[Linux kernel] __switch_to (RISC-V)

The following routine performs the context switching:

 

ENTRY(__switch_to)
/* Save context into prev->thread */
li    a4,  TASK_THREAD_RA
add   a3, a0, a4
add   a4, a1, a4
REG_S ra,  TASK_THREAD_RA_RA(a3)
REG_S sp,  TASK_THREAD_SP_RA(a3)
REG_S s0,  TASK_THREAD_S0_RA(a3)  // x8
REG_S s1,  TASK_THREAD_S1_RA(a3)  // x9
REG_S s2,  TASK_THREAD_S2_RA(a3)  // x18 
REG_S s3,  TASK_THREAD_S3_RA(a3)  // x19
REG_S s4,  TASK_THREAD_S4_RA(a3)  // x20 
REG_S s5,  TASK_THREAD_S5_RA(a3)  // x21 
REG_S s6,  TASK_THREAD_S6_RA(a3)  // x22 
REG_S s7,  TASK_THREAD_S7_RA(a3)  // x23 
REG_S s8,  TASK_THREAD_S8_RA(a3)  // x24 
REG_S s9,  TASK_THREAD_S9_RA(a3)  // x25
REG_S s10, TASK_THREAD_S10_RA(a3) // x26
REG_S s11, TASK_THREAD_S11_RA(a3) // x27
/* Restore context from next->thread */
REG_L ra,  TASK_THREAD_RA_RA(a4)
REG_L sp,  TASK_THREAD_SP_RA(a4)
REG_L s0,  TASK_THREAD_S0_RA(a4)
REG_L s1,  TASK_THREAD_S1_RA(a4)
REG_L s2,  TASK_THREAD_S2_RA(a4)
REG_L s3,  TASK_THREAD_S3_RA(a4)
REG_L s4,  TASK_THREAD_S4_RA(a4)
REG_L s5,  TASK_THREAD_S5_RA(a4)
REG_L s6,  TASK_THREAD_S6_RA(a4)
REG_L s7,  TASK_THREAD_S7_RA(a4)
REG_L s8,  TASK_THREAD_S8_RA(a4)
REG_L s9,  TASK_THREAD_S9_RA(a4)
REG_L s10, TASK_THREAD_S10_RA(a4)
REG_L s11, TASK_THREAD_S11_RA(a4)
/* The offset of thread_info in task_struct is zero. */
move tp, a1
ret
ENDPROC(__switch_to)