From: H.J. Lu Date: Mon, 13 Apr 2026 00:23:05 +0000 (+0800) Subject: elf: Support THP segment load with madvise enabled THP X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=HEAD;p=thirdparty%2Fglibc.git elf: Support THP segment load with madvise enabled THP The current THP segment load approach works only when THP is enabled with always in the kernel. If THP is enabled with madvise in the kernel, to enable THP segment load in an application, madvise should be called with MADV_HUGEPAGE on all THP eligible PT_LOAD segments: 1. Define DL_MAP_DEFAULT_THP_PAGESIZE in hugepages.h and default it to 0. If DL_MAP_DEFAULT_THP_PAGESIZE is defined, assume kernel THP madvise mode. If kernel THP mode is always or never, there is an extra madvise call which has no impact. DL_MAP_DEFAULT_THP_PAGESIZE is defined for x86-64 and 64-bit loongarch. 2. Update _dl_map_segment_align to support madvise THP mode. This fixes BZ #34079. 3. Call _dl_executable_postprocess in rtld_setup_main_map for dynamic executables and in LIBC_START_MAIN for static executables, which calls madvise with MADV_HUGEPAGE on all THP eligible PT_LOAD segments in executable. This fixes BZ #34080 for both dynamic and static executables. 4. Call _dl_postprocess_loadcmd_extra in _dl_postprocess_loadcmd, which calls madvise with MADV_HUGEPAGE on all THP eligible PT_LOAD segments when loading an object after they have been mapped in. This fixes BZ #34080 for shared objects. 5. Set the maximum page alignment on THP tests to THP page size as the default maximum page alignment may be smaller than THP page size. 6. Add tests to verify that large executable PT_LOAD segments in executables are mapped at addresses aligned to THP page size when the kernel is configured to use THP in "always" mode or "madvise" mode by inspecting /proc/self/maps to check that the mapping address is aligned to THP page size reported by the kernel. Also verify that madvise is called with MADV_HUGEPAGE when the glibc tunable glibc.elf.thp=1 is used and madvise isn't called with MADV_HUGEPAGE when the glibc tunable glibc.elf.thp=0 is used. Skip these tests if THP page size cannot be determined or if THP is not enabled in "always" mode nor "madvise" mode. Quote WANG Rui : From benchmarking a clang build of the Linux kernel on x86_64 with your patch in THP madvise mode, I observed that iTLB misses were reduced, similar to what we see in THP always mode. NB: Some THP tests fail on arm due to limitations of arm32 kABI: https://sourceware.org/bugzilla/show_bug.cgi?id=34096 Signed-off-by: H.J. Lu Reviewed-by: Adhemerval Zanella --- diff --git a/csu/libc-start.c b/csu/libc-start.c index 1bd2184e46..67aa981246 100644 --- a/csu/libc-start.c +++ b/csu/libc-start.c @@ -204,6 +204,7 @@ call_fini (void *unused) #endif /* !SHARED */ #include +#include STATIC int LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL), @@ -307,6 +308,11 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL), _dl_relocate_static_pie_ifunc (); ARCH_SETUP_IREL (); + /* This must run after the IFUNC relocations: _dl_executable_postprocess + may call IFUNC-resolved routines. */ + struct link_map *main_map = _dl_get_dl_main_map (); + _dl_executable_postprocess (main_map, GL(dl_phdr), GL(dl_phnum)); + /* Initialize libpthread if linked in. */ if (__pthread_initialize_minimal != NULL) __pthread_initialize_minimal (); diff --git a/elf/dl-load.h b/elf/dl-load.h index 80ae5db4b3..84b82e183d 100644 --- a/elf/dl-load.h +++ b/elf/dl-load.h @@ -112,6 +112,7 @@ struct loadcmd int prot; /* PROT_* bits. */ }; +#include /* Iterator for program header segments. Initialize with _dl_pt_load_iterator_init, then either walk PT_LOAD segments via @@ -215,6 +216,8 @@ _dl_postprocess_loadcmd (struct link_map *l, const ElfW(Ehdr) *header, /* Found the program header in this segment. */ l->l_phdr = (void *) (uintptr_t) (c->mapstart + header->e_phoff - c->mapoff); + + _dl_postprocess_loadcmd_extra (l, c); } diff --git a/elf/dl-support.c b/elf/dl-support.c index 0508d6113b..b57fd74670 100644 --- a/elf/dl-support.c +++ b/elf/dl-support.c @@ -179,6 +179,12 @@ int _dl_stack_cache_lock; #endif struct dl_scope_free_list *_dl_scope_free_list; +#ifdef HAVE_THP +enum dl_elf_thp_control_t _dl_elf_thp_control; +enum thp_mode_t _dl_thp_mode; +size_t _dl_elf_thp_pagesize; +#endif + #ifdef NEED_DL_SYSINFO /* Needed for improved syscall handling on at least x86/Linux. NB: Don't initialize it here to avoid RELATIVE relocation in static PIE. */ diff --git a/elf/rtld.c b/elf/rtld.c index f2be6239b3..e5ba71fef1 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -53,6 +53,7 @@ #include #include #include +#include #include @@ -1203,14 +1204,8 @@ rtld_setup_main_map (struct link_map *main_map) main_map->l_relro_size = ph->p_memsz; break; } - /* Process program headers again, but scan them backwards since - PT_GNU_PROPERTY is close to the end of program headers. */ - for (const ElfW(Phdr) *ph = &phdr[phnum]; ph != phdr; --ph) - if (ph[-1].p_type == PT_GNU_PROPERTY) - { - _dl_process_pt_gnu_property (main_map, -1, &ph[-1]); - break; - } + + _dl_executable_postprocess (main_map, phdr, phnum); /* Adjust the address of the TLS initialization image in case the executable is actually an ET_DYN object. */ @@ -1583,6 +1578,9 @@ dl_main (const ElfW(Phdr) *phdr, { RTLD_TIMING_VAR (start); rtld_timer_start (&start); +#ifdef HAVE_THP + _dl_get_thp_config (); +#endif _dl_map_object (NULL, rtld_progname, lt_executable, 0, __RTLD_OPENEXEC, LM_ID_BASE); rtld_timer_stop (&load_time, start); diff --git a/support/support_check_hugetlb.c b/support/support_check_hugetlb.c index c73946c894..b1c2a8e7cd 100644 --- a/support/support_check_hugetlb.c +++ b/support/support_check_hugetlb.c @@ -27,23 +27,67 @@ #include #include -bool -support_thp_work_madvise (void) +enum thp_mode_t +support_get_thp_mode (void) { - int fd = open ("/sys/kernel/mm/transparent_hugepage/enabled", O_RDONLY); + int fd = open ("/sys/kernel/mm/transparent_hugepage/enabled", + O_RDONLY, 0); if (fd == -1) - return false; + return thp_mode_not_supported; -#define MODE_MADVISE "always [madvise] never\n" -#define MODE_ALWAYS "[always] madvise never\n" + static const char mode_always[] = "[always] madvise never\n"; + static const char mode_madvise[] = "always [madvise] never\n"; + static const char mode_never[] = "always madvise [never]\n"; - char str[sizeof(MODE_MADVISE)]; + char str[sizeof(mode_always)]; ssize_t s = read (fd, str, sizeof (str)); close (fd); - if (s != sizeof (str) - 1) - return false; + if (s < 0 || s >= sizeof str) + return thp_mode_not_supported; str[s] = '\0'; - return strcmp (str, MODE_MADVISE) == 0 || strcmp (str, MODE_ALWAYS) == 0; + + if (s == sizeof (mode_always) - 1) + { + if (strcmp (str, mode_always) == 0) + return thp_mode_always; + else if (strcmp (str, mode_madvise) == 0) + return thp_mode_madvise; + else if (strcmp (str, mode_never) == 0) + return thp_mode_never; + } + return thp_mode_not_supported; +} + +unsigned long int +support_get_thp_size (void) +{ + int fd = open ("/sys/kernel/mm/transparent_hugepage/hpage_pmd_size", + O_RDONLY, 0); + if (fd == -1) + return 0; + + char str[INT_BUFSIZE_BOUND (unsigned long int)]; + ssize_t s = read (fd, str, sizeof (str)); + close (fd); + if (s < 0) + return 0; + + unsigned long int r = 0; + for (ssize_t i = 0; i < s; i++) + { + if (str[i] == '\n') + break; + r *= 10; + r += str[i] - '0'; + } + return r; +} + +bool +support_thp_work_madvise (void) +{ + enum thp_mode_t mode = support_get_thp_mode (); + return mode == thp_mode_always || mode == thp_mode_madvise; } bool @@ -56,7 +100,7 @@ support_hugepages_reserved (void) char str[INT_BUFSIZE_BOUND(unsigned long int)]; ssize_t s = read (fd, str, sizeof (str)); close (fd); - if (s >= sizeof str || s < 0) + if (s < 0 || s >= sizeof str) return false; str[s] = '\0'; unsigned long int n = 0; diff --git a/support/support_check_hugetlb.h b/support/support_check_hugetlb.h index 2c5f5cb80c..6f55405c27 100644 --- a/support/support_check_hugetlb.h +++ b/support/support_check_hugetlb.h @@ -21,6 +21,10 @@ #include #include +#undef attribute_hidden +#define attribute_hidden +#include /* For enum thp_mode_t. */ +#undef attribute_hidden __BEGIN_DECLS @@ -43,6 +47,14 @@ bool support_hugepages_reserved (void); so it is safe to call unconditionally. */ void support_check_malloc_hugetlb (void); +/* Returns Transparent Huge Pages (THP) mode from + /sys/kernel/mm/transparent_hugepage/enabled. */ +extern enum thp_mode_t support_get_thp_mode (void); + +/* Returns Transparent Huge Pages (THP) page size from + /sys/kernel/mm/transparent_hugepage/hpage_pmd_size. */ +extern unsigned long int support_get_thp_size (void); + __END_DECLS #endif /* SUPPORT_SUPPORT_CHECK_HUGETLB_H */ diff --git a/sysdeps/generic/dl-exec-post.h b/sysdeps/generic/dl-exec-post.h new file mode 100644 index 0000000000..f5dcdc093a --- /dev/null +++ b/sysdeps/generic/dl-exec-post.h @@ -0,0 +1,34 @@ +/* _dl_executable_postprocess. Generic version. + Copyright (C) 2026 Free Software Foundation, Inc. + Copyright The GNU Toolchain Authors. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +static inline void +_dl_executable_postprocess (struct link_map *main_map, + const ElfW(Phdr) *phdr, ElfW(Word) phnum) +{ +#ifdef SHARED + /* Process program headers again, but scan them backwards since + PT_GNU_PROPERTY is close to the end of program headers. */ + for (const ElfW(Phdr) *ph = &phdr[phnum]; ph != phdr; --ph) + if (ph[-1].p_type == PT_GNU_PROPERTY) + { + _dl_process_pt_gnu_property (main_map, -1, &ph[-1]); + break; + } +#endif +} diff --git a/sysdeps/generic/dl-load-post.h b/sysdeps/generic/dl-load-post.h new file mode 100644 index 0000000000..1a6d205e33 --- /dev/null +++ b/sysdeps/generic/dl-load-post.h @@ -0,0 +1,23 @@ +/* _dl_postprocess_loadcmd_extra. Generic version. + Copyright (C) 2026 Free Software Foundation, Inc. + Copyright The GNU Toolchain Authors. