* using void variables as linker-script symbol refs
@ 2003-10-10 17:49 David Howells
2003-10-10 20:44 ` Richard Henderson
0 siblings, 1 reply; 2+ messages in thread
From: David Howells @ 2003-10-10 17:49 UTC (permalink / raw)
To: gcc; +Cc: linux-kernel
I've got a situation in which I'd like to use something like the following to
refer to constants defined in the linker script:
extern const void _stext, _etext;
#define __kernel_size ((unsigned long)&_etext - (unsigned long)&_stext)
Rather than:
extern int _stext, _etext;
Or:
extern int _stext[], _etext[];
Or:
struct __not_really_a_struct;
struct __not_really_a_struct _stext, _etext;
This has a couple of advantages:
(1) You can't accidentally read/set such variables directly.
(2) GCC doesn't assume they can be referenced by register-relative means, if
the CPU has a special data pointer (such as a small-data pointer).
Any thoughts? Or is this just a straight forward shooting offence?
David
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: using void variables as linker-script symbol refs
2003-10-10 17:49 using void variables as linker-script symbol refs David Howells
@ 2003-10-10 20:44 ` Richard Henderson
0 siblings, 0 replies; 2+ messages in thread
From: Richard Henderson @ 2003-10-10 20:44 UTC (permalink / raw)
To: David Howells; +Cc: gcc, linux-kernel
On Fri, Oct 10, 2003 at 06:49:28PM +0100, David Howells wrote:
> extern int _stext[], _etext[];
s/int/char/ and this is the most correct way. Really.
r~
^ permalink raw reply [flat|nested] 2+ messages in thread
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