linux-kernel - [PATCH v2 01/10] powerpc/6xx: fix setup and use of SPRN_SPRG

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Date:   Mon, 11 Mar 2019 08:30:27 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, ruscur@...sell.cc
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v2 01/10] powerpc/6xx: fix setup and use of SPRN_SPRG_PGDIR
 for hash32

Not only the 603 but all 6xx need SPRN_SPRG_PGDIR to be initialised at
startup. This patch move it from __setup_cpu_603() to start_here()
and __secondary_start(), close to the initialisation of SPRN_THREAD.

Previously, virt addr of PGDIR was retrieved from thread struct.
Now that it is the phys addr which is stored in SPRN_SPRG_PGDIR,
hash_page() shall not convert it to phys anymore.
This patch removes the conversion.

Fixes: 93c4a162b014("powerpc/6xx: Store PGDIR physical address in a SPRG")
Reported-by: Guenter Roeck <linux@...ck-us.net>
Tested-by: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 arch/powerpc/kernel/cpu_setup_6xx.S | 3 ---
 arch/powerpc/kernel/head_32.S       | 6 ++++++
 arch/powerpc/mm/hash_low_32.S       | 8 ++++----
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/kernel/cpu_setup_6xx.S b/arch/powerpc/kernel/cpu_setup_6xx.S
index 6f1c11e0691f..7534ecff5e92 100644
--- a/arch/powerpc/kernel/cpu_setup_6xx.S
+++ b/arch/powerpc/kernel/cpu_setup_6xx.S
@@ -24,9 +24,6 @@ BEGIN_MMU_FTR_SECTION
 	li	r10,0
 	mtspr	SPRN_SPRG_603_LRU,r10		/* init SW LRU tracking */
 END_MMU_FTR_SECTION_IFSET(MMU_FTR_NEED_DTLB_SW_LRU)
-	lis	r10, (swapper_pg_dir - PAGE_OFFSET)@h
-	ori	r10, r10, (swapper_pg_dir - PAGE_OFFSET)@l
-	mtspr	SPRN_SPRG_PGDIR, r10
 
 BEGIN_FTR_SECTION
 	bl	__init_fpu_registers
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index ce6a972f2584..48051c8977c5 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -855,6 +855,9 @@ __secondary_start:
 	li	r3,0
 	stw	r3, RTAS_SP(r4)		/* 0 => not in RTAS */
 #endif
+	lis	r4, (swapper_pg_dir - PAGE_OFFSET)@h
+	ori	r4, r4, (swapper_pg_dir - PAGE_OFFSET)@l
+	mtspr	SPRN_SPRG_PGDIR, r4
 
 	/* enable MMU and jump to start_secondary */
 	li	r4,MSR_KERNEL
@@ -942,6 +945,9 @@ start_here:
 	li	r3,0
 	stw	r3, RTAS_SP(r4)		/* 0 => not in RTAS */
 #endif
+	lis	r4, (swapper_pg_dir - PAGE_OFFSET)@h
+	ori	r4, r4, (swapper_pg_dir - PAGE_OFFSET)@l
+	mtspr	SPRN_SPRG_PGDIR, r4
 
 	/* stack */
 	lis	r1,init_thread_union@ha
diff --git a/arch/powerpc/mm/hash_low_32.S b/arch/powerpc/mm/hash_low_32.S
index 1f13494efb2b..a6c491f18a04 100644
--- a/arch/powerpc/mm/hash_low_32.S
+++ b/arch/powerpc/mm/hash_low_32.S
@@ -70,12 +70,12 @@ _GLOBAL(hash_page)
 	lis	r0,KERNELBASE@h		/* check if kernel address */
 	cmplw	0,r4,r0
 	ori	r3,r3,_PAGE_USER|_PAGE_PRESENT /* test low addresses as user */
-	mfspr	r5, SPRN_SPRG_PGDIR	/* virt page-table root */
+	mfspr	r5, SPRN_SPRG_PGDIR	/* phys page-table root */
 	blt+	112f			/* assume user more likely */
-	lis	r5,swapper_pg_dir@ha	/* if kernel address, use */
-	addi	r5,r5,swapper_pg_dir@l	/* kernel page table */
+	lis	r5, (swapper_pg_dir - PAGE_OFFSET)@ha	/* if kernel address, use */
+	addi	r5 ,r5 ,(swapper_pg_dir - PAGE_OFFSET)@l	/* kernel page table */
 	rlwimi	r3,r9,32-12,29,29	/* MSR_PR -> _PAGE_USER */
-112:	tophys(r5, r5)
+112:
 #ifndef CONFIG_PTE_64BIT
 	rlwimi	r5,r4,12,20,29		/* insert top 10 bits of address */
 	lwz	r8,0(r5)		/* get pmd entry */
-- 
2.13.3