From mboxrd@z Thu Jan 1 00:00:00 1970 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 79A2014D6E4; Mon, 10 Jun 2024 20:48:51 +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=1718052531; cv=none; b=h5RdNCTI32Nhqa34XakL4twgKnQOFtQZnDI4jgUXs3hntuhlBXJaZvgKQQAuGojJa0boH0odxO1xek9/KGrkfkWyYDK9/Ia3kJ9AA8bwbkjMG81xBkTco7p+Mnz04P+hdkuxFMh2FTioysKfRffVzkZ6olIvx1rXl14on/VIsJ8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718052531; c=relaxed/simple; bh=qEWhUwOtY4dP2oKEOdCg3gFZW6ZZXNIFIaLC2/7lZ38=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FaLzT9OIYcy0PZDWpA+ASm5FZd+CseCksekHT7fux31YZlvngmVKkFqdNdtmPrQXqS4a7eJ+pQUBRBlWmTYMtVuWGhsELXj+f91dUtW5AQaCPcpl4XgnPu1XXXba+zCEq89m/kInVrO4VzMAd05iB7pZ5MF23Nszenkt2G6eIpk= 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=JiH6A5U0; 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="JiH6A5U0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C0984C2BBFC; Mon, 10 Jun 2024 20:48:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1718052531; bh=qEWhUwOtY4dP2oKEOdCg3gFZW6ZZXNIFIaLC2/7lZ38=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JiH6A5U0arD1NhlbdfpjK8+SD3NECg/OLaKv9RnBd5T4AY15CPLPBn42T6GSAQYe0 huRV6nMOULL9ce93ox3iDF9DgMHNhwPGXHnXzZuoAnF9gMVEKsa6esEKLrVWVk74Q7 1anFZ5tXKEpPNvsXPKCh2bUP4fB3HkiBWds2d1Io= 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 3/7] x86: add 'runtime constant' support Date: Mon, 10 Jun 2024 13:48:17 -0700 Message-ID: <20240610204821.230388-4-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-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit This implements the runtime constant infrastructure for x86, 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/x86/include/asm/runtime-const.h | 61 ++++++++++++++++++++++++++++ arch/x86/kernel/vmlinux.lds.S | 3 ++ 2 files changed, 64 insertions(+) create mode 100644 arch/x86/include/asm/runtime-const.h diff --git a/arch/x86/include/asm/runtime-const.h b/arch/x86/include/asm/runtime-const.h new file mode 100644 index 000000000000..24e3a53ca255 --- /dev/null +++ b/arch/x86/include/asm/runtime-const.h @@ -0,0 +1,61 @@ +/* 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("mov %1,%0\n1:\n" \ + ".pushsection runtime_ptr_" #sym ",\"a\"\n\t" \ + ".long 1b - %c2 - .\n\t" \ + ".popsection" \ + :"=r" (__ret) \ + :"i" ((unsigned long)0x0123456789abcdefull), \ + "i" (sizeof(long))); \ + __ret; }) + +// The 'typeof' will create at _least_ a 32-bit type, but +// will happily also take a bigger type and the 'shrl' will +// clear the upper bits +#define runtime_const_shift_right_32(val, sym) ({ \ + typeof(0u+(val)) __ret = (val); \ + asm_inline("shrl $12,%k0\n1:\n" \ + ".pushsection runtime_shift_" #sym ",\"a\"\n\t" \ + ".long 1b - 1 - .\n\t" \ + ".popsection" \ + :"+r" (__ret)); \ + __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) + +/* + * The text patching is trivial - you can only do this at init time, + * when the text section hasn't been marked RO, and before the text + * has ever been executed. + */ +static inline void __runtime_fixup_ptr(void *where, unsigned long val) +{ + *(unsigned long *)where = val; +} + +static inline void __runtime_fixup_shift(void *where, unsigned long val) +{ + *(unsigned char *)where = val; +} + +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/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 3509afc6a672..6e73403e874f 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -357,6 +357,9 @@ SECTIONS PERCPU_SECTION(INTERNODE_CACHE_BYTES) #endif + RUNTIME_CONST(shift, d_hash_shift) + RUNTIME_CONST(ptr, dentry_hashtable) + . = ALIGN(PAGE_SIZE); /* freed after init ends here */ -- 2.45.1.209.gc6f12300df