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From:   Mark Brown <broonie@kernel.org>
Date:   Mon, 31 Jul 2023 14:43:45 +0100
Subject: [PATCH v3 36/36] kselftest/arm64: Enable GCS for the FP stress
 tests
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To:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Andrew Morton <akpm@linux-foundation.org>,
        Marc Zyngier <maz@kernel.org>,
        Oliver Upton <oliver.upton@linux.dev>,
        James Morse <james.morse@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Arnd Bergmann <arnd@arndb.de>, Oleg Nesterov <oleg@redhat.com>,
        Eric Biederman <ebiederm@xmission.com>,
        Kees Cook <keescook@chromium.org>,
        Shuah Khan <shuah@kernel.org>,
        "Rick P. Edgecombe" <rick.p.edgecombe@intel.com>,
        Deepak Gupta <debug@rivosinc.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        Szabolcs Nagy <Szabolcs.Nagy@arm.com>
Cc:     "H.J. Lu" <hjl.tools@gmail.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        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 <broonie@kernel.org>
Precedence: bulk

While it's a bit off topic for them the floating point stress tests do give
us some coverage of context thrashing cases, and also of active signal
delivery separate to the relatively complicated framework in the actual
signals tests. Have the tests enable GCS on startup, ignoring failures so
they continue to work as before on systems without GCS.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/arm64/fp/assembler.h   | 15 +++++++++++++++
 tools/testing/selftests/arm64/fp/fpsimd-test.S |  2 ++
 tools/testing/selftests/arm64/fp/sve-test.S    |  2 ++
 tools/testing/selftests/arm64/fp/za-test.S     |  2 ++
 tools/testing/selftests/arm64/fp/zt-test.S     |  2 ++
 5 files changed, 23 insertions(+)

diff --git a/tools/testing/selftests/arm64/fp/assembler.h b/tools/testing/selftests/arm64/fp/assembler.h
index 9b38a0da407d..7012f9f796de 100644
--- a/tools/testing/selftests/arm64/fp/assembler.h
+++ b/tools/testing/selftests/arm64/fp/assembler.h
@@ -65,4 +65,19 @@ endfunction
 	bl	puts
 .endm
 
+#define PR_SET_SHADOW_STACK_STATUS      72
+# define PR_SHADOW_STACK_ENABLE         (1UL << 0)
+
+.macro enable_gcs
+	// Run with GCS
+	mov	x0, PR_SET_SHADOW_STACK_STATUS
+	mov	x1, PR_SHADOW_STACK_ENABLE
+	mov	x2, xzr
+	mov	x3, xzr
+	mov	x4, xzr
+	mov	x5, xzr
+	mov	x8, #__NR_prctl
+	svc	#0
+.endm
+
 #endif /* ! ASSEMBLER_H */
diff --git a/tools/testing/selftests/arm64/fp/fpsimd-test.S b/tools/testing/selftests/arm64/fp/fpsimd-test.S
index 8b960d01ed2e..b16fb7f42e3e 100644
--- a/tools/testing/selftests/arm64/fp/fpsimd-test.S
+++ b/tools/testing/selftests/arm64/fp/fpsimd-test.S
@@ -215,6 +215,8 @@ endfunction
 // Main program entry point
 .globl _start
 function _start
+	enable_gcs
+
 	mov	x23, #0		// signal count
 
 	mov	w0, #SIGINT
diff --git a/tools/testing/selftests/arm64/fp/sve-test.S b/tools/testing/selftests/arm64/fp/sve-test.S
index 4328895dfc87..486634bc7def 100644
--- a/tools/testing/selftests/arm64/fp/sve-test.S
+++ b/tools/testing/selftests/arm64/fp/sve-test.S
@@ -378,6 +378,8 @@ endfunction
 // Main program entry point
 .globl _start
 function _start
+	enable_gcs
+
 	mov	x23, #0		// Irritation signal count
 
 	mov	w0, #SIGINT
diff --git a/tools/testing/selftests/arm64/fp/za-test.S b/tools/testing/selftests/arm64/fp/za-test.S
index 9dcd70911397..f789694fa3ea 100644
--- a/tools/testing/selftests/arm64/fp/za-test.S
+++ b/tools/testing/selftests/arm64/fp/za-test.S
@@ -231,6 +231,8 @@ endfunction
 // Main program entry point
 .globl _start
 function _start
+	enable_gcs
+
 	mov	x23, #0		// signal count
 
 	mov	w0, #SIGINT
diff --git a/tools/testing/selftests/arm64/fp/zt-test.S b/tools/testing/selftests/arm64/fp/zt-test.S
index d63286397638..ea5e55310705 100644
--- a/tools/testing/selftests/arm64/fp/zt-test.S
+++ b/tools/testing/selftests/arm64/fp/zt-test.S
@@ -200,6 +200,8 @@ endfunction
 // Main program entry point
 .globl _start
 function _start
+	enable_gcs
+
 	mov	x23, #0		// signal count
 
 	mov	w0, #SIGINT

-- 
2.30.2