Zou, Nanhai wrote:
On Thu, 2006-09-21 at 15:31, bibo,mao wrote: > Hi, > On IA64 instruction opcode must be 16 bytes alignment, in kprobe > structure there is one element to save original instruction, currently > saved opcode is not statically allocated in kprobe structure, that can > not assure 16 bytes alignment. This patch dynamically allocated kprobe > instruction opcode to assure 16 bytes alignment. > > signed-off-by: bibo mao <bibo.mao@xxxxxxxxx> > > thanks > bibo,mao > > diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c > index 781960f..e6cf5d4 100644 > --- a/arch/ia64/kernel/kprobes.c > +++ b/arch/ia64/kernel/kprobes.c > @@ -136,10 +136,8 @@ static void __kprobes update_kprobe_inst > static int __kprobes unsupported_inst(uint template, uint slot, > uint major_opcode, > unsigned long kprobe_inst, > - struct kprobe *p) > + unsigned long addr) > { > - unsigned long addr = (unsigned long)p->addr; > - > if (bundle_encoding[template][slot] == I) { > switch (major_opcode) { > case 0x0: //I_UNIT_MISC_OPCODE: > @@ -217,7 +215,7 @@ static void __kprobes prepare_break_inst > struct kprobe *p) > { > unsigned long break_inst = BREAK_INST; > - bundle_t *bundle = &p->ainsn.insn.bundle; > + bundle_t *bundle = &p->opcode.bundle;> > /*> * Copy the original kprobe_inst qualifying predicate(qp) > @@ -423,11 +421,9 @@ int __kprobes arch_prepare_kprobe(struct > unsigned long *kprobe_addr = (unsigned long *)(addr & > ~0xFULL); > unsigned long kprobe_inst=0; > unsigned int slot = addr & 0xf, template, major_opcode = 0; > - bundle_t *bundle = &p->ainsn.insn.bundle; > - > - memcpy(&p->opcode.bundle, kprobe_addr, sizeof(bundle_t)); > - memcpy(&p->ainsn.insn.bundle, kprobe_addr, sizeof(bundle_t)); > + bundle_t *bundle;> > + bundle = &((kprobe_opcode_t *)kprobe_addr)->bundle;> template = bundle->quad0.template;> > if(valid_kprobe_addr(template, slot, addr))> @@ -440,20 +436,19 @@ int __kprobes arch_prepare_kprobe(struct > /* Get kprobe_inst and major_opcode from the bundle */ > get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);> > - if (unsupported_inst(template, slot, major_opcode,> kprobe_inst, p)) > + if (unsupported_inst(template, slot, major_opcode, > kprobe_inst, addr)) > return -EINVAL;> > - prepare_break_inst(template, slot, major_opcode, kprobe_inst,> p);> > - return 0;> -} > + p->ainsn.insn = get_insn_slot(); > + if (!p->ainsn.insn) > + return -ENOMEM; > + memcpy(&p->opcode, kprobe_addr, sizeof(kprobe_opcode_t)); > + memcpy(p->ainsn.insn, kprobe_addr, sizeof(kprobe_opcode_t));> > -void __kprobes flush_insn_slot(struct kprobe *p)> -{ > - unsigned long arm_addr; > + prepare_break_inst(template, slot, major_opcode, kprobe_inst, > p);> > - arm_addr = ((unsigned long)&p->opcode.bundle) & ~0xFULL;> - flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t)); > + return 0; > }> > void __kprobes arch_arm_kprobe(struct kprobe *p)> @@ -461,9 +456,10 @@ void __kprobes arch_arm_kprobe(struct kp > unsigned long addr = (unsigned long)p->addr; > unsigned long arm_addr = addr & ~0xFULL;> > - flush_insn_slot(p);> - memcpy((char *)arm_addr, &p->ainsn.insn.bundle, > sizeof(bundle_t)); > - flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t)); > + flush_icache_range((unsigned long)p->ainsn.insn, > + (unsigned long)p->ainsn.insn + > sizeof(kprobe_opcode_t)); > + memcpy((char *)arm_addr, &p->opcode, sizeof(kprobe_opcode_t)); > + flush_icache_range(arm_addr, arm_addr + > sizeof(kprobe_opcode_t)); > }> > void __kprobes arch_disarm_kprobe(struct kprobe *p)> @@ -471,11 +467,18 @@ void __kprobes arch_disarm_kprobe(struct > unsigned long addr = (unsigned long)p->addr; > unsigned long arm_addr = addr & ~0xFULL;> > - /* p->opcode contains the original unaltered bundle */> - memcpy((char *) arm_addr, (char *) &p->opcode.bundle, > sizeof(bundle_t)); > - flush_icache_range(arm_addr, arm_addr + sizeof(bundle_t)); > + /* p->ainsn.insn contains the original unaltered > kprobe_opcode_t */ > + memcpy((char *) arm_addr, (char *) p->ainsn.insn, > + sizeof(kprobe_opcode_t)); > + flush_icache_range(arm_addr, arm_addr + > sizeof(kprobe_opcode_t)); > }> > +void __kprobes arch_remove_kprobe(struct kprobe *p)> +{ > + mutex_lock(&kprobe_mutex); > + free_insn_slot(p->ainsn.insn); > + mutex_unlock(&kprobe_mutex); > +} > /* > * We are resuming execution after a single step fault, so the > pt_regs > * structure reflects the register state after we executed the > instruction > @@ -486,12 +489,12 @@ void __kprobes arch_disarm_kprobe(struct > */ > static void __kprobes resume_execution(struct kprobe *p, struct > pt_regs *regs) > { > - unsigned long bundle_addr = ((unsigned long) > (&p->opcode.bundle)) & ~0xFULL; > + unsigned long bundle_addr = (unsigned long) > (&p->ainsn.insn->bundle); > unsigned long resume_addr = (unsigned long)p->addr & ~0xFULL; > unsigned long template; > int slot = ((unsigned long)p->addr & 0xf);> > - template = p->opcode.bundle.quad0.template;> + template = p->ainsn.insn->bundle.quad0.template;> > if (slot == 1 && bundle_encoding[template][1] == L)> slot = 2; > @@ -553,7 +556,7 @@ turn_ss_off:> > static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs> *regs) > { > - unsigned long bundle_addr = (unsigned long) &p->opcode.bundle; > + unsigned long bundle_addr = (unsigned long) > &p->ainsn.insn->bundle; > unsigned long slot = (unsigned long)p->addr & 0xf;> > /* single step inline if break instruction */> diff --git a/include/asm-i386/kprobes.h b/include/asm-i386/kprobes.h > diff --git a/include/asm-ia64/kprobes.h b/include/asm-ia64/kprobes.h > index 9389049..1b45b71 100644 > --- a/include/asm-ia64/kprobes.h > +++ b/include/asm-ia64/kprobes.h > @@ -29,7 +29,8 @@ #include <linux/ptrace.h> > #include <linux/percpu.h> > #include <asm/break.h>> > -#define MAX_INSN_SIZE 16> +#define __ARCH_WANT_KPROBES_INSN_SLOT > +#define MAX_INSN_SIZE 1 > #define BREAK_INST (long)(__IA64_BREAK_KPROBE << 6)> > typedef union cmp_inst {> @@ -94,7 +95,7 @@ #define IP_RELATIVE_BRANCH_OPCODE (4) > #define IP_RELATIVE_PREDICT_OPCODE (7) > #define LONG_BRANCH_OPCODE (0xC) > #define LONG_CALL_OPCODE (0xD) > -#define arch_remove_kprobe(p) do {} while (0) > +#define flush_insn_slot(p) do { } while (0)> > typedef struct kprobe_opcode {> bundle_t bundle; > @@ -108,7 +109,7 @@ struct fnptr { > /* Architecture specific copy of original instruction*/ > struct arch_specific_insn { > /* copy of the instruction to be emulated */ > - kprobe_opcode_t insn; > + kprobe_opcode_t *insn; > #define INST_FLAG_FIX_RELATIVE_IP_ADDR 1 > #define INST_FLAG_FIX_BRANCH_REG 2 > #define INST_FLAG_BREAK_INST 4 > @@ -125,6 +126,6 @@ static inline void jprobe_return(void) > } > extern void invalidate_stacked_regs(void); > extern void flush_register_stack(void); > -extern void flush_insn_slot(struct kprobe *p); > +extern void arch_remove_kprobe(struct kprobe *p);> > #endif /* _ASM_KPROBES_H */> - I think it is DEBUG_SLAB that breaks the nature alignment of the kmalloced area. On a system without DEBUG_SLAB, ARCH_KMALLOC_MINALIGN is 128, and bundle_t is declared as __aligned__(16);. It is impossible to see insn aligned to a 8 byte boundary. But with DEBUG_SLAB enabled, ARCH_KMALLOC_MINALIGN may shrink to 8 bytes.
yes, in my kernel configuration DEBUG_SLAB is enabled so that memory address is not 16 bytes alignment. I think that kmalloc function has no problem, so here in my patch kprobe opcode is dynamically allocated so that it is 16 bytes alignment. thanks bibo,mao
ThanksZou Nan hai
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