diff options
Diffstat (limited to 'rts/linker/MachO.c')
| -rw-r--r-- | rts/linker/MachO.c | 158 |
1 files changed, 9 insertions, 149 deletions
diff --git a/rts/linker/MachO.c b/rts/linker/MachO.c index 3da4f690f2..5ae7620fc7 100644 --- a/rts/linker/MachO.c +++ b/rts/linker/MachO.c @@ -2,10 +2,6 @@ #if defined(darwin_HOST_OS) || defined(ios_HOST_OS) -#if defined(ios_HOST_OS) && !RTS_LINKER_USE_MMAP -#error "ios must use mmap and mprotect!" -#endif - /* for roundUpToPage */ #include "sm/OSMem.h" @@ -80,13 +76,6 @@ bool makeGot(ObjectCode * oc); void freeGot(ObjectCode * oc); #endif /* aarch64_HOST_ARCH */ -#if defined(ios_HOST_OS) -/* on iOS we need to ensure we only have r+w or r+x pages hence we need to mmap - * pages r+w and r+x mprotect them later on. - */ -bool ocMprotect_MachO( ObjectCode *oc ); -#endif /* ios_HOST_OS */ - /* * Initialize some common data in the object code so we don't have to * continuously look up the addresses. @@ -1016,25 +1005,6 @@ relocateSection(ObjectCode* oc, int curSection) } #endif /* x86_64_HOST_ARCH */ -/* Note [mmap r+w+x] - * ~~~~~~~~~~~~~~~~~ - * - * iOS does not permit to mmap r+w+x, hence wo only mmap r+w, and later change - * to r+x via mprotect. While this could would be nice to have for all hosts - * and not just for iOS, it entail that the rest of the linker code supports - * that, this includes: - * - * - mmap and mprotect need to be available. - * - text and data sections need to be mapped into different pages. Ideally - * the text and data sections would be aggregated, to prevent using a single - * page for every section, however tiny. - * - the relocation code for each object file format / architecture, needs to - * respect the (now) non-contiguousness of the sections. - * - with sections being mapped potentially far apart from each other, it must - * be made sure that the pages are reachable within the architectures - * addressability for relative or absolute access. - */ - SectionKind getSectionKind_MachO(MachOSection *section) { @@ -1235,107 +1205,6 @@ ocGetNames_MachO(ObjectCode* oc) IF_DEBUG(linker, debugBelch("ocGetNames_MachO: will load %d sections\n", oc->n_sections)); -#if defined(ios_HOST_OS) - for(int i=0; i < oc->n_sections; i++) - { - MachOSection * section = &oc->info->macho_sections[i]; - - IF_DEBUG(linker, debugBelch("ocGetNames_MachO: section %d\n", i)); - - if (section->size == 0) { - IF_DEBUG(linker, debugBelch("ocGetNames_MachO: found a zero length section, skipping\n")); - continue; - } - - SectionKind kind = getSectionKind_MachO(section); - - switch(section->flags & SECTION_TYPE) { - case S_ZEROFILL: - case S_GB_ZEROFILL: { - // See Note [mmap r+w+x] - void * mem = mmap(NULL, section->size, - PROT_READ | PROT_WRITE, - MAP_ANON | MAP_PRIVATE, - -1, 0); - if( mem == MAP_FAILED ) { - barf("failed to mmap allocate memory for zerofill section %d of size %d. errno = %d", - i, section->size, errno); - } - addSection(&secArray[i], kind, SECTION_MMAP, mem, section->size, - 0, mem, roundUpToPage(section->size)); - addProddableBlock(oc, mem, (int)section->size); - - secArray[i].info->nstubs = 0; - secArray[i].info->stub_offset = NULL; - secArray[i].info->stub_size = 0; - secArray[i].info->stubs = NULL; - - secArray[i].info->macho_section = section; - secArray[i].info->relocation_info - = (MachORelocationInfo*)(oc->image + section->reloff); - break; - } - default: { - // The secion should have a non-zero offset. As the offset is - // relativ to the image, and must be somewhere after