Date: Thu, 7 Apr 2022 14:38:49 GMT From: Andrew Turner <andrew@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: e85eaa930862 - main - Have rtld query the page size from the kernel Message-ID: <202204071438.237Ecn2A012737@gitrepo.freebsd.org>
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The branch main has been updated by andrew: URL: https://cgit.FreeBSD.org/src/commit/?id=e85eaa930862d5b4dc917bc31e8d7254a693635d commit e85eaa930862d5b4dc917bc31e8d7254a693635d Author: Andrew Turner <andrew@FreeBSD.org> AuthorDate: 2022-04-04 15:05:40 +0000 Commit: Andrew Turner <andrew@FreeBSD.org> CommitDate: 2022-04-07 14:37:37 +0000 Have rtld query the page size from the kernel To allow for a dynamic page size on arm64 have the runtime linker query the kernel for the currentl page size. Reviewed by: kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D34765 --- libexec/rtld-elf/map_object.c | 54 +++++++++++++++++----------------- libexec/rtld-elf/rtld-libc/rtld_libc.c | 24 ++------------- libexec/rtld-elf/rtld.c | 35 +++++++++++++++------- libexec/rtld-elf/rtld.h | 3 ++ 4 files changed, 58 insertions(+), 58 deletions(-) diff --git a/libexec/rtld-elf/map_object.c b/libexec/rtld-elf/map_object.c index 2da323c115cc..7c637fe1d6ba 100644 --- a/libexec/rtld-elf/map_object.c +++ b/libexec/rtld-elf/map_object.c @@ -49,8 +49,7 @@ int __getosreldate(void); static bool phdr_in_zero_page(const Elf_Ehdr *hdr) { - return (hdr->e_phoff + hdr->e_phnum * sizeof(Elf_Phdr) <= - (size_t)PAGE_SIZE); + return (hdr->e_phoff + hdr->e_phnum * sizeof(Elf_Phdr) <= page_size); } /* @@ -134,14 +133,15 @@ map_object(int fd, const char *path, const struct stat *sb) case PT_LOAD: segs[++nsegs] = phdr; - if ((segs[nsegs]->p_align & (PAGE_SIZE - 1)) != 0) { + if ((segs[nsegs]->p_align & (page_size - 1)) != 0) { _rtld_error("%s: PT_LOAD segment %d not page-aligned", path, nsegs); goto error; } if ((segs[nsegs]->p_flags & PF_X) == PF_X) { text_end = MAX(text_end, - round_page(segs[nsegs]->p_vaddr + segs[nsegs]->p_memsz)); + rtld_round_page(segs[nsegs]->p_vaddr + + segs[nsegs]->p_memsz)); } break; @@ -168,18 +168,18 @@ map_object(int fd, const char *path, const struct stat *sb) break; case PT_NOTE: - if (phdr->p_offset > PAGE_SIZE || - phdr->p_offset + phdr->p_filesz > PAGE_SIZE) { - note_map_len = round_page(phdr->p_offset + - phdr->p_filesz) - trunc_page(phdr->p_offset); + if (phdr->p_offset > page_size || + phdr->p_offset + phdr->p_filesz > page_size) { + note_map_len = rtld_round_page(phdr->p_offset + + phdr->p_filesz) - rtld_trunc_page(phdr->p_offset); note_map = mmap(NULL, note_map_len, PROT_READ, - MAP_PRIVATE, fd, trunc_page(phdr->p_offset)); + MAP_PRIVATE, fd, rtld_trunc_page(phdr->p_offset)); if (note_map == MAP_FAILED) { _rtld_error("%s: error mapping PT_NOTE (%d)", path, errno); goto error; } note_start = (Elf_Addr)(note_map + phdr->p_offset - - trunc_page(phdr->p_offset)); + rtld_trunc_page(phdr->p_offset)); } else { note_start = (Elf_Addr)(char *)hdr + phdr->p_offset; } @@ -203,13 +203,13 @@ map_object(int fd, const char *path, const struct stat *sb) * Map the entire address space of the object, to stake out our * contiguous region, and to establish the base address for relocation. */ - base_vaddr = trunc_page(segs[0]->p_vaddr); - base_vlimit = round_page(segs[nsegs]->p_vaddr + segs[nsegs]->p_memsz); + base_vaddr = rtld_trunc_page(segs[0]->p_vaddr); + base_vlimit = rtld_round_page(segs[nsegs]->p_vaddr + segs[nsegs]->p_memsz); mapsize = base_vlimit - base_vaddr; base_addr = (caddr_t) base_vaddr; base_flags = __getosreldate() >= P_OSREL_MAP_GUARD ? MAP_GUARD : MAP_PRIVATE | MAP_ANON | MAP_NOCORE; - if (npagesizes > 1 && round_page(segs[0]->p_filesz) >= pagesizes[1]) + if (npagesizes > 1 && rtld_round_page(segs[0]->p_filesz) >= pagesizes[1]) base_flags |= MAP_ALIGNED_SUPER; if (base_vaddr != 0) base_flags |= MAP_FIXED | MAP_EXCL; @@ -228,9 +228,9 @@ map_object(int fd, const