linux-kernel - [PATCH] selftests: sud_test: return correct emulated syscall value on RISC-V

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Message-Id: <20230913140711.266975-1-cleger@rivosinc.com>
Date:   Wed, 13 Sep 2023 16:07:11 +0200
From:   Clément Léger <cleger@...osinc.com>
To:     Shuah Khan <shuah@...nel.org>,
        Gabriel Krisman Bertazi <krisman@...labora.com>,
        linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-riscv@...ts.infradead.org
Cc:     Clément Léger <cleger@...osinc.com>
Subject: [PATCH] selftests: sud_test: return correct emulated syscall value on RISC-V

Currently, the sud_test expects the emulated syscall to return the
emulated syscall number. This assumption only works on architectures
were the syscall calling convention use the same register for syscall
number/syscall return value. This is not the case for RISC-V and thus
the return value must be also emulated using the provided ucontext.

Signed-off-by: Clément Léger <cleger@...osinc.com>
---
 tools/testing/selftests/syscall_user_dispatch/sud_test.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tools/testing/selftests/syscall_user_dispatch/sud_test.c b/tools/testing/selftests/syscall_user_dispatch/sud_test.c
index b5d592d4099e..1b5553c19700 100644
--- a/tools/testing/selftests/syscall_user_dispatch/sud_test.c
+++ b/tools/testing/selftests/syscall_user_dispatch/sud_test.c
@@ -158,6 +158,14 @@ static void handle_sigsys(int sig, siginfo_t *info, void *ucontext)
 
 	/* In preparation for sigreturn. */
 	SYSCALL_DISPATCH_OFF(glob_sel);
+
+	/*
+	 * Modify interrupted context returned value according to syscall
+	 * calling convention
+	 */
+#if defined(__riscv)
+	((ucontext_t*)ucontext)->uc_mcontext.__gregs[REG_A0] = MAGIC_SYSCALL_1;
+#endif
 }
 
 TEST(dispatch_and_return)
-- 
2.40.1