diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2025-01-12 23:39:01 -0600 |
|---|---|---|
| committer | Kees Cook <kees@kernel.org> | 2025-02-06 07:35:38 -0800 |
| commit | b029628be267cba3c7684ec684749fe3e4372398 (patch) | |
| tree | de3f5609ffe6e8b60cc1b4b186cd33e0e8e6a4c4 /arch/alpha/kernel/osf_sys.c | |
| parent | 55cf2f4b945f6a6416cc2524ba740b83cc9af25a (diff) | |
alpha/elf: Fix misc/setarch test of util-linux by removing 32bit support
Richard Henderson <richard.henderson@linaro.org> writes[1]:
> There was a Spec benchmark (I forget which) which was memory bound and ran
> twice as fast with 32-bit pointers.
>
> I copied the idea from DEC to the ELF abi, but never did all the other work
> to allow the toolchain to take advantage.
>
> Amusingly, a later Spec changed the benchmark data sets to not fit into a
> 32-bit address space, specifically because of this.
>
> I expect one could delete the ELF bit and personality and no one would
> notice. Not even the 10 remaining Alpha users.
In [2] it was pointed out that parts of setarch weren't working
properly on alpha because it has it's own SET_PERSONALITY
implementation. In the discussion that followed Richard Henderson
pointed out that the 32bit pointer support for alpha was never
completed.
Fix this by removing alpha's 32bit pointer support.
As a bit of paranoia refuse to execute any alpha binaries that have
the EF_ALPHA_32BIT flag set. Just in case someone somewhere has
binaries that try to use alpha's 32bit pointer support.
Link: https://lkml.kernel.org/r/CAFXwXrkgu=4Qn-v1PjnOR4SG0oUb9LSa0g6QXpBq4ttm52pJOQ@mail.gmail.com [1]
Link: https://lkml.kernel.org/r/20250103140148.370368-1-glaubitz@physik.fu-berlin.de [2]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: https://lore.kernel.org/r/87y0zfs26i.fsf_-_@email.froward.int.ebiederm.org
Signed-off-by: Kees Cook <kees@kernel.org>
Diffstat (limited to 'arch/alpha/kernel/osf_sys.c')
| -rw-r--r-- | arch/alpha/kernel/osf_sys.c | 11 |
1 files changed, 2 insertions, 9 deletions
diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c index c0424de9e7cd..077a1407be6d 100644 --- a/arch/alpha/kernel/osf_sys.c +++ b/arch/alpha/kernel/osf_sys.c @@ -1211,8 +1211,7 @@ SYSCALL_DEFINE1(old_adjtimex, struct timex32 __user *, txc_p) return ret; } -/* Get an address range which is currently unmapped. Similar to the - generic version except that we know how to honor ADDR_LIMIT_32BIT. */ +/* Get an address range which is currently unmapped. */ static unsigned long arch_get_unmapped_area_1(unsigned long addr, unsigned long len, @@ -1231,13 +1230,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags, vm_flags_t vm_flags) { - unsigned long limit; - - /* "32 bit" actually means 31 bit, since pointers sign extend. */ - if (current->personality & ADDR_LIMIT_32BIT) - limit = 0x80000000; - else - limit = TASK_SIZE; + unsigned long limit = TASK_SIZE; if (len > limit) return -ENOMEM; |