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[libunwind] Add SME detection for Apple platforms (#193630)

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Copy SME detection sysctl code from ZA test. Also fix a
logic issue in the original code while being reviewed.
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Brad Smith 2026-05-04 22:25:33 -04:00 committed by GitHub
parent b5f4f16fd9
commit 94b475dae6
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2 changed files with 13 additions and 2 deletions
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13
libunwind/src/Registers.hpp
View file

@ -20,6 +20,9 @@
#include "libunwind_ext.h"
#include "shadow_stack_unwind.h"
#if defined(__APPLE__)
#include <sys/sysctl.h>
#endif
#if defined(_LIBUNWIND_HAVE_GETAUXVAL) || defined(_LIBUNWIND_HAVE_ELF_AUX_INFO)
#include <sys/auxv.h>
#endif
@ -1940,7 +1943,15 @@ private:
_LIBUNWIND_ABORT("SME ZA disable failed");
}
#if defined(_LIBUNWIND_HAVE_GETAUXVAL)
#if defined(__APPLE__)
static bool checkHasSME() {
int has_sme = 0;
size_t size = sizeof(has_sme);
if (sysctlbyname("hw.optional.arm.FEAT_SME", &has_sme, &size, NULL, 0))
return false;
return has_sme != 0;
}
#elif defined(_LIBUNWIND_HAVE_GETAUXVAL)
static bool checkHasSME() {
constexpr int hwcap2_sme = (1 << 23);
unsigned long hwcap2 = getauxval(AT_HWCAP2);

2
libunwind/test/aarch64_za_unwind.pass.cpp
View file

@ -29,7 +29,7 @@
static bool checkHasSME() {
int has_sme = 0;
size_t size = sizeof(has_sme);
if (!sysctlbyname("hw.optional.arm.FEAT_SME", &has_sme, &size, NULL, 0))
if (sysctlbyname("hw.optional.arm.FEAT_SME", &has_sme, &size, NULL, 0))
return false;
return has_sme != 0;
}