linker: Add PAGE_START/OFFSET/END convenience macros
This patch adds a few macros related to memory pages to help
clarify some of the code in linker.c
Change-Id: I36c727132d257b1497398dd0a9e8a5a4505467ca
diff --git a/linker/linker.c b/linker/linker.c
index 1dd1d09..93819e4 100644
--- a/linker/linker.c
+++ b/linker/linker.c
@@ -768,10 +768,10 @@
}
/* truncate min_vaddr down to page boundary */
- min_vaddr &= ~PAGE_MASK;
+ min_vaddr = PAGE_START(min_vaddr);
/* round max_vaddr up to the next page */
- max_vaddr = (max_vaddr + PAGE_SIZE - 1) & ~PAGE_MASK;
+ max_vaddr = PAGE_END(max_vaddr);
*total_sz = (max_vaddr - min_vaddr);
return (unsigned)req_base;
@@ -892,7 +892,7 @@
* header table appear in ascending order, sorted on the
* p_vaddr member."
*/
- si->load_offset = phdr->p_vaddr & (~PAGE_MASK);
+ si->load_offset = PAGE_START(phdr->p_vaddr);
break;
}
}
@@ -907,16 +907,16 @@
if (phdr->p_type == PT_LOAD) {
DEBUG_DUMP_PHDR(phdr, "PT_LOAD", pid);
/* we want to map in the segment on a page boundary */
- tmp = base + (phdr->p_vaddr & (~PAGE_MASK));
+ tmp = base + PAGE_START(phdr->p_vaddr);
/* add the # of bytes we masked off above to the total length. */
- len = phdr->p_filesz + (phdr->p_vaddr & PAGE_MASK);
+ len = phdr->p_filesz + PAGE_OFFSET(phdr->p_vaddr);
TRACE("[ %d - Trying to load segment from '%s' @ 0x%08x "
"(0x%08x). p_vaddr=0x%08x p_offset=0x%08x ]\n", pid, si->name,
(unsigned)tmp, len, phdr->p_vaddr, phdr->p_offset);
pbase = mmap((void *)tmp, len, PFLAGS_TO_PROT(phdr->p_flags),
MAP_PRIVATE | MAP_FIXED, fd,
- phdr->p_offset & (~PAGE_MASK));
+ PAGE_START(phdr->p_offset));
if (pbase == MAP_FAILED) {
DL_ERR("%d failed to map segment from '%s' @ 0x%08x (0x%08x). "
"p_vaddr=0x%08x p_offset=0x%08x", pid, si->name,
@@ -926,8 +926,8 @@
/* If 'len' didn't end on page boundary, and it's a writable
* segment, zero-fill the rest. */
- if ((len & PAGE_MASK) && (phdr->p_flags & PF_W))
- memset((void *)(pbase + len), 0, PAGE_SIZE - (len & PAGE_MASK));
+ if (PAGE_OFFSET(len) > 0 && (phdr->p_flags & PF_W) != 0)
+ memset((void *)(pbase + len), 0, PAGE_SIZE - PAGE_OFFSET(len));
/* Check to see if we need to extend the map for this segment to
* cover the diff between filesz and memsz (i.e. for bss).
@@ -956,8 +956,7 @@
* | |
* _+---------------------+ page boundary
*/
- tmp = (Elf32_Addr)(((unsigned)pbase + len + PAGE_SIZE - 1) &
- (~PAGE_MASK));
+ tmp = (Elf32_Addr)PAGE_END((unsigned)pbase + len);
if (tmp < (base + phdr->p_vaddr + phdr->p_memsz)) {
extra_len = base + phdr->p_vaddr + phdr->p_memsz - tmp;
TRACE("[ %5d - Need to extend segment from '%s' @ 0x%08x "
@@ -988,8 +987,7 @@
}
/* set the len here to show the full extent of the segment we
* just loaded, mostly for debugging */
- len = (((unsigned)base + phdr->p_vaddr + phdr->p_memsz +
- PAGE_SIZE - 1) & (~PAGE_MASK)) - (unsigned)pbase;
+ len = PAGE_END((unsigned)base + phdr->p_vaddr + phdr->p_memsz) - (unsigned)pbase;
TRACE("[ %5d - Successfully loaded segment from '%s' @ 0x%08x "
"(0x%08x). p_vaddr=0x%08x p_offset=0x%08x\n", pid, si->name,
(unsigned)pbase, len, phdr->p_vaddr, phdr->p_offset);
@@ -1051,7 +1049,7 @@
* vaddr p_vaddr p_offset
* ----- ------------ --------
* base 0
- * si->base phdr0->p_vaddr & ~PAGE_MASK
+ * si->base PAGE_START(phdr0->p_vaddr)
* phdr0->p_vaddr phdr0->p_offset
* phdr ehdr->e_phoff
*/
@@ -1091,7 +1089,7 @@
unsigned wr_offset = 0xffffffff;
shdr_start = mmap(0, shdr_sz, PROT_READ, MAP_PRIVATE, fd,
- ehdr->e_shoff & (~PAGE_MASK));
+ PAGE_START(ehdr->e_shoff));
if (shdr_start == MAP_FAILED) {
WARN("%5d - Could not read section header info from '%s'. Will not "
"not be able to determine write-protect offset.\n", pid, name);
@@ -1264,7 +1262,7 @@
* in soinfo_link_image. This is needed to undo the DT_NEEDED hack below.
*/
if ((si->gnu_relro_start != 0) && (si->gnu_relro_len != 0)) {
- Elf32_Addr start = (si->gnu_relro_start & ~PAGE_MASK);
+ Elf32_Addr start = PAGE_START(si->gnu_relro_start);
unsigned len = (si->gnu_relro_start - start) + si->gnu_relro_len;
if (mprotect((void *) start, len, PROT_READ | PROT_WRITE) < 0)
DL_ERR("%5d %s: could not undo GNU_RELRO protections. "
@@ -1756,8 +1754,7 @@
if (base + phdr->p_vaddr < si->wrprotect_start)
si->wrprotect_start = base + phdr->p_vaddr;
- _end = (((base + phdr->p_vaddr + phdr->p_memsz + PAGE_SIZE - 1) &
- (~PAGE_MASK)));
+ _end = PAGE_END(base + phdr->p_vaddr + phdr->p_memsz);
if (_end > si->wrprotect_end)
si->wrprotect_end = _end;
/* Make the section writable just in case we'll have to
@@ -1980,7 +1977,7 @@
#endif
if (si->gnu_relro_start != 0 && si->gnu_relro_len != 0) {
- Elf32_Addr start = (si->gnu_relro_start & ~PAGE_MASK);
+ Elf32_Addr start = PAGE_START(si->gnu_relro_start);
unsigned len = (si->gnu_relro_start - start) + si->gnu_relro_len;
if (mprotect((void *) start, len, PROT_READ) < 0) {
DL_ERR("%5d GNU_RELRO mprotect of library '%s' failed: %d (%s)\n",
