Index: head/lib/libc/gen/tls.c =================================================================== --- head/lib/libc/gen/tls.c (revision 326793) +++ head/lib/libc/gen/tls.c (revision 326794) @@ -1,377 +1,473 @@ /*- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD * * Copyright (c) 2004 Doug Rabson * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD$ */ /* * Define stubs for TLS internals so that programs and libraries can * link. These functions will be replaced by functional versions at * runtime from ld-elf.so.1. */ #include #include #include #include #include #include #include "libc_private.h" #define tls_assert(cond) ((cond) ? (void) 0 : \ (tls_msg(#cond ": assert failed: " __FILE__ ":" \ __XSTRING(__LINE__) "\n"), abort())) #define tls_msg(s) write(STDOUT_FILENO, s, strlen(s)) /* Provided by jemalloc to avoid bootstrapping issues. */ void *__je_bootstrap_malloc(size_t size); void *__je_bootstrap_calloc(size_t num, size_t size); void __je_bootstrap_free(void *ptr); __weak_reference(__libc_allocate_tls, _rtld_allocate_tls); __weak_reference(__libc_free_tls, _rtld_free_tls); #ifdef __i386__ __weak_reference(___libc_tls_get_addr, ___tls_get_addr); __attribute__((__regparm__(1))) void * ___libc_tls_get_addr(void *); #endif void * __libc_tls_get_addr(void *); __weak_reference(__libc_tls_get_addr, __tls_get_addr); void *_rtld_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign); void _rtld_free_tls(void *tls, size_t tcbsize, size_t tcbalign); void *__libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign); void __libc_free_tls(void *tls, size_t tcbsize, size_t tcbalign); #if defined(__amd64__) #define TLS_TCB_ALIGN 16 #elif defined(__aarch64__) || defined(__arm__) || defined(__i386__) || \ defined(__mips__) || defined(__powerpc__) || defined(__riscv) || \ defined(__sparc64__) #define TLS_TCB_ALIGN sizeof(void *) #else #error TLS_TCB_ALIGN undefined for target architecture #endif #if defined(__aarch64__) || defined(__arm__) || defined(__mips__) || \ defined(__powerpc__) || defined(__riscv) #define TLS_VARIANT_I #endif #if defined(__i386__) || defined(__amd64__) || defined(__sparc64__) #define TLS_VARIANT_II #endif +#if defined(__mips__) || defined(__powerpc__) || defined(__riscv) +#define DTV_OFFSET 0x8000 +#else +#define DTV_OFFSET 0 +#endif + #ifndef PIC static size_t tls_static_space; static size_t tls_init_size; static size_t tls_init_align; static void *tls_init; #endif #ifdef __i386__ /* GNU ABI */ __attribute__((__regparm__(1))) void * ___libc_tls_get_addr(void *ti __unused) { return (0); } #endif void * __libc_tls_get_addr(void *ti __unused) { return (0); } #ifndef PIC static void * malloc_aligned(size_t size, size_t align) { void *mem, *res; if (align < sizeof(void *)) align = sizeof(void *); mem = __je_bootstrap_malloc(size + sizeof(void *) + align - 1); res = (void *)roundup2((uintptr_t)mem + sizeof(void *), align); *(void **)((uintptr_t)res - sizeof(void *)) = mem; return (res); } static void free_aligned(void *ptr) { void *mem; uintptr_t x; if (ptr == NULL) return; x = (uintptr_t)ptr; x -= sizeof(void *); mem = *(void **)x; __je_bootstrap_free(mem); } #ifdef TLS_VARIANT_I +/* + * There are two versions of variant I of TLS + * + * - ARM and aarch64 uses original variant I as is described in [1] and [2], + * where TP points to start of TCB followed by aligned TLS segment. + * Both TCB and TLS must be aligned to alignment of TLS section. The TCB[0] + * points to DTV vector and DTV values are real addresses (without bias). + * Note: for Local Exec TLS Model, the offsets from TP (TCB in this case) to + * TLS variables are computed by linker, so we cannot overalign TLS section. + * + * - MIPS, PowerPC and RISC-V use modified version of variant I, + * described in [3] where TP points (with bias) to TLS and TCB immediately + * precedes TLS without any alignment gap[4]. Only TLS should be aligned. + * The TCB[0] points to DTV vector and DTV values are biased by constant + * value (0x8000) from real