On Thu, Jan 28, 2021 at 9:51 AM Adhemerval Zanella wrote: > > > > On 27/01/2021 09:27, H.J. Lu wrote: > > commit 94cd37ebb293321115a36a422b091fdb72d2fb08 > > Author: H.J. Lu > > Date: Wed Sep 16 05:27:32 2020 -0700 > > > > x86: Use HAS_CPU_FEATURE with IBT and SHSTK [BZ #26625] > > > > broke > > > > GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK > > > > since it can no longer disable IBT nor SHSTK. Handle IBT and SHSTK with: > > > > 1. Revert commit 94cd37ebb293321115a36a422b091fdb72d2fb08. > > 2. Clears the usable CET feature bits if kernel doesn't support CET. > > 3. Add GLIBC_TUNABLES tests without dlopen. > > 4. Add tests to verify that CPU_FEATURE_USABLE on IBT and SHSTK matches > > _get_ssp. > > 5. Update GLIBC_TUNABLES tests with dlopen to verify that CET is disabled > > with GLIBC_TUNABLES. > > Patch looks ok with some minot nit below, but I am kind worried it would > require a lot of x86 testing where there are already results posted on > release wiki. I have tested the fixed glibc on i686, x32, x86-64 with --enable-cet on Tiger Lake and legacy CPU. There are no differences in test results. > Carlos and Florian, what do you think? Should we push it for the 2.33 release > on backport on the release branch? I prefer to fix it for glibc 2.33. It has happened multiple times to me when I need $ export GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK to update OS on Tiger Lake. > > --- > > sysdeps/x86/Makefile | 8 ++++- > > sysdeps/x86/cpu-features.c | 11 +++++-- > > sysdeps/x86/dl-cet.c | 4 +-- > > sysdeps/x86/tst-cet-legacy-10-static.c | 1 + > > sysdeps/x86/tst-cet-legacy-10.c | 43 ++++++++++++++++++++++++++ > > sysdeps/x86/tst-cet-legacy-5.c | 11 ++++--- > > sysdeps/x86/tst-cet-legacy-6.c | 11 ++++--- > > sysdeps/x86/tst-cet-legacy-9-static.c | 1 + > > sysdeps/x86/tst-cet-legacy-9.c | 41 ++++++++++++++++++++++++ > > sysdeps/x86/tst-get-cpu-features.c | 2 ++ > > 10 files changed, 120 insertions(+), 13 deletions(-) > > create mode 100644 sysdeps/x86/tst-cet-legacy-10-static.c > > create mode 100644 sysdeps/x86/tst-cet-legacy-10.c > > create mode 100644 sysdeps/x86/tst-cet-legacy-9-static.c > > create mode 100644 sysdeps/x86/tst-cet-legacy-9.c > > > > diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile > > index 7549507a9a..dd82674342 100644 > > --- a/sysdeps/x86/Makefile > > +++ b/sysdeps/x86/Makefile > > @@ -82,7 +82,9 @@ sysdep-dl-routines += dl-cet > > tests += tst-cet-legacy-1 tst-cet-legacy-1a tst-cet-legacy-2 \ > > tst-cet-legacy-2a tst-cet-legacy-3 tst-cet-legacy-4 \ > > tst-cet-legacy-5a tst-cet-legacy-6a tst-cet-legacy-7 \ > > - tst-cet-legacy-8 > > + tst-cet-legacy-8 tst-cet-legacy-9 tst-cet-legacy-9-static \ > > + tst-cet-legacy-10 tst-cet-legacy-10-static > > +tests-static += tst-cet-legacy-9-static tst-cet-legacy-10-static > > Do we need to stat the static variant to 'tests' rule as well? I always add the static variants to 'tests'. > > tst-cet-legacy-1a-ARGS = -- $(host-test-program-cmd) > > ifneq (no,$(have-tunables)) > > tests += tst-cet-legacy-4a tst-cet-legacy-4b tst-cet-legacy-4c \ > > @@ -123,6 +125,8 @@ CFLAGS-tst-cet-legacy-mod-6b.c += -fcf-protection > > CFLAGS-tst-cet-legacy-mod-6c.c += -fcf-protection > > CFLAGS-tst-cet-legacy-7.c += -fcf-protection=none > > CFLAGS-tst-cet-legacy-8.c += -mshstk > > +CFLAGS-tst-cet-legacy-10.c += -mshstk > > +CFLAGS-tst-cet-legacy-10-static.c += -mshstk > > > > $(objpfx)tst-cet-legacy-1: $(objpfx)tst-cet-legacy-mod-1.so \ > > $(objpfx)tst-cet-legacy-mod-2.so > > Ok. > > > @@ -163,6 +167,8 @@ $(objpfx)tst-cet-legacy-6b: $(libdl) > > $(objpfx)tst-cet-legacy-6b.out: $(objpfx)tst-cet-legacy-mod-6a.so \ > > $(objpfx)tst-cet-legacy-mod-6b.so > > tst-cet-legacy-6b-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK > > +tst-cet-legacy-9-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK > > +tst-cet-legacy-9-static-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK > > endif > > endif > > > > Ok. > > > diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c > > index 6496512a0d..73b0a4dc9a 100644 > > --- a/sysdeps/x86/cpu-features.c > > +++ b/sysdeps/x86/cpu-features.c > > @@ -75,6 +75,7 @@ update_usable (struct cpu_features *cpu_features) > > CPU_FEATURE_SET_USABLE (cpu_features, PREFETCHWT1); > > CPU_FEATURE_SET_USABLE (cpu_features, OSPKE); > > CPU_FEATURE_SET_USABLE (cpu_features, WAITPKG); > > + CPU_FEATURE_SET_USABLE (cpu_features, SHSTK); > > CPU_FEATURE_SET_USABLE (cpu_features, GFNI); > > CPU_FEATURE_SET_USABLE (cpu_features, RDPID); > > CPU_FEATURE_SET_USABLE (cpu_features, RDRAND); > > @@ -84,6 +85,7 @@ update_usable (struct cpu_features *cpu_features) > > CPU_FEATURE_SET_USABLE (cpu_features, FSRM); > > CPU_FEATURE_SET_USABLE (cpu_features, SERIALIZE); > > CPU_FEATURE_SET_USABLE (cpu_features, TSXLDTRK); > > + CPU_FEATURE_SET_USABLE (cpu_features, IBT); > > CPU_FEATURE_SET_USABLE (cpu_features, LAHF64_SAHF64); > > CPU_FEATURE_SET_USABLE (cpu_features, LZCNT); > > CPU_FEATURE_SET_USABLE (cpu_features, SSE4A); > > Ok. > > > @@ -705,6 +707,11 @@ no_cpuid: > > /* Check CET status. */ > > unsigned int cet_status = get_cet_status (); > > > > + if ((cet_status & GNU_PROPERTY_X86_FEATURE_1_IBT) == 0) > > + CPU_FEATURE_UNSET (cpu_features, IBT) > > + if ((cet_status & GNU_PROPERTY_X86_FEATURE_1_SHSTK) == 0) > > + CPU_FEATURE_UNSET (cpu_features, SHSTK) > > + > > if (cet_status) > > { > > GL(dl_x86_feature_1) = cet_status; > > Ok > > > @@ -720,9 +727,9 @@ no_cpuid: > > GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK > > */ > > unsigned int cet_feature = 0; > > - if (!HAS_CPU_FEATURE (IBT)) > > + if (!CPU_FEATURE_USABLE (IBT)) > > cet_feature |= GNU_PROPERTY_X86_FEATURE_1_IBT; > > - if (!HAS_CPU_FEATURE (SHSTK)) > > + if (!CPU_FEATURE_USABLE (SHSTK)) > > cet_feature |= GNU_PROPERTY_X86_FEATURE_1_SHSTK; > > > > if (cet_feature) > > Ok, it is changing the check from 'cpuid' field to 'usable'. > > > diff --git a/sysdeps/x86/dl-cet.c b/sysdeps/x86/dl-cet.c > > index a63b9c7164..c74e577289 100644 > > --- a/sysdeps/x86/dl-cet.c > > +++ b/sysdeps/x86/dl-cet.c > > @@ -77,11 +77,11 @@ dl_cet_check (struct link_map *m, const char *program) > > > > GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK > > */ > > - enable_ibt &= (HAS_CPU_FEATURE (IBT) > > + enable_ibt &= (CPU_FEATURE_USABLE (IBT) > > && (enable_ibt_type == cet_always_on > > || (m->l_x86_feature_1_and > > & GNU_PROPERTY_X86_FEATURE_1_IBT) != 0)); > > - enable_shstk &= (HAS_CPU_FEATURE (SHSTK) > > + enable_shstk &= (CPU_FEATURE_USABLE (SHSTK) > > && (enable_shstk_type == cet_always_on > > || (m->l_x86_feature_1_and > > & GNU_PROPERTY_X86_FEATURE_1_SHSTK) != 0)); > > Ok. > > > diff --git a/sysdeps/x86/tst-cet-legacy-10-static.c b/sysdeps/x86/tst-cet-legacy-10-static.c > > new file mode 100644 > > index 0000000000..ecc1208e35 > > --- /dev/null > > +++ b/sysdeps/x86/tst-cet-legacy-10-static.c > > @@ -0,0 +1 @@ > > +#include "tst-cet-legacy-10.c" > > Ok. > > > diff --git a/sysdeps/x86/tst-cet-legacy-10.c b/sysdeps/x86/tst-cet-legacy-10.c > > new file mode 100644 > > index 0000000000..a618557f45 > > --- /dev/null > > +++ b/sysdeps/x86/tst-cet-legacy-10.c > > @@ -0,0 +1,43 @@ > > +/* Check CPU_FEATURE_USABLE on IBT and SHSTK. > > + Copyright (C) 2021 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 > > + > > +/* Check that CPU_FEATURE_USABLE on IBT and SHSTK matches _get_ssp. */ > > + > > +static int > > +do_test (void) > > +{ > > + if (_get_ssp () != 0) > > + { > > + if (CPU_FEATURE_USABLE (IBT) && CPU_FEATURE_USABLE (SHSTK)) > > + return EXIT_SUCCESS; > > + } > > + else > > + { > > + if (!CPU_FEATURE_USABLE (IBT) && !CPU_FEATURE_USABLE (SHSTK)) > > + return EXIT_SUCCESS; > > + } > > + > > + return EXIT_FAILURE; > > +} > > + > > +#include > > Ok. Checking on the _get_ssp documentation the idea is on hardware without CET > support it returns 0, right? Correct. > > diff --git a/sysdeps/x86/tst-cet-legacy-5.c b/sysdeps/x86/tst-cet-legacy-5.c > > index e3efeb1f4e..d870de3eae 100644 > > --- a/sysdeps/x86/tst-cet-legacy-5.c > > +++ b/sysdeps/x86/tst-cet-legacy-5.c > > @@ -37,6 +37,12 @@ do_test_1 (const char *modname, bool fail) > > int (*fp) (void); > > void *h; > > > > + /* NB: dlopen should never fail on non-CET platforms. If SHSTK is > > + disabled, assuming IBT is also disabled. */ > > + bool cet_enabled = _get_ssp () != 0 && !CET_MAYBE_DISABLED; > > + if (!cet_enabled) > > + fail = false; > > + > > h = dlopen (modname, RTLD_LAZY); > > if (h == NULL) > > { > > @@ -53,10 +59,7 @@ do_test_1 (const char *modname, bool fail) > > FAIL_EXIT1 ("cannot open '%s': %s\n", modname, err); > > } > > > > - /* NB: dlopen should never fail on non-CET platforms. If SHSTK is > > - disabled, assuming IBT is also disabled. */ > > - bool cet_enabled = _get_ssp () != 0 && !CET_MAYBE_DISABLED; > > - if (fail && cet_enabled) > > + if (fail) > > FAIL_EXIT1 ("dlopen should have failed\n"); > > > > fp = dlsym (h, "test"); > > Ok. > > > diff --git a/sysdeps/x86/tst-cet-legacy-6.c b/sysdeps/x86/tst-cet-legacy-6.c > > index 44b2ef5c7a..8e82ee2246 100644 > > --- a/sysdeps/x86/tst-cet-legacy-6.c > > +++ b/sysdeps/x86/tst-cet-legacy-6.c > > @@ -37,6 +37,12 @@ do_test_1 (const char *modname, bool fail) > > int (*fp) (void); > > void *h; > > > > + /* NB: