Applied, thanks!
Sergey Bugaev, le lun. 24 avril 2023 00:55:23 +0300, a ecrit:
> This is a flag that can be passed to mmap () to request that the mapping
> being established should be located in the lower 2 GB area of the
> address space, so only the lower 31 (not 32) bits can be set in its
> address, and the address can be represented as a 32-bit integer without
> truncating it.
>
> This flag is intended to be compatible with Linux, FreeBSD, and Darwin
> flags of the same name. Out of those systems, it appears Linux and
> FreeBSD take MAP_32BIT to mean "map 31 bit", whereas Darwin allows the
> 32nd bit to be set in the address as well. The Hurd follows Linux and
> FreeBSD behavior.
>
> Unlike on those systems, on the Hurd MAP_32BIT is defined on all
> supported architectures (which currently are only i386 and x86_64).
>
> Signed-off-by: Sergey Bugaev <buga...@gmail.com>
> ---
> sysdeps/mach/hurd/bits/mman_ext.h | 1 +
> sysdeps/mach/hurd/dl-sysdep.c | 8 +++++---
> sysdeps/mach/hurd/mmap.c | 10 ++++++----
> 3 files changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/sysdeps/mach/hurd/bits/mman_ext.h
> b/sysdeps/mach/hurd/bits/mman_ext.h
> index f022826e..bbb94743 100644
> --- a/sysdeps/mach/hurd/bits/mman_ext.h
> +++ b/sysdeps/mach/hurd/bits/mman_ext.h
> @@ -22,4 +22,5 @@
>
> #ifdef __USE_GNU
> # define SHM_ANON ((const char *) 1)
> +# define MAP_32BIT 0x1000
> #endif /* __USE_GNU */
> diff --git a/sysdeps/mach/hurd/dl-sysdep.c b/sysdeps/mach/hurd/dl-sysdep.c
> index 6e167e12..d7b309e0 100644
> --- a/sysdeps/mach/hurd/dl-sysdep.c
> +++ b/sysdeps/mach/hurd/dl-sysdep.c
> @@ -451,7 +451,7 @@ __mmap (void *addr, size_t len, int prot, int flags, int
> fd, off_t offset)
> {
> error_t err;
> vm_prot_t vmprot;
> - vm_address_t mapaddr;
> + vm_address_t mapaddr, mask;
> mach_port_t memobj_rd, memobj_wr;
>
> vmprot = VM_PROT_NONE;
> @@ -462,6 +462,8 @@ __mmap (void *addr, size_t len, int prot, int flags, int
> fd, off_t offset)
> if (prot & PROT_EXEC)
> vmprot |= VM_PROT_EXECUTE;
>
> + mask = (flags & MAP_32BIT) ? ~(vm_address_t) 0x7FFFFFFF : 0;
> +
> if (flags & MAP_ANON)
> memobj_rd = MACH_PORT_NULL;
> else
> @@ -476,7 +478,7 @@ __mmap (void *addr, size_t len, int prot, int flags, int
> fd, off_t offset)
>
> mapaddr = (vm_address_t) addr;
> err = __vm_map (__mach_task_self (),
> - &mapaddr, (vm_size_t) len, 0,
> + &mapaddr, (vm_size_t) len, mask,
> !(flags & MAP_FIXED),
> memobj_rd,
> (vm_offset_t) offset,
> @@ -491,7 +493,7 @@ __mmap (void *addr, size_t len, int prot, int flags, int
> fd, off_t offset)
> if (! err)
> err = __vm_map (__mach_task_self (),
> &mapaddr, (vm_size_t) len,
> - 0,
> + mask,
> !(flags & MAP_FIXED),
> memobj_rd, (vm_offset_t) offset,
> flags & (MAP_COPY|MAP_PRIVATE),
> diff --git a/sysdeps/mach/hurd/mmap.c b/sysdeps/mach/hurd/mmap.c
> index 20a41e36..c3cc1856 100644
> --- a/sysdeps/mach/hurd/mmap.c
> +++ b/sysdeps/mach/hurd/mmap.c
> @@ -36,7 +36,7 @@ __mmap (void *addr, size_t len, int prot, int flags, int
> fd, off_t offset)
> error_t err;
> vm_prot_t vmprot, max_vmprot;
> memory_object_t memobj;
> - vm_address_t mapaddr;
> + vm_address_t mapaddr, mask;
> boolean_t copy;
>
> mapaddr = (vm_address_t) addr;
> @@ -55,6 +55,8 @@ __mmap (void *addr, size_t len, int prot, int flags, int
> fd, off_t offset)
>
> copy = ! (flags & MAP_SHARED);
>
> + mask = (flags & MAP_32BIT) ? ~(vm_address_t) 0x7FFFFFFF : 0;
> +
> switch (flags & MAP_TYPE)
> {
> default:
> @@ -134,7 +136,7 @@ __mmap (void *addr, size_t len, int prot, int flags, int
> fd, off_t offset)
> max_vmprot = VM_PROT_ALL;
>
> err = __vm_map (__mach_task_self (),
> - &mapaddr, (vm_size_t) len, (vm_address_t) 0,
> + &mapaddr, (vm_size_t) len, mask,
> mapaddr == 0,
> memobj, (vm_offset_t) offset,
> copy, vmprot, max_vmprot,
> @@ -149,7 +151,7 @@ __mmap (void *addr, size_t len, int prot, int flags, int
> fd, off_t offset)
> err = __vm_deallocate (__mach_task_self (), mapaddr, len);
> if (! err)
> err = __vm_map (__mach_task_self (),
> - &mapaddr, (vm_size_t) len, (vm_address_t) 0,
> + &mapaddr, (vm_size_t) len, mask,
> 0, memobj, (vm_offset_t) offset,
> copy, vmprot, max_vmprot,
> copy ? VM_INHERIT_COPY : VM_INHERIT_SHARE);
> @@ -159,7 +161,7 @@ __mmap (void *addr, size_t len, int prot, int flags, int
> fd, off_t offset)
> {
> if (mapaddr != 0 && (err == KERN_NO_SPACE || err ==
> KERN_INVALID_ADDRESS))
> err = __vm_map (__mach_task_self (),
> - &mapaddr, (vm_size_t) len, (vm_address_t) 0,
> + &mapaddr, (vm_size_t) len, mask,
> 1, memobj, (vm_offset_t) offset,
> copy, vmprot, max_vmprot,
> copy ? VM_INHERIT_COPY : VM_INHERIT_SHARE);
> --
> 2.40.0
>
--
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.
