From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id 1894E4C588 for ; Mon, 29 Jul 2024 19:44:08 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id D52DE68D6F4; Mon, 29 Jul 2024 22:44:05 +0300 (EEST) Received: from ursule.remlab.net (vps-a2bccee9.vps.ovh.net [51.75.19.47]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id CB2DF68D077 for ; Mon, 29 Jul 2024 22:43:58 +0300 (EEST) Received: from basile.remlab.net (localhost [IPv6:::1]) by ursule.remlab.net (Postfix) with ESMTP id 6B1CAC0140 for ; Mon, 29 Jul 2024 22:43:58 +0300 (EEST) From: =?UTF-8?q?R=C3=A9mi=20Denis-Courmont?= To: ffmpeg-devel@ffmpeg.org Date: Mon, 29 Jul 2024 22:43:58 +0300 Message-ID: <20240729194358.129575-1-remi@remlab.net> X-Mailer: git-send-email 2.45.2 MIME-Version: 1.0 Subject: [FFmpeg-devel] [PATCH] checkasm/riscv: preserve T1 whilst calling... X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: This preserves T1 whilst calling the instrumented function. In a Sci-Fi setting where type-based Control Flow Integrity (CFI) is supported, the calling code (i.e., the `checkasm` test case) will set T1 to the expected value of the landing pad label (LPL) of the instrumented function. The call wrapper will always use LPL zero which is a wild card. We should preserve the value of T1 at least until the indirect call to the instrumented function. Of course this is Sci-Fi, because: 1) there is no hardware (or even QEMU) support yet, 2) all our assembler functions currently use LPL zero anyway. This uses T3 rather than T2 because indirect branches with T2 is reserved for notionally direct calls made with an indirect call instruction (e.g. due to GOT indirection), and are exempted from forward-edge CFI checks. --- tests/checkasm/riscv/checkasm.S | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/tests/checkasm/riscv/checkasm.S b/tests/checkasm/riscv/checkasm.S index e8bcbb271e..c4b034ae23 100644 --- a/tests/checkasm/riscv/checkasm.S +++ b/tests/checkasm/riscv/checkasm.S @@ -89,8 +89,8 @@ func checkasm_get_wrapper, v /* Clobber the vector configuration */ li t0, 0 /* Vector length: zero */ - li t1, -1 << 31 /* Vector type: illegal */ - vsetvl zero, t0, t1 + li t2, -4 /* Vector type: illegal */ + vsetvl zero, t0, t2 csrwi vxrm, 3 /* Rounding mode: round-to-odd */ csrwi vxsat, 1 /* Saturation: encountered */ @@ -120,7 +120,7 @@ func checkasm_get_wrapper, v /* Clobber the saved and temporary registers */ .irp n, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 - .if (\n > 0 && \n < 7) + .if (\n > 1 && \n < 7) mv t\n, t0 .endif fmv.d.x ft\n, t0 @@ -131,9 +131,9 @@ func checkasm_get_wrapper, v /* Call the tested function */ la.tls.ie t0, checked_func add t0, tp, t0 - ld t1, (t0) + ld t3, (t0) sd zero, (t0) - jalr t1 + jalr t3 /* Check special register values */ la.tls.ie t0, saved_regs -- 2.45.2 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".