dlopen should never fail on non-CET platforms. If SHSTK is > > + disabled, assuming IBT is also disabled. */ > > + bool cet_enabled = _get_ssp () != 0 && !CET_MAYBE_DISABLED; > > + if (!cet_enabled) > > + fail = false; > > + > > h = dlopen (modname, RTLD_LAZY); > > if (h == NULL) > > { > > @@ -53,10 +59,7 @@ do_test_1 (const char *modname, bool fail) > > FAIL_EXIT1 ("cannot open '%s': %s\n", modname, err); > > } > > > > - /* NB: dlopen should never fail on non-CET platforms. If SHSTK is > > - disabled, assuming IBT is also disabled. */ > > - bool cet_enabled = _get_ssp () != 0 && !CET_MAYBE_DISABLED; > > - if (fail && cet_enabled) > > + if (fail) > > FAIL_EXIT1 ("dlopen should have failed\n"); > > > > fp = dlsym (h, "test"); > > Ok. > > > diff --git a/sysdeps/x86/tst-cet-legacy-9-static.c b/sysdeps/x86/tst-cet-legacy-9-static.c > > new file mode 100644 > > index 0000000000..f9a8518b99 > > --- /dev/null > > +++ b/sysdeps/x86/tst-cet-legacy-9-static.c > > @@ -0,0 +1 @@ > > +#include "tst-cet-legacy-9.c" > > Ok. > > > diff --git a/sysdeps/x86/tst-cet-legacy-9.c b/sysdeps/x86/tst-cet-legacy-9.c > > new file mode 100644 > > index 0000000000..2b526c9055 > > --- /dev/null > > +++ b/sysdeps/x86/tst-cet-legacy-9.c > > @@ -0,0 +1,41 @@ > > +/* Check CET compatibility with legacy JIT engine via GLIBC_TUNABLES. > > + Copyright (C) 2021 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 > > +#include > > + > > +/* Check that mmapped legacy code won't trigger segfault with > > + -fcf-protection and GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK. */ > > + > > +static int > > +do_test (void) > > +{ > > + void (*funcp) (void); > > + funcp = xmmap (NULL, 0x1000, PROT_EXEC | PROT_READ | PROT_WRITE, > > + MAP_ANONYMOUS | MAP_PRIVATE, -1); > > Although x86_64 only support 4k page currently (not counting large > pages, but which requires an additional mmap flag anyway), I think it > should use xsysconf (_SC_PAGESIZE) to be future-proof. Fixed. > > + printf ("mmap = %p\n", funcp); > > + /* Write RET instruction. */ > > + *(char *) funcp = 0xc3; > > + funcp (); > > + return EXIT_SUCCESS; > > +} > > + > > +#include > > Ok. > > > diff --git a/sysdeps/x86/tst-get-cpu-features.c b/sysdeps/x86/tst-get-cpu-features.c > > index dcdb86bb93..b5e7f6e7b0 100644 > > --- a/sysdeps/x86/tst-get-cpu-features.c > > +++ b/sysdeps/x86/tst-get-cpu-features.c > > @@ -301,6 +301,7 @@ do_test (void) > > CHECK_CPU_FEATURE_USABLE (OSPKE); > > CHECK_CPU_FEATURE_USABLE (WAITPKG); > > CHECK_CPU_FEATURE_USABLE (AVX512_VBMI2); > > + CHECK_CPU_FEATURE_USABLE (SHSTK); > > CHECK_CPU_FEATURE_USABLE (GFNI); > > CHECK_CPU_FEATURE_USABLE (VAES); > > CHECK_CPU_FEATURE_USABLE (VPCLMULQDQ); > > @@ -324,6 +325,7 @@ do_test (void) > > CHECK_CPU_FEATURE_USABLE (HYBRID); > > CHECK_CPU_FEATURE_USABLE (TSXLDTRK); > > CHECK_CPU_FEATURE_USABLE (PCONFIG); > > + CHECK_CPU_FEATURE_USABLE (IBT); > > CHECK_CPU_FEATURE_USABLE (AMX_BF16); > > CHECK_CPU_FEATURE_USABLE (AVX512_FP16); > > CHECK_CPU_FEATURE_USABLE (AMX_TILE); > > > > Ok.+ Here is the updated patch. OK for master? Thanks/ -- H.J.