Revert "Re-land linker support for MTE globals"
Revert submission 3236258
Reason for revert: b/374452952
Reverted changes: /q/submissionid:3236258
(cherry picked from https://android-review.googlesource.com/q/commit:272c2e3c637381c31c9f46a8f4acecea0c34b191)
Merged-In: I98d6d0d9a424c0d54fd148829ece8d6de6f2e121
Change-Id: I98d6d0d9a424c0d54fd148829ece8d6de6f2e121
Staged CLs so I don't have to wait for merges before I CP
diff --git a/libc/bionic/__libc_init_main_thread.cpp b/libc/bionic/__libc_init_main_thread.cpp
index 0d557f1..1b539f2 100644
--- a/libc/bionic/__libc_init_main_thread.cpp
+++ b/libc/bionic/__libc_init_main_thread.cpp
@@ -44,7 +44,7 @@
// Declared in "private/bionic_ssp.h".
uintptr_t __stack_chk_guard = 0;
-BIONIC_USED_BEFORE_LINKER_RELOCATES static pthread_internal_t main_thread;
+static pthread_internal_t main_thread;
// Setup for the main thread. For dynamic executables, this is called by the
// linker _before_ libc is mapped in memory. This means that all writes to
diff --git a/libc/bionic/bionic_call_ifunc_resolver.cpp b/libc/bionic/bionic_call_ifunc_resolver.cpp
index d5a812c..e44d998 100644
--- a/libc/bionic/bionic_call_ifunc_resolver.cpp
+++ b/libc/bionic/bionic_call_ifunc_resolver.cpp
@@ -31,7 +31,6 @@
#include <sys/hwprobe.h>
#include <sys/ifunc.h>
-#include "bionic/macros.h"
#include "private/bionic_auxv.h"
// This code is called in the linker before it has been relocated, so minimize calls into other
@@ -41,8 +40,8 @@
ElfW(Addr) __bionic_call_ifunc_resolver(ElfW(Addr) resolver_addr) {
#if defined(__aarch64__)
typedef ElfW(Addr) (*ifunc_resolver_t)(uint64_t, __ifunc_arg_t*);
- BIONIC_USED_BEFORE_LINKER_RELOCATES static __ifunc_arg_t arg;
- BIONIC_USED_BEFORE_LINKER_RELOCATES static bool initialized = false;
+ static __ifunc_arg_t arg;
+ static bool initialized = false;
if (!initialized) {
initialized = true;
arg._size = sizeof(__ifunc_arg_t);
diff --git a/libc/bionic/libc_init_static.cpp b/libc/bionic/libc_init_static.cpp
index ae86da1..7c46113 100644
--- a/libc/bionic/libc_init_static.cpp
+++ b/libc/bionic/libc_init_static.cpp
@@ -344,12 +344,19 @@
// This function is called from the linker before the main executable is relocated.
__attribute__((no_sanitize("hwaddress", "memtag"))) void __libc_init_mte(
const memtag_dynamic_entries_t* memtag_dynamic_entries, const void* phdr_start, size_t phdr_ct,
- uintptr_t load_bias) {
+ uintptr_t load_bias, void* stack_top) {
bool memtag_stack = false;
HeapTaggingLevel level =
__get_tagging_level(memtag_dynamic_entries, phdr_start, phdr_ct, load_bias, &memtag_stack);
- __libc_shared_globals()->initial_memtag_stack = memtag_stack;
-
+ // initial_memtag_stack is used by the linker (in linker.cpp) to communicate than any library
+ // linked by this executable enables memtag-stack.
+ // memtag_stack is also set for static executables if they request memtag stack via the note,
+ // in which case it will differ from initial_memtag_stack.
