Commit bb7f054f authored by Christophe Leroy's avatar Christophe Leroy Committed by Madhavan Srinivasan
Browse files

objtool/powerpc: Add support for decoding all types of uncond branches 

Add support for 'bla' instruction.

This is done by 'flagging' the address as an absolute address so that
arch_jump_destination() can calculate it as expected. Because code is
_always_ 4 bytes aligned, use bit 30 as flag.

Also add support for 'b' and 'ba' instructions. Objtool call them jumps.

And make sure the special 'bl .+4' used by clang in relocatable code is
not seen as an 'unannotated intra-function call'. clang should use the
special 'bcl 20,31,.+4' form like gcc but for the time being it does not
so lets work around that.

Link: https://github.com/llvm/llvm-project/issues/128644


Reviewed-by: default avatarSegher Boessenkool <segher@kewrnel.crashing.org>
Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMadhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/bf0b4d554547bc34fa3d1af5b4e62a84c0bc182b.1740470510.git.christophe.leroy@csgroup.eu
parent d856bc3a

tools/objtool/arch/powerpc/decode.c

+9 −1
Original line number Diff line number Diff line
@@ -55,12 +55,17 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec 


	switch (opcode) {

	case 18: /* b[l][a] */

		if ((ins & 3) == 1) /* bl */

		if (ins == 0x48000005)	/* bl .+4 */

			typ = INSN_OTHER;

		else if (ins & 1)	/* bl[a] */

			typ = INSN_CALL;

		else		/* b[a] */

			typ = INSN_JUMP_UNCONDITIONAL;



		imm = ins & 0x3fffffc;

		if (imm & 0x2000000)

			imm -= 0x4000000;

		imm |= ins & 2;	/* AA flag */

		break;

	}
@@ -77,6 +82,9 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec 


unsigned long arch_jump_destination(struct instruction *insn)

{

	if (insn->immediate & 2)

		return insn->immediate & ~2;



	return insn->offset + insn->immediate;

}