Merge "linker: Set VMA name for bss sections"
am: a40a1442a8
Change-Id: I0f4c3458f6e8d76311b3e691581755191011822b
diff --git a/linker/linker_main.cpp b/linker/linker_main.cpp
index 11d3d29..fd1592d 100644
--- a/linker/linker_main.cpp
+++ b/linker/linker_main.cpp
@@ -63,6 +63,8 @@
static void get_elf_base_from_phdr(const ElfW(Phdr)* phdr_table, size_t phdr_count,
ElfW(Addr)* base, ElfW(Addr)* load_bias);
+static void set_bss_vma_name(soinfo* si);
+
// These should be preserved static to avoid emitting
// RELATIVE relocations for the part of the code running
// before linker links itself.
@@ -366,6 +368,8 @@
si->set_main_executable();
init_link_map_head(*si);
+ set_bss_vma_name(si);
+
// Use the executable's PT_INTERP string as the solinker filename in the
// dynamic linker's module list. gdb reads both PT_INTERP and the module list,
// and if the paths for the linker are different, gdb will report that the
@@ -570,6 +574,31 @@
async_safe_fatal("Could not find a PHDR: broken executable?");
}
+/*
+ * Set anonymous VMA name for .bss section. For DSOs loaded by the linker, this
+ * is done by ElfReader. This function is here for DSOs loaded by the kernel,
+ * namely the linker itself and the main executable.
+ */
+static void set_bss_vma_name(soinfo* si) {
+ for (size_t i = 0; i < si->phnum; ++i) {
+ auto phdr = &si->phdr[i];
+
+ if (phdr->p_type != PT_LOAD) {
+ continue;
+ }
+
+ ElfW(Addr) seg_start = phdr->p_vaddr + si->load_bias;
+ ElfW(Addr) seg_page_end = PAGE_END(seg_start + phdr->p_memsz);
+ ElfW(Addr) seg_file_end = PAGE_END(seg_start + phdr->p_filesz);
+
+ if (seg_page_end > seg_file_end) {
+ prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME,
+ reinterpret_cast<void*>(seg_file_end), seg_page_end - seg_file_end,
+ ".bss");
+ }
+ }
+}
+
// Detect an attempt to run the linker on itself. e.g.:
// /system/bin/linker64 /system/bin/linker64
// Use priority-1 to run this constructor before other constructors.
@@ -660,6 +689,9 @@
// couldn't make system calls on x86 at that point, but we can now...
if (!tmp_linker_so.protect_relro()) __linker_cannot_link(args.argv[0]);
+ // And we can set VMA name for the bss section now
+ set_bss_vma_name(&tmp_linker_so);
+
// Initialize the linker's static libc's globals
__libc_init_globals();