/* Register Standard Service Calls as runtime service */
DECLARE_RT_SVC(
arm_arch_svc,
OEN_ARM_START,
OEN_ARM_END,
SMC_TYPE_FAST,
NULL,
arm_arch_svc_smc_handler
);
/* Define a runtime service descriptor for fast SMC calls */
DECLARE_RT_SVC(
mediatek_sip_svc,
OEN_SIP_START,
OEN_SIP_END,
SMC_TYPE_FAST,
NULL,
sip_smc_handler
);
smc_handler64:
/* NOTE: The code below must preserve x0-x4 */
/*
* Save general purpose and ARMv8.3-PAuth registers (if enabled).
* If Secure Cycle Counter is not disabled in MDCR_EL3 when
* ARMv8.5-PMU is implemented, save PMCR_EL0 and disable Cycle Counter.
*/
bl save_gp_pmcr_pauth_regs
#if ENABLE_PAUTH
/* Load and program APIAKey firmware key */
bl pauth_load_bl31_apiakey
#endif
/*
* Populate the parameters for the SMC handler.
* We already have x0-x4 in place. x5 will point to a cookie (not used
* now). x6 will point to the context structure (SP_EL3) and x7 will
* contain flags we need to pass to the handler.
*/
mov x5, xzr
mov x6, sp
/*
* Restore the saved C runtime stack value which will become the new
* SP_EL0 i.e. EL3 runtime stack. It was saved in the 'cpu_context'
* structure prior to the last ERET from EL3.
*/
ldr x12, [x6, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]
/* Switch to SP_EL0 */
msr spsel, #MODE_SP_EL0
/*
* Save the SPSR_EL3, ELR_EL3, & SCR_EL3 in case there is a world
* switch during SMC handling.
* TODO: Revisit if all system registers can be saved later.
*/
mrs x16, spsr_el3
mrs x17, elr_el3
mrs x18, scr_el3
stp x16, x17, [x6, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
str x18, [x6, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
/* Copy SCR_EL3.NS bit to the flag to indicate caller's security */
bfi x7, x18, #0, #1
mov sp, x12
/* Get the unique owning entity number */
ubfx x16, x0, #FUNCID_OEN_SHIFT, #FUNCID_OEN_WIDTH ---------------- 擷取FUNCID_OEN_SHIFT，對應第一節中的OEN_TOS_START
ubfx x15, x0, #FUNCID_TYPE_SHIFT, #FUNCID_TYPE_WIDTH ---------------- 擷取FUNCID_TYPE_SHIFT，對應第一節中的SMC_TYPE_FAST(fast還是yield,yield其實就是standard)
orr x16, x16, x15, lsl #FUNCID_OEN_WIDTH
/* Load descriptor index from array of indices */
adrp x14, rt_svc_descs_indices ----在runtime_svc_init()中會将所有的section rt_svc_descs段放入rt_svc_descs_indices數組，這裡擷取該數組位址
add x14, x14, :lo12:rt_svc_descs_indices
ldrb w15, [x14, x16] ---找到rt_svc在rt_svc_descs_indices數組中的index
/* Any index greater than 127 is invalid. Check bit 7. */
tbnz w15, 7, smc_unknown
/*
* Get the descriptor using the index
* x11 = (base + off), w15 = index -------------------------重要的注釋
*
* handler = (base + off) + (index << log2(size)) ------ 這句注釋特别重要，整段彙編看不懂沒關系，這句注釋看懂就行
*/
adr x11, (__RT_SVC_DESCS_START__ + RT_SVC_DESC_HANDLE)
lsl w10, w15, #RT_SVC_SIZE_LOG2
ldr x15, [x11, w10, uxtw] ------------------------------這句話對應的就是上述注釋:handler = (base + off) + (index << log2(size))
/*
* Call the Secure Monitor Call handler and then drop directly into
* el3_exit() which will program any remaining architectural state
* prior to issuing the ERET to the desired lower EL.
*/
#if DEBUG
cbz x15, rt_svc_fw_critical_error
#endif
blr x15 -------------------------------------跳轉到handler
b el3_exit
