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[MIPS] Discard .exit.text and .exit.data at runtime.

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While the recent cset 86384d5441 did improve
things it didn't resolve all the problems.  So bite the bullet and discard
.exit.text and .exit.data at runtime.  Which of course sucks because it
bloats binaries with code that will never ever be used but it's the only
thing that will work reliable as demonstrated by the function sd_major() in
drivers/scsi/sd.c.

Gcc may compile sd_major() using a jump table which it will put into
.rodata.  If it also inlines sd_major's function body into exit_sd() which
gcc > 3.4.x does.  If CONFIG_BLK_DEV_SD has been set to y we would like ld
to discard exit_sd's code at link time.  However sd_major happens to
contain a switch statement which gcc will compile using a jump table in
.rodata on the architectures I checked.  So, when ld later discards
.exit.text only the jump table in .rodata with its stale references to
the discard .exit.text will be left which any no antique ld will honor
with a link error.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Ralf Baechle 2006-12-11 11:54:52 +00:00
parent 8b2f35504d
commit 2efac77e82
1 changed files with 4 additions and 2 deletions
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6
arch/mips/kernel/vmlinux.lds.S
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@ -109,6 +109,10 @@ SECTIONS
.con_initcall.init : { *(.con_initcall.init) }
__con_initcall_end = .;
SECURITY_INIT
/* .exit.text is discarded at runtime, not link time, to deal with
references from .rodata */
.exit.text : { *(.exit.text) }
.exit.data : { *(.exit.data) }
. = ALIGN(_PAGE_SIZE);
__initramfs_start = .;
.init.ramfs : { *(.init.ramfs) }
@ -136,8 +140,6 @@ SECTIONS
/* Sections to be discarded */
/DISCARD/ : {
*(.exit.text)
*(.exit.data)
*(.exitcall.exit)
/* ABI crap starts here */