llvm::AArch64PAuth Namespace Reference

Enumerations
enum class	AuthCheckMethod {   None , DummyLoad , HighBitsNoTBI , XPACHint ,   XPAC }
	Variants of check performed on an authenticated pointer. More...

Functions
unsigned	getCheckerSizeInBytes (AuthCheckMethod Method)
	Returns the number of bytes added by checkAuthenticatedRegister.

Enumeration Type Documentation

AuthCheckMethod

enum class llvm::AArch64PAuth::AuthCheckMethod

strong

Variants of check performed on an authenticated pointer.

In cases such as authenticating the LR value when performing a tail call or when re-signing a signed pointer with a different signing schema, a failed authentication may not generate an exception on its own and may create an authentication or signing oracle if not checked explicitly.

A number of check methods modify control flow in a similar way by rewriting the code

<authenticate LR>
<more instructions>

as follows:

  <authenticate LR>
  <method-specific checker>
on_fail:
  brk <code>
on_success:
  <more instructions>

Enumerator
None	Do not check the value at all.
DummyLoad	Perform a load to a temporary register.
HighBitsNoTBI	Check by comparing bits 62 and 61 of the authenticated address. This method modifies control flow and inserts the following checker: eor Xtmp, Xn, Xn, lsl #1 tbz Xtmp, #62, on_success
XPACHint	Check by comparing the authenticated value with an XPAC-ed one without using PAuth instructions not encoded as HINT. Can only be applied to LR. This method modifies control flow and inserts the following checker: mov Xtmp, LR xpaclri ; encoded as "hint #7" ; Note: at this point, the LR register contains the address as if ; the authentication succeeded and the temporary register contains the ; *real* result of authentication. cmp Xtmp, LR b.eq on_success
XPAC	Similar to XPACHint but using Armv8.3-only XPAC instruction, thus not restricted to LR: mov Xtmp, Xn xpac(i|d) Xn cmp Xtmp, Xn b.eq on_success

Definition at line 44 of file AArch64PointerAuth.h.

Function Documentation

getCheckerSizeInBytes()

unsigned llvm::AArch64PAuth::getCheckerSizeInBytes

(

AuthCheckMethod

Method

)

Returns the number of bytes added by checkAuthenticatedRegister.

Definition at line 237 of file AArch64PointerAuth.cpp.

References llvm_unreachable.

Referenced by llvm::AArch64InstrInfo::getInstSizeInBytes().