the header. - if(section->offset == 0) barf("section with zero offset!"); - /* on iOS, we must allocate the code in r+x sections and - * the data in r+w sections, as the system does not allow - * for r+w+x, we must allocate each section in a new page - * range. - * - * copy the sections's memory to some page-aligned place via - * mmap and memcpy. This will later allow us to selectively - * use mprotect on pages with data (r+w) and pages text (r+x). - * We initially start with r+w, so that we can modify the - * pages during relocations, prior to setting it r+x. - */ - - /* We also need space for stubs. As pages can be assigned - * randomly in the addressable space, we need to keep the - * stubs close to the section. The strategy we are going - * to use is to allocate them right after the section. And - * we are going to be generous and allocare a stub slot - * for each relocation to keep it simple. - */ - size_t n_ext_sec_sym = section->nreloc; /* number of relocations - * for this section. Should - * be a good upper bound - */ - size_t stub_space = /* eight bytes for the 64 bit address, - * and another eight bytes for the two - * instructions (ldr, br) for each relocation. - */ 16 * n_ext_sec_sym; - // See Note [mmap r+w+x] - void * mem = mmap(NULL, section->size+stub_space, - PROT_READ | PROT_WRITE, - MAP_ANON | MAP_PRIVATE, - -1, 0); - if( mem == MAP_FAILED ) { - barf("failed to mmap allocate memory to load section %d. errno = %d", i, errno ); - } - memcpy( mem, oc->image + section->offset, section->size); - - addSection(&secArray[i], kind, SECTION_MMAP, - mem, section->size, - 0, mem, roundUpToPage(section->size+stub_space)); - addProddableBlock(oc, mem, (int)section->size); - - secArray[i].info->nstubs = 0; - secArray[i].info->stub_offset = ((uint8_t*)mem) + section->size; - secArray[i].info->stub_size = stub_space; - secArray[i].info->stubs = NULL; - - secArray[i].info->macho_section = section; - secArray[i].info->relocation_info - = (MachORelocationInfo*)(oc->image + section->reloff); - break; - } - } - } -#else /* !ios_HOST_OS */ - IF_DEBUG(linker, debugBelch("ocGetNames_MachO: building segments\n")); - CHECKM(ocBuildSegments_MachO(oc), "ocGetNames_MachO: failed to build segments\n"); for (int seg_n = 0; seg_n < oc->n_segments; seg_n++) { @@ -1399,7 +1268,6 @@ ocGetNames_MachO(ObjectCode* oc) } } -#endif /* now, as all sections have been loaded, we can resolve the absolute * address of symbols defined in those sections. @@ -1564,25 +1432,19 @@ ocGetNames_MachO(ObjectCode* oc) return 1; } -#if defined(ios_HOST_OS) -bool -ocMprotect_MachO( ObjectCode *oc ) { - for(int i=0; i < oc->n_sections; i++) { - Section * section = &oc->sections[i]; - if(section->size == 0) continue; - if( (section->info->macho_section->flags & SECTION_ATTRIBUTES_USR) - == S_ATTR_PURE_INSTRUCTIONS) { - if( 0 != mprotect(section->start, - section->size + section->info->stub_size, - PROT_READ | PROT_EXEC) ) { - barf("mprotect failed! errno = %d", errno); - return false; - } +static bool +ocMprotect_MachO( ObjectCode *oc ) +{ + for(int i=0; i < oc->n_segments; i++) { + Segment *segment = &oc->segments[i]; + if(segment->size == 0) continue; + + if(segment->prot == SEGMENT_PROT_RX) { + mmapForLinkerMarkExecutable(segment->start, segment->size); } } return true; } -#endif int ocResolve_MachO(ObjectCode* oc) @@ -1668,10 +1530,8 @@ ocResolve_MachO(ObjectCode* oc) return 0; #endif } -#if defined(ios_HOST_OS) if(!ocMprotect_MachO ( oc )) return 0; -#endif return 1; } |