commit 94cd37ebb293321115a36a422b091fdb72d2fb08
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Wed Sep 16 05:27:32 2020 -0700
x86: Use HAS_CPU_FEATURE with IBT and SHSTK [BZ #26625]
commit 04bba1e5d84b6fd8d3a3b006bc240cd5d241ee30
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Wed Aug 5 13:51:56 2020 -0700
x86: Set CPU usable feature bits conservatively [BZ #26552]
Set CPU usable feature bits only for CPU features which are usable in
user space and whose usability can be detected from user space, excluding
features like FSGSBASE whose enable bit can only be checked in the kernel.
no longer turns on the usable bits of IBT and SHSTK since we don't know
if IBT and SHSTK are usable until much later. Use HAS_CPU_FEATURE to
check if the processor supports IBT and SHSTK.
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index 77a596a15404b575..7f2ff00f2b4b45f2 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -722,9 +722,9 @@ no_cpuid:
GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK
*/
unsigned int cet_feature = 0;
- if (!CPU_FEATURE_USABLE (IBT))
+ if (!HAS_CPU_FEATURE (IBT))
cet_feature |= GNU_PROPERTY_X86_FEATURE_1_IBT;
- if (!CPU_FEATURE_USABLE (SHSTK))
+ if (!HAS_CPU_FEATURE (SHSTK))
cet_feature |= GNU_PROPERTY_X86_FEATURE_1_SHSTK;
if (cet_feature)
diff --git a/sysdeps/x86/dl-cet.c b/sysdeps/x86/dl-cet.c
index 11ff0618fae7230f..d481bddc27e5d7cc 100644
--- a/sysdeps/x86/dl-cet.c
+++ b/sysdeps/x86/dl-cet.c
@@ -74,10 +74,10 @@ dl_cet_check (struct link_map *m, const char *program)
GLIBC_TUNABLES=glibc.cpu.hwcaps=-IBT,-SHSTK
*/
- enable_ibt &= (CPU_FEATURE_USABLE (IBT)
+ enable_ibt &= (HAS_CPU_FEATURE (IBT)
&& (enable_ibt_type == cet_always_on
|| (m->l_cet & lc_ibt) != 0));
- enable_shstk &= (CPU_FEATURE_USABLE (SHSTK)
+ enable_shstk &= (HAS_CPU_FEATURE (SHSTK)
&& (enable_shstk_type == cet_always_on
|| (m->l_cet & lc_shstk) != 0));
}
diff --git a/sysdeps/x86/tst-get-cpu-features.c b/sysdeps/x86/tst-get-cpu-features.c
index c01d701b52090983..3ec94e0c9a191f36 100644
--- a/sysdeps/x86/tst-get-cpu-features.c
+++ b/sysdeps/x86/tst-get-cpu-features.c
@@ -318,7 +318,6 @@ 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);
@@ -342,7 +341,6 @@ 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 (AMX_TILE);
CHECK_CPU_FEATURE_USABLE (AMX_INT8);