linux-kernel - Re: [PATCH 1/2] kallsyms: Allow kernel symbols in L1 to be found in Blackfin architecture

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Message-Id: <20080429150050.72750260.akpm@linux-foundation.org>
Date:	Tue, 29 Apr 2008 15:00:50 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Bryan Wu <cooloney@...nel.org>
Cc:	pmarques@...popie.com, linux-kernel@...r.kernel.org,
	robin.getz@...log.com, cooloney@...nel.org
Subject: Re: [PATCH 1/2] kallsyms: Allow kernel symbols in L1 to be found in
 Blackfin architecture

On Fri, 25 Apr 2008 18:28:18 +0800
Bryan Wu <cooloney@...nel.org> wrote:

> From: Robin Getz <robin.getz@...log.com>
> 
> Add _stext_l1, _etext_l1 for the L1 memory section in Blackfin.
> 
> Signed-off-by: Robin Getz <robin.getz@...log.com>
> Signed-off-by: Bryan Wu <cooloney@...nel.org>
> ---
>  kernel/kallsyms.c  |    6 +++++-
>  scripts/kallsyms.c |    8 +++++++-
>  2 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
> index f091d13..456d1f6 100644
> --- a/kernel/kallsyms.c
> +++ b/kernel/kallsyms.c
> @@ -55,7 +55,11 @@ static inline int is_kernel_inittext(unsigned long addr)
>  
>  static inline int is_kernel_text(unsigned long addr)
>  {
> -	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_etext)
> +	if ((addr >= (unsigned long)_stext && addr <= (unsigned long)_etext)
> +#if defined(CONFIG_BLACKFIN)
> +             || (addr >= (unsigned long)_stext_l1 && addr <= (unsigned long)_etext_l1)
> +#endif
> +	)

That's a bit grubby.  I suppose we could pretend not to have noticed, but
this really isn't the preferred way of putting arch-specific hooks into
arch-neutral code.

Nicer might be to add

void __weak arch_is_kernel_text(unsigned long addr)
{
	return 0;
}

with a declaration in linux/kallsyms.h and then override
arch_is_kernel_text() in arch/blackfin/ code.


>  		return 1;
>  	return in_gate_area_no_task(addr);
>  }
> diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
> index c912137..0f7269f 100644
> --- a/scripts/kallsyms.c
> +++ b/scripts/kallsyms.c
> @@ -41,6 +41,7 @@ struct sym_entry {
>  static struct sym_entry *table;
>  static unsigned int table_size, table_cnt;
>  static unsigned long long _text, _stext, _etext, _sinittext, _einittext;
> +static unsigned long long _stext_l1, _etext_l1;
>  static int all_symbols = 0;
>  static char symbol_prefix_char = '\0';
>  
> @@ -98,6 +99,10 @@ static int read_symbol(FILE *in, struct sym_entry *s)
>  		_sinittext = s->addr;
>  	else if (strcmp(sym, "_einittext") == 0)
>  		_einittext = s->addr;
> +	 else if (strcmp(sym, "_stext_l1" ) == 0)
        ^ stray space
                                         ^ and another one

> +		_stext_l1 = s->addr;
> +	else if (strcmp(sym, "_etext_l1" ) == 0)
> +		_etext_l1 = s->addr;
>  	else if (toupper(stype) == 'A')
>  	{
>  		/* Keep these useful absolute symbols */
> @@ -160,7 +165,8 @@ static int symbol_valid(struct sym_entry *s)
>  	 * and inittext sections are discarded */
>  	if (!all_symbols) {
>  		if ((s->addr < _stext || s->addr > _etext)
> -		    && (s->addr < _sinittext || s->addr > _einittext))
> +		    && (s->addr < _sinittext || s->addr > _einittext)
> +		    && (s->addr < _stext_l1 || s->addr > _etext_l1))

so... for non-blackfin, the above addition is equivalent to

	&& (s->addr < 0 || s->addr > 0)

which is always true, except for s->addr==0, in which case we just broke
it.

I guess addr==0 isn't an interesting case here.


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