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[FMV][AArch64] Add initial AT_HWCAP3 / AT_HWCAP4 support #161595

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Merged
merged 1 commit into from
Oct 7, 2025
Merged

[FMV][AArch64] Add initial AT_HWCAP3 / AT_HWCAP4 support #161595

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6 changes: 2 additions & 4 deletions compiler-rt/lib/builtins/cpu_model/aarch64.c
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Original file line number Diff line number Diff line change
Expand Up @@ -19,15 +19,13 @@
#error This file is intended only for aarch64-based targets
#endif

#if __has_include(<sys/ifunc.h>)
#include <sys/ifunc.h>
#else
typedef struct __ifunc_arg_t {
unsigned long _size;
unsigned long _hwcap;
unsigned long _hwcap2;
unsigned long _hwcap3;
unsigned long _hwcap4;
} __ifunc_arg_t;
#endif // __has_include(<sys/ifunc.h>)

// LSE support detection for out-of-line atomics
// using HWCAP and Auxiliary vector
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9 changes: 4 additions & 5 deletions compiler-rt/lib/builtins/cpu_model/aarch64/fmv/android.inc
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Expand Up @@ -25,12 +25,11 @@ void CONSTRUCTOR_ATTRIBUTE __init_cpu_features(void) {
if (__isExynos9810())
return;

unsigned long hwcap = getauxval(AT_HWCAP);
unsigned long hwcap2 = getauxval(AT_HWCAP2);

__ifunc_arg_t arg;
arg._size = sizeof(__ifunc_arg_t);
arg._hwcap = hwcap;
arg._hwcap2 = hwcap2;
arg._hwcap = getauxval(AT_HWCAP);
arg._hwcap2 = getauxval(AT_HWCAP2);
arg._hwcap3 = getauxval(AT_HWCAP3);
arg._hwcap4 = getauxval(AT_HWCAP4);
__init_cpu_features_constructor(hwcap | _IFUNC_ARG_HWCAP, &arg);
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@petrhosek petrhosek Oct 7, 2025 •
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The code is still referencing hwcap but the variable is no longer defined anywhere.

}
14 changes: 7 additions & 7 deletions compiler-rt/lib/builtins/cpu_model/aarch64/fmv/elf_aux_info.inc
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Original file line number Diff line number Diff line change
Expand Up @@ -7,21 +7,21 @@ void __init_cpu_features_resolver(unsigned long hwcap,
}

void CONSTRUCTOR_ATTRIBUTE __init_cpu_features(void) {
unsigned long hwcap = 0;
unsigned long hwcap2 = 0;
unsigned long hwcap, hwcap2, hwcap3, hwcap4 = 0;
// CPU features already initialized.
if (__atomic_load_n(&__aarch64_cpu_features.features, __ATOMIC_RELAXED))
return;

int res = 0;
res = elf_aux_info(AT_HWCAP, &hwcap, sizeof hwcap);
res |= elf_aux_info(AT_HWCAP2, &hwcap2, sizeof hwcap2);
if (res)
return;
elf_aux_info(AT_HWCAP, &hwcap, sizeof hwcap);
elf_aux_info(AT_HWCAP2, &hwcap2, sizeof hwcap2);
elf_aux_info(AT_HWCAP3, &hwcap3, sizeof hwcap3);
elf_aux_info(AT_HWCAP4, &hwcap4, sizeof hwcap4);

__ifunc_arg_t arg;
arg._size = sizeof(__ifunc_arg_t);
arg._hwcap = hwcap;
arg._hwcap2 = hwcap2;
arg._hwcap3 = hwcap3;
arg._hwcap4 = hwcap4;
__init_cpu_features_constructor(hwcap | _IFUNC_ARG_HWCAP, &arg);
}
9 changes: 4 additions & 5 deletions compiler-rt/lib/builtins/cpu_model/aarch64/fmv/getauxval.inc
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Original file line number Diff line number Diff line change
Expand Up @@ -10,12 +10,11 @@ void CONSTRUCTOR_ATTRIBUTE __init_cpu_features(void) {
if (__atomic_load_n(&__aarch64_cpu_features.features, __ATOMIC_RELAXED))
return;

unsigned long hwcap = getauxval(AT_HWCAP);
unsigned long hwcap2 = getauxval(AT_HWCAP2);

__ifunc_arg_t arg;
arg._size = sizeof(__ifunc_arg_t);
arg._hwcap = hwcap;
arg._hwcap2 = hwcap2;
arg._hwcap = getauxval(AT_HWCAP);
arg._hwcap2 = getauxval(AT_HWCAP2);
arg._hwcap3 = getauxval(AT_HWCAP3);
arg._hwcap4 = getauxval(AT_HWCAP4);
__init_cpu_features_constructor(hwcap | _IFUNC_ARG_HWCAP, &arg);
}
20 changes: 18 additions & 2 deletions compiler-rt/lib/builtins/cpu_model/aarch64/hwcap.inc
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@
#define _IFUNC_ARG_HWCAP (1ULL << 62)
#endif
#ifndef AT_HWCAP
#define AT_HWCAP 16
#define AT_HWCAP 16 // Linux value
#endif
#ifndef HWCAP_CPUID
#define HWCAP_CPUID (1 << 11)
Expand Down Expand Up @@ -95,7 +95,7 @@
#endif

#ifndef AT_HWCAP2
#define AT_HWCAP2 26
#define AT_HWCAP2 26 // Linux value
#endif
#ifndef HWCAP2_DCPODP
#define HWCAP2_DCPODP (1 << 0)
Expand Down Expand Up @@ -190,3 +190,19 @@
#ifndef HWCAP2_CSSC
#define HWCAP2_CSSC (1UL << 34)
#endif

#ifndef AT_HWCAP3
#ifdef __linux__
#define AT_HWCAP3 29 // Linux value
#else
#define AT_HWCAP3 38 // BSD value
#endif
#endif

#ifndef AT_HWCAP4
#ifdef __linux__
#define AT_HWCAP4 30 // Linux value
#else
#define AT_HWCAP4 39 // BSD value
#endif
#endif