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +static inline void +_dl_postprocess_loadcmd_extra (struct link_map *l, const struct loadcmd *c) +{ +} diff --git a/sysdeps/generic/hugepages.h b/sysdeps/generic/hugepages.h index 5fc9b5c8de..8e54661527 100644 --- a/sysdeps/generic/hugepages.h +++ b/sysdeps/generic/hugepages.h @@ -21,15 +21,26 @@ #include +/* The THP segment load control mode. */ +enum dl_elf_thp_control_t +{ + /* To be enabled or disabled by GLIBC_TUNABLES. */ + dl_elf_thp_control_default = 0, + /* Enabled by GLIBC_TUNABLES=glibc.elf.thp=1. */ + dl_elf_thp_control_enabled, + /* Disabled by GLIBC_TUNABLES=glibc.elf.thp=0. */ + dl_elf_thp_control_disabled +}; + /* Return the default transparent huge page size. */ unsigned long int __get_thp_size (void) attribute_hidden; enum thp_mode_t { + thp_mode_not_supported = 0, thp_mode_always, thp_mode_madvise, - thp_mode_never, - thp_mode_not_supported + thp_mode_never }; enum thp_mode_t __get_thp_mode (void) attribute_hidden; @@ -45,6 +56,10 @@ void __get_hugepage_config (size_t requested, size_t *pagesize, int *flags) # define MALLOC_DEFAULT_THP_PAGESIZE 0 #endif +#ifndef DL_MAP_DEFAULT_THP_PAGESIZE +# define DL_MAP_DEFAULT_THP_PAGESIZE 0 +#endif + #ifndef MAX_THP_PAGESIZE # define MAX_THP_PAGESIZE (32 * 1024 * 1024) #endif diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h index 24529db8a1..f94247ad9f 100644 --- a/sysdeps/generic/ldsodefs.h +++ b/sysdeps/generic/ldsodefs.h @@ -39,6 +39,7 @@ #include #include #include +#include __BEGIN_DECLS @@ -477,6 +478,14 @@ struct rtld_global EXTERN struct __pthread **_dl_pthread_threads; __mach_rwlock_define (EXTERN, _dl_pthread_threads_lock) #endif +#ifdef HAVE_THP + /* The THP segment load control. */ + EXTERN enum dl_elf_thp_control_t _dl_elf_thp_control; + /* The kernel THP mode. */ + EXTERN enum thp_mode_t _dl_thp_mode; + /* Page size used for THP segment load. */ + EXTERN size_t _dl_elf_thp_pagesize; +#endif #ifdef SHARED }; # define __rtld_global_attribute__ diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index 7d87888dab..a048dbc732 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -697,11 +697,15 @@ $(objpfx)pldd: $(objpfx)xmalloc.o tests += \ tst-rseq-tls-range \ tst-rseq-tls-range-4096 \ + tst-thp-1 \ + tst-thp-1-pde \ + tst-thp-1-static \ tst-thp-align \ # tests tests-static += \ tst-rseq-tls-range-4096-static \ tst-rseq-tls-range-static \ + tst-thp-1-static \ # tests-static modules-names += \ tst-rseq-tls-range-mod \ @@ -711,15 +715,12 @@ CFLAGS-tst-rseq-tls-range.c += -DMAIN_TLS_ALIGN=4 CFLAGS-tst-rseq-tls-range-4096.c += -DMAIN_TLS_ALIGN=4096 CFLAGS-tst-rseq-tls-range-static.c += -DMAIN_TLS_ALIGN=4 CFLAGS-tst-rseq-tls-range-4096-static.c += -DMAIN_TLS_ALIGN=4096 -LDFLAGS-tst-thp-size-mod.so += -Wl,-z,noseparate-code $(objpfx)tst-rseq-tls-range.out: $(objpfx)tst-rseq-tls-range-mod.so $(objpfx)tst-rseq-tls-range-4096.out: $(objpfx)tst-rseq-tls-range-mod.so $(objpfx)tst-rseq-tls-range-static.out: $(objpfx)tst-rseq-tls-range-mod.so $(objpfx)tst-rseq-tls-range-4096-static.out: $(objpfx)tst-rseq-tls-range-mod.so -$(objpfx)tst-thp-align.out: $(objpfx)tst-thp-size-mod.so tst-rseq-tls-range-static-ENV = LD_LIBRARY_PATH=$(objpfx):$(common-objpfx) tst-rseq-tls-range-4096-static-ENV = LD_LIBRARY_PATH=$(objpfx):$(common-objpfx) -tst-thp-align-ENV = GLIBC_TUNABLES=glibc.elf.thp=1 test-internal-extras += tst-nolink-libc ifeq ($(run-built-tests),yes) @@ -728,6 +729,186 @@ tests-special += \ $(objpfx)tst-nolink-libc-2.out \ # tests-special endif + +ifndef THP-PAGE-SIZE +# Align PT_LOAD segments in THP tests to THP page size so that kernel will +# map PIE to the address aligned to THP page size. Default THP page size +# to 2MB which can be overridden in Makefile in subdirectories. +THP-PAGE-SIZE = 0x200000 +endif + +THP-PAGE-SIZE-LDFLAGS = -Wl,-z,max-page-size=$(THP-PAGE-SIZE) + +# -Wl,-z,max-page-size=$(THP-PAGE-SIZE) alone doesn't work for PDE when +# text-segment address is lower than the maximum page size: +# https://sourceware.org/bugzilla/show_bug.cgi?id=34184 +ifneq (,$(load-address-ldflag)) +LOAD-THP-ADDRESS-LDFLAGS = $(load-address-ldflag)=$(THP-PAGE-SIZE) +endif + +LDFLAGS-tst-thp-size-mod.so = -Wl,-z,noseparate-code \ + $(THP-PAGE-SIZE-LDFLAGS) +tst-thp-align-ENV = GLIBC_TUNABLES=glibc.elf.thp=1 +$(objpfx)tst-thp-align.out: $(objpfx)tst-thp-size-mod.so + +tests += \ + tst-thp-1-no-s-code \ + tst-thp-1-no-s-code-pde \ + tst-thp-1-no-s-code-static \ +# tests +tests-static += \ + tst-thp-1-no-s-code-static \ +# tests-static + +ifeq (yes,$(with-lld)) +# -z noseparate-code is a nop for lld. It doesn't create an executable +# segment placed at 0 file offset. +test-xfail-tst-thp-1-no-s-code = yes +test-xfail-tst-thp-1-no-s-code-pde = yes +test-xfail-tst-thp-1-no-s-code-static = yes +endif + +LDFLAGS-tst-thp-1 = -Wl,-z,separate-code $(THP-PAGE-SIZE-LDFLAGS) +LDFLAGS-tst-thp-1-pde = -Wl,-z,separate-code $(THP-PAGE-SIZE-LDFLAGS) \ + $(LOAD-THP-ADDRESS-LDFLAGS) +LDFLAGS-tst-thp-1-static = -Wl,-z,separate-code $(THP-PAGE-SIZE-LDFLAGS) +ifneq (yes,$(enable-static-pie)) +LDFLAGS-tst-thp-1-static += $(LOAD-THP-ADDRESS-LDFLAGS) +endif +LDFLAGS-tst-thp-1-no-s-code = -Wl,-z,noseparate-code \ + $(THP-PAGE-SIZE-LDFLAGS) +LDFLAGS-tst-thp-1-no-s-code-pde = -Wl,-z,noseparate-code \ + $(THP-PAGE-SIZE-LDFLAGS) \ + $(LOAD-THP-ADDRESS-LDFLAGS) +LDFLAGS-tst-thp-1-no-s-code-static = -Wl,-z,noseparate-code \ + $(THP-PAGE-SIZE-LDFLAGS) +ifneq (yes,$(enable-static-pie)) +LDFLAGS-tst-thp-1-no-s-code-static += $(LOAD-THP-ADDRESS-LDFLAGS) +endif + +$(objpfx)tst-thp-1-no-s-code: $(objpfx)tst-thp-size-mod.o +$(objpfx)tst-thp-1-no-s-code-pde: $(objpfx)tst-thp-size-mod.o +$(objpfx)tst-thp-1-no-s-code-static: $(objpfx)tst-thp-size-mod.o + +tst-thp-1-no-s-code-ENV = GLIBC_TUNABLES=glibc.elf.thp=1 +tst-thp-1-no-s-code-pde-ENV = GLIBC_TUNABLES=glibc.elf.thp=1 +tst-thp-1-no-s-code-static-ENV = GLIBC_TUNABLES=glibc.elf.thp=1 + +tst-thp-1-no-s-code-pde-no-pie = yes + +tst-thp-1-ENV = GLIBC_TUNABLES=glibc.elf.thp=1 +tst-thp-1-pde-ENV = GLIBC_TUNABLES=glibc.elf.thp=1 +tst-thp-1-static-ENV = GLIBC_TUNABLES=glibc.elf.thp=1 + +$(objpfx)tst-thp-1: $(objpfx)tst-thp-size-mod.o +$(objpfx)tst-thp-1-pde: $(objpfx)tst-thp-size-mod.o +$(objpfx)tst-thp-1-static: $(objpfx)tst-thp-size-mod.o + +tst-thp-1-pde-no-pie = yes + +# Don't run strace tests for cross-compiling. +ifeq (no,$(cross-compiling)) +thp-kernel-status = $(shell grep madvise /sys/kernel/mm/transparent_hugepage/enabled) +# Verify that madvise is called with MADV_HUGEPAGE when THP is enabled +# under madvise THP kernel. +ifneq ($(findstring [madvise],$(thp-kernel-status)),) +tests-special += \ + $(objpfx)strace-tst-thp-1-disabled.out \ + $(objpfx)strace-tst-thp-1-enabled.out \ + $(objpfx)strace-tst-thp-1-pde-disabled.out \ + $(objpfx)strace-tst-thp-1-pde-enabled.out \ + $(objpfx)strace-tst-thp-1-static-disabled.out \ + $(objpfx)strace-tst-thp-1-static-enabled.out \ + $(objpfx)strace-tst-thp-align-default.out \ + $(objpfx)strace-tst-thp-align-disabled.out \ + $(objpfx)strace-tst-thp-align-enabled.out \ +# tests-special + +ifeq (yes,$(build-hardcoded-path-in-tests)) +strace-test-via-rtld-prefix = +else +strace-test-via-rtld-prefix = $(rtld-prefix) +endif + +$(objpfx)strace-tst-thp-1-enabled.out: \ + $(..)sysdeps/unix/sysv/linux/strace-tst-thp.sh $(objpfx)ld.so \ + $(objpfx)tst-thp-1 + $(SHELL) $< '$(strace-test-via-rtld-prefix)' \ + '$(test-wrapper-env)' \ + '$(run-program-env) GLIBC_TUNABLES=glibc.elf.thp=1' \ + $(objpfx)tst-thp-1 > $@; \ + $(evaluate-test) + +$(objpfx)strace-tst-thp-1-disabled.out: \ + $(..)sysdeps/unix/sysv/linux/strace-tst-thp.sh $(objpfx)ld.so \ + $(objpfx)tst-thp-1 + $(SHELL) $< '$(strace-test-via-rtld-prefix)' \ + '$(test-wrapper-env)' \ + '$(run-program-env) GLIBC_TUNABLES=glibc.elf.thp=0' \ + $(objpfx)tst-thp-1 > $@; \ + $(evaluate-test) + +$(objpfx)strace-tst-thp-1-pde-enabled.out: \ + $(..)sysdeps/unix/sysv/linux/strace-tst-thp.sh $(objpfx)ld.so \ + $(objpfx)tst-thp-1-pde + $(SHELL) $< '$(strace-test-via-rtld-prefix)' \ + '$(test-wrapper-env)' \ + '$(run-program-env) GLIBC_TUNABLES=glibc.elf.thp=1' \ + $(objpfx)tst-thp-1-pde > $@; \ + $(evaluate-test) + +$(objpfx)strace-tst-thp-1-pde-disabled.out: \ + $(..)sysdeps/unix/sysv/linux/strace-tst-thp.sh $(objpfx)ld.so \ + $(objpfx)tst-thp-1-pde + $(SHELL) $< '$(strace-test-via-rtld-prefix)' \ + '$(test-wrapper-env)' \ + '$(run-program-env) GLIBC_TUNABLES=glibc.elf.thp=0' \ + $(objpfx)tst-thp-1-pde > $@; \ + $(evaluate-test) + +$(objpfx)strace-tst-thp-1-static-enabled.out: \ + $(..)sysdeps/unix/sysv/linux/strace-tst-thp.sh \ + $(objpfx)tst-thp-1-static + $(SHELL) $< '' '$(test-wrapper-env)' \ + '$(run-program-env) GLIBC_TUNABLES=glibc.elf.thp=1' \ + $(objpfx)tst-thp-1-static > $@; \ + $(evaluate-test) + +$(objpfx)strace-tst-thp-1-static-disabled.out: \ + $(..)sysdeps/unix/sysv/linux/strace-tst-thp.sh \ + $(objpfx)tst-thp-1-static + $(SHELL) $< '' '$(test-wrapper-env)' \ + '$(run-program-env) GLIBC_TUNABLES=glibc.elf.thp=0' \ + $(objpfx)tst-thp-1-static > $@; \ + $(evaluate-test) + +$(objpfx)strace-tst-thp-align-default.out: \ + $(..)sysdeps/unix/sysv/linux/strace-tst-thp.sh $(objpfx)ld.so \ + $(objpfx)tst-thp-align + $(SHELL) $< '$(strace-test-via-rtld-prefix)' \ + '$(test-wrapper-env)' '$(run-program-env)' \ + $(objpfx)tst-thp-align > $@; \ + $(evaluate-test) + +$(objpfx)strace-tst-thp-align-enabled.out: \ + $(..)sysdeps/unix/sysv/linux/strace-tst-thp.sh $(objpfx)ld.so \ + $(objpfx)tst-thp-align + $(SHELL) $< '$(strace-test-via-rtld-prefix)' \ + '$(test-wrapper-env)' \ + '$(run-program-env) GLIBC_TUNABLES=glibc.elf.thp=1' \ + $(objpfx)tst-thp-align > $@; \ + $(evaluate-test) + +$(objpfx)strace-tst-thp-align-disabled.out: \ + $(..)sysdeps/unix/sysv/linux/strace-tst-thp.sh $(objpfx)ld.so \ + $(objpfx)tst-thp-align + $(SHELL) $< '$(strace-test-via-rtld-prefix)' \ + '$(test-wrapper-env)' \ + '$(run-program-env) GLIBC_TUNABLES=glibc.elf.thp=0' \ + $(objpfx)tst-thp-align > $@; \ + $(evaluate-test) +endif # [madvise] +endif # $(cross-compiling) endif # $(subdir) == elf ifeq ($(subdir),rt) diff --git a/sysdeps/unix/sysv/linux/arm/Makefile b/sysdeps/unix/sysv/linux/arm/Makefile index e73ce4f811..428949fefd 100644 --- a/sysdeps/unix/sysv/linux/arm/Makefile +++ b/sysdeps/unix/sysv/linux/arm/Makefile @@ -3,6 +3,13 @@ sysdep-rtld-routines += aeabi_read_tp libc-do-syscall # The test uses INTERNAL_SYSCALL_CALL. In thumb mode, this uses # an undefined reference to __libc_do_syscall. CFLAGS-tst-nolink-libc.c += -marm + +ifeq (yes,$(enable-static-pie)) +# These static PIE tests fail on arm due to limitations of arm32 kABI: +# https://sourceware.org/bugzilla/show_bug.cgi?id=34096 +test-xfail-tst-thp-1-no-s-code-static = yes +test-xfail-tst-thp-1-static = yes +endif endif ifeq ($(subdir),misc) diff --git a/sysdeps/unix/sysv/linux/dl-exec-post.h b/sysdeps/unix/sysv/linux/dl-exec-post.h new file mode 100644 index 0000000000..dd8a379809 --- /dev/null +++ b/sysdeps/unix/sysv/linux/dl-exec-post.h @@ -0,0 +1,137 @@ +/* _dl_executable_postprocess. Linux version. + Copyright (C) 2026 Free Software Foundation, Inc. + Copyright The GNU Toolchain Authors. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +static inline void +_dl_get_thp_config (void) +{ + /* Check if there is GLIBC_TUNABLES=glibc.elf.thp=[0|1]. */ + if (TUNABLE_GET_FULL (glibc, elf, thp, int32_t, NULL) == 0) + GL(dl_elf_thp_control) = dl_elf_thp_control_disabled; + else + GL(dl_elf_thp_control) = dl_elf_thp_control_enabled; + + /* Return if the tunable is not set or THP is disabled by the + tunable. */ + if (GL(dl_elf_thp_control) == dl_elf_thp_control_disabled) + return; + + verify (DL_MAP_DEFAULT_THP_PAGESIZE <= MAX_THP_PAGESIZE); + + /* NB: Accessing /sys/kernel/mm files is quite expensive and the file + may not be accessible in containers. If DL_MAP_DEFAULT_THP_PAGESIZE + is non-zero, assume THP mode is madvise and always call madvise. + Since madvise is a fast system call, it adds only a small overhead + compared to the cost of accessing /sys/kernel/mm files. */ + if (DL_MAP_DEFAULT_THP_PAGESIZE != 0) + { + GL(dl_elf_thp_pagesize) = DL_MAP_DEFAULT_THP_PAGESIZE; + GL(dl_thp_mode) = thp_mode_madvise; + } + else + { + GL(dl_thp_mode) = __get_thp_mode (); + if (GL(dl_thp_mode) == thp_mode_always + || GL(dl_thp_mode) == thp_mode_madvise) + { + GL(dl_elf_thp_pagesize) = __get_thp_size (); + /* We cap the huge page size at MAX_THP_PAGESIZE to avoid + over-aligning on systems with very large normal pages + (like 64K pages with 512M huge pages). */ + if (GL(dl_elf_thp_pagesize) > MAX_THP_PAGESIZE) + GL(dl_elf_thp_pagesize) = 0; + } + else + GL(dl_elf_thp_pagesize) = 0; + + if (GL(dl_elf_thp_pagesize) == 0) + { + GL(dl_elf_thp_control) = dl_elf_thp_control_disabled; + GL(dl_thp_mode) = thp_mode_not_supported; + } + } +} + +static inline void +_dl_executable_postprocess (struct link_map *main_map, + const ElfW(Phdr) *phdr, ElfW(Word) phnum) +{ + /* NB: In static executable, PT_GNU_PROPERTY is processed in target + libc-start.h if it is needed by target. When ld.so is used, if + a target doesn't need PT_GNU_PROPERTY, _dl_process_pt_gnu_property + is an empty function. */ +#ifdef SHARED + /* Process program headers again, but scan them backwards since + PT_GNU_PROPERTY is close to the end of program headers. */ + for (const ElfW(Phdr) *ph = &phdr[phnum]; ph != phdr; --ph) + if (ph[-1].p_type == PT_GNU_PROPERTY) + { + _dl_process_pt_gnu_property (main_map, -1, &ph[-1]); + break; + } +#endif + + /* If THP state was not yet initialized, the main executable was mapped + by the kernel; in that case this function is the only place that can + apply MADV_HUGEPAGE to the main executable's segments. Otherwise, + _dl_get_thp_config has already run earlier in dl_main and + _dl_map_segments has just mapped the main executable, so + _dl_postprocess_loadcmd_extra has already done the madvise pass; do + not repeat it here. */ + if (GL(dl_elf_thp_control) != dl_elf_thp_control_default) + return; + + _dl_get_thp_config (); + + /* Return if THP segment load isn't enabled. */ + if (GL(dl_elf_thp_control) != dl_elf_thp_control_enabled) + return; + + /* NB: If DL_MAP_DEFAULT_THP_PAGESIZE is non-zero, dl_thp_mode is set + to thp_mode_madvise. */ + if (DL_MAP_DEFAULT_THP_PAGESIZE == 0 + && GL(dl_thp_mode) != thp_mode_madvise) + return; + + /* When we get here, the main executable have been mapped in. Call + madvise with MADV_HUGEPAGE for all THP eligible PT_LOAD segments. */ + + const ElfW(Phdr) *ph; + + size_t thp_pagesize = GL(dl_elf_thp_pagesize); + + /* Call __madvise if offset and address of the PT_LOAD segment are + aligned to THP page size and it is read-only. */ + for (ph = phdr; ph < &phdr[phnum]; ++ph) + if (ph->p_type == PT_LOAD + && ph->p_memsz >= thp_pagesize + && ((ph->p_vaddr | ph->p_offset) & (thp_pagesize - 1)) == 0 + && (ph->p_flags & (PF_W | PF_R)) == PF_R) + { + int ret = __madvise ((void *) (main_map->l_addr + ph->p_vaddr), + ph->p_memsz, MADV_HUGEPAGE); + if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)) + _dl_debug_printf ("\ +madvise (0x%0*lx, 0x%0*lx, MADV_HUGEPAGE) returns %d\n", +(int) sizeof (void *) * 2, +(unsigned long int) (main_map->l_addr + ph->p_vaddr), +(int) sizeof (void *) * 2, +(unsigned long int) ph->p_memsz, +ret); + } +} diff --git a/sysdeps/unix/sysv/linux/dl-load-post.h b/sysdeps/unix/sysv/linux/dl-load-post.h new file mode 100644 index 0000000000..741c4ddcb1 --- /dev/null +++ b/sysdeps/unix/sysv/linux/dl-load-post.h @@ -0,0 +1,42 @@ +/* _dl_postprocess_loadcmd_extra. Linux version. + Copyright (C) 2026 Free Software Foundation, Inc. + Copyright The GNU Toolchain Authors. