The BPIALL characteristics are:
Invalidate all entries from branch predictors.
This System instruction is part of the Cache maintenance instructions functional group.
In an implementation where the branch predictors are architecturally invisible, this instruction can execute as a NOP.
BPIALL is a 32-bit System instruction.
BPIALL ignores the value in the register specified by the instruction encoding. Software does not have to write a value to the register before issuing this instruction.
This instruction is executed using MCR with the following syntax:
MCR <syntax>
This syntax uses the following encoding in the System instruction encoding space:
<syntax> | opc1 | opc2 | CRn | coproc | CRm |
---|---|---|---|---|---|
p15, 0, <Rt>, c7, c5, 6 | 000 | 110 | 0111 | 1111 | 0101 |
The PE ignores the value of <Rt>. Software does not have to write a value to this register before issuing this instruction.
The instruction is executable as follows:
Control | Accessibility | |||||
---|---|---|---|---|---|---|
E2H | TGE | NS | EL0 | EL1 | EL2 | EL3 |
x | x | 0 | - | WO | n/a | WO |
x | 0 | 1 | - | WO | WO | WO |
x | 1 | 1 | - | n/a | WO | WO |
This table applies to all syntax that can be used to execute this instruction.
When HCR.FB is 1, at Non-secure EL1 this instruction executes as a BPIALLIS.
For a description of the prioritization of any generated exceptions, see section G1.11.2 (Exception priority order) in the ARM® Architecture Reference Manual, ARMv8, for ARMv8-A architecture profile for exceptions taken to AArch32 state, and section D1.13.2 (Synchronous exception prioritization) for exceptions taken to AArch64 state. Subject to the prioritization rules, the following traps and enables are applicable when executing this System instruction.
When EL2 is implemented and is using AArch64 and SCR_EL3.NS==1 && HCR_EL2.E2H==0 :
If HSTR_EL2.T7==1, Non-secure execution of this instruction at EL1 is trapped to EL2.
When EL2 is implemented and is using AArch64 and SCR_EL3.NS==1 && HCR_EL2.E2H==1 && HCR_EL2.TGE==0 :
If HSTR_EL2.T7==1, Non-secure execution of this instruction at EL1 is trapped to EL2.
When EL2 is implemented and is using AArch32 and SCR_EL3.NS==1 :
If HSTR.T7==1, Non-secure execution of this instruction at EL1 is trapped to Hyp mode.
28/09/2017 08:24
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