From patchwork Wed Nov 22 09:42:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13464391 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8D2DA1DA53; Wed, 22 Nov 2023 09:47:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Y9kSWTAV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88DA2C433CB; Wed, 22 Nov 2023 09:47:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1700646429; bh=b3DUElLZ+Soh0Lccqy2ZSImkcM7zO9jMiCyb9nDJSwQ=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=Y9kSWTAVK98zhtVsyhDnKInGWdD30T07Ake/yR4jhC/+XLRShZE6i/o1V6NRBUhLz Dxrc74iwZWGjxvodTdGkItzPGoLKXLdxFS2Kgf26ynO1y5UO6mFbuGEYFRezPYZ3SN BJ6+Cpt7eYespf4hYmoUEvmoRFweNTPbyCFCCMewFKq5ZNXVlAgNurJYmvFMgcKAoz 6A5VkqVZkQux3aS2rdDhZOMzrDvsDBVF7gmWW8Wtj1s1MwxG9PDWzmbqkEHXCrQaYg nTZt+W8U2etS7jdzyurIciWhdn9ueX+xYQm+Qiv9r0ECdsUBfiYa9tDRxTCLuOOVc8 ssLs3BiYaclDw== From: Mark Brown Date: Wed, 22 Nov 2023 09:42:42 +0000 Subject: [PATCH v7 32/39] kselftest/arm64: Always run signals tests with GCS enabled Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20231122-arm64-gcs-v7-32-201c483bd775@kernel.org> References: <20231122-arm64-gcs-v7-0-201c483bd775@kernel.org> In-Reply-To: <20231122-arm64-gcs-v7-0-201c483bd775@kernel.org> To: Catalin Marinas , Will Deacon , Jonathan Corbet , Andrew Morton , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Arnd Bergmann , Oleg Nesterov , Eric Biederman , Kees Cook , Shuah Khan , "Rick P. Edgecombe" , Deepak Gupta , Ard Biesheuvel , Szabolcs Nagy Cc: "H.J. Lu" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Florian Weimer , Christian Brauner , Thiago Jung Bauermann , linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Mark Brown X-Mailer: b4 0.13-dev-0438c X-Developer-Signature: v=1; a=openpgp-sha256; l=3590; i=broonie@kernel.org; h=from:subject:message-id; bh=b3DUElLZ+Soh0Lccqy2ZSImkcM7zO9jMiCyb9nDJSwQ=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBlXc0Pq69NiV0DZvuQOBOHTJq4Hskdu8ueWsh0A OXrPDovxWCJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZV3NDwAKCRAk1otyXVSH 0AvKB/4gIm6EQumGj0Sww0FN0GocO/C+BLqTbwD6sziQA+cF0OfObYvSHOKFbMlhgZBDcbxRj+H 28uewK7t1SSYel2V8C+ykywrGEfBsUBjsriI5E5CfKOsPUhqtYwfEvHNoVySVobx5Rc1uodWehE wD4kxoZug4GzX0A1HdT4HPvZzCYUzCDXeyINi68DPqWrwit2CvDnkhjf8gGKqotnS4KnvHmhtcG C29Newlq2zS23qzht35JcPjfcn8Y1kR1IcN6GlS81iqTMkIEXYrjUAOl11+nDynG8e7kSOrapK7 71JfVueE4JJPVZeyyV05a7VJNsMwlN+yEcRjJzeJj1TAN/mD X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Since it is not possible to return from the function that enabled GCS without disabling GCS it is very inconvenient to use the signal handling tests to cover GCS when GCS is not enabled by the toolchain and runtime, something that no current distribution does. Since none of the testcases do anything with stacks that would cause problems with GCS we can sidestep this issue by unconditionally enabling GCS on startup and exiting with a call to exit() rather than a return from main(). Signed-off-by: Mark Brown --- .../testing/selftests/arm64/signal/test_signals.c | 17 ++++++++++++- .../selftests/arm64/signal/test_signals_utils.h | 29 ++++++++++++++++++++++ 2 files changed, 45 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/arm64/signal/test_signals.c b/tools/testing/selftests/arm64/signal/test_signals.c index 00051b40d71e..30e95f50db19 100644 --- a/tools/testing/selftests/arm64/signal/test_signals.c +++ b/tools/testing/selftests/arm64/signal/test_signals.c @@ -7,6 +7,10 @@ * Each test provides its own tde struct tdescr descriptor to link with * this wrapper. Framework provides common helpers. */ + +#include +#include + #include #include "test_signals.h" @@ -16,6 +20,16 @@ struct tdescr *current = &tde; int main(int argc, char *argv[]) { + /* + * Ensure GCS is at least enabled throughout the tests if + * supported, otherwise the inability to return from the + * function that enabled GCS makes it very inconvenient to set + * up test cases. The prctl() may fail if GCS was locked by + * libc setup code. + */ + if (getauxval(AT_HWCAP2) & HWCAP2_GCS) + gcs_set_state(PR_SHADOW_STACK_ENABLE); + ksft_print_msg("%s :: %s\n", current->name, current->descr); if (test_setup(current) && test_init(current)) { test_run(current); @@ -23,5 +37,6 @@ int main(int argc, char *argv[]) } test_result(current); - return current->result; + /* Do not return in case GCS was enabled */ + exit(current->result); } diff --git a/tools/testing/selftests/arm64/signal/test_signals_utils.h b/tools/testing/selftests/arm64/signal/test_signals_utils.h index 762c8fe9c54a..1e80808ee105 100644 --- a/tools/testing/selftests/arm64/signal/test_signals_utils.h +++ b/tools/testing/selftests/arm64/signal/test_signals_utils.h @@ -18,6 +18,35 @@ void test_cleanup(struct tdescr *td); int test_run(struct tdescr *td); void test_result(struct tdescr *td); +#ifndef __NR_prctl +#define __NR_prctl 167 +#endif + +/* + * The prctl takes 1 argument but we need to ensure that the other + * values passed in registers to the syscall are zero since the kernel + * validates them. + */ +#define gcs_set_state(state) \ + ({ \ + register long _num __asm__ ("x8") = __NR_prctl; \ + register long _arg1 __asm__ ("x0") = PR_SET_SHADOW_STACK_STATUS; \ + register long _arg2 __asm__ ("x1") = (long)(state); \ + register long _arg3 __asm__ ("x2") = 0; \ + register long _arg4 __asm__ ("x3") = 0; \ + register long _arg5 __asm__ ("x4") = 0; \ + \ + __asm__ volatile ( \ + "svc #0\n" \ + : "=r"(_arg1) \ + : "r"(_arg1), "r"(_arg2), \ + "r"(_arg3), "r"(_arg4), \ + "r"(_arg5), "r"(_num) \ + : "memory", "cc" \ + ); \ + _arg1; \ + }) + static inline bool feats_ok(struct tdescr *td) { if (td->feats_incompatible & td->feats_supported)