Re: [PATCH 12/15] selftests/seccomp: powerpc: Fix seccomp return value testing
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2020-09-14 03:38:50
Also in:
linux-arm-kernel, linux-kselftest, linux-mips, lkml
Kees Cook [off-list ref] writes:
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 <redacted> Signed-off-by: Thadeu Lima de Souza Cascardo <redacted> Link: https://lore.kernel.org/linux-kselftest/20200911181012.171027-1-cascardo@canonical.com/ (local) Fixes: 5d83c2b37d43 ("selftests/seccomp: Add powerpc support") Signed-off-by: Kees Cook <redacted> --- tools/testing/selftests/seccomp/seccomp_bpf.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
This looks right to me, and matches what strace does AFAICS. Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> cheers
quoted hunk ↗ jump to hunk
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