2012-05-08 08:03:09

by Stephen Rothwell

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Subject: linux-next: build failure after merge of the final tree (driver-core tree related)

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Hi all,

After merging the final tree, today's linux-next build (powerpc
allnoconfig) failed like this:

kernel/built-in.o: In function `devkmsg_read':
printk.c:(.text+0x27e8): undefined reference to `__udivdi3'

Caused by commit e11fea92e13f ("kmsg: export printk records to
the /dev/kmsg interface"). Most probably the "msg->ts_nsec / 1000" since
ts_nsec is a u64 and this is a 32 bit build ...

I have reverted that commit for today.
--
Cheers,
Stephen Rothwell [email protected]

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2012-05-08 11:04:52

by Kay Sievers

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Subject: Re: linux-next: build failure after merge of the final tree (driver-core tree related)

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On Tue, 2012-05-08 at 18:02 +1000, Stephen Rothwell wrote:
> After merging the final tree, today's linux-next build (powerpc
> allnoconfig) failed like this:
>
> kernel/built-in.o: In function `devkmsg_read':
> printk.c:(.text+0x27e8): undefined reference to `__udivdi3'

Oops, let's use do_div().

Thanks,
Kay


From: Kay Sievers <[email protected]>
Subject: kmsg: use do_div() to divide 64bit integer

On Tue, May 8, 2012 at 10:02 AM, Stephen Rothwell <[email protected]> wrote:
> kernel/built-in.o: In function `devkmsg_read':
> printk.c:(.text+0x27e8): undefined reference to `__udivdi3'
> Most probably the "msg->ts_nsec / 1000" since
> ts_nsec is a u64 and this is a 32 bit build ...

Signed-off-by: Kay Sievers <[email protected]>
---
kernel/printk.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -407,6 +407,7 @@ static ssize_t devkmsg_read(struct file
{
struct devkmsg_user *user = file->private_data;
struct log *msg;
+ u64 ts_usec;
size_t i;
size_t len;
ssize_t ret;
@@ -441,8 +442,10 @@ static ssize_t devkmsg_read(struct file
}

msg = log_from_idx(user->idx);
+ ts_usec = msg->ts_nsec;
+ do_div(ts_usec, 1000);
len = sprintf(user->buf, "%u,%llu,%llu;",
- msg->level, user->seq, msg->ts_nsec / 1000);
+ msg->level, user->seq, ts_usec);

/* escape non-printable characters */
for (i = 0; i < msg->text_len; i++) {