Re: [PATCH v23 1/4] arm64/sysreg: Add BRBE registers and fields

[Adam Young <admiyo@amperemail.onmicrosoft.com>]

tested-by: Adam Young<admiyo@os.amperecomputing.com>


Built and run on a BRBE capable machine.

Built userland perf tool

can run

perf record --branch-filter any,save_type,u true

as well as

perf record --branch-filter any,save_type,u ./sort

And will generate a perf.data file.

The mechanism applies cleanly and produced what looks like sane output.


On 6/11/25 14:01, Rob Herring (Arm) wrote:
> From: Anshuman Khandual <anshuman.khandual@arm.com>
>
> This patch adds definitions related to the Branch Record Buffer Extension
> (BRBE) as per ARM DDI 0487K.a. These will be used by KVM and a BRBE driver
> in subsequent patches.
>
> Some existing BRBE definitions in asm/sysreg.h are replaced with equivalent
> generated definitions.
>
> Cc: Marc Zyngier <maz@kernel.org>
> Reviewed-by: Mark Brown <broonie@kernel.org>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Tested-by: James Clark <james.clark@linaro.org>
> Acked-by: Will Deacon <will@kernel.org>
> Signed-off-by: "Rob Herring (Arm)" <robh@kernel.org>
> ---
> v19:
> - split BRBINF.CC field into mantissa and exponent
> ---
>   arch/arm64/include/asm/sysreg.h |  16 ++---
>   arch/arm64/tools/sysreg         | 132 ++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 138 insertions(+), 10 deletions(-)
>
> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
> index f1bb0d10c39a..ef76a4b9e240 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -202,16 +202,8 @@
>   #define SYS_DBGVCR32_EL2		sys_reg(2, 4, 0, 7, 0)
>   
>   #define SYS_BRBINF_EL1(n)		sys_reg(2, 1, 8, (n & 15), (((n & 16) >> 2) | 0))
> -#define SYS_BRBINFINJ_EL1		sys_reg(2, 1, 9, 1, 0)
>   #define SYS_BRBSRC_EL1(n)		sys_reg(2, 1, 8, (n & 15), (((n & 16) >> 2) | 1))
> -#define SYS_BRBSRCINJ_EL1		sys_reg(2, 1, 9, 1, 1)
>   #define SYS_BRBTGT_EL1(n)		sys_reg(2, 1, 8, (n & 15), (((n & 16) >> 2) | 2))
> -#define SYS_BRBTGTINJ_EL1		sys_reg(2, 1, 9, 1, 2)
> -#define SYS_BRBTS_EL1			sys_reg(2, 1, 9, 0, 2)
> -
> -#define SYS_BRBCR_EL1			sys_reg(2, 1, 9, 0, 0)
> -#define SYS_BRBFCR_EL1			sys_reg(2, 1, 9, 0, 1)
> -#define SYS_BRBIDR0_EL1			sys_reg(2, 1, 9, 2, 0)
>   
>   #define SYS_TRCITECR_EL1		sys_reg(3, 0, 1, 2, 3)
>   #define SYS_TRCACATR(m)			sys_reg(2, 1, 2, ((m & 7) << 1), (2 | (m >> 3)))
> @@ -277,8 +269,6 @@
>   /* ETM */
>   #define SYS_TRCOSLAR			sys_reg(2, 1, 1, 0, 4)
>   
> -#define SYS_BRBCR_EL2			sys_reg(2, 4, 9, 0, 0)
> -
>   #define SYS_MIDR_EL1			sys_reg(3, 0, 0, 0, 0)
>   #define SYS_MPIDR_EL1			sys_reg(3, 0, 0, 0, 5)
>   #define SYS_REVIDR_EL1			sys_reg(3, 0, 0, 0, 6)
> @@ -821,6 +811,12 @@
>   #define OP_COSP_RCTX			sys_insn(1, 3, 7, 3, 6)
>   #define OP_CPP_RCTX			sys_insn(1, 3, 7, 3, 7)
>   
> +/*
> + * BRBE Instructions
> + */
