[PATCH v7 1/3] riscv: add platform-specific double word shifts for riscv32
Dmitry Antipov <[email protected]>
| Newsgroups | org.kernel.vger.linux-efi,org.infradead.lists.linux-riscv,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
Add riscv32-specific '__ashldi3()', '__ashrdi3()', and '__lshrdi3()'. Initially it was intended to fix the following link error observed when building EFI-enabled kernel with CONFIG_EFI_STUB=y and CONFIG_EFI_GENERIC_STUB=y: riscv32-linux-gnu-ld: ./drivers/firmware/efi/libstub/lib-cmdline.stub.o: in function `__efistub_.L49': __efistub_cmdline.c:(.init.text+0x1f2): undefined reference to `__efistub___ashldi3' riscv32-linux-gnu-ld: __efistub_cmdline.c:(.init.text+0x202): undefined reference to `__efistub___lshrdi3' Reported at [1] trying to build https://patchew.org/linux/[email protected], tested with 'qemu-system-riscv32 -M virt' only. Reported-by: kernel test robot <[email protected]> Closes: https://lore.kernel.org/oe-kbuild-all/[email protected] [1] Suggested-by: Ard Biesheuvel <[email protected]> Tested-by: Charlie Jenkins <[email protected]> Assisted-by: gemini/gemini-3.1-pro-preview sashiko Signed-off-by: Dmitry Antipov <[email protected]> --- v7: export for stub and optimize '__ashrdi3()' (Sashiko) v4, v5, v6: and upwards: bump version to match the series v3: more tests by Charlie Jenkins v2: adjust commit message --- arch/riscv/Kconfig | 3 --- arch/riscv/kernel/image-vars.h | 9 +++++++++ arch/riscv/lib/Makefile | 1 + arch/riscv/lib/ashldi3.S | 36 ++++++++++++++++++++++++++++++++++ arch/riscv/lib/ashrdi3.S | 36 ++++++++++++++++++++++++++++++++++ arch/riscv/lib/lshrdi3.S | 36 ++++++++++++++++++++++++++++++++++ 6 files changed, 118 insertions(+), 3 deletions(-) create mode 100644 arch/riscv/lib/ashldi3.S create mode 100644 arch/riscv/lib/ashrdi3.S create mode 100644 arch/riscv/lib/lshrdi3.S diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index d235396c4514..b1198b41c486 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -404,9 +404,6 @@ config ARCH_RV32I bool "RV32I" depends on NONPORTABLE select 32BIT - select GENERIC_LIB_ASHLDI3 - select GENERIC_LIB_ASHRDI3 - select GENERIC_LIB_LSHRDI3 select GENERIC_LIB_UCMPDI2 config ARCH_RV64I diff --git a/arch/riscv/kernel/image-vars.h b/arch/riscv/kernel/image-vars.h index 3bd9d06a8b8f..7b44b94f1283 100644 --- a/arch/riscv/kernel/image-vars.h +++ b/arch/riscv/kernel/image-vars.h @@ -32,6 +32,15 @@ __efistub___init_text_end = __init_text_end; __efistub_sysfb_primary_display = sysfb_primary_display; #endif +/* + * These double-word integer shifts are used by the library code, and + * the first two of them are required to link EFI stub. Note __ashrdi3() + * is not actually used by the stub but this may change in the future. + */ +PROVIDE(__efistub___lshrdi3 = __lshrdi3); +PROVIDE(__efistub___ashldi3 = __ashldi3); +PROVIDE(__efistub___ashrdi3 = __ashrdi3); + #endif #endif /* __RISCV_KERNEL_IMAGE_VARS_H */ diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile index 6f767b2a349d..f668b98970bd 100644 --- a/arch/riscv/lib/Makefile +++ b/arch/riscv/lib/Makefile @@ -16,6 +16,7 @@ ifeq ($(CONFIG_MMU), y) lib-$(CONFIG_RISCV_ISA_V) += uaccess_vector.o endif lib-$(CONFIG_MMU) += uaccess.o +lib-$(CONFIG_32BIT) += ashldi3.o ashrdi3.o lshrdi3.o lib-$(CONFIG_64BIT) += tishift.o lib-$(CONFIG_RISCV_ISA_ZICBOZ) += clear_page.o obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o diff --git a/arch/riscv/lib/ashldi3.S b/arch/riscv/lib/ashldi3.S new file mode 100644 index 000000000000..c3408862e2f6 --- /dev/null +++ b/arch/riscv/lib/ashldi3.S @@ -0,0 +1,36 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/** + * Adopted for the Linux kernel from IPXE project, see + * https://github.com/ipxe/ipxe/blob/master/src/arch/riscv32/libgcc/llshift.S + */ + +#include <linux/linkage.h> +#include <asm/asm.h> + +/** + * Shift left + * + * @v a1:a0 Value to shift + * @v a2 Shift amount + * @ret a1:a0 Shifted value + */ + +SYM_FUNC_START(__ashldi3) + + /* Perform shift by 32 bits, if applicable */ + li t0, 32 + sub t1, t0, a2 + bgtz t1, 1f + mv a1, a0 + mv a0, zero +1: /* Perform shift by modulo-32 bits, if applicable */ + andi a2, a2, 0x1f + beqz a2, 2f + srl t2, a0, t1 + sll a0, a0, a2 + sll a1, a1, a2 + or a1, a1, t2 +2: ret + +SYM_FUNC_END(__ashldi3) +EXPORT_SYMBOL(__ashldi3) diff --git a/arch/riscv/lib/ashrdi3.S b/arch/riscv/lib/ashrdi3.S new file mode 100644 index 000000000000..426de0946606 --- /dev/null +++ b/arch/riscv/lib/ashrdi3.S @@ -0,0 +1,36 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/** + * Adopted for the Linux kernel from IPXE project, see + * https://github.com/ipxe/ipxe/blob/master/src/arch/riscv32/libgcc/llshift.S + */ + +#include <linux/linkage.h> +#include <asm/asm.h> + +/** + * Arithmetic shift right + * + * @v a1:a0 Value to shift + * @v a2 Shift amount + * @ret a1:a0 Shifted value + */ + +SYM_FUNC_START(__ashrdi3) + + /* Perform shift by 32 bits, if applicable */ + li t0, 32 + sub t1, t0, a2 + bgtz t1, 1f + mv a0, a1 + srai a1, a1, 31 +1: /* Perform shift by modulo-32 bits, if applicable */ + andi a2, a2, 0x1f + beqz a2, 2f + sll t2, a1, t1 + sra a1, a1, a2 + srl a0, a0, a2 + or a0, a0, t2 +2: ret + +SYM_FUNC_END(__ashrdi3) +EXPORT_SYMBOL(__ashrdi3) diff --git a/arch/riscv/lib/lshrdi3.S b/arch/riscv/lib/lshrdi3.S new file mode 100644 index 000000000000..1af03985ccb7 --- /dev/null +++ b/arch/riscv/lib/lshrdi3.S @@ -0,0 +1,36 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/** + * Adopted for the Linux kernel from IPXE project, see + * https://github.com/ipxe/ipxe/blob/master/src/arch/riscv32/libgcc/llshift.S + */ + +#include <linux/linkage.h> +#include <asm/asm.h> + +/** + * Logical shift right + * + * @v a1:a0 Value to shift + * @v a2 Shift amount + * @ret a1:a0 Shifted value + */ + +SYM_FUNC_START(__lshrdi3) + + /* Perform shift by 32 bits, if applicable */ + li t0, 32 + sub t1, t0, a2 + bgtz t1, 1f + mv a0, a1 + mv a1, zero +1: /* Perform shift by modulo-32 bits, if applicable */ + andi a2, a2, 0x1f + beqz a2, 2f + sll t2, a1, t1 + srl a1, a1, a2 + srl a0, a0, a2 + or a0, a0, t2 +2: ret + +SYM_FUNC_END(__lshrdi3) +EXPORT_SYMBOL(__lshrdi3) -- 2.53.0