[PATCH 12/15] selftests/seccomp: powerpc: Fix seccomp return value testing

Kees Cook
2020-09-12T11:10:23Z

On powerpc, the errno is not inverted, and depends on ccr.so being
set. Add this to a powerpc definition of SYSCALL_RET_SET().

Co-developed-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Link: https://lore.kernel.org/linux-kselftest/20200911181012.171027-1-cascardo@canonical.com/
Fixes: 5d83c2b37d43 ("selftests/seccomp: Add powerpc support")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
tools/testing/selftests/seccomp/seccomp_bpf.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 623953a53032..bbab2420d708 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -1750,6 +1750,21 @@ TEST_F(TRACE_poke, getpid_runs_normally)
# define ARCH_REGS struct pt_regs
# define SYSCALL_NUM(_regs) (_regs).gpr[0]
# define SYSCALL_RET(_regs) (_regs).gpr[3]
+# define SYSCALL_RET_SET(_regs, _val) \
+ do { \
+ typeof(_val) _result = (_val); \
+ /* \
+ * A syscall error is signaled by CR0 SO bit \
+ * and the code is stored as a positive value. \
+ */ \
+ if (_result < 0) { \
+ SYSCALL_RET(_regs) = -result; \
+ (_regs).ccr |= 0x10000000; \
+ } else { \
+ SYSCALL_RET(_regs) = result; \
+ (_regs).ccr &= ~0x10000000; \
+ } \
+ } while (0)
#elif defined(__s390__)
# define ARCH_REGS s390_regs
# define SYSCALL_NUM(_regs) (_regs).gprs[2]
--
2.25.1