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +static bool _dl_segment_thp_eligible (const struct loadcmd *, size_t); + +/* After L has been mapped in, call madvise with MADV_HUGEPAGE for THP + madvise mode if L is THP eligible. */ + +static inline void +_dl_postprocess_loadcmd_extra (struct link_map *l, const struct loadcmd *c) +{ + if (GL(dl_thp_mode) == thp_mode_madvise + && _dl_segment_thp_eligible (c, GL(dl_elf_thp_pagesize))) + { + int ret = __madvise ((void *) (l->l_addr + c->mapstart), + c->mapend - c->mapstart, MADV_HUGEPAGE); + if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES)) + _dl_debug_printf ("\ + madvise (0x%0*lx, 0x%0*lx, MADV_HUGEPAGE) returns %d\n", + (int) sizeof (void *) * 2, + (unsigned long int) (l->l_addr + c->mapstart), + (int) sizeof (void *) * 2, + (unsigned long int) (c->mapend - c->mapstart), + ret); + } +} diff --git a/sysdeps/unix/sysv/linux/dl-map-segment-align.c b/sysdeps/unix/sysv/linux/dl-map-segment-align.c index a39e74d91b..c062ba0c58 100644 --- a/sysdeps/unix/sysv/linux/dl-map-segment-align.c +++ b/sysdeps/unix/sysv/linux/dl-map-segment-align.c @@ -17,38 +17,24 @@ License along with the GNU C Library; if not, see . */ +#include #include -#include -#include + +/* Return the alignment of the PT_LOAD segment for THP. P_ALIGN_MAX is + the maximum p_align value in the PT_LOAD segment. */ ElfW (Addr) _dl_map_segment_align (const struct loadcmd *c, ElfW (Addr) p_align_max) { - static enum thp_mode_t thp_mode = thp_mode_not_supported; - static unsigned long int thp_pagesize; + size_t thp_pagesize = GL(dl_elf_thp_pagesize); - if (TUNABLE_GET (glibc, elf, thp, int32_t, NULL) == 0) + if (GL(dl_elf_thp_control) != dl_elf_thp_control_enabled + || p_align_max >= thp_pagesize) return p_align_max; - if (__glibc_unlikely (thp_mode == thp_mode_not_supported - || thp_pagesize == 0)) - { - unsigned long int default_thp_pagesize = DL_MAP_DEFAULT_THP_PAGESIZE; - thp_mode = default_thp_pagesize ? thp_mode_always : __get_thp_mode (); - thp_pagesize = default_thp_pagesize ? : __get_thp_size (); - } - - /* Aligning load segments that are large enough to the PMD size helps - improve THP eligibility and reduces TLB pressure. - We cap the huge page size at MAX_THP_PAGESIZE to avoid over-aligning - on systems with very large normal pages (like 64K pages with 512M - huge pages). */ - if (thp_mode == thp_mode_always - && thp_pagesize <= MAX_THP_PAGESIZE - && ((c->mapstart | c->mapoff) & (thp_pagesize - 1)) == 0 - && (c->mapend - c->mapstart) >= thp_pagesize - && p_align_max < thp_pagesize - && (c->prot & PROT_WRITE) == 0) + /* Return true if the segment is THP eligible. It helps improve THP + eligibility and reduces TLB pressure. */ + if (_dl_segment_thp_eligible (c, thp_pagesize)) return thp_pagesize; return p_align_max; diff --git a/sysdeps/unix/sysv/linux/dl-map-segment-align.h b/sysdeps/unix/sysv/linux/dl-map-segment-align.h index d9b05181b7..9a7fc3a10e 100644 --- a/sysdeps/unix/sysv/linux/dl-map-segment-align.h +++ b/sysdeps/unix/sysv/linux/dl-map-segment-align.h @@ -19,9 +19,18 @@ #include -#ifndef DL_MAP_DEFAULT_THP_PAGESIZE -# define DL_MAP_DEFAULT_THP_PAGESIZE 0 -#endif - extern ElfW (Addr) _dl_map_segment_align (const struct loadcmd *, ElfW (Addr)) attribute_hidden; + +/* Return true only if the loadcmd C is THP eligible with THP page size + THP_PAGESIZE, which means that it is read-only, its size >= THP page + size, its offset and address of the loadcmd C are aligned to THP page + size. */ + +static inline bool +_dl_segment_thp_eligible (const struct loadcmd *c, size_t thp_pagesize) +{ + return ((c->prot & (PROT_WRITE | PROT_READ)) == PROT_READ + && (c->mapend - c->mapstart) >= thp_pagesize + && ((c->mapstart | c->mapoff) & (thp_pagesize - 1)) == 0); +} diff --git a/sysdeps/unix/sysv/linux/ldsodefs.h b/sysdeps/unix/sysv/linux/ldsodefs.h index c63b649432..e39d9afe34 100644 --- a/sysdeps/unix/sysv/linux/ldsodefs.h +++ b/sysdeps/unix/sysv/linux/ldsodefs.h @@ -21,6 +21,9 @@ /* We have the auxiliary vector. */ #define HAVE_AUX_VECTOR +/* We have transparent huge page. */ +#define HAVE_THP + /* Get the real definitions. */ #include_next diff --git a/sysdeps/unix/sysv/linux/loongarch/Makefile b/sysdeps/unix/sysv/linux/loongarch/Makefile index 0d5f087862..d5beb62440 100644 --- a/sysdeps/unix/sysv/linux/loongarch/Makefile +++ b/sysdeps/unix/sysv/linux/loongarch/Makefile @@ -12,3 +12,6 @@ abi-ilp32s-condition := __WORDSIZE == 32 && defined __loongarch_soft_float abi-ilp32d-condition := __WORDSIZE == 32 && defined __loongarch_double_float abi-lp64s-condition := __WORDSIZE == 64 && defined __loongarch_soft_float abi-lp64d-condition := __WORDSIZE == 64 && defined __loongarch_double_float + +# Align THP tests to 32MB. +THP-PAGE-SIZE = 0x2000000 diff --git