linux-kernel - [PATCH 4/7] powerpc/8xx: unpin all TLBs before flushing

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Date:	Tue,  3 May 2016 17:01:24 +0200 (CEST)
From:	Christophe Leroy <christophe.leroy@....fr>
To:	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Paul Mackerras <paulus@...ba.org>,
	Michael Ellerman <mpe@...erman.id.au>,
	Scott Wood <oss@...error.net>
Cc:	linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH 4/7] powerpc/8xx: unpin all TLBs before flushing

Bootloader may have pinned some TLB entries so the kernel must
unpin them before flushing TLBs with tlbia otherwise pinned TLB
entries won't get flushed

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 arch/powerpc/kernel/head_8xx.S | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 44f4edb..d9a1656 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -797,6 +797,14 @@ start_here:
  * these mappings is mapped by page tables.
  */
 initial_mmu:
+	li	r8, 0
+	mtspr	SPRN_MI_CTR, r8		/* remove PINNED ITLB entries */
+	lis	r10, MD_RESETVAL@h
+#ifndef CONFIG_8xx_COPYBACK
+	oris	r10, r10, MD_WTDEF@h
+#endif
+	mtspr	SPRN_MD_CTR, r10	/* remove PINNED DTLB entries */
+
 	tlbia			/* Invalidate all TLB entries */
 /* Always pin the first 8 MB ITLB to prevent ITLB
    misses while mucking around with SRR0/SRR1 in asm
@@ -807,16 +815,10 @@ initial_mmu:
 	mtspr	SPRN_MI_CTR, r8	/* Set instruction MMU control */
 
 #ifdef CONFIG_PIN_TLB
-	lis	r10, (MD_RSV4I | MD_RESETVAL)@h
+	oris	r10, r10, MD_RSV4I@h
 	ori	r10, r10, 0x1c00
-	mr	r8, r10
-#else
-	lis	r10, MD_RESETVAL@h
-#endif
-#ifndef CONFIG_8xx_COPYBACK
-	oris	r10, r10, MD_WTDEF@h
-#endif
 	mtspr	SPRN_MD_CTR, r10	/* Set data TLB control */
+#endif
 
 	/* Now map the lower 8 Meg into the TLBs.  For this quick hack,
 	 * we can load the instruction and data TLB registers with the
-- 
2.1.0