Rollup merge of rust-lang#155453 - ferrocene:a53-linux-fix-errata, r=wesleywiser

apply Cortex-A53 errata 843419 mitigation to the AArch64 Linux targets

as it's done for other AArch64 targets

although the linker (GCC) _may_ be configured to apply the fix by default it's preferred to have rustc pass the flag to the linker to ensure the mitigation is always applied

for example, the Arm GNU toolchain does _not_ enable the errata mitigation by default (checked version: 13.3.Rel1)

see rust-lang#118095 for background information

Author: JonathanBrouwer

compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_gnu.rs

@@ -1,5 +1,6 @@
 use crate::spec::{
-    Arch, FramePointer, SanitizerSet, StackProbeType, Target, TargetMetadata, TargetOptions, base,
+    Arch, Cc, FramePointer, LinkerFlavor, Lld, SanitizerSet, StackProbeType, Target,
+    TargetMetadata, TargetOptions, base,
 };
 
 pub(crate) fn target() -> Target {
@@ -15,6 +16,11 @@ pub(crate) fn target() -> Target {
         data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: Arch::AArch64,
         options: TargetOptions {
+            // Enable the Cortex-A53 errata 843419 mitigation by default
+            pre_link_args: TargetOptions::link_args(
+                LinkerFlavor::Gnu(Cc::Yes, Lld::No),
+                &["-mfix-cortex-a53-843419"],
+            ),
             features: "+v8a,+outline-atomics".into(),
             // the AAPCS64 expects use of non-leaf frame pointers per
             // https://github.com/ARM-software/abi-aa/blob/4492d1570eb70c8fd146623e0db65b2d241f12e7/aapcs64/aapcs64.rst#the-frame-pointer

compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_musl.rs

@@ -1,5 +1,6 @@
 use crate::spec::{
-    Arch, FramePointer, SanitizerSet, StackProbeType, Target, TargetMetadata, TargetOptions, base,
+    Arch, Cc, FramePointer, LinkerFlavor, Lld, SanitizerSet, StackProbeType, Target,
+    TargetMetadata, TargetOptions, base,
 };
 
 pub(crate) fn target() -> Target {
@@ -29,6 +30,11 @@ pub(crate) fn target() -> Target {
         data_layout: "e-m:e-p270:32:32-p271:32:32-p272:64:64-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128-Fn32".into(),
         arch: Arch::AArch64,
         options: TargetOptions {
+            // Enable the Cortex-A53 errata 843419 mitigation by default
+            pre_link_args: TargetOptions::link_args(
+                LinkerFlavor::Gnu(Cc::Yes, Lld::No),
+                &["-mfix-cortex-a53-843419"],
+            ),
             // the AAPCS64 expects use of non-leaf frame pointers per
             // https://github.com/ARM-software/abi-aa/blob/4492d1570eb70c8fd146623e0db65b2d241f12e7/aapcs64/aapcs64.rst#the-frame-pointer
             // and we tend to encounter interesting bugs in AArch64 unwinding code if we do not