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[153.223.134.223]) by smtp.googlemail.com with ESMTPSA id 41be03b00d2f7-c642a9f539dsm8866928a12.26.2026.01.30.23.44.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Jan 2026 23:44:58 -0800 (PST) From: Daniel Palmer To: linux@weissschuh.net, w@1wt.eu Cc: kees@kernel.org, linux-kernel@vger.kernel.org, Daniel Palmer Subject: [RFC PATCH 9/9] fs/binfmt_elf_fdpic: Reflect that PIE binaries also work in KConfig help Date: Sat, 31 Jan 2026 16:44:40 +0900 Message-ID: <20260131074440.732588-10-daniel@thingy.jp> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260131074440.732588-1-daniel@thingy.jp> References: <20260131074440.732588-1-daniel@thingy.jp> 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" Since commit 1bde925d2354 ("fs/binfmt_elf_fdpic.c: provide NOMMU loader for= regular ELF binaries") it has been possible to load some normal ELF binaries on nommu but it wasn't documented in the help. Since nolibc can generate static-pie binaries that work with this loader document that normal ELFs can work as long as they are PIE and you have a linker and that nolibc can also generate static-PIE binaries that can load without any assitance. Signed-off-by: Daniel Palmer --- fs/Kconfig.binfmt | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt index 1949e25c7741..71573bfd32ac 100644 --- a/fs/Kconfig.binfmt +++ b/fs/Kconfig.binfmt @@ -69,6 +69,16 @@ config BINFMT_ELF_FDPIC =20 It is also possible to run FDPIC ELF binaries on MMU linux also. =20 + On nommu systems this can also load normal ELF binaries as long as + the binary is linked as PIE. If the binary is not static PIE, does not + include it's own relocation code, this requires a linker like uldso to + be present and set as the interpreter. + + nolibc included in the kernel source can create static-PIE binaries + by including relocation code and the resulting binaries run on MMU + systems with the normal ELF loader and on nommu systems with this + loader. + config ELFCORE bool help --=20 2.51.0