From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f50.google.com (mail-pj1-f50.google.com [209.85.216.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BF1F03B5832 for ; Mon, 27 Apr 2026 10:47:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.50 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777286865; cv=none; b=XIuO+GmZ2Nmpfl0YCNC0bArlZu4HGp5mJQpoU7WUy6Ag2ODn8P8VG1zjpMXGdgIbt7Aqxt0cckKRMcX7luZzXSnrK8c4jf9FMAtYRUW7zwfPmsGM6sEtFY8OZRzcRhJ3NZb102oC0PyJqUbQ6hNGXd6NGz+FX7FcvEvu3lT5J6M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777286865; c=relaxed/simple; bh=MK9MxhznQ/DE9fRBF+ryEug0t7fwbSkm35OOxaXAc7o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=f0AkSH4uSgjxpTRMTOve4OmxZgIte5mMHERS3FGUzPQ3VlRwmr8j2g9fSHGc10eWdOCDJCyZ/WIz6mc7p7jl4cNutGTHZtwO3T8HGxN0ILmr6umGanT+DfN3KufQx5MSAjrqOSsLY180cyqU6Yr+mykadCAtu7i9IjWSWPl3qfA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=hev.cc; spf=pass smtp.mailfrom=hev.cc; dkim=pass (2048-bit key) header.d=hev-cc.20251104.gappssmtp.com header.i=@hev-cc.20251104.gappssmtp.com header.b=gAMnEAAX; arc=none smtp.client-ip=209.85.216.50 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=hev.cc Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=hev.cc Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=hev-cc.20251104.gappssmtp.com header.i=@hev-cc.20251104.gappssmtp.com header.b="gAMnEAAX" Received: by mail-pj1-f50.google.com with SMTP id 98e67ed59e1d1-362e30526f8so1531291a91.3 for ; Mon, 27 Apr 2026 03:47:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=hev-cc.20251104.gappssmtp.com; s=20251104; t=1777286863; x=1777891663; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=PIBge1O7GywppeH3FxYzvTz5haKfwUyb1lL4zzJi9B4=; b=gAMnEAAX1OdDdpm68rbgotfb5OYSp8JbVpK+mHThmGyCYfq4OalfZiDkzOK6w9vP4h 15qgyOaVXOiEOg7y6zOyc+9t9kLWZm9PfUDKGXqIHm+Z1cbci7rQuCQUzsZTlYcV76xK qtobmJA1IcwYKO+KUwsk95dW6OwAsAJCPKdh+xx8leBYFGaKnLix2numQgYPFRk7aUWP M1Qhtb/gLY0irbkS0/UrrLrYuS8NwfRaivATWLdqBC2obDZdmtnEMdM1aICmcLjyiLn2 OvWx1U7BOVpNyqPIgX7i2DJdx366bGemExOZbhlc+uUB/SD369/EsDfYkgkyUD9ix/AB 50Hg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777286863; x=1777891663; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=PIBge1O7GywppeH3FxYzvTz5haKfwUyb1lL4zzJi9B4=; b=O4LR9D6fZ/62Cl0WCYM2NM/xiBq25ej4I48d+kBov6LuLiHVghL/LiPgczrHYFWekt lQCVTrOoVTcFQHHDKG74jx7UvmnfQh2BZC87EIEBjwZm6cnTDcx8b66VkTDq3h99Fxo1 KLQDqZpfz9bFCaQRQ3UgkGRsjNOoKupaUvOuw6ejxWBY9Rg79GqTURPKAhd35Ax5MSPG 3j+IO7NSfurExzJIMNdoNcSf6HZyOnesj6S41m1NVD5wzt0ISPgtn+qWRocmUFovP1UW jzcN81iDN5GyGltHeC3yG9DcYmx3GH9fW4Ej0iUBQ6cBhlAhoMT9Zmc3TdyfzjIglbhW pXSA== X-Forwarded-Encrypted: i=1; AFNElJ8T4w0qthdqyc16dxR4DoCJRQ91NOqLFEtlswfwyM73P+3VOLOtD+4i5meKuu4ujojLtRAU/txyu7Q=@vger.kernel.org X-Gm-Message-State: AOJu0YxWTebLQ4vdQFOZEdIkesbxJ2l1iJTTeHq7KC1S8JWVig+oOdZc KD9joaTVDSHZZLDcLr/ZzWJ3zM3sHmzHWLfdjR4aZ24M8PE7FZHhq7xUzRldHiGDb58= X-Gm-Gg: AeBDievWtg0x1mb0A+tbPcnpdu2qKJ7aQi/R8QZIZqeAnkkwh5S5rJ4e+UQQA0T3yEe QziEC285kpk0HqqUnqUM+lNeZpzHaRd9e0HZhHXXf1f4hTnlQYfRbYx299w0aSJkf+aAyI5LZL5 VDuzWGvNmS+G/Gh2zmWi7vY/qWYS0/lt7erdm08uZxLqMbL7Y5yC/eD7GcgHXuFdXeu2mIaNckJ TfMyNatPG/fPjW23jh3rLs8AvQ0Ei17k+vh/ToJxHUAsL1Ue2n4NLYMfdsLbSGeMyxAO9p23zkc eOHycX2OWgDBe8Xy4euZwO5+7zUgY7RBg1UCi7CGe8C4G+qeroUMxPP7F3iAfgPx8ci9PGZR/Fc EWjXP2KN9qF5BacGQOv6awtXnUdV0y3sTAkkqB5WGbea7EmsSuGdnHnOYUMHHgwduTsgYPeuYE4 XOCtzJFNNGHZQ= X-Received: by 2002:a17:90b:2e46:b0:359:8dfd:64c8 with SMTP id 98e67ed59e1d1-361404a81e0mr41584514a91.24.1777286863074; Mon, 27 Apr 2026 03:47:43 -0700 (PDT) Received: from xpc ([2400:8902:e002:def5:7882:53a7:6a48:4d11]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-362dde4ccbfsm16227029a91.1.2026.04.27.03.47.