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SubjectRe: [PATCH] trace: don't use __weak in header files
(2015/03/13 0:14), Steven Rostedt wrote:
>
> Masami and Srikar,
>
> Can I get your ACKs for this?

Yes, looks good and clean to me :)

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Thanks!

>
> Thanks,
>
> -- Steve
>
>
> On Thu, 12 Mar 2015 16:58:34 +1100
> Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
>> The commit that added a check for this to checkpatch says:
>>
>> "Using weak declarations can have unintended link defects. The __weak on
>> the declaration causes non-weak definitions to become weak."
>>
>> In this case, when a PowerPC kernel is built with CONFIG_KPROBE_EVENT
>> but not CONFIG_UPROBE_EVENT, it generates the following warning:
>>
>> WARNING: 1 bad relocations
>> c0000000014f2190 R_PPC64_ADDR64 uprobes_fetch_type_table
>>
>> This is fixed by passing the fetch_table arrays to
>> traceprobe_parse_probe_arg() which also means that they can never be NULL.
>>
>> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
>> ---
>> kernel/trace/trace_kprobe.c | 5 +++--
>> kernel/trace/trace_probe.c | 19 +++++++------------
>> kernel/trace/trace_probe.h | 10 ++--------
>> kernel/trace/trace_uprobe.c | 5 +++--
>> 4 files changed, 15 insertions(+), 24 deletions(-)
>>
>> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
>> index 5edb518be345..e6f9cbf4388d 100644
>> --- a/kernel/trace/trace_kprobe.c
>> +++ b/kernel/trace/trace_kprobe.c
>> @@ -250,7 +250,7 @@ DEFINE_FETCH_symbol(string_size)
>> #define fetch_file_offset_string_size NULL
>>
>> /* Fetch type information table */
>> -const struct fetch_type kprobes_fetch_type_table[] = {
>> +static const struct fetch_type kprobes_fetch_type_table[] = {
>> /* Special types */
>> [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
>> sizeof(u32), 1, "__data_loc char[]"),
>> @@ -760,7 +760,8 @@ static int create_trace_kprobe(int argc, char **argv)
>>
>> /* Parse fetch argument */
>> ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
>> - is_return, true);
>> + is_return, true,
>> + kprobes_fetch_type_table);
>> if (ret) {
>> pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
>> goto error;
>> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
>> index b983b2fd2ca1..1769a81da8a7 100644
>> --- a/kernel/trace/trace_probe.c
>> +++ b/kernel/trace/trace_probe.c
>> @@ -356,17 +356,14 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
>>
>> /* Recursive argument parser */
>> static int parse_probe_arg(char *arg, const struct fetch_type *t,
>> - struct fetch_param *f, bool is_return, bool is_kprobe)
>> + struct fetch_param *f, bool is_return, bool is_kprobe,
>> + const struct fetch_type *ftbl)
>> {
>> - const struct fetch_type *ftbl;
>> unsigned long param;
>> long offset;
>> char *tmp;
>> int ret = 0;
>>
>> - ftbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table;
>> - BUG_ON(ftbl == NULL);
>> -
>> switch (arg[0]) {
>> case '$':
>> ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe);
>> @@ -447,7 +444,7 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,
>> dprm->fetch_size = get_fetch_size_function(t,
>> dprm->fetch, ftbl);
>> ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
>> - is_kprobe);
>> + is_kprobe, ftbl);
>> if (ret)
>> kfree(dprm);
>> else {
>> @@ -505,15 +502,12 @@ static int __parse_bitfield_probe_arg(const char *bf,
>>
>> /* String length checking wrapper */
>> int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
>> - struct probe_arg *parg, bool is_return, bool is_kprobe)
>> + struct probe_arg *parg, bool is_return, bool is_kprobe,
>> + const struct fetch_type *ftbl)
>> {
>> - const struct fetch_type *ftbl;
>> const char *t;
>> int ret;
>>
>> - ftbl = is_kprobe ? kprobes_fetch_type_table : uprobes_fetch_type_table;
>> - BUG_ON(ftbl == NULL);
>> -
>> if (strlen(arg) > MAX_ARGSTR_LEN) {
>> pr_info("Argument is too long.: %s\n", arg);
>> return -ENOSPC;
>> @@ -535,7 +529,8 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
>> }
>> parg->offset = *size;
>> *size += parg->type->size;
>> - ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, is_kprobe);
>> + ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return,
>> + is_kprobe, ftbl);
>>
>> if (ret >= 0 && t != NULL)
>> ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
>> diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
>> index 4f815fbce16d..e30f6cce4af6 100644
>> --- a/kernel/trace/trace_probe.h
>> +++ b/kernel/trace/trace_probe.h
>> @@ -229,13 +229,6 @@ ASSIGN_FETCH_FUNC(file_offset, ftype), \
>> #define FETCH_TYPE_STRING 0
>> #define FETCH_TYPE_STRSIZE 1
>>
>> -/*
>> - * Fetch type information table.
>> - * It's declared as a weak symbol due to conditional compilation.
>> - */
>> -extern __weak const struct fetch_type kprobes_fetch_type_table[];
>> -extern __weak const struct fetch_type uprobes_fetch_type_table[];
>> -
>> #ifdef CONFIG_KPROBE_EVENT
>> struct symbol_cache;
>> unsigned long update_symbol_cache(struct symbol_cache *sc);
>> @@ -333,7 +326,8 @@ find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file)
>> }
>>
>> extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
>> - struct probe_arg *parg, bool is_return, bool is_kprobe);
>> + struct probe_arg *parg, bool is_return, bool is_kprobe,
>> + const struct fetch_type *ftbl);
>>
>> extern int traceprobe_conflict_field_name(const char *name,
>> struct probe_arg *args, int narg);
>> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
>> index 8520acc34b18..be8a7b1947d8 100644
>> --- a/kernel/trace/trace_uprobe.c
>> +++ b/kernel/trace/trace_uprobe.c
>> @@ -196,7 +196,7 @@ DEFINE_FETCH_file_offset(string)
>> DEFINE_FETCH_file_offset(string_size)
>>
>> /* Fetch type information table */
>> -const struct fetch_type uprobes_fetch_type_table[] = {
>> +static const struct fetch_type uprobes_fetch_type_table[] = {
>> /* Special types */
>> [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
>> sizeof(u32), 1, "__data_loc char[]"),
>> @@ -535,7 +535,8 @@ static int create_trace_uprobe(int argc, char **argv)
>>
>> /* Parse fetch argument */
>> ret = traceprobe_parse_probe_arg(arg, &tu->tp.size, parg,
>> - is_return, false);
>> + is_return, false,
>> + uprobes_fetch_type_table);
>> if (ret) {
>> pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
>> goto error;
>
>


--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com




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