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 intel.com>
> >
> > 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
>
> Thanks
> Zou Nan hai
>
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