On 7/13/26 03:36, Matt Turner wrote:
Alpha has never set AT_HWCAP in linux-user emulation, so getauxval(AT_HWCAP)
always returned 0 regardless of the emulated CPU model.
The Linux kernel computes ELF_HWCAP as ~amask(-1), i.e. the set of ISA
extension bits that the amask instruction reports as supported (cleared in
its output). env->amask stores exactly those bits with the same layout
(BWX=0x1, FIX=0x2, CIX=0x4, MVI=0x100, TRAP=0x200, PREFETCH=0x1000), so
returning it directly from get_elf_hwcap matches the kernel convention.
Add HAVE_ELF_HWCAP to target_elf.h and implement get_elf_hwcap() in
elfload.c to expose the emulated CPU's capability mask to user-space
programs via the auxiliary vector.
Without this fix, programs using getauxval(AT_HWCAP) to detect BWX/FIX/CIX
(such as glibc's memcpy or JIT compilers targeting Alpha) incorrectly
concluded that no extensions were available even when emulating ev56+.
---
linux-user/alpha/elfload.c | 11 +++++++++++
linux-user/alpha/target_elf.h | 1 +
2 files changed, 12 insertions(+)
Reviewed-by: Helge Deller <[email protected]>
I'll include this patch in the next linux-user pull request.
Helge
