal(instr, ppc_inst(bpinstr)) > && patch_instruction( > - (struct ppc_inst *)bp->address, bp->instr[0]) != 0) > + (struct ppc_inst *)bp->address, ppc_inst_read(bp- > >instr)) != 0) > printf("Couldn't remove breakpoint at %lx\n", > bp->address); > }