diff mbox

[Zesty] UBUNTU: SAUCE: powerpc: Only do ERAT invalidate

Message ID 1498590564-11306-1-git-send-email-leitao@debian.org
State New
Headers show

Commit Message

Breno Leitao June 27, 2017, 7:09 p.m. UTC 
From: Michael Neuling <mikey@neuling.org>

BugLink: https://bugs.launchpad.net/ubuntu/+bug/1700819

On P9 (Nimbus) DD2 and later, in radix mode, the move to the PID
register will implicitly invalidate the user space ERAT entries
and leave the kernel ones alone. Thus the only thing needed is
an isync() to synchronize this with subsequent uaccess's

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 arch/powerpc/mm/mmu_context_book3s64.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

Comments

Seth Forshee June 29, 2017, 9:07 p.m. UTC | #1 
On Tue, Jun 27, 2017 at 04:09:24PM -0300, Breno Leitao wrote:
> From: Michael Neuling <mikey@neuling.org>
> 
> BugLink: https://bugs.launchpad.net/ubuntu/+bug/1700819
> 
> On P9 (Nimbus) DD2 and later, in radix mode, the move to the PID
> register will implicitly invalidate the user space ERAT entries
> and leave the kernel ones alone. Thus the only thing needed is
> an isync() to synchronize this with subsequent uaccess's
> 
> Signed-off-by: Michael Neuling <mikey@neuling.org>
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Signed-off-by: Breno Leitao <leitao@debian.org>

Note to whoever applies this, this is now commit
74e27c6af56fe6898c3c8c451595746a992f0f0f in linux-next, so it can be
applied as a cherry-pick and not a sauce patch.

Acked-by: Seth Forshee <seth.forshee@canonical.com>

Also cherry picked from linux-next to artful/master-next and
unstable/master. Thanks!
Stefan Bader July 10, 2017, 12:29 p.m. UTC | #2 
On 29.06.2017 23:07, Seth Forshee wrote:
> On Tue, Jun 27, 2017 at 04:09:24PM -0300, Breno Leitao wrote:
>> From: Michael Neuling <mikey@neuling.org>
>>
>> BugLink: https://bugs.launchpad.net/ubuntu/+bug/1700819
>>
>> On P9 (Nimbus) DD2 and later, in radix mode, the move to the PID
>> register will implicitly invalidate the user space ERAT entries
>> and leave the kernel ones alone. Thus the only thing needed is
>> an isync() to synchronize this with subsequent uaccess's
>>
>> Signed-off-by: Michael Neuling <mikey@neuling.org>
>> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> Signed-off-by: Breno Leitao <leitao@debian.org>
> 
> Note to whoever applies this, this is now commit
> 74e27c6af56fe6898c3c8c451595746a992f0f0f in linux-next, so it can be
> applied as a cherry-pick and not a sauce patch.
> 
> Acked-by: Seth Forshee <seth.forshee@canonical.com>

Also ACK from me but with the additional note that this now is upstream (same
SHA1) and different (was the same on next) commit msg: "powerpc: Only do ERAT
invalidate on radix context switch on P9 DD1"

-Stefan

> 
> Also cherry picked from linux-next to artful/master-next and
> unstable/master. Thanks!
> 
>
Thadeu Lima de Souza Cascardo July 11, 2017, 4:55 p.m. UTC | #3 
Applied to zesty master-next branch, as a cherry-pick of the upstream
commit.

Thanks.
Cascardo.
diff mbox

Patch

diff --git a/arch/powerpc/mm/mmu_context_book3s64.c b/arch/powerpc/mm/mmu_context_book3s64.c
index f6976b783b89..371b20f9de95 100644
--- a/arch/powerpc/mm/mmu_context_book3s64.c
+++ b/arch/powerpc/mm/mmu_context_book3s64.c
@@ -182,10 +182,15 @@  void destroy_context(struct mm_struct *mm)
 #ifdef CONFIG_PPC_RADIX_MMU
 void radix__switch_mmu_context(struct mm_struct *prev, struct mm_struct *next)
 {
-	asm volatile("isync": : :"memory");
-	mtspr(SPRN_PID, next->context.id);
-	asm volatile("isync \n"
-		     PPC_SLBIA(0x7)
-		     : : :"memory");
+
+	if (cpu_has_feature(CPU_FTR_POWER9_DD1)) {
+		isync();
+		mtspr(SPRN_PID, next->context.id);
+		isync();
+		asm volatile(PPC_INVALIDATE_ERAT : : :"memory");
+	} else {
+		mtspr(SPRN_PID, next->context.id);
+		isync();
+	}
 }
 #endif