From: "Clément Léger" <cleger@rivosinc.com> To: Thomas Gleixner <tglx@linutronix.de>, Shuah Khan <shuah@kernel.org>, Gabriel Krisman Bertazi <krisman@collabora.com>, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Cc: "Clément Léger" <cleger@rivosinc.com>, "Palmer Dabbelt" <palmer@rivosinc.com>, "Björn Töpel" <bjorn@rivosinc.com> Subject: [PATCH v2] selftests: sud_test: return correct emulated syscall value on RISC-V Date: Wed, 6 Dec 2023 14:44:37 +0100 [thread overview] Message-ID: <20231206134438.473166-1-cleger@rivosinc.com> (raw) 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> --- Changes in V2: - Changes comment to be more explicit - Use A7 syscall arg rather than hardcoding MAGIC_SYSCALL_1 --- .../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 b5d592d4099e..d975a6767329 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
WARNING: multiple messages have this Message-ID (diff)
From: "Clément Léger" <cleger@rivosinc.com> To: Thomas Gleixner <tglx@linutronix.de>, Shuah Khan <shuah@kernel.org>, Gabriel Krisman Bertazi <krisman@collabora.com>, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Cc: "Clément Léger" <cleger@rivosinc.com>, "Palmer Dabbelt" <palmer@rivosinc.com>, "Björn Töpel" <bjorn@rivosinc.com> Subject: [PATCH v2] selftests: sud_test: return correct emulated syscall value on RISC-V Date: Wed, 6 Dec 2023 14:44:37 +0100 [thread overview] Message-ID: <20231206134438.473166-1-cleger@rivosinc.com> (raw) 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> --- Changes in V2: - Changes comment to be more explicit - Use A7 syscall arg rather than hardcoding MAGIC_SYSCALL_1 --- .../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 b5d592d4099e..d975a6767329 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 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next reply other threads:[~2023-12-06 13:45 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-12-06 13:44 Clément Léger [this message] 2023-12-06 13:44 ` [PATCH v2] selftests: sud_test: return correct emulated syscall value on RISC-V Clément Léger 2023-12-06 16:29 ` Palmer Dabbelt 2023-12-06 16:29 ` Palmer Dabbelt 2024-04-10 14:20 ` patchwork-bot+linux-riscv 2024-04-10 14:20 ` patchwork-bot+linux-riscv
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