[PATCH 1/2] binfmt_elf_fdpic: support 64-bit systems
Greg Ungerer
gerg at kernel.org
Wed Mar 29 06:48:55 PDT 2023
On 22/3/23 08:49, Palmer Dabbelt wrote:
> On Tue, 28 Feb 2023 05:51:25 PST (-0800), gerg at 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 at 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 at 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.
Just following up. I haven't seen any feedback on this - did I miss any?
Regards
Greg
>> 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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