rdpkru

Read Protection Key Rights

RDPKRU

Reads PKRU register into EAX (User-mode pages).

Pseudocode Operation

// Read PKRU into EAX, zero EDX
EAX ← PKRU;
EDX ← 0;
// No flags modified; instruction is serializing

Encoding

Binary Layout

Format Legacy

Opcode NP 0F 01 EE

Extension PKU

Operands

Reference

View in Intel® 64 and IA-32 Architectures SDM ↗ Intel® SDM

Instruction Forms

Opcode	Instruction	Op/En	64/32-bit Mode	CPUID	Description
NP 0F 01 EE	RDPKRU	ZO	V/V	OSPKE	Reads PKRU into EAX.

Description

Reads the value of PKRU into EAX and clears EDX. ECX must be 0 when RDPKRU is executed; otherwise, a generalprotection exception (#GP) occurs. RDPKRU can be executed only if CR4.PKE = 1; otherwise, an invalid-opcode exception (#UD) occurs. Software can discover the value of CR4.PKE by examining CPUID.07H.00H:ECX.OSPKE[4]. On processors that support the Intel 64 Architecture, the high-order 32-bits of RCX are ignored and the high-order 32-bits of RDX and RAX are cleared.

Operation

IF (ECX = 0)
THEN
EAX := PKRU;
EDX := 0;
ELSE #GP(0);
FI;

Flags Affected

None. C/C++ Compiler Intrinsic Equivalent RDPKRU uint32_t _rdpkru_u32(void);

Exceptions

Protected Mode Exceptions

#GP(0) If ECX ≠ 0. #UD If the LOCK prefix is used. If CR4.PKE = 0.

Real-Address Mode Exceptions

Same exceptions as in protected mode.

Virtual-8086 Mode Exceptions