Messages in this thread | | | Date | Tue, 21 Mar 2023 15:49:40 -0700 (PDT) | Subject | Re: [PATCH 1/2] binfmt_elf_fdpic: support 64-bit systems | From | Palmer Dabbelt <> |
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On Tue, 28 Feb 2023 05:51:25 PST (-0800), gerg@kernel.org wrote: > The binfmt_flat_fdpic code has a number of 32-bit specific data > structures associated with it. Extend it to be able to support and > be used on 64-bit systems as well. > > The new code defines a number of key 64-bit variants of the core > elf-fdpic data structures - along side the existing 32-bit sized ones. > A common set of generic named structures are defined to be either > the 32-bit or 64-bit ones as required at compile time. This is a > similar technique to that used in the ELF binfmt loader. > > For example: > > elf_fdpic_loadseg is either elf32_fdpic_loadseg or elf64_fdpic_loadseg > elf_fdpic_loadmap is either elf32_fdpic_loadmap or elf64_fdpic_loadmap > > the choice based on ELFCLASS32 or ELFCLASS64. > > Signed-off-by: Greg Ungerer <gerg@kernel.org> > --- > fs/binfmt_elf_fdpic.c | 38 +++++++++++++++++----------------- > include/linux/elf-fdpic.h | 14 ++++++++++++- > include/uapi/linux/elf-fdpic.h | 15 ++++++++++++++ > 3 files changed, 47 insertions(+), 20 deletions(-)
Adding some of the binfmt/fs folks, who weren't directly on the mail. It's looking like we're generally OK with this in RISC-V land, though there's still no userspace posted. I don't think there's any rush here and it might be prudent to wait for userspace to start going through a bit of a review, but figured I'd at least poke everyone to see if there's any thoughts.
I'm fine either way, so
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
if that helps any. Also happy to take this through the RISC-V tree along with the other if that's easier, but again no rush.
> > diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c > index a05eafcacfb27..2eea6dd429fd6 100644 > --- a/fs/binfmt_elf_fdpic.c > +++ b/fs/binfmt_elf_fdpic.c > @@ -138,7 +138,7 @@ static int is_constdisp(struct elfhdr *hdr) > static int elf_fdpic_fetch_phdrs(struct elf_fdpic_params *params, > struct file *file) > { > - struct elf32_phdr *phdr; > + struct elf_phdr *phdr; > unsigned long size; > int retval, loop; > loff_t pos = params->hdr.e_phoff; > @@ -560,8 +560,8 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm, > sp &= ~7UL; > > /* stack the load map(s) */ > - len = sizeof(struct elf32_fdpic_loadmap); > - len += sizeof(struct elf32_fdpic_loadseg) * exec_params->loadmap->nsegs; > + len = sizeof(struct elf_fdpic_loadmap); > + len += sizeof(struct elf_fdpic_loadseg) * exec_params->loadmap->nsegs; > sp = (sp - len) & ~7UL; > exec_params->map_addr = sp; > > @@ -571,8 +571,8 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm, > current->mm->context.exec_fdpic_loadmap = (unsigned long) sp; > > if (interp_params->loadmap) { > - len = sizeof(struct elf32_fdpic_loadmap); > - len += sizeof(struct elf32_fdpic_loadseg) * > + len = sizeof(struct elf_fdpic_loadmap); > + len += sizeof(struct elf_fdpic_loadseg) * > interp_params->loadmap->nsegs; > sp = (sp - len) & ~7UL; > interp_params->map_addr = sp; > @@ -740,12 +740,12 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params, > struct mm_struct *mm, > const char *what) > { > - struct elf32_fdpic_loadmap *loadmap; > + struct elf_fdpic_loadmap *loadmap; > #ifdef CONFIG_MMU > - struct elf32_fdpic_loadseg *mseg; > + struct elf_fdpic_loadseg *mseg; > #endif > - struct elf32_fdpic_loadseg *seg; > - struct elf32_phdr *phdr; > + struct elf_fdpic_loadseg *seg; > + struct elf_phdr *phdr; > unsigned long load_addr, stop; > unsigned nloads, tmp; > size_t size; > @@ -767,7 +767,7 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params, > > params->loadmap = loadmap; > > - loadmap->version = ELF32_FDPIC_LOADMAP_VERSION; > + loadmap->version = ELF_FDPIC_LOADMAP_VERSION; > loadmap->nsegs = nloads; > > load_addr = params->load_addr; > @@ -843,8 +843,8 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params, > if (phdr->p_vaddr >= seg->p_vaddr && > phdr->p_vaddr + phdr->p_memsz <= > seg->p_vaddr + seg->p_memsz) { > - Elf32_Dyn __user *dyn; > - Elf32_Sword d_tag; > + Elf_Dyn __user *dyn; > + Elf_Sword d_tag; > > params->dynamic_addr = > (phdr->p_vaddr - seg->p_vaddr) + > @@ -854,11 +854,11 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params, > * one item, and that the last item is a NULL > * entry */ > if (phdr->p_memsz == 0 || > - phdr->p_memsz % sizeof(Elf32_Dyn) != 0) > + phdr->p_memsz % sizeof(Elf_Dyn) != 0) > goto dynamic_error; > > - tmp = phdr->p_memsz / sizeof(Elf32_Dyn); > - dyn = (Elf32_Dyn __user *)params->dynamic_addr; > + tmp = phdr->p_memsz / sizeof(Elf_Dyn); > + dyn = (Elf_Dyn __user *)params->dynamic_addr; > if (get_user(d_tag, &dyn[tmp - 1].d_tag) || > d_tag != 0) > goto dynamic_error; > @@ -927,8 +927,8 @@ static int elf_fdpic_map_file_constdisp_on_uclinux( > struct file *file, > struct mm_struct *mm) > { > - struct elf32_fdpic_loadseg *seg; > - struct elf32_phdr *phdr; > + struct elf_fdpic_loadseg *seg; > + struct elf_phdr *phdr; > unsigned long load_addr, base = ULONG_MAX, top = 0, maddr = 0; > int loop, ret; > > @@ -1011,8 +1011,8 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params, > struct file *file, > struct mm_struct *mm) > { > - struct elf32_fdpic_loadseg *seg; > - struct elf32_phdr *phdr; > + struct elf_fdpic_loadseg *seg; > + struct elf_phdr *phdr; > unsigned long load_addr, delta_vaddr; > int loop, dvset; > > diff --git a/include/linux/elf-fdpic.h b/include/linux/elf-fdpic.h > index 3bea95a1af537..e533f45131945 100644 > --- a/include/linux/elf-fdpic.h > +++ b/include/linux/elf-fdpic.h > @@ -10,13 +10,25 @@ > > #include <uapi/linux/elf-fdpic.h> > > +#if ELF_CLASS == ELFCLASS32 > +#define Elf_Sword Elf32_Sword > +#define elf_fdpic_loadseg elf32_fdpic_loadseg > +#define elf_fdpic_loadmap elf32_fdpic_loadmap > +#define ELF_FDPIC_LOADMAP_VERSION ELF32_FDPIC_LOADMAP_VERSION > +#else > +#define Elf_Sword Elf64_Sxword > +#define elf_fdpic_loadmap elf64_fdpic_loadmap > +#define elf_fdpic_loadseg elf64_fdpic_loadseg > +#define ELF_FDPIC_LOADMAP_VERSION ELF64_FDPIC_LOADMAP_VERSION > +#endif > + > /* > * binfmt binary parameters structure > */ > struct elf_fdpic_params { > struct elfhdr hdr; /* ref copy of ELF header */ > struct elf_phdr *phdrs; /* ref copy of PT_PHDR table */ > - struct elf32_fdpic_loadmap *loadmap; /* loadmap to be passed to userspace */ > + struct elf_fdpic_loadmap *loadmap; /* loadmap to be passed to userspace */ > unsigned long elfhdr_addr; /* mapped ELF header user address */ > unsigned long ph_addr; /* mapped PT_PHDR user address */ > unsigned long map_addr; /* mapped loadmap user address */ > diff --git a/include/uapi/linux/elf-fdpic.h b/include/uapi/linux/elf-fdpic.h > index 4fcc6cfebe185..ec23f08711292 100644 > --- a/include/uapi/linux/elf-fdpic.h > +++ b/include/uapi/linux/elf-fdpic.h > @@ -32,4 +32,19 @@ struct elf32_fdpic_loadmap { > > #define ELF32_FDPIC_LOADMAP_VERSION 0x0000 > > +/* segment mappings for ELF FDPIC libraries/executables/interpreters */ > +struct elf64_fdpic_loadseg { > + Elf64_Addr addr; /* core address to which mapped */ > + Elf64_Addr p_vaddr; /* VMA recorded in file */ > + Elf64_Word p_memsz; /* allocation size recorded in file */ > +}; > + > +struct elf64_fdpic_loadmap { > + Elf64_Half version; /* version of these structures, just in case... */ > + Elf64_Half nsegs; /* number of segments */ > + struct elf64_fdpic_loadseg segs[]; > +}; > + > +#define ELF64_FDPIC_LOADMAP_VERSION 0x0000 > + > #endif /* _UAPI_LINUX_ELF_FDPIC_H */
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