Messages in this thread | | | From | Sergey Senozhatsky <> | Date | Thu, 21 May 2020 21:48:56 +0900 | Subject | Re: [RFC PATCH 2/2] init: Allow multi-line output of kernel command line |
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On (20/05/20 21:40), Andrew Morton wrote: > > On (20/05/20 18:00), Andrew Morton wrote: > > [..] > > > I'm wondering if we shold add a kernel puts() (putsk()? yuk) which can > > > puts() a string of any length. > > > > > > I'm counting around 150 instances of printk("%s", ...) and pr_foo("%s", > > > ...) which could perhaps be converted, thus saving an argument. > > > > Can you point me at some examples? > > > > ./arch/powerpc/kernel/udbg.c: printk("%s", s); > ./arch/powerpc/xmon/nonstdio.c: printk("%s", xmon_outbuf); > ./arch/um/os-Linux/drivers/ethertap_user.c: printk("%s", output); > ./arch/um/os-Linux/drivers/ethertap_user.c: printk("%s", output); > ./arch/um/os-Linux/drivers/tuntap_user.c: printk("%s", out
Hmm, interesting.
output = uml_kmalloc(UM_KERN_PAGE_SIZE, UM_GFP_KERNEL); read_output(fd, output, UM_KERN_PAGE_SIZE); printk("%s", output); kfree(output);
> etc. > > My point is, if we created a length-unlimited puts() function for printing the > kernel command line, it could be reused in such places
A function that prints the kernel command line is a bit different in the way that we can split command line arguments - they are space separated, which is very convenient - so we would pr_cont() parts of command line individually. This has an advantage that we won't \r\n in the middle of the parameter.
Looking at examples, it seems that most of them simply do a single printk() with arbitrary sized buffers that contain random data, not necessarily space separated. So same problem - we truncate messages (maybe?), but needs a slightly different solution (?).
-ss
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