addresses[5]. + * + * [1] Ulrich Drepper: ELF Handling for Thread-Local Storage + * www.akkadia.org/drepper/tls.pdf + * + * [2] ARM IHI 0045E: Addenda to, and Errata in, the ABI for the ARM(r) + * Architecture + * infocenter.arm.com/help/topic/com.arm.doc.ihi0045e/IHI0045E_ABI_addenda.pdf + * + * [3] OpenPOWER: Power Architecture 64-Bit ELF V2 ABI Specification + * https://members.openpowerfoundation.org/document/dl/576 + * + * [4] Its unclear if "without any alignment gap" is hard ABI requirement, + * but we must follow this rule due to suboptimal _set_tp() + * (aka _SET_TP) implementation. This function doesn't expect TP but + * TCB as argument. + * + * [5] I'm not able to validate "values are biased" assertions. + */ + #define TLS_TCB_SIZE (2 * sizeof(void *)) /* - * Free Static TLS using the Variant I method. + * Return pointer to allocated TLS block */ +static void * +get_tls_block_ptr(void *tcb, size_t tcbsize) +{ + size_t extra_size, post_size, pre_size, tls_block_size; + + /* Compute fragments sizes. */ + extra_size = tcbsize - TLS_TCB_SIZE; +#if defined(__aarch64__) || defined(__arm__) + post_size = roundup2(TLS_TCB_SIZE, tls_init_align) - TLS_TCB_SIZE; +#else + post_size = 0; +#endif + tls_block_size = tcbsize + post_size; + pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; + + return ((char *)tcb - pre_size - extra_size); +} + +/* + * Free Static TLS using the Variant I method. The tcbsize + * and tcbalign parameters must be the same as those used to allocate + * the block. + */ void -__libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign __unused) +__libc_free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) { Elf_Addr *dtv; Elf_Addr **tls; tls = (Elf_Addr **)tcb; dtv = tls[0]; __je_bootstrap_free(dtv); - free_aligned(tls); + free_aligned(get_tls_block_ptr(tcb, tcbsize)); } /* * Allocate Static TLS using the Variant I method. + * + * To handle all above requirements, we setup the following layout for + * TLS block: + * (whole memory block is aligned with MAX(TLS_TCB_ALIGN, tls_init_align)) + * + * +----------+--------------+--------------+-----------+------------------+ + * | pre gap | extended TCB | TCB | post gap | TLS segment | + * | pre_size | extra_size | TLS_TCB_SIZE | post_size | tls_static_space | + * +----------+--------------+--------------+-----------+------------------+ + * + * where: + * extra_size is tcbsize - TLS_TCB_SIZE + * post_size is used to adjust TCB to TLS aligment for first version of TLS + * layout and is always 0 for second version. + * pre_size is used to adjust TCB aligment for first version and to adjust + * TLS alignment for second version. + * */ void * __libc_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign) { - Elf_Addr *dtv; - Elf_Addr **tls; + Elf_Addr *dtv, **tcb; + char *tls_block, *tls; + size_t extra_size, maxalign, post_size, pre_size, tls_block_size; if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) return (oldtcb); tls_assert(tcbalign >= TLS_TCB_ALIGN); - tls_assert(tcbsize == TLS_TCB_SIZE); + maxalign = MAX(tcbalign, tls_init_align); - tcbsize = roundup2(tcbsize, tcbalign); - tls = malloc_aligned(tcbsize + tls_static_space, tcbalign); - if (tls == NULL) { + /* Compute fragmets sizes. */ + extra_size = tcbsize - TLS_TCB_SIZE; +#if defined(__aarch64__) || defined(__arm__) + post_size = roundup2(TLS_TCB_SIZE, tls_init_align) - TLS_TCB_SIZE; +#else + post_size = 0; +#endif + tls_block_size = tcbsize + post_size; + pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; + tls_block_size += pre_size + tls_static_space; + + /* Allocate whole TLS block */ + tls_block = malloc_aligned(tls_block_size, maxalign); + if (tls_block == NULL) { tls_msg("__libc_allocate_tls: Out of memory.