MdePkg/BaseLib AARCH64: Make asm files BTI compatible

Add the BTI instructions and the associated note to make the AArch64 asm
objects compatible with BTI enforcement.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>
Reviewed-by: Oliver Smith-Denny <osd@smith-denny.com>

MdePkg/Library/BaseLib/AArch64/CpuBreakpoint.S

@@ -27,5 +27,6 @@ GCC_ASM_EXPORT(CpuBreakpoint)
 #  );
 #
 ASM_PFX(CpuBreakpoint):
+    AARCH64_BTI(c)
     svc   0xdbdb    // Superviser exception. Takes 16bit arg -> Armv7 had 'swi' here.
     ret

MdePkg/Library/BaseLib/AArch64/DisableInterrupts.S

@@ -26,5 +26,6 @@ GCC_ASM_EXPORT(DisableInterrupts)
 #  );
 #
 ASM_PFX(DisableInterrupts):
+   AARCH64_BTI(c)
    msr  daifset, #DAIF_WR_IRQ_BIT
    ret

MdePkg/Library/BaseLib/AArch64/EnableInterrupts.S

@@ -26,5 +26,6 @@ GCC_ASM_EXPORT(EnableInterrupts)
 #  );
 #
 ASM_PFX(EnableInterrupts):
+    AARCH64_BTI(c)
     msr  daifclr, #DAIF_WR_IRQ_BIT
     ret

MdePkg/Library/BaseLib/AArch64/GetInterruptsState.S

@@ -33,6 +33,7 @@ GCC_ASM_EXPORT(GetInterruptState)
 # );
 #
 ASM_PFX(GetInterruptState):
+    AARCH64_BTI(c)
     mrs    x0, daif
     tst    x0, #DAIF_RD_IRQ_BIT   // Check IRQ mask; set Z=1 if clear/unmasked
     cset   w0, eq                 // if Z=1 (eq) return 1, else 0

MdePkg/Library/BaseLib/AArch64/MemoryFence.S

@@ -28,6 +28,7 @@ GCC_ASM_EXPORT(MemoryFence)
 #  );
 #
 ASM_PFX(MemoryFence):
+    AARCH64_BTI(c)
     // System wide Data Memory Barrier.
     dmb sy
     ret

MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.S

@@ -46,6 +46,7 @@ GCC_ASM_EXPORT(InternalLongJump)
 #  );
 #
 ASM_PFX(SetJump):
+        AARCH64_BTI(c)
         mov     x16, sp // use IP0 so save SP
 #define REG_PAIR(REG1, REG2, OFFS)      stp REG1, REG2, [x0, OFFS]
 #define REG_ONE(REG1, OFFS)             str REG1, [x0, OFFS]
@@ -75,6 +76,7 @@ ASM_PFX(SetJump):
 #  );
 #
 ASM_PFX(InternalLongJump):
+        AARCH64_BTI(c)
 #define REG_PAIR(REG1, REG2, OFFS)      ldp REG1, REG2, [x0, OFFS]
 #define REG_ONE(REG1, OFFS)             ldr REG1, [x0, OFFS]
         GPR_LAYOUT

MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.S

@@ -28,6 +28,7 @@ GCC_ASM_EXPORT(SpeculationBarrier)
 #  );
 #
 ASM_PFX(SpeculationBarrier):
+    AARCH64_BTI(c)
     dsb  sy
     isb
     ret

MdePkg/Library/BaseLib/AArch64/SwitchStack.S

@@ -35,6 +35,7 @@ GCC_ASM_EXPORT(CpuPause)
 #  );
 #
 ASM_PFX(InternalSwitchStackAsm):
+    AARCH64_BTI(c)
     mov   x29, #0
     mov   x30, x0
     mov   sp, x3
@@ -57,6 +58,7 @@ ASM_PFX(InternalSwitchStackAsm):
 #  )
 #
 ASM_PFX(CpuPause):
+    AARCH64_BTI(c)
     nop
     nop
     nop