a/sysdeps/unix/sysv/linux/loongarch/lp64/dl-map-segment-align.h b/sysdeps/unix/sysv/linux/loongarch/lp64/hugepages.h similarity index 90% rename from sysdeps/unix/sysv/linux/loongarch/lp64/dl-map-segment-align.h rename to sysdeps/unix/sysv/linux/loongarch/lp64/hugepages.h index c51ee4ac47..30252a9b86 100644 --- a/sysdeps/unix/sysv/linux/loongarch/lp64/dl-map-segment-align.h +++ b/sysdeps/unix/sysv/linux/loongarch/lp64/hugepages.h @@ -1,4 +1,4 @@ -/* _dl_map_segment_align. LoongArch64 Linux version. +/* Huge Page support. LoongArch64 Linux version. Copyright (C) 2026 Free Software Foundation, Inc. Copyright The GNU Toolchain Authors. This file is part of the GNU C Library. @@ -19,4 +19,4 @@ #define DL_MAP_DEFAULT_THP_PAGESIZE (32 * 1024 * 1024) -#include_next +#include_next diff --git a/sysdeps/unix/sysv/linux/strace-tst-thp.sh b/sysdeps/unix/sysv/linux/strace-tst-thp.sh new file mode 100644 index 0000000000..bff7d3e7a0 --- /dev/null +++ b/sysdeps/unix/sysv/linux/strace-tst-thp.sh @@ -0,0 +1,62 @@ +#!/bin/bash +# Run THP test under strace to verify control of the THP segment load. +# Copyright (C) 2026 Free Software Foundation, Inc. +# This file is part of the GNU C Library. + +# The GNU C Library is free software; you can redistribute it and/or +# modify it under the terms of the GNU Lesser General Public +# License as published by the Free Software Foundation; either +# version 2.1 of the License, or (at your option) any later version. + +# The GNU C Library is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# Lesser General Public License for more details. + +# You should have received a copy of the GNU Lesser General Public +# License along with the GNU C Library; if not, see +# . + +set -e + +rtld="$1" +test_wrapper_env="$2" +run_program_env="$3" +test_prog="$4" + +cmd="${test_wrapper_env} ${run_program_env} strace -X raw ${rtld} ${test_prog}" + +TIMEOUTFACTOR=${TIMEOUTFACTOR:-1} + +case x"${run_program_env}" in +*glibc.elf.thp=1*) + strace_expected=yes + ;; +*) + strace_expected=no + ;; +esac + +# Verify strace is not just present, but works in this environment. If +# not, skip the test. +/bin/sh -c \ + "${test_wrapper_env} ${run_program_env} \ + strace -X raw -e trace=none -- /bin/true" > /dev/null 2>&1 || exit 77 + +# Finally the actual test inside the test environment, using the just +# build ld.so and new libraries to run the THP test under strace. +if /bin/sh -c \ + "timeout -k 4 $((3*$TIMEOUTFACTOR)) ${cmd} --direct 2>&1 \ + | grep -E \"madvise\(0x[0-9a-f]+, [0-9]+, 0xe)\""; then + if test ${strace_expected} = yes; then + exit 0 + else + exit 1 + fi +else + if test ${strace_expected} = no; then + exit 0 + else + exit 1 + fi +fi diff --git a/sysdeps/unix/sysv/linux/tst-thp-1-no-s-code-pde.c b/sysdeps/unix/sysv/linux/tst-thp-1-no-s-code-pde.c new file mode 100644 index 0000000000..3fd01e9bfe --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-thp-1-no-s-code-pde.c @@ -0,0 +1,19 @@ +/* Test PDE with THP segment load linked with -Wl,-z,noseparate-code. + Copyright (C) 2026 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include "tst-thp-1.c" diff --git a/sysdeps/unix/sysv/linux/tst-thp-1-no-s-code-static.c b/sysdeps/unix/sysv/linux/tst-thp-1-no-s-code-static.c new file mode 100644 index 0000000000..d0ae0f1ff0 --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-thp-1-no-s-code-static.c @@ -0,0 +1,19 @@ +/* Test static with THP segment load linked with -Wl,-z,noseparate-code. + Copyright (C) 2026 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include "tst-thp-1.c" diff --git a/sysdeps/unix/sysv/linux/tst-thp-1-no-s-code.c b/sysdeps/unix/sysv/linux/tst-thp-1-no-s-code.c new file mode 100644 index 0000000000..5eb1e005ed --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-thp-1-no-s-code.c @@ -0,0 +1,19 @@ +/* Test THP segment load linked with -Wl,-z,noseparate-code. + Copyright (C) 2026 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include "tst-thp-1.c" diff --git a/sysdeps/unix/sysv/linux/tst-thp-1-pde.c b/sysdeps/unix/sysv/linux/tst-thp-1-pde.c new file mode 100644 index 0000000000..d854dd43da --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-thp-1-pde.c @@ -0,0 +1,19 @@ +/* Test PDE with THP segment load linked with -Wl,-z,separate-code. + Copyright (C) 2026 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include "tst-thp-1.c" diff --git a/sysdeps/unix/sysv/linux/tst-thp-1-static.c b/sysdeps/unix/sysv/linux/tst-thp-1-static.c new file mode 100644 index 0000000000..66d7e12954 --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-thp-1-static.c @@ -0,0 +1,19 @@ +/* Test static with THP segment load linked with -Wl,-z,separate-code. + Copyright (C) 2026 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include "tst-thp-1.c" diff --git a/sysdeps/unix/sysv/linux/tst-thp-1.c b/sysdeps/unix/sysv/linux/tst-thp-1.c new file mode 100644 index 0000000000..49eea7069c --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-thp-1.c @@ -0,0 +1,28 @@ +/* Test THP segment load linked with -Wl,-z,separate-code. + Copyright (C) 2026 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include "tst-thp-align-check.h" + +static int +do_test (void) +{ + check_align ("tst-thp-1"); + return 0; +} + +#include diff --git a/sysdeps/unix/sysv/linux/tst-thp-align-check.h b/sysdeps/unix/sysv/linux/tst-thp-align-check.h new file mode 100644 index 0000000000..c71ac887d1 --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-thp-align-check.h @@ -0,0 +1,67 @@ +/* Test the THP compatible alignment of PT_LOAD segments. + + Copyright (C) 2026 Free Software Foundation, Inc. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static void +check_align (const char *name) +{ + unsigned long int thp_size = support_get_thp_size (); + enum thp_mode_t thp_mode = support_get_thp_mode (); + + if (thp_size == 0) + FAIL_UNSUPPORTED ("unable to get THP size.\n"); + + if (thp_size > MAX_THP_PAGESIZE) + FAIL_UNSUPPORTED ("THP size exceeds MAX_THP_PAGESIZE.\n"); + + if (thp_mode != thp_mode_always && thp_mode != thp_mode_madvise) + FAIL_UNSUPPORTED ("THP mode is not always nor madvise.\n"); + + FILE *f = xfopen ("/proc/self/maps", "r"); + char *line = NULL; + size_t len; + + while (xgetline (&line, &len, f)) + { + uintptr_t from, to; + char *prot = NULL, *path = NULL; + int r = sscanf (line, "%" SCNxPTR "-%" SCNxPTR "%ms%*s%*s%*s%ms", + &from, &to, &prot, &path); + + TEST_VERIFY (r == 3 || r == 4); + + if (path != NULL && strstr (prot, "x") && strstr (path, name)) + TEST_COMPARE (from % thp_size, 0); + + free (prot); + free (path); + } + + free (line); + xfclose (f); +} diff --git a/sysdeps/unix/sysv/linux/tst-thp-align.c b/sysdeps/unix/sysv/linux/tst-thp-align.c index 0b3f18e000..2e44109ba6 100644 --- a/sysdeps/unix/sysv/linux/tst-thp-align.c +++ b/sysdeps/unix/sysv/linux/tst-thp-align.c @@ -16,129 +16,10 @@ License along with the GNU C Library; if not, see . */ -#include -#include -#include -#include -#include -#include -#include #include -#include -#include +#include "tst-thp-align-check.h" #define THP_SIZE_MOD_NAME "tst-thp-size-mod.so" -#define MAX_THP_PAGESIZE (32 * 1024 * 1024) - -enum thp_mode_t -{ - thp_mode_always, - thp_mode_madvise, - thp_mode_never, - thp_mode_not_supported -}; - -static unsigned long int -get_thp_size (void) -{ - int fd = open ("/sys/kernel/mm/transparent_hugepage/hpage_pmd_size", - O_RDONLY, 0); - if (fd == -1) - return 0; - - char str[INT_BUFSIZE_BOUND (unsigned long int)]; - ssize_t s = read (fd, str, sizeof (str)); - close (fd); - if (s < 0) - return 0; - - unsigned long int r = 0; - for (ssize_t i = 0; i < s; i++) - { - if (str[i] == '\n') - break; - r *= 10; - r += str[i] - '0'; - } - return r; -} - -static enum thp_mode_t -get_thp_mode (void) -{ - int fd = open ("/sys/kernel/mm/transparent_hugepage/enabled", O_RDONLY, 0); - if (fd == -1) - return thp_mode_not_supported; - - static const char mode_always[] = "[always] madvise never\n"; - static const char mode_madvise[] = "always [madvise] never\n"; - static const char mode_never[] = "always madvise [never]\n"; - - char str[sizeof(mode_always)]; - ssize_t s = read (fd, str, sizeof (str)); - if (s >= sizeof str || s < 0) - return thp_mode_not_supported; - str[s] = '\0'; - close (fd); - - if (s == sizeof (mode_always) - 1) - { - if (strcmp (str, mode_always) == 0) - return thp_mode_always; - else if (strcmp (str, mode_madvise) == 0) - return thp_mode_madvise; - else if (strcmp (str, mode_never) == 0) - return thp_mode_never; - } - return thp_mode_not_supported; -} - -static void -check_align (void) -{ - unsigned long int thp_size = get_thp_size (); - enum thp_mode_t thp_mode = get_thp_mode (); - - if (thp_size == 0) - { - FAIL_UNSUPPORTED ("unable to get THP size.\n"); - return; - } - - if (thp_size > MAX_THP_PAGESIZE) - { - FAIL_UNSUPPORTED ("THP size exceeds MAX_THP_PAGESIZE.\n"); - return; - } - - if (thp_mode != thp_mode_always) - { - FAIL_UNSUPPORTED ("THP mode is not always.\n"); - return; - } - - FILE *f = xfopen ("/proc/self/maps", "r"); - char *line = NULL; - size_t len; - - while (xgetline (&line, &len, f)) - { - uintptr_t from, to; - char *prot = NULL, *path = NULL; - int r = sscanf (line, "%" SCNxPTR "-%" SCNxPTR "%ms%*s%*s%*s%ms", - &from, &to, &prot, &path); - - TEST_VERIFY (r == 3 || r == 4); - - if (strstr (prot, "x") && strstr (path, THP_SIZE_MOD_NAME)) - TEST_COMPARE (from % thp_size, 0); - - free (path); - } - - free (line); - xfclose (f); -} static int do_test (void) @@ -146,7 +27,7 @@ do_test (void) void *dl; dl = xdlopen (THP_SIZE_MOD_NAME, RTLD_NOW); - check_align (); + check_align (THP_SIZE_MOD_NAME); xdlclose (dl); return 0; diff --git a/sysdeps/unix/sysv/linux/x86_64/hugepages.h b/sysdeps/unix/sysv/linux/x86_64/hugepages.h new file mode 100644 index 0000000000..74a3833842 --- /dev/null +++ b/sysdeps/unix/sysv/linux/x86_64/hugepages.h @@ -0,0 +1,22 @@ +/* Huge Page support. Linux/x86-64 version. + Copyright (C) 2026 Free Software Foundation, Inc. + Copyright The GNU Toolchain Authors. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#define DL_MAP_DEFAULT_THP_PAGESIZE (2 * 1024 * 1024) + +#include_next