char *path, const struct stat *sb) for (i = 0; i <= nsegs; i++) { /* Overlay the segment onto the proper region. */ - data_offset = trunc_page(segs[i]->p_offset); - data_vaddr = trunc_page(segs[i]->p_vaddr); - data_vlimit = round_page(segs[i]->p_vaddr + segs[i]->p_filesz); + data_offset = rtld_trunc_page(segs[i]->p_offset); + data_vaddr = rtld_trunc_page(segs[i]->p_vaddr); + data_vlimit = rtld_round_page(segs[i]->p_vaddr + segs[i]->p_filesz); data_addr = mapbase + (data_vaddr - base_vaddr); data_prot = convert_prot(segs[i]->p_flags); data_flags = convert_flags(segs[i]->p_flags) | MAP_FIXED; @@ -248,12 +248,12 @@ map_object(int fd, const char *path, const struct stat *sb) /* Clear any BSS in the last page of the segment. */ clear_vaddr = segs[i]->p_vaddr + segs[i]->p_filesz; clear_addr = mapbase + (clear_vaddr - base_vaddr); - clear_page = mapbase + (trunc_page(clear_vaddr) - base_vaddr); + clear_page = mapbase + (rtld_trunc_page(clear_vaddr) - base_vaddr); if ((nclear = data_vlimit - clear_vaddr) > 0) { /* Make sure the end of the segment is writable */ if ((data_prot & PROT_WRITE) == 0 && -1 == - mprotect(clear_page, PAGE_SIZE, data_prot|PROT_WRITE)) { + mprotect(clear_page, page_size, data_prot|PROT_WRITE)) { _rtld_error("%s: mprotect failed: %s", path, rtld_strerror(errno)); goto error1; @@ -263,12 +263,12 @@ map_object(int fd, const char *path, const struct stat *sb) /* Reset the data protection back */ if ((data_prot & PROT_WRITE) == 0) - mprotect(clear_page, PAGE_SIZE, data_prot); + mprotect(clear_page, page_size, data_prot); } /* Overlay the BSS segment onto the proper region. */ bss_vaddr = data_vlimit; - bss_vlimit = round_page(segs[i]->p_vaddr + segs[i]->p_memsz); + bss_vlimit = rtld_round_page(segs[i]->p_vaddr + segs[i]->p_memsz); bss_addr = mapbase + (bss_vaddr - base_vaddr); if (bss_vlimit > bss_vaddr) { /* There is something to do */ if (mmap(bss_addr, bss_vlimit - bss_vaddr, data_prot, @@ -324,14 +324,14 @@ map_object(int fd, const char *path, const struct stat *sb) obj->tlsinit = mapbase + phtls->p_vaddr; } obj->stack_flags = stack_flags; - obj->relro_page = obj->relocbase + trunc_page(relro_page); - obj->relro_size = trunc_page(relro_page + relro_size) - - trunc_page(relro_page); + obj->relro_page = obj->relocbase + rtld_trunc_page(relro_page); + obj->relro_size = rtld_trunc_page(relro_page + relro_size) - + rtld_trunc_page(relro_page); if (note_start < note_end) digest_notes(obj, note_start, note_end); if (note_map != NULL) munmap(note_map, note_map_len); - munmap(hdr, PAGE_SIZE); + munmap(hdr, page_size); return (obj); error1: @@ -341,7 +341,7 @@ error: munmap(note_map, note_map_len); if (!phdr_in_zero_page(hdr)) munmap(phdr, hdr->e_phnum * sizeof(phdr[0])); - munmap(hdr, PAGE_SIZE); + munmap(hdr, page_size); return (NULL); } @@ -391,7 +391,7 @@ get_elf_header(int fd, const char *path, const struct stat *sbp, return (NULL); } - hdr = mmap(NULL, PAGE_SIZE, PROT_READ, MAP_PRIVATE | MAP_PREFAULT_READ, + hdr = mmap(NULL, page_size, PROT_READ, MAP_PRIVATE | MAP_PREFAULT_READ, fd, 0); if (hdr == MAP_FAILED) { _rtld_error("%s: read error: %s", path, rtld_strerror(errno)); @@ -423,7 +423,7 @@ get_elf_header(int fd, const char *path, const struct stat *sbp, return (hdr); error: - munmap(hdr, PAGE_SIZE); + munmap(hdr, page_size); return (NULL); } diff --git a/libexec/rtld-elf/rtld-libc/rtld_libc.c b/libexec/rtld-elf/rtld-libc/rtld_libc.c index dfad9465f4e8..69e801191db4 100644 --- a/libexec/rtld-elf/rtld-libc/rtld_libc.c +++ b/libexec/rtld-elf/rtld-libc/rtld_libc.c @@ -98,31 +98,13 @@ __assert(const char *func, const char *file, int line, const char *failedexpr) /* * Avoid pulling in all of pthreads from getpagesize(). * It normally uses libc/gen/auxv.c which pulls in pthread_once(). + * This relies on init_pagesizes setting page_size so must not be called + * before that. */ int getpagesize(void) { - int mib[2], value; - size_t