\n"); abort(); } - memset(tls, 0, tcbsize + tls_static_space); + memset(tls_block, 0, tls_block_size); + tcb = (Elf_Addr **)(tls_block + pre_size + extra_size); + tls = (char *)tcb + TLS_TCB_SIZE + post_size; if (oldtcb != NULL) { - memcpy(tls, oldtcb, tcbsize + tls_static_space); - __je_bootstrap_free(oldtcb); + memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), + tls_block_size); + free_aligned(oldtcb); /* Adjust the DTV. */ - dtv = tls[0]; - dtv[2] = (Elf_Addr)tls + tcbsize; + dtv = tcb[0]; + dtv[2] = (Elf_Addr)(tls + DTV_OFFSET); } else { dtv = __je_bootstrap_malloc(3 * sizeof(Elf_Addr)); if (dtv == NULL) { tls_msg("__libc_allocate_tls: Out of memory.\n"); abort(); } - tls[0] = dtv; + /* Build the DTV. */ + tcb[0] = dtv; dtv[0] = 1; /* Generation. */ dtv[1] = 1; /* Segments count. */ - dtv[2] = (Elf_Addr)tls + tcbsize; + dtv[2] = (Elf_Addr)(tls + DTV_OFFSET); if (tls_init_size > 0) - memcpy((void*)dtv[2], tls_init, tls_init_size); + memcpy(tls, tls_init, tls_init_size); } - return (tls); + return (tcb); } #endif #ifdef TLS_VARIANT_II #define TLS_TCB_SIZE (3 * sizeof(Elf_Addr)) /* * Free Static TLS using the Variant II method. */ void __libc_free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign) { size_t size; Elf_Addr* dtv; Elf_Addr tlsstart, tlsend; /* * Figure out the size of the initial TLS block so that we can * find stuff which ___tls_get_addr() allocated dynamically. */ + tcbalign = MAX(tcbalign, tls_init_align); size = roundup2(tls_static_space, tcbalign); dtv = ((Elf_Addr**)tcb)[1]; tlsend = (Elf_Addr) tcb; tlsstart = tlsend - size; free_aligned((void*)tlsstart); __je_bootstrap_free(dtv); } /* * Allocate Static TLS using the Variant II method. */ void * __libc_allocate_tls(void *oldtls, size_t tcbsize, size_t tcbalign) { size_t size; char *tls; Elf_Addr *dtv; Elf_Addr segbase, oldsegbase; + tcbalign = MAX(tcbalign, tls_init_align); size = roundup2(tls_static_space, tcbalign); if (tcbsize < 2 * sizeof(Elf_Addr)) tcbsize = 2 * sizeof(Elf_Addr); tls = malloc_aligned(size + tcbsize, tcbalign); if (tls == NULL) { tls_msg("__libc_allocate_tls: Out of memory.\n"); abort(); } memset(tls, 0, size + tcbsize); dtv = __je_bootstrap_malloc(3 * sizeof(Elf_Addr)); if (dtv == NULL) { tls_msg("__libc_allocate_tls: Out of memory.\n"); abort(); } segbase = (Elf_Addr)(tls + size); ((Elf_Addr*)segbase)[0] = segbase; ((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv; dtv[0] = 1; dtv[1] = 1; dtv[2] = segbase - tls_static_space; if (oldtls) { /* * Copy the static TLS block over whole. */ oldsegbase = (Elf_Addr) oldtls; memcpy((void *)(segbase - tls_static_space), (const void *)(oldsegbase - tls_static_space), tls_static_space); /* * We assume that this block was the one we created with * allocate_initial_tls(). */ _rtld_free_tls(oldtls, 2*sizeof(Elf_Addr), sizeof(Elf_Addr)); } else { memcpy((void *)(segbase - tls_static_space), tls_init, tls_init_size); memset((void *)(segbase - tls_static_space + tls_init_size), 0, tls_static_space - tls_init_size); } return (void*) segbase; } #endif /* TLS_VARIANT_II */ #else void * __libc_allocate_tls(void *oldtls __unused, size_t tcbsize __unused, size_t tcbalign __unused) { return (0); } void __libc_free_tls(void *tcb __unused, size_t tcbsize __unused, size_t tcbalign __unused) { } #endif /* PIC */ extern char **environ; void _init_tls(void) { #ifndef PIC Elf_Addr *sp; Elf_Auxinfo *aux, *auxp; Elf_Phdr *phdr; size_t phent, phnum; int i; void *tls; sp = (Elf_Addr *) environ; while (*sp++ != 0) ; aux = (Elf_Auxinfo *) sp; phdr = NULL; phent = phnum = 0; for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { switch (auxp->a_type) { case AT_PHDR: phdr = auxp->a_un.a_ptr; break; case AT_PHENT: phent = auxp->a_un.a_val; break; case AT_PHNUM: phnum = auxp->a_un.a_val; break; } } if (phdr == NULL || phent != sizeof(Elf_Phdr) || phnum == 0) return; for (i = 0; (unsigned) i < phnum; i++) { if (phdr[i].p_type == PT_TLS) { tls_static_space = roundup2(phdr[i].p_memsz, phdr[i].p_align); tls_init_size = phdr[i].p_filesz; tls_init_align = phdr[i].p_align; tls_init = (void*) phdr[i].p_vaddr; break; } } - - tls = _rtld_allocate_tls(NULL, TLS_TCB_SIZE, - MAX(TLS_TCB_ALIGN, tls_init_align)); + tls = _rtld_allocate_tls(NULL, TLS_TCB_SIZE, TLS_TCB_ALIGN); _set_tp(tls); #endif }