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Apr 2026 03:47:42 -0700 (PDT) From: WANG Rui To: Huacai Chen , Ard Biesheuvel Cc: WANG Xuerui , Ilias Apalodimas , loongarch@lists.linux.dev, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, WANG Rui Subject: [PATCH 2/3] efi/loongarch: Randomize kernel preferred address for KASLR Date: Mon, 27 Apr 2026 18:47:20 +0800 Message-ID: <20260427104721.47724-3-r@hev.cc> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260427104721.47724-1-r@hev.cc> References: <20260427104721.47724-1-r@hev.cc> Precedence: bulk X-Mailing-List: linux-efi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Introduce efi_get_kimg_kaslr_address() to compute the preferred kernel image address dynamically when CONFIG_RANDOMIZE_BASE is enabled. The function derives a random offset using EFI-provided randomness combined with the timer value, and constrains it within CONFIG_RANDOMIZE_BASE_MAX_OFFSET. Update EFI_KIMG_PREFERRED_ADDRESS to call this helper so that the EFI stub can select a randomized load address when KASLR is active, while preserving the original base address behavior when KASLR is disabled or nokaslr is specified. Signed-off-by: WANG Rui --- arch/loongarch/Kconfig | 2 +- arch/loongarch/include/asm/efi.h | 4 +++- drivers/firmware/efi/libstub/loongarch.c | 16 ++++++++++++++++ 3 files changed, 20 insertions(+), 2 deletions(-) diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index 3b042dbb2c41..a5afb70f73d9 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -730,7 +730,7 @@ config RANDOMIZE_BASE config RANDOMIZE_BASE_MAX_OFFSET hex "Maximum KASLR offset" if EXPERT depends on RANDOMIZE_BASE - range 0x0 0x10000000 + range 0x20000 0x10000000 default "0x01000000" help When KASLR is active, this provides the maximum offset that will diff --git a/arch/loongarch/include/asm/efi.h b/arch/loongarch/include/asm/efi.h index eddc8e79b3fa..f831320efd41 100644 --- a/arch/loongarch/include/asm/efi.h +++ b/arch/loongarch/include/asm/efi.h @@ -30,6 +30,8 @@ static inline unsigned long efi_get_kimg_min_align(void) return SZ_2M; } -#define EFI_KIMG_PREFERRED_ADDRESS PHYSADDR(VMLINUX_LOAD_ADDRESS) +unsigned long efi_get_kimg_kaslr_address(void); + +#define EFI_KIMG_PREFERRED_ADDRESS efi_get_kimg_kaslr_address() #endif /* _ASM_LOONGARCH_EFI_H */ diff --git a/drivers/firmware/efi/libstub/loongarch.c b/drivers/firmware/efi/libstub/loongarch.c index 9825f5218137..df67ef8c68ab 100644 --- a/drivers/firmware/efi/libstub/loongarch.c +++ b/drivers/firmware/efi/libstub/loongarch.c @@ -38,6 +38,22 @@ static efi_status_t exit_boot_func(struct efi_boot_memmap *map, void *priv) return EFI_SUCCESS; } +unsigned long efi_get_kimg_kaslr_address(void) +{ + unsigned int random_offset = 0; + +#ifdef CONFIG_RANDOMIZE_BASE + if (!efi_nokaslr) { + efi_get_random_bytes(sizeof(random_offset), (u8 *)&random_offset); + random_offset ^= (rdtime_l() << 16); + random_offset &= (CONFIG_RANDOMIZE_BASE_MAX_OFFSET - SZ_64K - 1); + random_offset = ALIGN(random_offset, SZ_64K) + SZ_64K; + } +#endif + + return PHYSADDR(VMLINUX_LOAD_ADDRESS) + random_offset; +} + unsigned long __weak kernel_entry_address(unsigned long kernel_addr, efi_loaded_image_t *image) { -- 2.54.0