powerpc-darwin does not have ppc_debug_state (unlike i386/arm): is anything suitable as a fallback?

[barracuda156]

@trufae This is a follow-up to #25144

It is desirable to replace a hack which was used earlier to make radare2 compile on powerpc with a proper fix, adding implementation for it. PowerPC has most of the stuff which is used in xnu_threads. However, it does not have ppc_debug_state_t, apparently.
The code uses *_debug state for i386 and arm here:

radare2/libr/debug/p/native/xnu/xnu_threads.h

Lines 60 to 71 in 29f4d28

	#if __arm64 || __aarch64 || __arm64__ || __aarch64__ || __arm64e__
	union {
	arm_debug_state32_t drx32;
	arm_debug_state64_t drx64;
	} debug;
	#elif __arm__ || __arm || __armv7__
	union {
	arm_debug_state_t drx;
	} debug;
	#elif __x86_64__ || __i386__
	x86_debug_state_t drx;
	#endif

Corresponding .c file has commented out chunk with it:

radare2/libr/debug/p/native/xnu/xnu_threads.c

Lines 138 to 147 in 29f4d28

	#elif __POWERPC__
	/* not supported */
	# ifndef PPC_DEBUG_STATE32
	# define PPC_DEBUG_STATE32 1
	# endif
	//ppc_debug_state_t *regs;
	//thread->flavor = PPC_DEBUG_STATE32;
	//thread->count = R_MIN (thread->count, sizeof (regs->uds.ds32));
	return false;
	#else

However that won’t really work in that form, AFAICT.

Compare:
i386 has debug_state: https://github.com/alexey-lysiuk/macos-sdk/blob/78bd32056afc9a4720580f82d4ac839e7e831b6e/MacOSX10.6.sdk/usr/include/mach/i386/thread_status.h#L109-L111
powerpc does not: https://github.com/alexey-lysiuk/macos-sdk/blob/78bd32056afc9a4720580f82d4ac839e7e831b6e/MacOSX10.6.sdk/usr/include/mach/ppc/thread_status.h#L44-L50
Likewise, LLVM docs do not mention it for powerpc: https://llvm.org/doxygen/BinaryFormat_2MachO_8h_source.html

So the question is whether something can be done about that, using what exists on powerpc, or we are out of luck here, and just keep it disabled indefinitely?

[barracuda156]

Can we just use normal ppc_thread_state_t/ppc_thread_state64_t instead of *_debug_* ones?

[trufae]

Maybe we can just define those structs in the code and dont expect them to be available by the kernel headers. Can you give it a try and implement it and test it? I have the hw but no time for it

[trufae]

ping