| Message ID | d387e58f08b929357a2651e82d2ee18bcf681e40.1733998168.git.thehajime@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
Hajime Tazaki <thehajime@gmail.com> writes: > 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. Why does the no mmu case need an alternative elf loader? Last time I looked the regular binfmt_elf works just fine without an mmu. I looked again and at a quick skim the regular elf loader still looks like it will work without an MMU. You would need ET_DYN binaries just so they will load and run in a position independent way. But even that seems a common configuration even with a MMU these days. There are some funny things in elf_fdpic where it departs from the ELF standard and is no fun to support unless it is necessary. So I am not excited to see more architectures supporting ELF_FDPIC. Eric > 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 > 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 a3eaca41ff61..01422b761aa0 100644 > --- a/arch/um/include/asm/mmu.h > +++ b/arch/um/include/asm/mmu.h > @@ -14,6 +14,11 @@ 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 4696f24d1492..4ff844bcb1cd 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
diff --git a/arch/um/include/asm/mmu.h b/arch/um/include/asm/mmu.h index a3eaca41ff61..01422b761aa0 100644 --- a/arch/um/include/asm/mmu.h +++ b/arch/um/include/asm/mmu.h @@ -14,6 +14,11 @@ 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 4696f24d1492..4ff844bcb1cd 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