From: Vladimir Murzin <vladimir.murzin@arm•com>
To: Mark Rutland <mark.rutland@arm•com>,
linux-arm-kernel@lists•infradead.org, kvmarm@lists•linux.dev
Cc: broonie@kernel•org, catalin.marinas@arm•com, james.morse@arm•com,
maz@kernel•org, oupton@kernel•org, tabba@google•com,
will@kernel•org
Subject: Re: [PATCH v2 10/18] arm64: sysreg: Add FPCR and FPSR
Date: Fri, 29 May 2026 09:42:20 +0100 [thread overview]
Message-ID: <b097ee0f-e517-47e3-9bfc-167f72e177a3@arm.com> (raw)
In-Reply-To: <20260528165446.701944-11-mark.rutland@arm.com>
On 5/28/26 17:54, Mark Rutland wrote:
> Add sysreg definitions for FPCR and FPSR.
>
> Some versions of LLVM will refuse to assemble accesses to FPCR and FPSR
> unless the "fp" arch extension is enabled, which we don't currently do
> for read_sysreg() and write_sysreg(). In general, handling feature
> dependencies would complicate read_sysreg() and write_sysreg(), and it's
> simpler to use read_sysreg_s() and write_sysreg_s() instead, requiring
> sysreg definitions.
>
> The values used can be found in ARM ARM issue M.b:
>
> https://developer.arm.com/documentation/ddi0487/mb/
>
> ... in sections:
>
> * C5.2.8 ("FPCR, Floating-point Control Register")
> * C5.2.10 ("FPSR, Floating-point Status Register")
>
> Signed-off-by: Mark Rutland <mark.rutland@arm•com>
> Cc: Catalin Marinas <catalin.marinas@arm•com>
> Cc: Fuad Tabba <tabba@google•com>
> Cc: James Morse <james.morse@arm•com>
> Cc: Marc Zyngier <maz@kernel•org>
> Cc: Mark Brown <broonie@kernel•org>
> Cc: Oliver Upton <oupton@kernel•org>
> Cc: Will Deacon <will@kernel•org>
> ---
> arch/arm64/tools/sysreg | 45 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 45 insertions(+)
>
> diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
> index 6c3ff14e561e6..8b219d6566608 100644
> --- a/arch/arm64/tools/sysreg
> +++ b/arch/arm64/tools/sysreg
> @@ -3790,6 +3790,51 @@ Field 1 ZA
> Field 0 SM
> EndSysreg
>
> +Sysreg FPCR 3 3 4 4 0
> +Res0 63:27
> +Field 26 AHP
> +Field 25 DN
> +Field 24 FZ
> +Enum 23:22 RMode
> + 0b00 RN
> + 0b01 RP
> + 0b10 RM
> + 0b11 RZ
> +EndEnum
> +Field 21:20 Stride
> +Field 19 FZ16
> +Field 18:16 Len
> +Field 15 IDE
> +Res0 14
> +Field 13 EBF
> +Field 12 IXE
> +Field 11 UFE
> +Field 10 OFE
> +Field 9 DZE
> +Field 8 IOE
> +Res0 7:3
> +Field 2 NEP
> +Field 1 AH
> +Field 0 FIZ
> +EndSysreg
> +
> +Sysreg FPSR 3 3 4 4 1
> +Res0 63:32
> +Field 31 N
> +Field 30 Z
> +Field 29 C
> +Field 28 V
> +Field 27 QC
> +Res0 26:8
> +Field 7 IDC
> +Res0 6:5
> +Field 4 IXC
> +Field 3 UFC
> +Field 2 OFC
> +Field 1 DZC
> +Field 0 IOC
> +EndSysreg
> +
> Sysreg FPMR 3 3 4 4 2
> Res0 63:38
> Field 37:32 LSCALE2
> -- 2.30.2
>
FWIW,
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm•com>
next prev parent reply other threads:[~2026-05-29 8:42 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-28 16:54 [PATCH v2 00/18] arm64+KVM: FPSIMD/SVE/SME cleanups Mark Rutland
2026-05-28 16:54 ` [PATCH v2 01/18] KVM: arm64: Don't include <asm/fpsimdmacros.h> Mark Rutland
2026-05-28 16:54 ` [PATCH v2 02/18] KVM: arm64: Don't override FFR save/restore argument Mark Rutland
2026-05-28 16:54 ` [PATCH v2 03/18] KVM: arm64: pkvm: Save host FPMR in host cpu context Mark Rutland
2026-05-28 16:54 ` [PATCH v2 04/18] KVM: arm64: pkvm: Remove struct cpu_sve_state Mark Rutland
2026-05-28 16:54 ` [PATCH v2 05/18] arm64: fpsimd: Fold sve_init_regs() into do_sve_acc() Mark Rutland
2026-05-28 16:54 ` [PATCH v2 06/18] arm64: fpsimd: Remove sve_set_vq() and sme_set_vq() Mark Rutland
2026-05-28 16:54 ` [PATCH v2 07/18] arm64: fpsimd: Use assembler for SVE instructions Mark Rutland
2026-05-29 8:41 ` Vladimir Murzin
2026-05-28 16:54 ` [PATCH v2 08/18] arm64: fpsimd: Use assembler for baseline SME instructions Mark Rutland
2026-05-28 16:54 ` [PATCH v2 09/18] arm64: fpsimd: Move sve_get_vl() and sme_get_vl() inline Mark Rutland
2026-05-28 16:54 ` [PATCH v2 10/18] arm64: sysreg: Add FPCR and FPSR Mark Rutland
2026-05-28 17:11 ` Mark Brown
2026-05-29 8:42 ` Vladimir Murzin [this message]
2026-05-28 16:54 ` [PATCH v2 11/18] arm64: fpsimd: Split FPSR/FPCR from SVE save/restore Mark Rutland
2026-05-28 17:17 ` Mark Brown
2026-05-28 16:54 ` [PATCH v2 12/18] arm64: fpsimd: Move fpsimd save/restore inline Mark Rutland
2026-05-29 8:43 ` Vladimir Murzin
2026-05-28 16:54 ` [PATCH v2 13/18] arm64: fpsimd: Use opaque type for SVE state Mark Rutland
2026-05-28 16:54 ` [PATCH v2 14/18] arm64: fpsimd: Use opaque type for SME state Mark Rutland
2026-05-28 16:54 ` [PATCH v2 15/18] arm64: fpsimd: Move SVE save/restore inline Mark Rutland
2026-05-28 16:54 ` [PATCH v2 16/18] arm64: fpsimd: Move sve_flush_live() inline Mark Rutland
2026-05-28 16:54 ` [PATCH v2 17/18] arm64: fpsimd: Move SME save/restore inline Mark Rutland
2026-05-29 8:51 ` Vladimir Murzin
2026-05-28 16:54 ` [PATCH v2 18/18] arm64: fpsimd: Remove <asm/fpsimdmacros.h> Mark Rutland
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