From da7c3e786e34390d9c2edda44333209076df995f Mon Sep 17 00:00:00 2001 From: Rogerio Alves Date: Wed, 16 May 2018 14:20:53 -0500 Subject: [PATCH v4] powerpc: Always restore TOC on longjmp. This patch change longjmp to always restore the TOC pointer (r2 register) to the caller frame on powerpc. This is related to bug 21895[1] that reports a situation where you have a static longjmp to a shared object file. [1] https://sourceware.org/bugzilla/show_bug.cgi?id=21895 2018-05-16 Rogerio A. Cardoso *sysdeps/powerpc/powerpc64/__longjmp-common.S: Remove condition code for restore r2 on longjmp. *sysdeps/powerpc/powerpc64/Makefile: Added tst-setjmp-bug21895-static to test list. Added rules to build test tst-setjmp-bug21895-static. Added module setjmp-bug21895 and rules to build a shared object from it. *sysdeps/powerpc/powerpc64/setjmp-bug21895.c: New test file. *sysdeps/powerpc/powerpc64/tst-setjmp-bug21895-static.c: New test file. --- Changes in v4: Per Florian and Tulio review. The tests now uses inline asm specific for Power so the tests was moved to sysdep/powerpc/powerpc64. Changes in v3: as pointed out by Alexander Monakov we can't rely on alloca/memset since gcc can optimize this out or it can save the registers on the stack and the test will no longer make sense. Now I use a small asm code to deliberately overwrite TOC area on caller frame with zero. If the TOC is not restored by longjmp the test will fail. Changes in v2: Per Adhemerval Zanella. Fix test fail using the suggestions given. Fix changelog. Fix copyright and indentation for new tests. Change tests to use libsupport instead old test-skeleton. Fix a extra space in __longjmp-common. sysdeps/powerpc/powerpc64/Makefile | 12 ++++ sysdeps/powerpc/powerpc64/__longjmp-common.S | 5 +- sysdeps/powerpc/powerpc64/setjmp-bug21895.c | 52 ++++++++++++++ .../powerpc/powerpc64/tst-setjmp-bug21895-static.c | 81 ++++++++++++++++++++++ 5 files changed, 146 insertions(+), 5 deletions(-) create mode 100644 sysdeps/powerpc/powerpc64/setjmp-bug21895.c create mode 100644 sysdeps/powerpc/powerpc64/tst-setjmp-bug21895-static.c diff --git a/sysdeps/powerpc/powerpc64/Makefile b/sysdeps/powerpc/powerpc64/Makefile index 9d15db0..a0bd0c9 100644 --- a/sysdeps/powerpc/powerpc64/Makefile +++ b/sysdeps/powerpc/powerpc64/Makefile @@ -47,3 +47,15 @@ ifeq ($(subdir),gmon) CFLAGS-mcount.c += $(no-special-regs) sysdep_routines += ppc-mcount endif + +ifeq ($(subdir),setjmp) +tests += tst-setjmp-bug21895-static +tests-static += tst-setjmp-bug21895-static +modules-names += setjmp-bug21895 + +$(objpfx)tst-setjmp-bug21895-static: $(common-objpfx)dlfcn/libdl.a +$(objpfx)tst-setjmp-bug21895-static.out: $(objpfx)setjmp-bug21895.so + +tst-setjmp-bug21895-static-ENV = \ + LD_LIBRARY_PATH=$(objpfx):$(common-objpfx):$(common-objpfx)setjmp:$(common-objpfx)elf +endif diff --git a/sysdeps/powerpc/powerpc64/__longjmp-common.S b/sysdeps/powerpc/powerpc64/__longjmp-common.S index 0e10b8d..99c17c5 100644 --- a/sysdeps/powerpc/powerpc64/__longjmp-common.S +++ b/sysdeps/powerpc/powerpc64/__longjmp-common.S @@ -130,9 +130,6 @@ L(no_vmx): ld r0,(JB_LR*8)(r3) ld r14,((JB_GPRS+0)*8)(r3) lfd fp14,((JB_FPRS+0)*8)(r3) -#if defined SHARED && !IS_IN (rtld) - std r2,FRAME_TOC_SAVE(r1) /* Restore the callers TOC save area. */ -#endif ld r15,((JB_GPRS+1)*8)(r3) lfd fp15,((JB_FPRS+1)*8)(r3) ld r16,((JB_GPRS+2)*8)(r3) @@ -152,7 +149,7 @@ L(no_vmx): second argument (-4@4), and target address (8@0), respectively. */ LIBC_PROBE (longjmp, 3, 8@3, -4@4, 8@0) mtlr r0 -/* std r2,FRAME_TOC_SAVE(r1) Restore the TOC save area. */ + std r2,FRAME_TOC_SAVE(r1) /* Restore the TOC save area. */ ld r21,((JB_GPRS+7)*8)(r3) lfd fp21,((JB_FPRS+7)*8)(r3) ld r22,((JB_GPRS+8)*8)(r3) diff --git a/sysdeps/powerpc/powerpc64/setjmp-bug21895.c b/sysdeps/powerpc/powerpc64/setjmp-bug21895.c new file mode 100644 index 0000000..9e65f23 --- /dev/null +++ b/sysdeps/powerpc/powerpc64/setjmp-bug21895.c @@ -0,0 +1,52 @@ +/* Shared object part of test for setjmp interoperability with static + dlopen BZ #21895. + Copyright (C) 2017-2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include + +/* Copy r1 adress to a local variable. */ +#define GET_STACK_POINTER(sp) \ + ({ \ + asm volatile ("mr %0, 1\n\t" \ + : "=r" (sp) \ + ); \ + }) + +jmp_buf jb; +void (*bar)(jmp_buf, unsigned long); + +void +lbar (unsigned long sp) +{ + bar(jb, sp); + for(;;); +} + +void +foo (void) +{ + unsigned long sp; + /* Copy r1 (stack pointer) to sp. It will be use later to get + TOC area. */ + GET_STACK_POINTER(sp); + setjmp(jb); + lbar(sp); + + for(;;); +} diff --git a/sysdeps/powerpc/powerpc64/tst-setjmp-bug21895-static.c b/sysdeps/powerpc/powerpc64/tst-setjmp-bug21895-static.c new file mode 100644 index 0000000..235ba50 --- /dev/null +++ b/sysdeps/powerpc/powerpc64/tst-setjmp-bug21895-static.c @@ -0,0 +1,81 @@ +/* Test setjmp interoperability with static dlopen BZ #21895. + Copyright (C) 2017-2018 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include + +/* Set TOC area pointed by sp to zero. */ +#define SET_TOC_TO_ZERO(sp) \ + ({ \ + unsigned int zero = 0; \ + asm volatile( \ + "std %0, 24(%1)\n\t" \ + :: "r" (zero), "r" (sp) \ + ); \ + }) + +static void +bar (jmp_buf jb, unsigned long sp) +{ + static int i; + if (i++==1) + exit(0); /* Success. */ + + /* This will set TOC are on caller frame (foo) to zero. __longjmp + must restore r2 otherwise a segmentation fault will happens after + it jumps back to foo. */ + SET_TOC_TO_ZERO(sp); + longjmp(jb, i); +} + +static int +do_test (void) +{ + void *h = dlopen("setjmp-bug21895.so", RTLD_NOW); + if (!h) + { + puts(dlerror()); + return 1; + } + + void (*pfoo)(void) = dlsym(h, "foo"); + if (!pfoo) + { + puts(dlerror()); + return 1; + } + + void (**ppbar)(jmp_buf, unsigned long) = dlsym(h, "bar"); + if (!ppbar) + { + puts(dlerror()); + return 1; + } + + *ppbar = bar; + pfoo(); + + for(;;); +} + +/* Make sure the test will not stuck if jmp fails and fall into one of + for(;;). */ +#define TIMEOUT 100 +#include -- 2.7.4