From: Hajime Tazaki <thehajime@gmail.com>
To: linux-um@lists.infradead.org
Cc: thehajime@gmail.com, ricarkol@google.com,
Liam.Howlett@oracle.com, linux-kernel@vger.kernel.org,
Eric Biederman <ebiederm@xmission.com>,
Kees Cook <kees@kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH v11 01/14] x86/um: nommu: elf loader for fdpic
Date: Thu, 18 Sep 2025 14:15:54 +0900 [thread overview]
Message-ID: <5a4932bbcdbf79facd544fec7e3d6a6969a40aa1.1758171893.git.thehajime@gmail.com> (raw)
In-Reply-To: <cover.1758171893.git.thehajime@gmail.com>
As UML supports CONFIG_MMU=n case, it has to use an alternate ELF
loader, FDPIC ELF loader. In this commit, we added necessary
definitions in the arch, as UML has not been used so far. It also
updates Kconfig file to use BINFMT_ELF_FDPIC under !MMU environment.
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: linux-mm@kvack.org
Cc: linux-fsdevel@vger.kernel.org
Acked-by: Kees Cook <kees@kernel.org>
Signed-off-by: Hajime Tazaki <thehajime@gmail.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
arch/um/include/asm/mmu.h | 5 +++++
arch/um/include/asm/ptrace-generic.h | 6 ++++++
arch/x86/um/asm/elf.h | 8 ++++++--
fs/Kconfig.binfmt | 2 +-
4 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/arch/um/include/asm/mmu.h b/arch/um/include/asm/mmu.h
index 4d0e4239f3cc..e9661846b4a3 100644
--- a/arch/um/include/asm/mmu.h
+++ b/arch/um/include/asm/mmu.h
@@ -17,6 +17,11 @@ typedef struct mm_context {
/* Address range in need of a TLB sync */
unsigned long sync_tlb_range_from;
unsigned long sync_tlb_range_to;
+
+#ifdef CONFIG_BINFMT_ELF_FDPIC
+ unsigned long exec_fdpic_loadmap;
+ unsigned long interp_fdpic_loadmap;
+#endif
} mm_context_t;
#endif
diff --git a/arch/um/include/asm/ptrace-generic.h b/arch/um/include/asm/ptrace-generic.h
index 86d74f9d33cf..62e9916078ec 100644
--- a/arch/um/include/asm/ptrace-generic.h
+++ b/arch/um/include/asm/ptrace-generic.h
@@ -29,6 +29,12 @@ struct pt_regs {
#define PTRACE_OLDSETOPTIONS 21
+#ifdef CONFIG_BINFMT_ELF_FDPIC
+#define PTRACE_GETFDPIC 31
+#define PTRACE_GETFDPIC_EXEC 0
+#define PTRACE_GETFDPIC_INTERP 1
+#endif
+
struct task_struct;
extern long subarch_ptrace(struct task_struct *child, long request,
diff --git a/arch/x86/um/asm/elf.h b/arch/x86/um/asm/elf.h
index 62ed5d68a978..33f69f1eac10 100644
--- a/arch/x86/um/asm/elf.h
+++ b/arch/x86/um/asm/elf.h
@@ -9,6 +9,7 @@
#include <skas.h>
#define CORE_DUMP_USE_REGSET
+#define ELF_FDPIC_CORE_EFLAGS 0
#ifdef CONFIG_X86_32
@@ -190,8 +191,11 @@ extern int arch_setup_additional_pages(struct linux_binprm *bprm,
extern unsigned long um_vdso_addr;
#define AT_SYSINFO_EHDR 33
-#define ARCH_DLINFO NEW_AUX_ENT(AT_SYSINFO_EHDR, um_vdso_addr)
-
+#define ARCH_DLINFO \
+do { \
+ NEW_AUX_ENT(AT_SYSINFO_EHDR, um_vdso_addr); \
+ NEW_AUX_ENT(AT_MINSIGSTKSZ, 0); \
+} while (0)
#endif
typedef unsigned long elf_greg_t;
diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt
index bd2f530e5740..419ba0282806 100644
--- a/fs/Kconfig.binfmt
+++ b/fs/Kconfig.binfmt
@@ -58,7 +58,7 @@ config ARCH_USE_GNU_PROPERTY
config BINFMT_ELF_FDPIC
bool "Kernel support for FDPIC ELF binaries"
default y if !BINFMT_ELF
- depends on ARM || ((M68K || RISCV || SUPERH || XTENSA) && !MMU)
+ depends on ARM || ((M68K || RISCV || SUPERH || UML || XTENSA) && !MMU)
select ELFCORE
help
ELF FDPIC binaries are based on ELF, but allow the individual load
--
2.43.0
next prev parent reply other threads:[~2025-09-18 5:16 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-18 5:15 [PATCH v11 00/14] nommu UML Hajime Tazaki
2025-09-18 5:15 ` Hajime Tazaki [this message]
2025-09-18 5:15 ` [PATCH v11 02/14] um: decouple MMU specific code from the common part Hajime Tazaki
2025-09-18 5:15 ` [PATCH v11 03/14] um: nommu: memory handling Hajime Tazaki
2025-09-18 5:15 ` [PATCH v11 04/14] x86/um: nommu: syscall handling Hajime Tazaki
2025-09-18 5:15 ` [PATCH v11 05/14] um: nommu: seccomp syscalls hook Hajime Tazaki
2025-09-18 5:15 ` [PATCH v11 06/14] fixup seccomp Hajime Tazaki
2025-09-18 5:16 ` [PATCH v11 07/14] x86/um: nommu: process/thread handling Hajime Tazaki
2025-09-18 5:16 ` [PATCH v11 08/14] um: nommu: configure fs register on host syscall invocation Hajime Tazaki
2025-09-18 5:16 ` [PATCH v11 09/14] x86/um/vdso: nommu: vdso memory update Hajime Tazaki
2025-09-18 5:16 ` [PATCH v11 10/14] x86/um: nommu: signal handling Hajime Tazaki
2025-09-18 5:16 ` [PATCH v11 11/14] um: nommu: a work around for MMU dependency to PCI driver Hajime Tazaki
2025-09-18 5:16 ` [PATCH v11 12/14] um: change machine name for uname output Hajime Tazaki
2025-09-18 5:16 ` [PATCH v11 13/14] um: nommu: add documentation of nommu UML Hajime Tazaki
2025-09-18 5:16 ` [PATCH v11 14/14] um: nommu: plug nommu code into build system Hajime Tazaki
2025-09-18 7:38 ` [PATCH v11 00/14] nommu UML Hajime Tazaki
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