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Message-ID: <88e4f6eb-9ce5-4f52-9f4c-4511fe054b94@arm.com> Date: Mon, 5 Aug 2024 08:30:48 +0530 From: Anshuman Khandual <anshuman.khandual@....com> To: Mark Rutland <mark.rutland@....com> Cc: linux-arm-kernel@...ts.infradead.org, Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org Subject: Re: [PATCH 0/1] arm64/tools/sysreg: Add Sysreg128/SysregFields128 On 8/3/24 16:37, Mark Rutland wrote: > On Thu, Aug 01, 2024 at 11:14:35AM +0530, Anshuman Khandual wrote: >> FEAT_SYSREG128 enables 128 bit wide system registers which also need to be >> defined in (arch/arm64/toos/sysreg) for auto mask generation. This adds two >> new field types i.e Sysreg128 and SysregFields128 for that same purpose. It >> utilizes recently added macro GENMASK_U128() while also adding some helpers >> such as define_field_128() and parse_bitdef_128(). >> >> This patch applies after the following series which adds GENMASK_U128() >> >> https://lore.kernel.org/all/20240725054808.286708-1-anshuman.khandual@arm.com/ > > Is that patch merged or not? It wouod make a lot more sense to send them > together as one series. The latest series [1] here has been reviewed and merged in bitmap-for-next tree for testing purpose. Also there has been an additional patch [2] just to keep the GENMASK_U128() helpers inside !__ASSEMBLY__ guard. [1] https://lore.kernel.org/all/20240801071646.682731-1-anshuman.khandual@arm.com/ [2] https://lore.kernel.org/all/20240803133753.1598137-1-yury.norov@gmail.com/ GENMASK_U128() series could have been part of this series, although 128 bit mask creation seems generic enough to stand on its own. > >> >> A. Example for SysregFields128 >> >> ------------------------------ >> SysregFields128 TTBRx_D128_EL1 >> Res0 127:88 >> Field 87:80 BADDR_HIGH >> Res0 79:64 >> Field 63:48 ASID >> Field 47:5 BADDR_LOW >> Res0 4:3 >> Field 2:1 SKL >> Field 0 CnP >> EndSysregFields128 >> ------------------------------ > > Ok, so we get the definitions, but do we have all the other helpers we'd > need to make that useable, i.e. The first objective was to get the definitions right, so that they could be stored in the new gcc __unit128 data type. > > * read_sysreg() and write_sysreg() variants that can use MRRS/MSRR > > * Macros for assembly to use these? > > * Other bitfield manipulation helpers that can operate on U128, e.g. > FIELD_GET() and FIELD_PREP() ? These are still work in progress, but will share when available. > > Without end-to-end usage this is a bit academic. If the U128 definitions > are oainful to use from asm we might want separate hi64/lo64 > definitions. Right, U128 definitions are difficult to use in asm code because they way gcc compiler deals with 128 bit data types. Should the separate hi64/lo64 definitions be generic or platform specific without adding them to kernel bitops ? > > Mark. > >> The above input generates the following macros >> >> #define TTBRx_D128_EL1_BADDR_HIGH GENMASK_U128(87, 80) >> #define TTBRx_D128_EL1_BADDR_HIGH_MASK GENMASK_U128(87, 80) >> #define TTBRx_D128_EL1_BADDR_HIGH_SHIFT 80 >> #define TTBRx_D128_EL1_BADDR_HIGH_WIDTH 8 >> >> #define TTBRx_D128_EL1_ASID