The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From aa4113340ae6c2811e046f08c2bc21011d20a072 Mon Sep 17 00:00:00 2001
From: Laurentiu Tudor laurentiu.tudor@nxp.com Date: Thu, 23 Jan 2020 11:19:25 +0000 Subject: [PATCH] powerpc/fsl_booke: Avoid creating duplicate tlb1 entry
In the current implementation, the call to loadcam_multi() is wrapped between switch_to_as1() and restore_to_as0() calls so, when it tries to create its own temporary AS=1 TLB1 entry, it ends up duplicating the existing one created by switch_to_as1(). Add a check to skip creating the temporary entry if already running in AS=1.
Fixes: d9e1831a4202 ("powerpc/85xx: Load all early TLB entries at once") Cc: stable@vger.kernel.org # v4.4+ Signed-off-by: Laurentiu Tudor laurentiu.tudor@nxp.com Acked-by: Scott Wood oss@buserror.net Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20200123111914.2565-1-laurentiu.tudor@nxp.com
diff --git a/arch/powerpc/mm/nohash/tlb_low.S b/arch/powerpc/mm/nohash/tlb_low.S index 2ca407cedbe7..eaeee402f96e 100644 --- a/arch/powerpc/mm/nohash/tlb_low.S +++ b/arch/powerpc/mm/nohash/tlb_low.S @@ -397,7 +397,7 @@ _GLOBAL(set_context) * extern void loadcam_entry(unsigned int index) * * Load TLBCAM[index] entry in to the L2 CAM MMU - * Must preserve r7, r8, r9, and r10 + * Must preserve r7, r8, r9, r10 and r11 */ _GLOBAL(loadcam_entry) mflr r5 @@ -433,6 +433,10 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_BIG_PHYS) */ _GLOBAL(loadcam_multi) mflr r8 + /* Don't switch to AS=1 if already there */ + mfmsr r11 + andi. r11,r11,MSR_IS + bne 10f
/* * Set up temporary TLB entry that is the same as what we're @@ -458,6 +462,7 @@ _GLOBAL(loadcam_multi) mtmsr r6 isync
+10: mr r9,r3 add r10,r3,r4 2: bl loadcam_entry @@ -466,6 +471,10 @@ _GLOBAL(loadcam_multi) mr r3,r9 blt 2b
+ /* Don't return to AS=0 if we were in AS=1 at function start */ + andi. r11,r11,MSR_IS + bne 3f + /* Return to AS=0 and clear the temporary entry */ mfmsr r6 rlwinm. r6,r6,0,~(MSR_IS|MSR_DS) @@ -481,6 +490,7 @@ _GLOBAL(loadcam_multi) tlbwe isync
+3: mtlr r8 blr #endif