Re: [PATCH v4 2/4] objtool/powerpc: Add support for decoding all types of uncond branches
From: Segher Boessenkool <hidden>
Date: 2024-12-04 14:16:48
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On Tue, Dec 03, 2024 at 08:44:50PM +0100, Christophe Leroy wrote:
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.
The AA field already is there, so why not, eh :-)
Also add support for 'b' and 'ba' instructions. Objtool call them jumps.
Signed-off-by: Christophe Leroy <redacted>
Reviewed-by: Segher Boessenkool <redacted>
quoted hunk ↗ jump to hunk
--- a/tools/objtool/arch/powerpc/decode.c +++ b/tools/objtool/arch/powerpc/decode.c@@ -55,12 +55,15 @@ 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 & 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 */
You could of course put that together with the 3fffffc thing, but you can leave that to the compiler as well :-) Segher