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From 8191e8bdb07fd35d25bc3a50353f188e88fb11ac Mon Sep 17 00:00:00 2001
From: Aurelien Jarno <aurelien@aurel32.net>
Date: Sat, 26 Oct 2024 22:41:09 +0200
Subject: [PATCH] Revert "AArch64: Check kernel version for SVE ifuncs"
This reverts commit 24de733967029fd902c34073d2ab25b900887352.
---
sysdeps/aarch64/multiarch/init-arch.h | 2 -
sysdeps/aarch64/multiarch/memcpy.c | 2 +-
sysdeps/aarch64/multiarch/memmove.c | 2 +-
.../unix/sysv/linux/aarch64/cpu-features.c | 48 -------------------
.../unix/sysv/linux/aarch64/cpu-features.h | 1 -
5 files changed, 2 insertions(+), 53 deletions(-)
diff --git a/sysdeps/aarch64/multiarch/init-arch.h b/sysdeps/aarch64/multiarch/init-arch.h
index 5b2cf5cb12..5da1656954 100644
--- a/sysdeps/aarch64/multiarch/init-arch.h
+++ b/sysdeps/aarch64/multiarch/init-arch.h
@@ -36,7 +36,5 @@
MTE_ENABLED (); \
bool __attribute__((unused)) sve = \
GLRO(dl_aarch64_cpu_features).sve; \
- bool __attribute__((unused)) prefer_sve_ifuncs = \
- GLRO(dl_aarch64_cpu_features).prefer_sve_ifuncs; \
bool __attribute__((unused)) mops = \
GLRO(dl_aarch64_cpu_features).mops;
diff --git a/sysdeps/aarch64/multiarch/memcpy.c b/sysdeps/aarch64/multiarch/memcpy.c
index 3de66c14d4..d1cf5bec16 100644
--- a/sysdeps/aarch64/multiarch/memcpy.c
+++ b/sysdeps/aarch64/multiarch/memcpy.c
@@ -47,7 +47,7 @@ select_memcpy_ifunc (void)
{
if (IS_A64FX (midr))
return __memcpy_a64fx;
- return prefer_sve_ifuncs ? __memcpy_sve : __memcpy_generic;
+ return __memcpy_sve;
}
if (IS_THUNDERX (midr))
diff --git a/sysdeps/aarch64/multiarch/memmove.c b/sysdeps/aarch64/multiarch/memmove.c
index fdcf418820..90729e0275 100644
--- a/sysdeps/aarch64/multiarch/memmove.c
+++ b/sysdeps/aarch64/multiarch/memmove.c
@@ -47,7 +47,7 @@ select_memmove_ifunc (void)
{
if (IS_A64FX (midr))
return __memmove_a64fx;
- return prefer_sve_ifuncs ? __memmove_sve : __memmove_generic;
+ return __memmove_sve;
}
if (IS_THUNDERX (midr))
diff --git a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
index 2543128352..6ee1cb4bc2 100644
--- a/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
+++ b/sysdeps/unix/sysv/linux/aarch64/cpu-features.c
@@ -20,7 +20,6 @@
#include <sys/auxv.h>
#include <elf/dl-hwcaps.h>
#include <sys/prctl.h>
-#include <sys/utsname.h>
#define DCZID_DZP_MASK (1 << 4)
#define DCZID_BS_MASK (0xf)
@@ -60,46 +59,6 @@ get_midr_from_mcpu (const char *mcpu)
}
#endif
-#if __LINUX_KERNEL_VERSION < 0x060200
-
-/* Return true if we prefer using SVE in string ifuncs. Old kernels disable
- SVE after every system call which results in unnecessary traps if memcpy
- uses SVE. This is true for kernels between 4.15.0 and before 6.2.0, except
- for 5.14.0 which was patched. For these versions return false to avoid using
- SVE ifuncs.
- Parse the kernel version into a 24-bit kernel.major.minor value without
- calling any library functions. If uname() is not supported or if the version
- format is not recognized, assume the kernel is modern and return true. */
-
-static inline bool
-prefer_sve_ifuncs (void)
-{
- struct utsname buf;
- const char *p = &buf.release[0];
- int kernel = 0;
- int val;
-
- if (__uname (&buf) < 0)
- return true;
-
- for (int shift = 16; shift >= 0; shift -= 8)
- {
- for (val = 0; *p >= '0' && *p <= '9'; p++)
- val = val * 10 + *p - '0';
- kernel |= (val & 255) << shift;
- if (*p++ != '.')
- break;
- }
-
- if (kernel >= 0x060200 || kernel == 0x050e00)
- return true;
- if (kernel >= 0x040f00)
- return false;
- return true;
-}
-
-#endif
-
static inline void
init_cpu_features (struct cpu_features *cpu_features)
{
@@ -166,13 +125,6 @@ init_cpu_features (struct cpu_features *cpu_features)
/* Check if SVE is supported. */
cpu_features->sve = GLRO (dl_hwcap) & HWCAP_SVE;
- cpu_features->prefer_sve_ifuncs = cpu_features->sve;
-
-#if __LINUX_KERNEL_VERSION < 0x060200
- if (cpu_features->sve)
- cpu_features->prefer_sve_ifuncs = prefer_sve_ifuncs ();
-#endif
-
/* Check if MOPS is supported. */
cpu_features->mops = GLRO (dl_hwcap2) & HWCAP2_MOPS;
}
diff --git a/sysdeps/unix/sysv/linux/aarch64/cpu-features.h b/sysdeps/unix/sysv/linux/aarch64/cpu-features.h
index d51597b923..b4bd43a228 100644
--- a/sysdeps/unix/sysv/linux/aarch64/cpu-features.h
+++ b/sysdeps/unix/sysv/linux/aarch64/cpu-features.h
@@ -71,7 +71,6 @@ struct cpu_features
/* Currently, the GLIBC memory tagging tunable only defines 8 bits. */
uint8_t mte_state;
bool sve;
- bool prefer_sve_ifuncs;
bool mops;
};
--
2.45.2
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