From 145097dff170507fe73190e8e41194f5b5f7e6bf Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Fri, 28 Mar 2025 09:26:59 +0100 Subject: [PATCH] x86: Use separate variable for TLSDESC XSAVE/XSAVEC state size (bug 32810) Previously, the initialization code reused the xsave_state_full_size member of struct cpu_features for the TLSDESC state size. However, the tunable processing code assumes that this member has the original XSAVE (non-compact) state size, so that it can use its value if XSAVEC is disabled via tunable. This change uses a separate variable and not a struct member because the value is only needed in ld.so and the static libc, but not in libc.so. As a result, struct cpu_features layout does not change, helping a future backport of this change. Fixes commit 9b7091415af47082664717210ac49d51551456ab ("x86-64: Update _dl_tlsdesc_dynamic to preserve AMX registers"). Reviewed-by: H.J. Lu --- sysdeps/x86/Makefile | 19 +++++++++++++++++++ sysdeps/x86/cpu-features.c | 11 ++++++----- sysdeps/x86/cpu-tunables.c | 2 ++ sysdeps/x86/dl-diagnostics-cpu.c | 2 ++ sysdeps/x86/include/cpu-features.h | 9 +++++++-- sysdeps/x86/tst-gnu2-tls2-x86-noxsave.c | 1 + sysdeps/x86/tst-gnu2-tls2-x86-noxsavec.c | 1 + sysdeps/x86/tst-gnu2-tls2-x86-noxsavexsavec.c | 1 + sysdeps/x86_64/dl-tlsdesc-dynamic.h | 2 +- 9 files changed, 40 insertions(+), 8 deletions(-) create mode 100644 sysdeps/x86/tst-gnu2-tls2-x86-noxsave.c create mode 100644 sysdeps/x86/tst-gnu2-tls2-x86-noxsavec.c create mode 100644 sysdeps/x86/tst-gnu2-tls2-x86-noxsavexsavec.c diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile index 5311b594af..8819fba1b7 100644 --- a/sysdeps/x86/Makefile +++ b/sysdeps/x86/Makefile @@ -21,6 +21,9 @@ tests += \ tst-cpu-features-supports-static \ tst-get-cpu-features \ tst-get-cpu-features-static \ + tst-gnu2-tls2-x86-noxsave \ + tst-gnu2-tls2-x86-noxsavec \ + tst-gnu2-tls2-x86-noxsavexsavec \ tst-hwcap-tunables \ # tests tests-static += \ @@ -91,6 +94,22 @@ CFLAGS-tst-gnu2-tls2.c += -msse CFLAGS-tst-gnu2-tls2mod0.c += -msse2 -mtune=haswell CFLAGS-tst-gnu2-tls2mod1.c += -msse2 -mtune=haswell CFLAGS-tst-gnu2-tls2mod2.c += -msse2 -mtune=haswell + +LDFLAGS-tst-gnu2-tls2-x86-noxsave += -Wl,-z,lazy +LDFLAGS-tst-gnu2-tls2-x86-noxsavec += -Wl,-z,lazy +LDFLAGS-tst-gnu2-tls2-x86-noxsavexsavec += -Wl,-z,lazy + +# Test for bug 32810: incorrect XSAVE state size if XSAVEC is disabled +# via tunable. +tst-gnu2-tls2-x86-noxsave-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-XSAVE +tst-gnu2-tls2-x86-noxsavec-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-XSAVEC +tst-gnu2-tls2-x86-noxsavexsavec-ENV = GLIBC_TUNABLES=glibc.cpu.hwcaps=-XSAVE,-XSAVEC +$(objpfx)tst-gnu2-tls2-x86-noxsave.out \ +$(objpfx)tst-gnu2-tls2-x86-noxsavec.out \ +$(objpfx)tst-gnu2-tls2-x86-noxsavexsavec.out: \ + $(objpfx)tst-gnu2-tls2mod0.so \ + $(objpfx)tst-gnu2-tls2mod1.so \ + $(objpfx)tst-gnu2-tls2mod2.so endif ifeq ($(subdir),math) diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index 6dfb112038..6cf7e4caf1 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -84,6 +84,8 @@ extern void TUNABLE_CALLBACK (set_x86_shstk) (tunable_val_t *) # include #endif +unsigned long int _dl_x86_features_tlsdesc_state_size; + static void update_active (struct cpu_features *cpu_features) { @@ -318,6 +320,7 @@ update_active (struct cpu_features *cpu_features) = xsave_state_full_size; cpu_features->xsave_state_full_size = xsave_state_full_size; + _dl_x86_features_tlsdesc_state_size = xsave_state_full_size; /* Check if XSAVEC is available. */ if (CPU_FEATURES_CPU_P (cpu_features, XSAVEC)) @@ -406,11 +409,9 @@ update_active (struct cpu_features *cpu_features) = ALIGN_UP ((amx_size + TLSDESC_CALL_REGISTER_SAVE_AREA), 64); - /* Set xsave_state_full_size to the compact AMX - state