Ping: [PATCH] Arm64: support CLEARBHB alias

[Richard Earnshaw]

On 28/09/2022 13:00, Jan Beulich via Binutils wrote:
> On 12.09.2022 10:40, Jan Beulich via Binutils wrote:
>> While the Arm v8 ARM (rev I-a) still doesn't mention this alias, it is
>> (typically via a macro) already in use in kernels and alike.
> 
> May I ask for feedback here? Without hearing back, I guess I'll simply
> put this in some time next week.
> 
> Jan

Sorry for the delay.  The details on this instruction were only made 
public earlier today. 
(https://developer.arm.com/documentation/ddi0602/2022-09/Base-Instructions/CLRBHB--Clear-Branch-History-?lang=en)

OK.

R.

> 
>> ---
>> Diffs of generated files omitted.
>>
>> --- a/gas/testsuite/gas/aarch64/system.d
>> +++ b/gas/testsuite/gas/aarch64/system.d
>> @@ -12,6 +12,7 @@ Disassembly of section \.text:
>>   .*:	d503207f 	wfi
>>   .*:	d503209f 	sev
>>   .*:	d50320bf 	sevl
>> +.*:	d50322df 	clearbhb
>>   .*:	d503201f 	nop
>>   .*:	d503203f 	yield
>>   .*:	d503205f 	wfe
>> @@ -34,7 +35,7 @@ Disassembly of section \.text:
>>   .*:	d503227f 	hint	#0x13
>>   .*:	d503229f 	(hint	#0x14|csdb)
>>   .*:	d50322bf 	hint	#0x15
>> -.*:	d50322df 	hint	#0x16
>> +.*:	d50322df 	(hint	#0x16|clearbhb)
>>   .*:	d50322ff 	hint	#0x17
>>   .*:	d503231f 	(hint	#0x18|paciaz)
>>   .*:	d503233f 	(hint	#0x19|paciasp)
>> --- a/gas/testsuite/gas/aarch64/system.s
>> +++ b/gas/testsuite/gas/aarch64/system.s
>> @@ -11,6 +11,7 @@
>>   	wfi
>>   	sev
>>   	sevl
>> +	clearbhb
>>   
>>   	.macro	all_hints from=0, to=127
>>   	hint \from
>> --- a/opcodes/aarch64-tbl.h
>> +++ b/opcodes/aarch64-tbl.h
>> @@ -4034,6 +4034,7 @@ const struct aarch64_opcode aarch64_opco
>>     CORE_INSN ("esb", 0xd503221f, 0xffffffff, ic_system, 0, OP0 (), {}, F_ALIAS),
>>     CORE_INSN ("psb", 0xd503223f, 0xffffffff, ic_system, 0, OP1 (BARRIER_PSB), {}, F_ALIAS),
>>     CORE_INSN ("tsb", 0xd503225f, 0xffffffff, ic_system, 0, OP1 (BARRIER_PSB), {}, F_ALIAS),
>> +  CORE_INSN ("clearbhb", 0xd50322df, 0xffffffff, ic_system, 0, OP0 (), {}, F_ALIAS),
>>     CORE_INSN ("clrex", 0xd503305f, 0xfffff0ff, ic_system, 0, OP1 (UIMM4), {}, F_OPD0_OPT | F_DEFAULT (0xF)),
>>     CORE_INSN ("dsb", 0xd503309f, 0xfffff0ff, ic_system, 0, OP1 (BARRIER), {}, F_HAS_ALIAS),
>>     V8_7_INSN ("dsb", 0xd503323f, 0xfffff3ff, ic_system, OP1 (BARRIER_DSB_NXS), {}, F_HAS_ALIAS),
>