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authorNicholas Piggin <npiggin@gmail.com>2021-05-20 21:19:30 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2021-05-21 00:58:03 +1000
commit5665bc35c1ed917ac8fd06cb651317bb47a65b10 (patch)
treea2be9f6c1edc3cbda85fcdd9d171591a6fb593d6 /tools
parente2f5efd0f0e229bd110eab513e7c0331d61a4649 (diff)
downloadlinux-5665bc35c1ed917ac8fd06cb651317bb47a65b10.tar.bz2
powerpc/64s/syscall: Use pt_regs.trap to distinguish syscall ABI difference between sc and scv syscalls
The sc and scv 0 system calls have different ABI conventions, and ptracers need to know which system call type is being used if they want to look at the syscall registers. Document that pt_regs.trap can be used for this, and fix one in-tree user to work with scv 0 syscalls. Fixes: 7fa95f9adaee ("powerpc/64s: system call support for scv/rfscv instructions") Cc: stable@vger.kernel.org # v5.9+ Reported-by: "Dmitry V. Levin" <ldv@altlinux.org> Suggested-by: "Dmitry V. Levin" <ldv@altlinux.org> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210520111931.2597127-1-npiggin@gmail.com
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/seccomp/seccomp_bpf.c27
1 files changed, 18 insertions, 9 deletions
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index 98c3b647f54d..e3d5c77a8612 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -1753,16 +1753,25 @@ TEST_F(TRACE_poke, getpid_runs_normally)
# 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 { \
+ if ((_regs.trap & 0xfff0) == 0x3000) { \
+ /* \
+ * scv 0 system call uses -ve result \
+ * for error, so no need to adjust. \
+ */ \
SYSCALL_RET(_regs) = _result; \
- (_regs).ccr &= ~0x10000000; \
+ } else { \
+ /* \
+ * A syscall error is signaled by the \
+ * 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)
# define SYSCALL_RET_SET_ON_PTRACE_EXIT