From: Paul Walmsley <paul.walmsley@sifive.com>
Date: Thu, 10 Oct 2019 22:57:58 +0000 (-0700)
Subject: riscv: tlbflush: remove confusing comment on local_flush_tlb_all()
X-Git-Tag: v5.4-rc4~9^2~1
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=4c8eb19cf9dc5fcc489757acbf93be90baf25848;p=users%2Fjedix%2Flinux-maple.git

riscv: tlbflush: remove confusing comment on local_flush_tlb_all()

Remove a confusing comment on our local_flush_tlb_all()
implementation.  Per an internal discussion with Andrew, while it's
true that the fence.i is not necessary, it's not the case that an
sfence.vma implies a fence.i.  We also drop the section about
"flush[ing] the entire local TLB" to better align with the language in
section 4.2.1 "Supervisor Memory-Management Fence Instruction" of the
RISC-V Privileged Specification v20190608.

Fixes: c901e45a999a1 ("RISC-V: `sfence.vma` orderes the instruction cache")
Reported-by: Alan Kao <alankao@andestech.com>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Andrew Waterman <andrew@sifive.com>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
---

diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
index 37ae4e367ad2..f02188a5b0f4 100644
--- a/arch/riscv/include/asm/tlbflush.h
+++ b/arch/riscv/include/asm/tlbflush.h
@@ -10,10 +10,6 @@
 #include <linux/mm_types.h>
 #include <asm/smp.h>
 
-/*
- * Flush entire local TLB.  'sfence.vma' implicitly fences with the instruction
- * cache as well, so a 'fence.i' is not necessary.
- */
 static inline void local_flush_tlb_all(void)
 {
 	__asm__ __volatile__ ("sfence.vma" : : : "memory");