+ if (__libc_shared_globals()->initial_memtag_stack || memtag_stack) {
+ memtag_stack = true;
+ __libc_shared_globals()->initial_memtag_stack_abi = true;
+ __get_bionic_tcb()->tls_slot(TLS_SLOT_STACK_MTE) = __allocate_stack_mte_ringbuffer(0, nullptr);
+ }
if (int64_t timed_upgrade = __get_memtag_upgrade_secs()) {
if (level == M_HEAP_TAGGING_LEVEL_ASYNC) {
async_safe_format_log(ANDROID_LOG_INFO, "libc",
@@ -373,7 +380,15 @@
if (prctl(PR_SET_TAGGED_ADDR_CTRL, prctl_arg | PR_MTE_TCF_SYNC, 0, 0, 0) == 0 ||
prctl(PR_SET_TAGGED_ADDR_CTRL, prctl_arg, 0, 0, 0) == 0) {
__libc_shared_globals()->initial_heap_tagging_level = level;
+ __libc_shared_globals()->initial_memtag_stack = memtag_stack;
+ if (memtag_stack) {
+ void* pg_start =
+ reinterpret_cast<void*>(page_start(reinterpret_cast<uintptr_t>(stack_top)));
+ if (mprotect(pg_start, page_size(), PROT_READ | PROT_WRITE | PROT_MTE | PROT_GROWSDOWN)) {
+ async_safe_fatal("error: failed to set PROT_MTE on main thread stack: %m");
+ }
+ }
struct sigaction action = {};
action.sa_flags = SA_SIGINFO | SA_RESTART;
action.sa_sigaction = __enable_mte_signal_handler;
@@ -389,36 +404,11 @@
}
// We did not enable MTE, so we do not need to arm the upgrade timer.
__libc_shared_globals()->heap_tagging_upgrade_timer_sec = 0;
+ // We also didn't enable memtag_stack.
+ __libc_shared_globals()->initial_memtag_stack = false;
}
-
-// Figure out whether we need to map the stack as PROT_MTE.
-// For dynamic executables, this has to be called after loading all
-// DT_NEEDED libraries, in case one of them needs stack MTE.
-__attribute__((no_sanitize("hwaddress", "memtag"))) void __libc_init_mte_stack(void* stack_top) {
- if (!__libc_shared_globals()->initial_memtag_stack) {
- return;
- }
-
- // Even if the device doesn't support MTE, we have to allocate stack
- // history buffers for code compiled for stack MTE. That is because the
- // codegen expects a buffer to be present in TLS_SLOT_STACK_MTE either
- // way.
- __libc_shared_globals()->initial_memtag_stack_abi = true;
- __get_bionic_tcb()->tls_slot(TLS_SLOT_STACK_MTE) = __allocate_stack_mte_ringbuffer(0, nullptr);
-
- if (!__libc_mte_enabled()) {
- __libc_shared_globals()->initial_memtag_stack = false;
- return;
- }
- void* pg_start = reinterpret_cast<void*>(page_start(reinterpret_cast<uintptr_t>(stack_top)));
- if (mprotect(pg_start, page_size(), PROT_READ | PROT_WRITE | PROT_MTE | PROT_GROWSDOWN)) {
- async_safe_fatal("error: failed to set PROT_MTE on main thread stack: %m");
- }
-}
-
#else // __aarch64__
-void __libc_init_mte(const memtag_dynamic_entries_t*, const void*, size_t, uintptr_t) {}
-void __libc_init_mte_stack(void*) {}
+void __libc_init_mte(const memtag_dynamic_entries_t*, const void*, size_t, uintptr_t, void*) {}
#endif // __aarch64__
void __libc_init_profiling_handlers() {
@@ -446,8 +436,7 @@
__libc_init_common();
__libc_init_mte(/*memtag_dynamic_entries=*/nullptr,
reinterpret_cast<ElfW(Phdr)*>(getauxval(AT_PHDR)), getauxval(AT_PHNUM),
- /*load_bias = */ 0);
- __libc_init_mte_stack(/*stack_top = */ raw_args);
+ /*load_bias = */ 0, /*stack_top = */ raw_args);
__libc_init_scudo();
__libc_init_profiling_handlers();
__libc_init_fork_handler();
@@ -519,11 +508,6 @@
// compiled with -ffreestanding to avoid implicit string.h function calls. (It shouldn't strictly
// be necessary, though.)
__LIBC_HIDDEN__ libc_shared_globals* __libc_shared_globals() {
- BIONIC_USED_BEFORE_LINKER_RELOCATES static libc_shared_globals globals;
+ static libc_shared_globals globals;
return &globals;
}
-
-__LIBC_HIDDEN__ bool __libc_mte_enabled() {
- HeapTaggingLevel lvl = __libc_shared_globals()->initial_heap_tagging_level;
- return lvl == M_HEAP_TAGGING_LEVEL_SYNC || lvl == M_HEAP_TAGGING_LEVEL_ASYNC;
-}