size for XSAVEC. NB: xsave_state_full_size - is only used in _dl_tlsdesc_dynamic_xsave and - _dl_tlsdesc_dynamic_xsavec. */ - cpu_features->xsave_state_full_size = amx_size; + /* Set TLSDESC state size to the compact AMX + state size for XSAVEC. */ + _dl_x86_features_tlsdesc_state_size = amx_size; #endif cpu_features->xsave_state_size = ALIGN_UP (size + TLSDESC_CALL_REGISTER_SAVE_AREA, diff --git a/sysdeps/x86/cpu-tunables.c b/sysdeps/x86/cpu-tunables.c index 3423176802..d692e0e0de 100644 --- a/sysdeps/x86/cpu-tunables.c +++ b/sysdeps/x86/cpu-tunables.c @@ -164,6 +164,8 @@ TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *valp) /* Update xsave_state_size to XSAVE state size. */ cpu_features->xsave_state_size = cpu_features->xsave_state_full_size; + _dl_x86_features_tlsdesc_state_size + = cpu_features->xsave_state_full_size; CPU_FEATURE_UNSET (cpu_features, XSAVEC); } } diff --git a/sysdeps/x86/dl-diagnostics-cpu.c b/sysdeps/x86/dl-diagnostics-cpu.c index 7d0373602d..870b1268db 100644 --- a/sysdeps/x86/dl-diagnostics-cpu.c +++ b/sysdeps/x86/dl-diagnostics-cpu.c @@ -89,6 +89,8 @@ _dl_diagnostics_cpu (void) cpu_features->xsave_state_size); print_cpu_features_value ("xsave_state_full_size", cpu_features->xsave_state_full_size); + print_cpu_features_value ("tlsdesc_state_full_size", + _dl_x86_features_tlsdesc_state_size); print_cpu_features_value ("data_cache_size", cpu_features->data_cache_size); print_cpu_features_value ("shared_cache_size", cpu_features->shared_cache_size); diff --git a/sysdeps/x86/include/cpu-features.h b/sysdeps/x86/include/cpu-features.h index 9c485d38ef..fbf1b89110 100644 --- a/sysdeps/x86/include/cpu-features.h +++ b/sysdeps/x86/include/cpu-features.h @@ -935,8 +935,6 @@ struct cpu_features /* The full state size for XSAVE when XSAVEC is disabled by GLIBC_TUNABLES=glibc.cpu.hwcaps=-XSAVEC - - and the AMX state size when XSAVEC is available. */ unsigned int xsave_state_full_size; /* Data cache size for use in memory and string routines, typically @@ -990,6 +988,13 @@ extern const struct cpu_features *_dl_x86_get_cpu_features (void) #define __get_cpu_features() _dl_x86_get_cpu_features() +#if IS_IN (rtld) || IS_IN (libc) +/* XSAVE/XSAVEC state size used by TLS descriptors. Compared to + xsave_state_size from struct cpu_features, this includes additional + registers. */ +extern unsigned long int _dl_x86_features_tlsdesc_state_size attribute_hidden; +#endif + #if defined (_LIBC) && !IS_IN (nonlib) /* Unused for x86. */ # define INIT_ARCH() diff --git a/sysdeps/x86/tst-gnu2-tls2-x86-noxsave.c b/sysdeps/x86/tst-gnu2-tls2-x86-noxsave.c new file mode 100644 index 0000000000..f0024c143d --- /dev/null +++ b/sysdeps/x86/tst-gnu2-tls2-x86-noxsave.c @@ -0,0 +1 @@ +#include diff --git a/sysdeps/x86/tst-gnu2-tls2-x86-noxsavec.c b/sysdeps/x86/tst-gnu2-tls2-x86-noxsavec.c new file mode 100644 index 0000000000..f0024c143d --- /dev/null +++ b/sysdeps/x86/tst-gnu2-tls2-x86-noxsavec.c @@ -0,0 +1 @@ +#include diff --git a/sysdeps/x86/tst-gnu2-tls2-x86-noxsavexsavec.c b/sysdeps/x86/tst-gnu2-tls2-x86-noxsavexsavec.c new file mode 100644 index 0000000000..f0024c143d --- /dev/null +++ b/sysdeps/x86/tst-gnu2-tls2-x86-noxsavexsavec.c @@ -0,0 +1 @@ +#include diff --git a/sysdeps/x86_64/dl-tlsdesc-dynamic.h b/sysdeps/x86_64/dl-tlsdesc-dynamic.h index 9965ddd2c0..4f496de8c8 100644 --- a/sysdeps/x86_64/dl-tlsdesc-dynamic.h +++ b/sysdeps/x86_64/dl-tlsdesc-dynamic.h @@ -99,7 +99,7 @@ _dl_tlsdesc_dynamic: # endif #else /* Allocate stack space of the required size to save the state. */ - sub _rtld_local_ro+RTLD_GLOBAL_RO_DL_X86_CPU_FEATURES_OFFSET+XSAVE_STATE_FULL_SIZE_OFFSET(%rip), %RSP_LP + sub _dl_x86_features_tlsdesc_state_size(%rip), %RSP_LP #endif /* Besides rdi and rsi, saved above, save rcx, rdx, r8, r9, r10 and r11. */