High-performance control of permanent magnet synchronous motors (PMSMs) necessitates precise rotor-position feedback. However, conventional solutions, including optical encoders, resolvers, and external magnetic encoders, suffer from excessive axial space occupation, structural complexity, and compromised output performance. Hence, embedded magnetic encoders (EMEs) have emerged as compact and cost-effective alternatives that leverage linear Hall sensors to extract rotor angle information from internal magnetic fields. The technological evolution of EMEs in three critical dimensions are comprehensively reviewed: ① Hall sensor configurations and signal acquisition methodologies across diverse motor topologies, ② disturbance mechanisms and error propagation characteristics under non-ideal operational conditions, and ③ advanced harmonic suppression techniques and angle-decoding algorithms. Finally, the shortcomings and urgent challenges in current technological development are summarized and valuable research priorities for future studies are identified.