From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Clément Léger" <cleger@rivosinc.com>,
"Palmer Dabbelt" <palmer@rivosinc.com>,
"Sasha Levin" <sashal@kernel.org>,
shuah@kernel.org, paul.walmsley@sifive.com, palmer@dabbelt.com,
aou@eecs.berkeley.edu, linux-kselftest@vger.kernel.org,
linux-riscv@lists.infradead.org
Subject: [PATCH AUTOSEL 6.8 20/23] selftests: sud_test: return correct emulated syscall value on RISC-V
Date: Tue, 7 May 2024 18:56:46 -0400 [thread overview]
Message-ID: <20240507225725.390306-20-sashal@kernel.org> (raw)
In-Reply-To: <20240507225725.390306-1-sashal@kernel.org>
From: Clément Léger <cleger@rivosinc.com>
[ Upstream commit 17c67ed752d6a456602b3dbb25c5ae4d3de5deab ]
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@rivosinc.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20231206134438.473166-1-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../selftests/syscall_user_dispatch/sud_test.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/tools/testing/selftests/syscall_user_dispatch/sud_test.c b/tools/testing/selftests/syscall_user_dispatch/sud_test.c
index b5d592d4099e8..d975a67673299 100644
--- a/tools/testing/selftests/syscall_user_dispatch/sud_test.c
+++ b/tools/testing/selftests/syscall_user_dispatch/sud_test.c
@@ -158,6 +158,20 @@ static void handle_sigsys(int sig, siginfo_t *info, void *ucontext)
/* In preparation for sigreturn. */
SYSCALL_DISPATCH_OFF(glob_sel);
+
+ /*
+ * The tests for argument handling assume that `syscall(x) == x`. This
+ * is a NOP on x86 because the syscall number is passed in %rax, which
+ * happens to also be the function ABI return register. Other
+ * architectures may need to swizzle the arguments around.
+ */
+#if defined(__riscv)
+/* REG_A7 is not defined in libc headers */
+# define REG_A7 (REG_A0 + 7)
+
+ ((ucontext_t *)ucontext)->uc_mcontext.__gregs[REG_A0] =
+ ((ucontext_t *)ucontext)->uc_mcontext.__gregs[REG_A7];
+#endif
}
TEST(dispatch_and_return)
--
2.43.0
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next parent reply other threads:[~2024-05-07 22:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240507225725.390306-1-sashal@kernel.org>
2024-05-07 22:56 ` Sasha Levin [this message]
2024-05-07 22:56 ` [PATCH AUTOSEL 6.8 21/23] riscv: thead: Rename T-Head PBMT to MAE Sasha Levin
2024-05-07 22:56 ` [PATCH AUTOSEL 6.8 22/23] riscv: T-Head: Test availability bit before enabling MAE errata Sasha Levin
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