From nobody Thu Feb 12 17:33:29 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4B6B514F9F2; Mon, 10 Jun 2024 20:48:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718052533; cv=none; b=DeFpLY5L9onn6Ir9NHroMmidT9nW3oXCXzoB1aSYSAXsWlTfPIRJYN/p/PJZVm55E37fysZT+EjGgE2qQXhXAblDXhpZUVGp+tCvif43w4WL4vUpKhQfWW0ygSFUR1tRscwLA1d7EY3HH9/xoHT/dXlhRb/nVAXFmLPz0UTsHIk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718052533; c=relaxed/simple; bh=7f3f228SGMKS0WITa2x2BowrmDUER/1fLEQ+DyBwzuw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eoatNG239RQrNuchl8PPJMvFgDzA85vOw3cwNdMGNNwQqGGc9Noe9iWxCrruvqmgs3XJqvWjq3k0v3tFnChhjMgUghfqbRcg1unCZAKQYG+t9mWXF2UQ5PyP4uo4P1QLt0O0nYDgnLnPrbAvGYKHrgDd8wS0rihFFKtGxuaPsDA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=YPwqi78X; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="YPwqi78X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F8FAC4AF1C; Mon, 10 Jun 2024 20:48:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1718052532; bh=7f3f228SGMKS0WITa2x2BowrmDUER/1fLEQ+DyBwzuw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YPwqi78XF8g+oefGjk6SWIu9gETbsXAcfc1xuXxesUVODbHxG6F+Ihl/hQS8A6wHG h+h5f5IcE9LJ94AoyVcNT9TRaIM1jZTVmlB+cNNR9Ws/oUpeqTbhAiEgblNqzvHmGB V1scnDa858xxUlqxCoLdiKtjB+7xyFKKBoIeCoB0= From: Linus Torvalds To: Peter Anvin , Ingo Molnar , Borislav Petkov , Thomas Gleixner , Rasmus Villemoes , Josh Poimboeuf , Catalin Marinas , Will Deacon Cc: Linux Kernel Mailing List , the arch/x86 maintainers , linux-arm-kernel@lists.infradead.org, linux-arch , Linus Torvalds Subject: [PATCH 4/7] arm64: add 'runtime constant' support Date: Mon, 10 Jun 2024 13:48:18 -0700 Message-ID: <20240610204821.230388-5-torvalds@linux-foundation.org> X-Mailer: git-send-email 2.45.1.209.gc6f12300df In-Reply-To: <20240610204821.230388-1-torvalds@linux-foundation.org> References: <20240610204821.230388-1-torvalds@linux-foundation.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This implements the runtime constant infrastructure for arm64, allowing the dcache d_hash() function to be generated using as a constant for hash table address followed by shift by a constant of the hash index. Signed-off-by: Linus Torvalds --- arch/arm64/include/asm/runtime-const.h | 75 ++++++++++++++++++++++++++ arch/arm64/kernel/vmlinux.lds.S | 3 ++ 2 files changed, 78 insertions(+) create mode 100644 arch/arm64/include/asm/runtime-const.h diff --git a/arch/arm64/include/asm/runtime-const.h b/arch/arm64/include/as= m/runtime-const.h new file mode 100644 index 000000000000..02462b2cb6f9 --- /dev/null +++ b/arch/arm64/include/asm/runtime-const.h @@ -0,0 +1,75 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_RUNTIME_CONST_H +#define _ASM_RUNTIME_CONST_H + +#define runtime_const_ptr(sym) ({ \ + typeof(sym) __ret; \ + asm_inline("1:\t" \ + "movz %0, #0xcdef\n\t" \ + "movk %0, #0x89ab, lsl #16\n\t" \ + "movk %0, #0x4567, lsl #32\n\t" \ + "movk %0, #0x0123, lsl #48\n\t" \ + ".pushsection runtime_ptr_" #sym ",\"a\"\n\t" \ + ".long 1b - .\n\t" \ + ".popsection" \ + :"=3Dr" (__ret)); \ + __ret; }) + +#define runtime_const_shift_right_32(val, sym) ({ \ + unsigned long __ret; \ + asm_inline("1:\t" \ + "lsr %w0,%w1,#12\n\t" \ + ".pushsection runtime_shift_" #sym ",\"a\"\n\t" \ + ".long 1b - .\n\t" \ + ".popsection" \ + :"=3Dr" (__ret) \ + :"r" (0u+(val))); \ + __ret; }) + +#define runtime_const_init(type, sym) do { \ + extern s32 __start_runtime_##type##_##sym[]; \ + extern s32 __stop_runtime_##type##_##sym[]; \ + runtime_const_fixup(__runtime_fixup_##type, \ + (unsigned long)(sym), \ + __start_runtime_##type##_##sym, \ + __stop_runtime_##type##_##sym); \ +} while (0) + +// 16-bit immediate for wide move (movz and movk) in bits 5..20 +static inline void __runtime_fixup_16(unsigned int *p, unsigned int val) +{ + unsigned int insn =3D *p; + insn &=3D 0xffe0001f; + insn |=3D (val & 0xffff) << 5; + *p =3D insn; +} + +static inline void __runtime_fixup_ptr(void *where, unsigned long val) +{ + unsigned int *p =3D lm_alias(where); + __runtime_fixup_16(p, val); + __runtime_fixup_16(p+1, val >> 16); + __runtime_fixup_16(p+2, val >> 32); + __runtime_fixup_16(p+3, val >> 48); +} + +// Immediate value is 5 bits starting at bit #16 +static inline void __runtime_fixup_shift(void *where, unsigned long val) +{ + unsigned int *p =3D lm_alias(where); + unsigned int insn =3D *p; + insn &=3D 0xffc0ffff; + insn |=3D (val & 63) << 16; + *p =3D insn; +} + +static inline void runtime_const_fixup(void (*fn)(void *, unsigned long), + unsigned long val, s32 *start, s32 *end) +{ + while (start < end) { + fn(*start + (void *)start, val); + start++; + } +} + +#endif diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.ld= s.S index 755a22d4f840..55a8e310ea12 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -264,6 +264,9 @@ SECTIONS EXIT_DATA } =20 + RUNTIME_CONST(shift, d_hash_shift) + RUNTIME_CONST(ptr, dentry_hashtable) + PERCPU_SECTION(L1_CACHE_BYTES) HYPERVISOR_PERCPU_SECTION =20 --=20 2.45.1.209.gc6f12300df