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 A839B3815C6 for ; Wed, 29 Apr 2026 08:55:54 +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=1777452954; cv=none; b=sW8QiEj1SYVh9XApVOCPCpPGNZaB1as7JIDmCapZXFBWR6cKb2vgM/M4ARC0F/wZnpq2tgNJRzfSCdG3UuC2V7Y25udoLwLN2vWNeH9WqS5JdW7pMYB6GoHuDCHLc5YuCxPpS/prwNzZix5LDhCGDmP0EV2ngGMhMk9A0h4PPo4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777452954; c=relaxed/simple; bh=O/GSs85hzvhIPvia2rR93WkBMTqT8ZjtriJwaDoYRSE=; h=MIME-Version:Date:From:To:Cc:Message-Id:In-Reply-To:References: Subject:Content-Type; b=VsbQ6IcAB1/kM/MtK08507tvGNw3xlxYBDbjGeTF5lbt0kADe5dwht2977xSTmi08t+LbyUl8Cyjzf0FrdIB3CXnd3TY3vD6U+WZt/b//Vy4oxGqmLHm76jvtwhC6zhKo0QpQb/4JUn1PL/rsg8xM9A8A3fZE1D+dpnasqjhmIo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ao+pO9gi; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ao+pO9gi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40F44C4AF09; Wed, 29 Apr 2026 08:55:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777452954; bh=O/GSs85hzvhIPvia2rR93WkBMTqT8ZjtriJwaDoYRSE=; h=Date:From:To:Cc:In-Reply-To:References:Subject:From; b=Ao+pO9gi/I3imCbNIy5j+uLyA/XLQrE2+a2fYp0glFV1aTonAYK1hF/q3WMwazKm3 /37N5d3uRKpIFHuQ9zQGOoepvkdPlt8ObKdTxUgaeZs7tjz732rYw+2WDvmmEFv8US Qa9I1thHu9VubGRAwcKLoxotRR+MgpNGZBkvXAud/KKQ8OQPEiAn42v5O63EaopNCY D9WQ8KI4iHH/caz6IZ/27HHvxkdEJpYTQP4E2acwEgocxUzO0ODKQrB8+PIW9aiJgR ssfaAtUVeFn1wPO6AKIH4wfQLwA3h8jXWXpPklzSThokvEq/y6n9F9yXRolZShDtNF 2382vloSwownQ== Received: from phl-compute-01.internal (phl-compute-01.internal [10.202.2.41]) by mailfauth.phl.internal (Postfix) with ESMTP id 39C0EF4006F; Wed, 29 Apr 2026 04:55:53 -0400 (EDT) Received: from phl-imap-02 ([10.202.2.81]) by phl-compute-01.internal (MEProxy); Wed, 29 Apr 2026 04:55:53 -0400 X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefhedrtddtgdekgedtudcutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpuffrtefokffrpgfnqfghnecuuegr ihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjug hrpefoggffhffvvefkjghfufgtgfesthejredtredttdenucfhrhhomhepfdetrhguuceu ihgvshhhvghuvhgvlhdfuceorghruggssehkvghrnhgvlhdrohhrgheqnecuggftrfgrth htvghrnhepvdeuheeitdevtdelkeduudetgffftdelteefteevjeevjeeiheefhfejieej fedunecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomheprg hrugdomhgvshhmthhprghuthhhphgvrhhsohhnrghlihhthidqudeijedthedttdejledq feefvdduieegudehqdgrrhgusgeppehkvghrnhgvlhdrohhrghesfihorhhkohhfrghrug drtghomhdpnhgspghrtghpthhtohepledpmhhouggvpehsmhhtphhouhhtpdhrtghpthht oheplhhishgrsegshihtvghflhihrdhsphgrtggvpdhrtghpthhtoheprheshhgvvhdrtg gtpdhrtghpthhtoheptghhvghnhhhurggtrghisehkvghrnhgvlhdrohhrghdprhgtphht thhopehilhhirghsrdgrphgrlhhoughimhgrsheslhhinhgrrhhordhorhhgpdhrtghpth htoheplhhoohhnghgrrhgthheslhhishhtshdrlhhinhhugidruggvvhdprhgtphhtthho pehsuhhnhhgrihihohhngheslhhoohhnghhsohhnrdgtnhdprhgtphhtthhopehlihhnuh igqdgvfhhisehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhinhhugidq khgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtohepkhgvrhhnvg hlseigvghntdhnrdhnrghmvg X-ME-Proxy: Feedback-ID: ice86485a:Fastmail Received: by mailuser.phl.internal (Postfix, from userid 501) id 172DB700065; Wed, 29 Apr 2026 04:55:53 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface Precedence: bulk X-Mailing-List: linux-efi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Wed, 29 Apr 2026 10:55:32 +0200 From: "Ard Biesheuvel" To: "WANG Rui" , "Huacai Chen" Cc: "WANG Xuerui" , "Ilias Apalodimas" , "Haiyong Sun" , "Lisa Robinson" , loongarch@lists.linux.dev, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org Message-Id: In-Reply-To: <20260429051318.1581350-2-r@hev.cc> References: <20260429051318.1581350-1-r@hev.cc> <20260429051318.1581350-2-r@hev.cc> Subject: Re: [PATCH v3 1/3] efi/loongarch: Randomize kernel preferred address for KASLR Content-Type: text/plain Content-Transfer-Encoding: 7bit On Wed, 29 Apr 2026, at 07:13, WANG Rui wrote: > 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/include/asm/efi.h | 4 +++- > drivers/firmware/efi/libstub/loongarch.c | 16 ++++++++++++++++ > 2 files changed, 19 insertions(+), 1 deletion(-) > > 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); > + Where is the call to this function being added? > +#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..51997a0e83bd 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 ^= (random_get_entropy() << 16); > + random_offset &= (CONFIG_RANDOMIZE_BASE_MAX_OFFSET - 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