[PATCH] powerpc/64s: Prevent fallthrough to hash TLB flush when using radix

[PATCH] powerpc/64s: Prevent fallthrough to hash TLB flush when using radix

[Benjamin Gray]

In the fix reconnecting hash__tlb_flush() to tlb_flush() the
void return on radix__tlb_flush() was not restored and subsequently
falls through to the restored hash__tlb_flush().

Guard hash__tlb_flush() under an else to prevent this.

Fixes: 1665c027afb2 ("powerpc/64s: Reconnect tlb_flush() to hash__tlb_flush()")
Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>

---

Bug report:
https://lore.kernel.org/linuxppc-dev/20230216005535.6bff7aa6@yea/
---
 arch/powerpc/include/asm/book3s/64/tlbflush.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/tlbflush.h b/arch/powerpc/include/asm/book3s/64/tlbflush.h
index d5cd16270c5d..2bbc0fcce04a 100644
--- a/arch/powerpc/include/asm/book3s/64/tlbflush.h
+++ b/arch/powerpc/include/asm/book3s/64/tlbflush.h
@@ -97,8 +97,8 @@ static inline void tlb_flush(struct mmu_gather *tlb)
 {
 	if (radix_enabled())
 		radix__tlb_flush(tlb);
-
-	return hash__tlb_flush(tlb);
+	else
+		hash__tlb_flush(tlb);
 }

 #ifdef CONFIG_SMP

base-commit: 0bfb97203f5f300777624a2ad6f8f84aea3e8658
--
2.39.1

Re: [PATCH] powerpc/64s: Prevent fallthrough to hash TLB flush when using radix

[Michael Ellerman]

On Fri, 17 Feb 2023 12:14:34 +1100, Benjamin Gray wrote:
> In the fix reconnecting hash__tlb_flush() to tlb_flush() the
> void return on radix__tlb_flush() was not restored and subsequently
> falls through to the restored hash__tlb_flush().
> 
> Guard hash__tlb_flush() under an else to prevent this.
> 
> 
> [...]

Applied to powerpc/fixes.

[1/1] powerpc/64s: Prevent fallthrough to hash TLB flush when using radix
      https://git.kernel.org/powerpc/c/4302abc628fc0dc08e5855f21bbfaed407a72bc3

cheers