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Date: Mon, 08 Apr 2013 20:02:50 +0900
From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To: Oskar Andero <oskar.andero@...ymobile.com>
Cc: linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
davem@...emloft.net, anil.s.keshavamurthy@...el.com,
ananth@...ibm.com, Joonsoo Kim <iamjoonsoo.kim@....com>,
radovan.lekanovic@...ymobile.com, bjorn.davidsson@...ymobile.com,
"yrl.pp-manager.tt@...achi.com" <yrl.pp-manager.tt@...achi.com>
Subject: Re: [PATCH v3 2/4] kprobes: split blacklist into common and arch
(2013/04/05 22:26), Oskar Andero wrote:
> Some blackpoints are only valid for specific architectures. To let each
> architecture specify its own blackpoints the list has been split in two
> lists: common and arch. The common list is kept in kernel/kprobes.c and
> the arch list is kept in the arch/ directory.
Looks good for me:)
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Thank you!
>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
> Cc: David S. Miller <davem@...emloft.net>
> Cc: linux-arch@...r.kernel.org
> Signed-off-by: Oskar Andero <oskar.andero@...ymobile.com>
> ---
> kernel/kprobes.c | 88 +++++++++++++++++++++++++++++++++++++-------------------
> 1 file changed, 59 insertions(+), 29 deletions(-)
>
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index c8c2281..2458ae1 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -68,7 +68,6 @@
> #endif
>
> static int kprobes_initialized;
> -static bool kprobe_blacklist_initialized;
> static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
> static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
>
> @@ -94,31 +93,64 @@ static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
> *
> * For such cases, we now have a blacklist
> */
> -static struct kprobe_blackpoint kprobe_blacklist[] = {
> - {"preempt_schedule",},
> - {"native_get_debugreg",},
> - {"irq_entries_start",},
> - {"common_interrupt",},
> - {"mcount",}, /* mcount can be called from everywhere */
> - {NULL} /* Terminator */
> +static const char * const common_kprobes_blacksyms[] = {
> + "preempt_schedule",
> + "native_get_debugreg",
> + "irq_entries_start",
> + "common_interrupt",
> + "mcount", /* mcount can be called from everywhere */
> };
> +static const size_t common_kprobes_blacksyms_size =
> + ARRAY_SIZE(common_kprobes_blacksyms);
> +
> +/*
> + * These weak symbols can be overridden from the arch/ directory for
> + * architecure specific blackpoints.
> + */
> +const char * const __weak arch_kprobes_blacksyms[] = {};
> +const size_t __weak arch_kprobes_blacksyms_size;
> +
> +static struct kprobe_blackpoint *kprobe_blacklist;
> +static size_t kprobe_blacklist_size;
> +
> +static void init_kprobe_blacklist_entry(struct kprobe_blackpoint *kb,
> + const char * const name)
> +{
> + const char *symbol_name;
> + char *modname, namebuf[128];
> + void *addr;
> + unsigned long offset = 0, size = 0;
> +
> + kb->name = name;
> + kprobe_lookup_name(kb->name, addr);
> + if (!addr)
> + return;
> +
> + kb->start_addr = (unsigned long)addr;
> + symbol_name = kallsyms_lookup(kb->start_addr,
> + &size, &offset, &modname, namebuf);
> + if (!symbol_name)
> + kb->range = 0;
> + else
> + kb->range = size;
> +}
>
> /* it can take some time ( > 100ms ) to initialise the
> * blacklist so we delay this until we actually need it
> */
> static void init_kprobe_blacklist(void)
> {
> - int i;
> - unsigned long offset = 0, size = 0;
> - char *modname, namebuf[128];
> - const char *symbol_name;
> - void *addr;
> + int i, j = 0;
> struct kprobe_blackpoint *kb;
>
> mutex_lock(&kprobe_mutex);
> - if (kprobe_blacklist_initialized)
> + if (kprobe_blacklist)
> goto out;
>
> + kprobe_blacklist_size = common_kprobes_blacksyms_size +
> + arch_kprobes_blacksyms_size;
> + kb = kzalloc(sizeof(*kb) * kprobe_blacklist_size, GFP_KERNEL);
> +
> /*
> * Lookup and populate the kprobe_blacklist.
> *
> @@ -127,18 +159,14 @@ static void init_kprobe_blacklist(void)
> * since a kprobe need not necessarily be at the beginning
> * of a function.
> */
> - for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
> - kprobe_lookup_name(kb->name, addr);
> - if (!addr)
> - continue;
> + for (i = 0; i < common_kprobes_blacksyms_size; i++, j++) {
> + init_kprobe_blacklist_entry(&kb[j],
> + common_kprobes_blacksyms[i]);
> + }
>
> - kb->start_addr = (unsigned long)addr;
> - symbol_name = kallsyms_lookup(kb->start_addr,
> - &size, &offset, &modname, namebuf);
> - if (!symbol_name)
> - kb->range = 0;
> - else
> - kb->range = size;
> + for (i = 0; i < arch_kprobes_blacksyms_size; i++, j++) {
> + init_kprobe_blacklist_entry(&kb[j],
> + arch_kprobes_blacksyms[i]);
> }
>
> if (kretprobe_blacklist_size) {
> @@ -153,7 +181,7 @@ static void init_kprobe_blacklist(void)
> }
>
> smp_wmb();
> - kprobe_blacklist_initialized = true;
> + kprobe_blacklist = kb;
>
> out:
> mutex_unlock(&kprobe_mutex);
> @@ -1384,18 +1412,20 @@ out:
> static int __kprobes in_kprobes_functions(unsigned long addr)
> {
> struct kprobe_blackpoint *kb;
> + int i;
>
> if (addr >= (unsigned long)__kprobes_text_start &&
> addr < (unsigned long)__kprobes_text_end)
> return -EINVAL;
>
> - if (unlikely(!kprobe_blacklist_initialized))
> + if (unlikely(!kprobe_blacklist))
> init_kprobe_blacklist();
> /*
> * If there exists a kprobe_blacklist, verify and
> * fail any probe registration in the prohibited area
> */
> - for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
> + for (i = 0; i < kprobe_blacklist_size; i++) {
> + kb = &kprobe_blacklist[i];
> if (kb->start_addr) {
> if (addr >= kb->start_addr &&
> addr < (kb->start_addr + kb->range))
> @@ -1876,7 +1906,7 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
> void *addr;
>
> if (kretprobe_blacklist_size) {
> - if (unlikely(!kprobe_blacklist_initialized))
> + if (unlikely(!kprobe_blacklist))
> init_kprobe_blacklist();
> addr = kprobe_addr(&rp->kp);
> if (IS_ERR(addr))
>
--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@...achi.com
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