arm64: use alternative auto-nop

Make use of the new alternative_if and alternative_else_nop_endif and
get rid of our homebew NOP sleds, making the code simpler to read.

Note that for cpu_do_switch_mm the ret has been moved out of the
alternative sequence, and in the default case there will be three
additional NOPs executed.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 2 insertions, 7 deletions

diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 5eb35964ab8e..1b11dcd7e851 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -127,17 +127,12 @@ ENTRY(cpu_do_switch_mm)
         bfi     x0, x1, #48, #16                // set the ASID
         msr     ttbr0_el1, x0                   // set TTBR0
         isb
-alternative_if_not ARM64_WORKAROUND_CAVIUM_27456
-        ret
-        nop
-        nop
-        nop
-alternative_else
+alternative_if ARM64_WORKAROUND_CAVIUM_27456
         ic      iallu
         dsb     nsh
         isb
+alternative_else_nop_endif
         ret
-alternative_endif
 ENDPROC(cpu_do_switch_mm)
 
         .pushsection ".idmap.text", "ax"