On Thu, Aug 11, 2016 at 06:31:41PM +0300, Aleksey Makarov wrote:
> +/**
> + * pl011_console_match - non-standard console matching
> + * @co: registering console
> + * @name: name from console command line
> + * @idx: index from console command line
> + * @options: ptr to option string from console command line
> + *
> + * Only attempts to match console command lines of the form:
> + * console=pl011,mmio|mmio32,<addr>[,<options>]
> + * console=pl011,0x<addr>[,<options>]
> + * This form is used to register an initial earlycon boot console and
> + * replace it with the amba_console at pl011 driver init.
> + *
> + * Performs console setup for a match (as required by interface)
> + * If no <options> are specified, then assume the h/w is already setup.
> + *
> + * Returns 0 if console matches; otherwise non-zero to use default matching
> + */
> +static int __init pl011_console_match(struct console *co, char *name, int idx,
> + char *options)
> +{
> + char match[] = "pl011"; /* pl011-specific earlycon name */
This is inefficient - the compiler will probably store "pl011" in the
rodata section, then allocate an array on the stack, and them memcpy()
it onto the stack. This is really a false optimisation.
> + unsigned char iotype;
> + unsigned long addr;
> + int i;
> +
> + if (strncmp(name, match, 5) != 0)
Just do:
if (strncmp(name, "pl011", 5) != 0)
here, and let the compiler work it out - it'll probably place "pl011"
in the rodata section, and use a pointer to it rather than messing around
with the stack.
What if "console=pl011x,..." is passed? Should this be matched too?
Maybe this should compare with "pl011," to ensure that the name is
correctly terminated?
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