Re: [PATCH] ARM: assembler: Drop obsolete VFP accessor fallback

Nathan Chancellor
2024-08-01T00:46:53Z

On Tue, Jul 30, 2024 at 11:48:59AM +0200, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@kernel.org>
>
> Now that the minimum supported binutils version is 2.25, we no longer
> need a workaround for binutils older than 2.24 for accessing VFP control
> registers from assembler.
>
> Cc: Calvin Owens <calvin@wbinvd.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Nathan Chancellor <nathan@kernel.org>
> Cc: clang-built-linux <clang-built-linux@googlegroups.com>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Very nice :)

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

> ---
> Note: applies onto 9410/1
>
> arch/arm/Kconfig | 2 --
> arch/arm/Kconfig.assembler | 6 ------
> arch/arm/include/asm/vfp.h | 10 ---------
> arch/arm/include/asm/vfpmacros.h | 11 ----------
> arch/arm/vfp/vfpinstr.h | 22 --------------------
> 5 files changed, 51 deletions(-)
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 54b2bb817a7f..854a12d89471 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1747,5 +1747,3 @@ config ARCH_HIBERNATION_POSSIBLE
> default y if ARCH_SUSPEND_POSSIBLE
>
> endmenu
> -
> -source "arch/arm/Kconfig.assembler"
> diff --git a/arch/arm/Kconfig.assembler b/arch/arm/Kconfig.assembler
> deleted file mode 100644
> index 5cb31aae1188..000000000000
> --- a/arch/arm/Kconfig.assembler
> +++ /dev/null
> @@ -1,6 +0,0 @@
> -# SPDX-License-Identifier: GPL-2.0
> -
> -config AS_VFP_VMRS_FPINST
> - def_bool $(as-instr,.fpu vfpv2\nvmrs r0$(comma)FPINST)
> - help
> - Supported by binutils >= 2.24 and LLVM integrated assembler.
> diff --git a/arch/arm/include/asm/vfp.h b/arch/arm/include/asm/vfp.h
> index 157ea3426158..85ccc422d4d0 100644
> --- a/arch/arm/include/asm/vfp.h
> +++ b/arch/arm/include/asm/vfp.h
> @@ -9,16 +9,6 @@
> #ifndef __ASM_VFP_H
> #define __ASM_VFP_H
>
> -#ifndef CONFIG_AS_VFP_VMRS_FPINST
> -#define FPSID cr0
> -#define FPSCR cr1
> -#define MVFR1 cr6
> -#define MVFR0 cr7
> -#define FPEXC cr8
> -#define FPINST cr9
> -#define FPINST2 cr10
> -#endif
> -
> /* FPSID bits */
> #define FPSID_IMPLEMENTER_BIT (24)
> #define FPSID_IMPLEMENTER_MASK (0xff << FPSID_IMPLEMENTER_BIT)
> diff --git a/arch/arm/include/asm/vfpmacros.h b/arch/arm/include/asm/vfpmacros.h
> index ba0d4cb5377e..e2e1d5a3727a 100644
> --- a/arch/arm/include/asm/vfpmacros.h
> +++ b/arch/arm/include/asm/vfpmacros.h
> @@ -8,7 +8,6 @@
>
> #include <asm/vfp.h>
>
> -#ifdef CONFIG_AS_VFP_VMRS_FPINST
> .macro VFPFMRX, rd, sysreg, cond
> vmrs\cond \rd, \sysreg
> .endm
> @@ -16,16 +15,6 @@
> .macro VFPFMXR, sysreg, rd, cond
> vmsr\cond \sysreg, \rd
> .endm
> -#else
> - @ Macros to allow building with old toolkits (with no VFP support)
> - .macro VFPFMRX, rd, sysreg, cond
> - MRC\cond p10, 7, \rd, \sysreg, cr0, 0 @ FMRX \rd, \sysreg
> - .endm
> -
> - .macro VFPFMXR, sysreg, rd, cond
> - MCR\cond p10, 7, \rd, \sysreg, cr0, 0 @ FMXR \sysreg, \rd
> - .endm
> -#endif
>
> @ read all the working registers back into the VFP
> .macro VFPFLDMIA, base, tmp
> diff --git a/arch/arm/vfp/vfpinstr.h b/arch/arm/vfp/vfpinstr.h
> index 32090b0fb250..a2f0c47e0ce7 100644
> --- a/arch/arm/vfp/vfpinstr.h
> +++ b/arch/arm/vfp/vfpinstr.h
> @@ -62,8 +62,6 @@
> #define FPSCR_C (1 << 29)
> #define FPSCR_V (1 << 28)
>
> -#ifdef CONFIG_AS_VFP_VMRS_FPINST
> -
> #define fmrx(_vfp_) ({ \
> u32 __v; \
> asm volatile (".fpu vfpv2\n" \
> @@ -78,26 +76,6 @@
> : : "r" (_var_) : "cc"); \
> })
>
> -#else
> -
> -#define vfpreg(_vfp_) #_vfp_
> -
> -#define fmrx(_vfp_) ({ \
> - u32 __v; \
> - asm volatile ("mrc p10, 7, %0, " vfpreg(_vfp_) "," \
> - "cr0, 0 @ fmrx %0, " #_vfp_ \
> - : "=r" (__v) : : "cc"); \
> - __v; \
> -})
> -
> -#define fmxr(_vfp_, _var_) ({ \
> - asm volatile ("mcr p10, 7, %0, " vfpreg(_vfp_) "," \
> - "cr0, 0 @ fmxr " #_vfp_ ", %0" \
> - : : "r" (_var_) : "cc"); \
> -})
> -
> -#endif
> -
> u32 vfp_single_cpdo(u32 inst, u32 fpscr);
> u32 vfp_single_cprt(u32 inst, u32 fpscr, struct pt_regs *regs);
>
> --
> 2.46.0.rc1.232.g9752f9e123-goog
>