[PATCH] riscv: mm: don't advertise 1 num_asid for 0 asid bits

From: Vineet Gupta
Date: Tue Sep 07 2021 - 16:03:56 EST


Even if mmu doesn't support ASID, current code calculates @num_asids=1
which is misleading, so avoid setting any asid related variables in such
a case.

Also while here, print the number of asid bits discovered even for the
disabled case.

Verified this on Hifive Unmatched.

Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxx>
---
arch/riscv/mm/context.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/mm/context.c b/arch/riscv/mm/context.c
index ee3459cb6750..c8c6f8831a3b 100644
--- a/arch/riscv/mm/context.c
+++ b/arch/riscv/mm/context.c
@@ -233,8 +233,10 @@ static int __init asids_init(void)
local_flush_tlb_all();

/* Pre-compute ASID details */
- num_asids = 1 << asid_bits;
- asid_mask = num_asids - 1;
+ if (asid_bits) {
+ num_asids = 1 << asid_bits;
+ asid_mask = num_asids - 1;
+ }

/*
* Use ASID allocator only if number of HW ASIDs are
@@ -255,7 +257,7 @@ static int __init asids_init(void)
pr_info("ASID allocator using %lu bits (%lu entries)\n",
asid_bits, num_asids);
} else {
- pr_info("ASID allocator disabled\n");
+ pr_info("ASID allocator disabled: %lu bits\n", asid_bits);
}

return 0;
--
2.30.2