Re: [PATCH 01/15] selftests/seccomp: Refactor arch register macros to avoid xtensa special case

[Christian Brauner]

On Sat, Sep 12, 2020 at 04:08:06AM -0700, Kees Cook wrote:
> To avoid an xtensa special-case, refactor all arch register macros to
> take the register variable instead of depending on the macro expanding
> as a struct member name.
> 
> Signed-off-by: Kees Cook 
> ---

Looks good!
Acked-by: Christian Brauner 

[PATCH 01/15] selftests/seccomp: Refactor arch register macros to avoid xtensa special case

[Kees Cook]

To avoid an xtensa special-case, refactor all arch register macros to
take the register variable instead of depending on the macro expanding
as a struct member name.

Signed-off-by: Kees Cook 
---
 tools/testing/selftests/seccomp/seccomp_bpf.c | 97 +--
 1 file changed, 47 insertions(+), 50 deletions(-)

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c 
b/tools/testing/selftests/seccomp/seccomp_bpf.c
index c5002fc25b00..fef15080b575 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -1698,64 +1698,64 @@ TEST_F(TRACE_poke, getpid_runs_normally)
 }
 
 #if defined(__x86_64__)
-# define ARCH_REGS struct user_regs_struct
-# define SYSCALL_NUM   orig_rax
-# define SYSCALL_RET   rax
+# define ARCH_REGS struct user_regs_struct
+# define SYSCALL_NUM(_regs)(_regs).orig_rax
+# define SYSCALL_RET(_regs)(_regs).rax
 #elif defined(__i386__)
-# define ARCH_REGS struct user_regs_struct
-# define SYSCALL_NUM   orig_eax
-# define SYSCALL_RET   eax
+# define ARCH_REGS struct user_regs_struct
+# define SYSCALL_NUM(_regs)(_regs).orig_eax
+# define SYSCALL_RET(_regs)(_regs).eax
 #elif defined(__arm__)
-# define ARCH_REGS struct pt_regs
-# define SYSCALL_NUM   ARM_r7
-# define SYSCALL_RET   ARM_r0
+# define ARCH_REGS struct pt_regs
+# define SYSCALL_NUM(_regs)(_regs).ARM_r7
+# define SYSCALL_RET(_regs)(_regs).ARM_r0
 #elif defined(__aarch64__)
-# define ARCH_REGS struct user_pt_regs
-# define SYSCALL_NUM   regs[8]
-# define SYSCALL_RET   regs[0]
+# define ARCH_REGS struct user_pt_regs
+# define SYSCALL_NUM(_regs)(_regs).regs[8]
+# define SYSCALL_RET(_regs)(_regs).regs[0]
 #elif defined(__riscv) && __riscv_xlen == 64
-# define ARCH_REGS struct user_regs_struct
-# define SYSCALL_NUM   a7
-# define SYSCALL_RET   a0
+# define ARCH_REGS struct user_regs_struct
+# define SYSCALL_NUM(_regs)(_regs).a7
+# define SYSCALL_RET(_regs)(_regs).a0
 #elif defined(__csky__)
-# define ARCH_REGS struct pt_regs
-#if defined(__CSKYABIV2__)
-# define SYSCALL_NUM   regs[3]
-#else
-# define SYSCALL_NUM   regs[9]
-#endif
-# define SYSCALL_RET   a0
+# define ARCH_REGS struct pt_regs
+#  if defined(__CSKYABIV2__)
+#   define SYSCALL_NUM(_regs)  (_regs).regs[3]
+#  else
+#   define SYSCALL_NUM(_regs)  (_regs).regs[9]
+#  endif
+# define SYSCALL_RET(_regs)(_regs).a0
 #elif defined(__hppa__)
-# define ARCH_REGS struct user_regs_struct
-# define SYSCALL_NUM   gr[20]
-# define SYSCALL_RET   gr[28]
+# define ARCH_REGS struct user_regs_struct
+# define SYSCALL_NUM(_regs)(_regs).gr[20]
+# define SYSCALL_RET(_regs)(_regs).gr[28]
 #elif defined(__powerpc__)
-# define ARCH_REGS struct pt_regs
-# define SYSCALL_NUM   gpr[0]
-# define SYSCALL_RET   gpr[3]
+# define ARCH_REGS struct pt_regs
+# define SYSCALL_NUM(_regs)(_regs).gpr[0]
+# define SYSCALL_RET(_regs)(_regs).gpr[3]
 #elif defined(__s390__)
-# define ARCH_REGS s390_regs
-# define SYSCALL_NUM   gprs[2]
-# define SYSCALL_RET   gprs[2]
+# define ARCH_REGS s390_regs
+# define SYSCALL_NUM(_regs)(_regs).gprs[2]
+# define SYSCALL_RET(_regs)(_regs).gprs[2]
 # define SYSCALL_NUM_RET_SHARE_REG
 #elif defined(__mips__)
-# define ARCH_REGS struct pt_regs
-# define SYSCALL_NUM   regs[2]
-# define SYSCALL_SYSCALL_NUM regs[4]
-# define SYSCALL_RET   regs[2]
+# define ARCH_REGS struct pt_regs
+# define SYSCALL_NUM(_regs)(_regs).regs[2]
+# define SYSCALL_SYSCALL_NUM   regs[4]
+# define SYSCALL_RET(_regs)(_regs).regs[2]
 # define SYSCALL_NUM_RET_SHARE_REG
 #elif defined(__xtensa__)
-# define ARCH_REGS struct user_pt_regs
-# define SYSCALL_NUM   syscall
+# define ARCH_REGS struct user_pt_regs
+# define SYSCALL_NUM(_regs)(_regs).syscall
 /*
  * On xtensa syscall return value is in the register
  * a2 of the current window which is not fixed.
  */
-#define SYSCALL_RET(reg) a[(reg).windowbase * 4 + 2]
+#define SYSCALL_RET(_regs) (_regs).a[(_regs).windowbase * 4 + 2]
 #elif defined(__sh__)
-# define ARCH_REGS struct pt_regs
-# define SYSCALL_NUM   gpr[3]
-# define SYSCALL_RET   gpr[0]
+# define ARCH_REGS struct pt_regs
+# define SYSCALL_NUM(_regs)(_regs).gpr[3]
+# define SYSCALL_RET(_regs)(_regs).gpr[0]
 #else
 # error "Do not know how to find your architecture's registers and syscalls"
 #endif
@@ -1804,10 +1804,10 @@ int get_syscall(struct __test_metadata *_metadata, 
pid_t tracee)
 #endif
 
 #if defined(__mips__)
-   if (regs.SYSCALL_NUM == __NR_O32_Linux)
+   if (SYSCALL_NUM(regs) == __NR_O32_Linux)
return regs.SYSCALL_SYSCALL_NUM;
 #endif
-   return regs.SYSCALL_NUM;
+   return SYSCALL_NUM(regs);
 }
 
 /* Architecture-specific syscall changing routine. */
@@ -1830,14 +1830,14 @@ void change_syscall(struct __test_metadata *_metadata,