diff options
Diffstat (limited to 'gdb/nat/x86-linux.c')
| -rw-r--r-- | gdb/nat/x86-linux.c | 61 |
1 files changed, 60 insertions, 1 deletions
diff --git a/gdb/nat/x86-linux.c b/gdb/nat/x86-linux.c index ad3ed3c..5515826 100644 --- a/gdb/nat/x86-linux.c +++ b/gdb/nat/x86-linux.c @@ -1,6 +1,6 @@ /* Native-dependent code for GNU/Linux x86 (i386 and x86-64). - Copyright (C) 1999-2024 Free Software Foundation, Inc. + Copyright (C) 1999-2025 Free Software Foundation, Inc. This file is part of GDB. @@ -17,6 +17,12 @@ You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#include "elf/common.h" +#include "gdbsupport/common-defs.h" +#include "nat/gdb_ptrace.h" +#include "nat/linux-ptrace.h" +#include "nat/x86-cpuid.h" +#include <sys/uio.h> #include "x86-linux.h" #include "x86-linux-dregs.h" #include "nat/gdb_ptrace.h" @@ -126,3 +132,56 @@ x86_linux_ptrace_get_arch_size (int tid) return x86_linux_arch_size (false, false); #endif } + +/* See nat/x86-linux.h. */ + +bool +x86_check_ssp_support (const int tid) +{ + /* It's not enough to check shadow stack support with the ptrace call + below only, as we cannot distinguish between shadow stack not enabled + for the current thread and shadow stack is not supported by HW. In + both scenarios the ptrace call fails with ENODEV. In case shadow + stack is not enabled for the current thread, we still want to return + true. */ + unsigned int eax, ebx, ecx, edx; + eax = ebx = ecx = edx = 0; + + if (!__get_cpuid_count (7, 0, &eax, &ebx, &ecx, &edx)) + return false; + + if ((ecx & bit_SHSTK) == 0) + return false; + + /* Further check for NT_X86_SHSTK kernel support. */ + uint64_t ssp; + iovec iov {&ssp, sizeof (ssp) }; + + errno = 0; + int res = ptrace (PTRACE_GETREGSET, tid, NT_X86_SHSTK, &iov); + if (res < 0) + { + if (errno == EINVAL) + { + /* The errno EINVAL for a PTRACE_GETREGSET call indicates that + kernel support is not available. */ + return false; + } + else if (errno == ENODEV) + { + /* At this point, since we already checked CPUID, the errno + ENODEV for a PTRACE_GETREGSET call indicates that shadow + stack is not enabled for the current thread. As it could be + enabled later, we still want to return true here. */ + return true; + } + else + { + warning (_("Unknown ptrace error for NT_X86_SHSTK: %s"), + safe_strerror (errno)); + return false; + } + } + + return true; +} |