> +#define BRB_IALL_INSN	__emit_inst(0xd5000000 | OP_BRB_IALL | (0x1f))
> +#define BRB_INJ_INSN	__emit_inst(0xd5000000 | OP_BRB_INJ  | (0x1f))
> +
>   /* Common SCTLR_ELx flags. */
>   #define SCTLR_ELx_ENTP2	(BIT(60))
>   #define SCTLR_ELx_DSSBS	(BIT(44))
> diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
> index 8a8cf6874298..81c4e214ba33 100644
> --- a/arch/arm64/tools/sysreg
> +++ b/arch/arm64/tools/sysreg
> @@ -1329,6 +1329,138 @@ UnsignedEnum	3:0	MTEPERM
>   EndEnum
>   EndSysreg
>   
> +
> +SysregFields BRBINFx_EL1
> +Res0	63:47
> +Field	46	CCU
> +Field	45:40	CC_EXP
> +Field	39:32	CC_MANT
> +Res0	31:18
> +Field	17	LASTFAILED
> +Field	16	T
> +Res0	15:14
> +Enum	13:8		TYPE
> +	0b000000	DIRECT_UNCOND
> +	0b000001	INDIRECT
> +	0b000010	DIRECT_LINK
> +	0b000011	INDIRECT_LINK
> +	0b000101	RET
> +	0b000111	ERET
> +	0b001000	DIRECT_COND
> +	0b100001	DEBUG_HALT
> +	0b100010	CALL
> +	0b100011	TRAP
> +	0b100100	SERROR
> +	0b100110	INSN_DEBUG
> +	0b100111	DATA_DEBUG
> +	0b101010	ALIGN_FAULT
> +	0b101011	INSN_FAULT
> +	0b101100	DATA_FAULT
> +	0b101110	IRQ
> +	0b101111	FIQ
> +	0b110000	IMPDEF_TRAP_EL3
> +	0b111001	DEBUG_EXIT
> +EndEnum
> +Enum	7:6	EL
> +	0b00	EL0
> +	0b01	EL1
> +	0b10	EL2
> +	0b11	EL3
> +EndEnum
> +Field	5	MPRED
> +Res0	4:2
> +Enum	1:0	VALID
> +	0b00	NONE
> +	0b01	TARGET
> +	0b10	SOURCE
> +	0b11	FULL
> +EndEnum
> +EndSysregFields
> +
> +SysregFields	BRBCR_ELx
> +Res0	63:24
> +Field	23 	EXCEPTION
> +Field	22 	ERTN
> +Res0	21:10
> +Field	9	FZPSS
> +Field	8 	FZP
> +Res0	7
> +Enum	6:5	TS
> +	0b01	VIRTUAL
> +	0b10	GUEST_PHYSICAL
> +	0b11	PHYSICAL
> +EndEnum
> +Field	4	MPRED
> +Field	3	CC
> +Res0	2
> +Field	1	ExBRE
> +Field	0	E0BRE
> +EndSysregFields
> +
> +Sysreg	BRBCR_EL1	2	1	9	0	0
> +Fields	BRBCR_ELx
> +EndSysreg
> +
> +Sysreg	BRBFCR_EL1	2	1	9	0	1
> +Res0	63:30
> +Enum	29:28	BANK
> +	0b00	BANK_0
> +	0b01	BANK_1
> +EndEnum
> +Res0	27:23
> +Field	22	CONDDIR
> +Field	21	DIRCALL
> +Field	20	INDCALL
> +Field	19	RTN
> +Field	18	INDIRECT
> +Field	17	DIRECT
> +Field	16	EnI
> +Res0	15:8
> +Field	7	PAUSED
> +Field	6	LASTFAILED
> +Res0	5:0
> +EndSysreg
> +
> +Sysreg	BRBTS_EL1	2	1	9	0	2
> +Field	63:0	TS
> +EndSysreg
> +
> +Sysreg	BRBINFINJ_EL1	2	1	9	1	0
> +Fields BRBINFx_EL1
> +EndSysreg
> +
> +Sysreg	BRBSRCINJ_EL1	2	1	9	1	1
> +Field	63:0 ADDRESS
> +EndSysreg
> +
> +Sysreg	BRBTGTINJ_EL1	2	1	9	1	2
> +Field	63:0 ADDRESS
> +EndSysreg
> +
> +Sysreg	BRBIDR0_EL1	2	1	9	2	0
> +Res0	63:16
> +Enum	15:12	CC
> +	0b0101	20_BIT
> +EndEnum
> +Enum	11:8	FORMAT
> +	0b0000	FORMAT_0
> +EndEnum
> +Enum	7:0		NUMREC
> +	0b00001000	8
> +	0b00010000	16
> +	0b00100000	32
> +	0b01000000	64
> +EndEnum
> +EndSysreg
> +
> +Sysreg	BRBCR_EL2	2	4	9	0	0
> +Fields	BRBCR_ELx
> +EndSysreg
> +
> +Sysreg	BRBCR_EL12	2	5	9	0	0
> +Fields	BRBCR_ELx
> +EndSysreg
> +
>   Sysreg	ID_AA64ZFR0_EL1	3	0	0	4	4
>   Res0	63:60
>   UnsignedEnum	59:56	F64MM
>