[PATCH] MIPS: Sanitise Cavium switch cases in TLB handler synthesizers

From: Maciej W. Rozycki
Date: Fri Mar 04 2022 - 16:13:16 EST


It makes no sense to fall through to `break'. Therefore reorder the
switch statements so as to have the Cavium cases first, followed by the
default case, which improves readability and pacifies code analysis
tools. No change in semantics, assembly produced is exactly the same.

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxx>
Fixes: bc431d2153cc ("MIPS: Fix fall-through warnings for Clang")
---
arch/mips/mm/tlbex.c | 23 ++++++++++-------------
1 file changed, 10 insertions(+), 13 deletions(-)

linux-mips-tlbex-cavium-odd-switch.diff
Index: linux-macro/arch/mips/mm/tlbex.c
===================================================================
--- linux-macro.orig/arch/mips/mm/tlbex.c
+++ linux-macro/arch/mips/mm/tlbex.c
@@ -2160,16 +2160,14 @@ static void build_r4000_tlb_load_handler
uasm_i_tlbr(&p);

switch (current_cpu_type()) {
- default:
- if (cpu_has_mips_r2_exec_hazard) {
- uasm_i_ehb(&p);
- fallthrough;
-
case CPU_CAVIUM_OCTEON:
case CPU_CAVIUM_OCTEON_PLUS:
case CPU_CAVIUM_OCTEON2:
- break;
- }
+ break;
+ default:
+ if (cpu_has_mips_r2_exec_hazard)
+ uasm_i_ehb(&p);
+ break;
}

/* Examine entrylo 0 or 1 based on ptr. */
@@ -2236,15 +2234,14 @@ static void build_r4000_tlb_load_handler
uasm_i_tlbr(&p);

switch (current_cpu_type()) {
- default:
- if (cpu_has_mips_r2_exec_hazard) {
- uasm_i_ehb(&p);
-
case CPU_CAVIUM_OCTEON:
case CPU_CAVIUM_OCTEON_PLUS:
case CPU_CAVIUM_OCTEON2:
- break;
- }
+ break;
+ default:
+ if (cpu_has_mips_r2_exec_hazard)
+ uasm_i_ehb(&p);
+ break;
}

/* Examine entrylo 0 or 1 based on ptr. */