| Message ID | 20190313124042.12855-7-pbonzini@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | CET support | expand |
On 3/13/19 5:40 AM, Paolo Bonzini wrote: > Because safe-syscall.S does not go through the C compiler, the > .note.gnu.property note has to be added manually. Safe syscalls do not > involve any indirect branch or stack unwinding, so they are trivially > safe for IBT or shadow stacks. > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > linux-user/host/i386/safe-syscall.inc.S | 19 +++++++++++++++++++ > linux-user/host/x86_64/safe-syscall.inc.S | 19 +++++++++++++++++++ > 2 files changed, 38 insertions(+) I suppose it's not worth trying to share these 19 lines... Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
On 14/03/19 00:52, Richard Henderson wrote: > On 3/13/19 5:40 AM, Paolo Bonzini wrote: >> Because safe-syscall.S does not go through the C compiler, the >> .note.gnu.property note has to be added manually. Safe syscalls do not >> involve any indirect branch or stack unwinding, so they are trivially >> safe for IBT or shadow stacks. >> >> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> >> --- >> linux-user/host/i386/safe-syscall.inc.S | 19 +++++++++++++++++++ >> linux-user/host/x86_64/safe-syscall.inc.S | 19 +++++++++++++++++++ >> 2 files changed, 38 insertions(+) > > I suppose it's not worth trying to share these 19 lines... They aren't exactly shared, one is .p2align 2, the other is .p2align 3. Paolo > Reviewed-by: Richard Henderson <richard.henderson@linaro.org> > > > r~ >
diff --git a/linux-user/host/i386/safe-syscall.inc.S b/linux-user/host/i386/safe-syscall.inc.S index 9e58fc6504..6c6d568d62 100644 --- a/linux-user/host/i386/safe-syscall.inc.S +++ b/linux-user/host/i386/safe-syscall.inc.S @@ -98,3 +98,22 @@ safe_syscall_end: .cfi_endproc .size safe_syscall_base, .-safe_syscall_base + + .pushsection ".note.gnu.property", "a" + .p2align 2 + .long 1f - 0f /* name length. */ + .long 4f - 1f /* data length. */ + .long 5 /* NT_GNU_PROPERTY_TYPE_0. */ +0: + .asciz "GNU" /* vendor name. */ + .p2align 2 +1: + /* GNU_PROPERTY_X86_FEATURE_1_AND. */ + .long 0xc0000002 /* pr_type. */ + .long 3f - 2f /* pr_datasz. */ +2: + .long 0x3 /* IBT, SHSTK */ +3: + .p2align 2 +4: + .popsection diff --git a/linux-user/host/x86_64/safe-syscall.inc.S b/linux-user/host/x86_64/safe-syscall.inc.S index f36992daa3..e1a57db338 100644 --- a/linux-user/host/x86_64/safe-syscall.inc.S +++ b/linux-user/host/x86_64/safe-syscall.inc.S @@ -89,3 +89,22 @@ safe_syscall_end: .cfi_endproc .size safe_syscall_base, .-safe_syscall_base + + .pushsection ".note.gnu.property", "a" + .p2align 3 + .long 1f - 0f /* name length. */ + .long 4f - 1f /* data length. */ + .long 5 /* NT_GNU_PROPERTY_TYPE_0. */ +0: + .asciz "GNU" /* vendor name. */ + .p2align 3 +1: + /* GNU_PROPERTY_X86_FEATURE_1_AND. */ + .long 0xc0000002 /* pr_type. */ + .long 3f - 2f /* pr_datasz. */ +2: + .long 0x3 /* IBT, SHSTK */ +3: + .p2align 3 +4: + .popsection
Because safe-syscall.S does not go through the C compiler, the .note.gnu.property note has to be added manually. Safe syscalls do not involve any indirect branch or stack unwinding, so they are trivially safe for IBT or shadow stacks. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- linux-user/host/i386/safe-syscall.inc.S | 19 +++++++++++++++++++ linux-user/host/x86_64/safe-syscall.inc.S | 19 +++++++++++++++++++ 2 files changed, 38 insertions(+)