Software can use the SPSel operand to write directly to PSTATE.SP. According to ARM DDI 0487F.b, page D1-2332, writes to PSTATE are self-synchronizing and no ISB is needed: "Writes to the PSTATE fields have side-effects on various aspects of the PE operation. All of these side-effects are guaranteed: - Not to be visible to earlier instructions in the execution stream. - To be visible to later instructions in the execution stream." Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx> --- arm/cstart64.S | 1 - 1 file changed, 1 deletion(-) diff --git a/arm/cstart64.S b/arm/cstart64.S index 0428014aa58a..fc1930bcdb53 100644 --- a/arm/cstart64.S +++ b/arm/cstart64.S @@ -54,7 +54,6 @@ start: /* set up stack */ mov x4, #1 msr spsel, x4 - isb adrp x4, stackptr add sp, x4, :lo12:stackptr -- 2.30.1
