linux-kernel - [PATCH v2 5/6] powerpc/32s: Kernel space starts at TASK

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Message-Id: <893425e32cd0a003539573b2d115e0ffa98bc26c.1593428200.git.christophe.leroy@csgroup.eu>
Date:   Mon, 29 Jun 2020 11:15:24 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v2 5/6] powerpc/32s: Kernel space starts at TASK_SIZE

Kernel space starts at TASK_SIZE. Select kernel page table
when address is over TASK_SIZE.

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/kernel/head_32.S       | 12 ++++++------
 arch/powerpc/mm/book3s32/hash_low.S |  2 +-
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 705c042309d8..bbef6ce8322b 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -474,7 +474,7 @@ InstructionTLBMiss:
 	/* Get PTE (linux-style) and check access */
 	mfspr	r3,SPRN_IMISS
 #if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC)
-	lis	r1,PAGE_OFFSET@h		/* check if kernel address */
+	lis	r1, TASK_SIZE@h		/* check if kernel address */
 	cmplw	0,r1,r3
 #endif
 	mfspr	r2, SPRN_SPRG_PGDIR
@@ -484,7 +484,7 @@ InstructionTLBMiss:
 	li	r1,_PAGE_PRESENT | _PAGE_EXEC
 #endif
 #if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC)
-	bge-	112f
+	bgt-	112f
 	lis	r2, (swapper_pg_dir - PAGE_OFFSET)@ha	/* if kernel address, use */
 	addi	r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l	/* kernel page table */
 #endif
@@ -541,7 +541,7 @@ DataLoadTLBMiss:
  */
 	/* Get PTE (linux-style) and check access */
 	mfspr	r3,SPRN_DMISS
-	lis	r1,PAGE_OFFSET@h		/* check if kernel address */
+	lis	r1, TASK_SIZE@h		/* check if kernel address */
 	cmplw	0,r1,r3
 	mfspr	r2, SPRN_SPRG_PGDIR
 #ifdef CONFIG_SWAP
@@ -549,7 +549,7 @@ DataLoadTLBMiss:
 #else
 	li	r1, _PAGE_PRESENT
 #endif
-	bge-	112f
+	bgt-	112f
 	lis	r2, (swapper_pg_dir - PAGE_OFFSET)@ha	/* if kernel address, use */
 	addi	r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l	/* kernel page table */
 112:	rlwimi	r2,r3,12,20,29		/* insert top 10 bits of address */
@@ -621,7 +621,7 @@ DataStoreTLBMiss:
  */
 	/* Get PTE (linux-style) and check access */
 	mfspr	r3,SPRN_DMISS
-	lis	r1,PAGE_OFFSET@h		/* check if kernel address */
+	lis	r1, TASK_SIZE@h		/* check if kernel address */
 	cmplw	0,r1,r3
 	mfspr	r2, SPRN_SPRG_PGDIR
 #ifdef CONFIG_SWAP
@@ -629,7 +629,7 @@ DataStoreTLBMiss:
 #else
 	li	r1, _PAGE_RW | _PAGE_DIRTY | _PAGE_PRESENT
 #endif
-	bge-	112f
+	bgt-	112f
 	lis	r2, (swapper_pg_dir - PAGE_OFFSET)@ha	/* if kernel address, use */
 	addi	r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l	/* kernel page table */
 112:	rlwimi	r2,r3,12,20,29		/* insert top 10 bits of address */
diff --git a/arch/powerpc/mm/book3s32/hash_low.S b/arch/powerpc/mm/book3s32/hash_low.S
index 923ad8f374eb..1690d369688b 100644
--- a/arch/powerpc/mm/book3s32/hash_low.S
+++ b/arch/powerpc/mm/book3s32/hash_low.S
@@ -62,7 +62,7 @@ _GLOBAL(hash_page)
 	isync
 #endif
 	/* Get PTE (linux-style) and check access */
-	lis	r0,KERNELBASE@h		/* check if kernel address */
+	lis	r0, TASK_SIZE@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	/* phys page-table root */
-- 
2.25.0