size; - static int pagesize; - - if (pagesize != 0) - return (pagesize); - - if (npagesizes > 0) - pagesize = pagesizes[0]; - - if (pagesize == 0) { - mib[0] = CTL_HW; - mib[1] = HW_PAGESIZE; - size = sizeof(value); - if (sysctl(mib, nitems(mib), &value, &size, NULL, 0) == -1) - pagesize = PAGE_SIZE; - else - pagesize = value; - } - - return (pagesize); + return (page_size); } extern int __sys___sysctl(const int *name, u_int namelen, void *oldp, diff --git a/libexec/rtld-elf/rtld.c b/libexec/rtld-elf/rtld.c index 6e499ebc5208..aa5400d29fc2 100644 --- a/libexec/rtld-elf/rtld.c +++ b/libexec/rtld-elf/rtld.c @@ -268,6 +268,7 @@ Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); int npagesizes; static int osreldate; size_t *pagesizes; +size_t page_size; static int stack_prot = PROT_READ | PROT_WRITE | RTLD_DEFAULT_STACK_EXEC; static int max_stack_flags; @@ -477,6 +478,18 @@ set_ld_elf_hints_path(void) ld_elf_hints_path = ld_elf_hints_default; } +uintptr_t +rtld_round_page(uintptr_t x) +{ + return (roundup2(x, page_size)); +} + +uintptr_t +rtld_trunc_page(uintptr_t x) +{ + return (rounddown2(x, page_size)); +} + /* * Main entry point for dynamic linking. The first argument is the * stack pointer. The stack is expected to be laid out as described @@ -1647,10 +1660,10 @@ digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) case PT_LOAD: if (nsegs == 0) { /* First load segment */ - obj->vaddrbase = trunc_page(ph->p_vaddr); + obj->vaddrbase = rtld_trunc_page(ph->p_vaddr); obj->mapbase = obj->vaddrbase + obj->relocbase; } else { /* Last load segment */ - obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - + obj->mapsize = rtld_round_page(ph->p_vaddr + ph->p_memsz) - obj->vaddrbase; } nsegs++; @@ -1674,9 +1687,9 @@ digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) break; case PT_GNU_RELRO: - obj->relro_page = obj->relocbase + trunc_page(ph->p_vaddr); - obj->relro_size = trunc_page(ph->p_vaddr + ph->p_memsz) - - trunc_page(ph->p_vaddr); + obj->relro_page = obj->relocbase + rtld_trunc_page(ph->p_vaddr); + obj->relro_size = rtld_trunc_page(ph->p_vaddr + ph->p_memsz) - + rtld_trunc_page(ph->p_vaddr); break; case PT_NOTE: @@ -2325,8 +2338,8 @@ parse_rtld_phdr(Obj_Entry *obj) break; case PT_GNU_RELRO: obj->relro_page = obj->relocbase + - trunc_page(ph->p_vaddr); - obj->relro_size = round_page(ph->p_memsz); + rtld_trunc_page(ph->p_vaddr); + obj->relro_size = rtld_round_page(ph->p_memsz); break; case PT_NOTE: note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; @@ -2455,6 +2468,8 @@ psa_filled: /* Discard any invalid entries at the end of the array. */ while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) npagesizes--; + + page_size = pagesizes[0]; } /* @@ -3208,9 +3223,9 @@ reloc_textrel_prot(Obj_Entry *obj, bool before) l--, ph++) { if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) continue; - base = obj->relocbase + trunc_page(ph->p_vaddr); - sz = round_page(ph->p_vaddr + ph->p_filesz) - - trunc_page(ph->p_vaddr); + base = obj->relocbase + rtld_trunc_page(ph->p_vaddr); + sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) - + rtld_trunc_page(ph->p_vaddr); prot = before ? (PROT_READ | PROT_WRITE) : convert_prot(ph->p_flags); if (mprotect(base, sz, prot) == -1) { diff --git a/libexec/rtld-elf/rtld.h b/libexec/rtld-elf/rtld.h index cbdbd29f2aa9..807437af5ff3 100644 --- a/libexec/rtld-elf/rtld.h +++ b/libexec/rtld-elf/rtld.h @@ -55,6 +55,7 @@ extern int tls_max_index; extern int npagesizes; extern size_t *pagesizes; +extern size_t page_size; extern int main_argc; extern char **main_argv; @@ -376,6 +377,8 @@ void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long); /* * Function declarations. */ +uintptr_t rtld_round_page(uintptr_t); +uintptr_t rtld_trunc_page(uintptr_t); unsigned long elf_hash(const char *); const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *);
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