| Message ID | 20231206134438.473166-1-cleger@rivosinc.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | bac292e849d76d78c3acbdef3c2fa56cf47ab69a |
| Headers | show |
| Series | [v2] selftests: sud_test: return correct emulated syscall value on RISC-V | expand |
On Wed, 06 Dec 2023 05:44:37 PST (-0800), cleger@rivosinc.com wrote: > 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) Thanks. Thomas: looks like you picked up all the commits that touched this? No rush on my end, just LMK if you want me to pick it up -- I'm going to leave it alone for now.
Hello: This patch was applied to riscv/linux.git (for-next) by Palmer Dabbelt <palmer@rivosinc.com>: On Wed, 6 Dec 2023 14:44:37 +0100 you wrote: > 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> > > [...] Here is the summary with links: - [v2] selftests: sud_test: return correct emulated syscall value on RISC-V https://git.kernel.org/riscv/c/bac292e849d7 You are awesome, thank you!
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)