gcc/libgcc/config/rs6000/tramp.S
Michael Meissner 9a30a3f06b Fix logic error in 32-bit trampolines.
The test in the PowerPC 32-bit trampoline support is backwards.  It aborts
if the trampoline size is greater than the expected size.  It should abort
when the trampoline size is less than the expected size.  I fixed the test
so the operands are reversed.  I then folded the load immediate into the
compare instruction.

I verified this by creating a 32-bit trampoline program and manually
changing the size of the trampoline to be 48 instead of 40.  The program
aborted with the larger size.  I updated this code and ran the test again
and it passed.

I added a test case that runs on PowerPC 32-bit Linux systems and it calls
the __trampoline_setup function with a larger buffer size than the
compiler uses.  The test is not run on 64-bit systems, since the function
__trampoline_setup is not called.  I also limited the test to just Linux
systems, in case trampolines are handled differently in other systems.

libgcc/
2021-04-23  Michael Meissner  <meissner@linux.ibm.com>

	PR target/98952
	* config/rs6000/tramp.S (__trampoline_setup, elfv1 #ifdef): Fix
	trampoline size comparison in 32-bit by reversing test and
	combining load immediate with compare.
	(__trampoline_setup, elfv2 #ifdef): Fix trampoline size comparison
	in 32-bit by reversing test and combining load immediate with
	compare.

gcc/testsuite/
2021-04-23  Michael Meissner  <meissner@linux.ibm.com>

	PR target/98952
	* gcc.target/powerpc/pr98952.c: New test.
2021-04-23 18:16:03 -04:00

194 lines
4.5 KiB
ArmAsm

/* Special support for trampolines
*
* Copyright (C) 1996-2021 Free Software Foundation, Inc.
* Written By Michael Meissner
*
* This file is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 3, or (at your option) any
* later version.
*
* This file is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* Under Section 7 of GPL version 3, you are granted additional
* permissions described in the GCC Runtime Library Exception, version
* 3.1, as published by the Free Software Foundation.
*
* You should have received a copy of the GNU General Public License and
* a copy of the GCC Runtime Library Exception along with this program;
* see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
* <http://www.gnu.org/licenses/>.
*/
/* Set up trampolines. */
.section ".text"
#include "ppc-asm.h"
#include "config.h"
#ifndef __powerpc64__
.type trampoline_initial,@object
.align 2
trampoline_initial:
mflr r0
bcl 20,31,1f
.Lfunc = .-trampoline_initial
.long 0 /* will be replaced with function address */
.Lchain = .-trampoline_initial
.long 0 /* will be replaced with static chain */
1: mflr r11
mtlr r0
lwz r0,0(r11) /* function address */
lwz r11,4(r11) /* static chain */
mtctr r0
bctr
trampoline_size = .-trampoline_initial
.size trampoline_initial,trampoline_size
/* R3 = stack address to store trampoline */
/* R4 = length of trampoline area */
/* R5 = function address */
/* R6 = static chain */
FUNC_START(__trampoline_setup)
.cfi_startproc
mflr r0 /* save return address */
bcl 20,31,.LCF0 /* load up __trampoline_initial into r7 */
.cfi_register lr,r0
.LCF0:
mflr r11
addi r7,r11,trampoline_initial-4-.LCF0 /* trampoline address -4 */
cmpwi cr1,r4,trampoline_size /* verify that the trampoline is big enough */
srwi r4,r4,2 /* # words to move */
addi r9,r3,-4 /* adjust pointer for lwzu */
mtctr r4
blt cr1,.Labort
mtlr r0
/* Copy the instructions to the stack */
.Lmove:
lwzu r10,4(r7)
stwu r10,4(r9)
bdnz .Lmove
/* Store correct function and static chain */
stw r5,.Lfunc(r3)
stw r6,.Lchain(r3)
/* Now flush both caches */
mtctr r4
.Lcache:
icbi 0,r3
dcbf 0,r3
addi r3,r3,4
bdnz .Lcache
/* Finally synchronize things & return */
sync
isync
blr
.Labort:
/* Use a longcall sequence in the non PIC case on VxWorks, to prevent
possible relocation errors if this is module-loaded very far away from
the 'abort' entry point. */
#if defined (__VXWORKS__) && ! (defined __PIC__ || defined __pic__)
lis r11,JUMP_TARGET(abort)@ha
addic r11,r11,JUMP_TARGET(abort)@l
mtlr r11
blrl
#else
#if (defined __PIC__ || defined __pic__) && defined HAVE_AS_REL16
bcl 20,31,1f
1: mflr r30
addis r30,r30,_GLOBAL_OFFSET_TABLE_-1b@ha
addi r30,r30,_GLOBAL_OFFSET_TABLE_-1b@l
#endif
bl JUMP_TARGET(abort)
#endif
.cfi_endproc
FUNC_END(__trampoline_setup)
#elif _CALL_ELF == 2
.type trampoline_initial,@object
.align 3
trampoline_initial:
ld r11,.Lchain(r12)
ld r12,.Lfunc(r12)
mtctr r12
bctr
.Lfunc = .-trampoline_initial
.quad 0 /* will be replaced with function address */
.Lchain = .-trampoline_initial
.quad 0 /* will be replaced with static chain */
trampoline_size = .-trampoline_initial
.size trampoline_initial,trampoline_size
/* R3 = stack address to store trampoline */
/* R4 = length of trampoline area */
/* R5 = function address */
/* R6 = static chain */
#ifndef __PCREL__
.pushsection ".toc","aw"
.LC0:
.quad trampoline_initial-8
.popsection
#endif
FUNC_START(__trampoline_setup)
.cfi_startproc
#ifdef __PCREL__
pla 7,(trampoline_initial-8)@pcrel
#else
addis 7,2,.LC0@toc@ha
ld 7,.LC0@toc@l(7) /* trampoline address -8 */
#endif
cmpwi cr1,r4,trampoline_size /* verify that the trampoline is big enough */
srwi r4,r4,3 /* # doublewords to move */
addi r9,r3,-8 /* adjust pointer for stdu */
mtctr r4
blt cr1,.Labort
/* Copy the instructions to the stack */
.Lmove:
ldu r10,8(r7)
stdu r10,8(r9)
bdnz .Lmove
/* Store correct function and static chain */
std r5,.Lfunc(r3)
std r6,.Lchain(r3)
/* Now flush both caches */
mtctr r4
.Lcache:
icbi 0,r3
dcbf 0,r3
addi r3,r3,8
bdnz .Lcache
/* Finally synchronize things & return */
sync
isync
blr
.Labort:
bl JUMP_TARGET(abort)
nop
.cfi_endproc
FUNC_END(__trampoline_setup)
#endif