GENMASK_U128(63, 48) >> #define TTBRx_D128_EL1_ASID_MASK GENMASK_U128(63, 48) >> #define TTBRx_D128_EL1_ASID_SHIFT 48 >> #define TTBRx_D128_EL1_ASID_WIDTH 16 >> >> #define TTBRx_D128_EL1_BADDR_LOW GENMASK_U128(47, 5) >> #define TTBRx_D128_EL1_BADDR_LOW_MASK GENMASK_U128(47, 5) >> #define TTBRx_D128_EL1_BADDR_LOW_SHIFT 5 >> #define TTBRx_D128_EL1_BADDR_LOW_WIDTH 43 >> >> #define TTBRx_D128_EL1_SKL GENMASK_U128(2, 1) >> #define TTBRx_D128_EL1_SKL_MASK GENMASK_U128(2, 1) >> #define TTBRx_D128_EL1_SKL_SHIFT 1 >> #define TTBRx_D128_EL1_SKL_WIDTH 2 >> >> #define TTBRx_D128_EL1_CnP GENMASK_U128(0, 0) >> #define TTBRx_D128_EL1_CnP_MASK GENMASK_U128(0, 0) >> #define TTBRx_D128_EL1_CnP_SHIFT 0 >> #define TTBRx_D128_EL1_CnP_WIDTH 1 >> >> #define TTBRx_D128_EL1_RES0 (UL(0) | GENMASK_U128(127, 88) | GENMASK_U128(79, 64) | GENMASK_U128(4, 3)) >> #define TTBRx_D128_EL1_RES1 (UL(0)) >> #define TTBRx_D128_EL1_UNKN (UL(0)) >> >> B. Example Sysreg128 >> >> ------------------------------ >> Sysreg128 TTBR1_D128_EL1 3 0 2 0 1 >> Res0 127:88 >> Field 87:80 BADDR_HIGH >> Res0 79:64 >> Field 63:48 ASID >> Field 47:5 BADDR_LOW >> Res0 4:3 >> Field 2:1 SKL >> Field 0 CnP >> EndSysreg128 >> ------------------------------ >> >> The above input generates the following macros >> >> #define REG_TTBR1_D128_EL1 S3_0_C2_C0_1 >> #define SYS_TTBR1_D128_EL1 sys_reg(3, 0, 2, 0, 1) >> #define SYS_TTBR1_D128_EL1_Op0 3 >> #define SYS_TTBR1_D128_EL1_Op1 0 >> #define SYS_TTBR1_D128_EL1_CRn 2 >> #define SYS_TTBR1_D128_EL1_CRm 0 >> #define SYS_TTBR1_D128_EL1_Op2 1 >> >> #define TTBR1_D128_EL1_BADDR_HIGH GENMASK_U128(87, 80) >> #define TTBR1_D128_EL1_BADDR_HIGH_MASK GENMASK_U128(87, 80) >> #define TTBR1_D128_EL1_BADDR_HIGH_SHIFT 80 >> #define TTBR1_D128_EL1_BADDR_HIGH_WIDTH 8 >> >> #define TTBR1_D128_EL1_ASID GENMASK_U128(63, 48) >> #define TTBR1_D128_EL1_ASID_MASK GENMASK_U128(63, 48) >> #define TTBR1_D128_EL1_ASID_SHIFT 48 >> #define TTBR1_D128_EL1_ASID_WIDTH 16 >> >> #define TTBR1_D128_EL1_BADDR_LOW GENMASK_U128(47, 5) >> #define TTBR1_D128_EL1_BADDR_LOW_MASK GENMASK_U128(47, 5) >> #define TTBR1_D128_EL1_BADDR_LOW_SHIFT 5 >> #define TTBR1_D128_EL1_BADDR_LOW_WIDTH 43 >> >> #define TTBR1_D128_EL1_SKL GENMASK_U128(2, 1) >> #define TTBR1_D128_EL1_SKL_MASK GENMASK_U128(2, 1) >> #define TTBR1_D128_EL1_SKL_SHIFT 1 >> #define TTBR1_D128_EL1_SKL_WIDTH 2 >> >> #define TTBR1_D128_EL1_CnP GENMASK_U128(0, 0) >> #define TTBR1_D128_EL1_CnP_MASK GENMASK_U128(0, 0) >> #define TTBR1_D128_EL1_CnP_SHIFT 0 >> #define TTBR1_D128_EL1_CnP_WIDTH 1 >> >> #define TTBR1_D128_EL1_RES0 (UL(0) | GENMASK_U128(127, 88) | GENMASK_U128(79, 64) | GENMASK_U128(4, 3)) >> #define TTBR1_D128_EL1_RES1 (UL(0)) >> #define TTBR1_D128_EL1_UNKN (UL(0)) >> >> Cc: Catalin Marinas <catalin.marinas@....com> >> Cc: Will Deacon <will@...nel.org> >> Cc: Mark Brown <broonie@...nel.org> >> Cc: linux-arm-kernel@...ts.infradead.org >> Cc: linux-kernel@...r.kernel.org >> >> Anshuman Khandual (1): >> arm64/tools/sysreg: Add Sysreg128/SysregFields128 >> >> arch/arm64/tools/gen-sysreg.awk | 231 ++++++++++++++++++++++++++++++++ >> 1 file changed, 231 insertions(+) >> >> -- >> 2.30.2 >> >>
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