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@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>
This commit is contained in:
Clément Léger 2023-12-06 14:44:37 +01:00 committed by Palmer Dabbelt
parent 5ea6764d90
commit 17c67ed752
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@ -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)