linux-kernel - [PATCH 4/5] powerpc/mm: Simplify update_mmu

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Message-Id: <35f143c6fe29f9fd25c7f3cd4448ae401029ce3c.1565933217.git.christophe.leroy@c-s.fr>
Date:   Fri, 16 Aug 2019 05:41:43 +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>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH 4/5] powerpc/mm: Simplify update_mmu_cache() on BOOK3S32

On BOOK3S32, hash_preload() neither use is_exec nor trap,
so drop those parameters and simplify update_mmu_cached().

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 arch/powerpc/mm/book3s32/mmu.c | 29 +++++++----------------------
 arch/powerpc/mm/mmu_decl.h     |  3 +--
 arch/powerpc/mm/pgtable_32.c   |  2 +-
 3 files changed, 9 insertions(+), 25 deletions(-)

diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
index 3e3c4077cdb7..3a62bf99f93f 100644
--- a/arch/powerpc/mm/book3s32/mmu.c
+++ b/arch/powerpc/mm/book3s32/mmu.c
@@ -297,8 +297,7 @@ void __init setbat(int index, unsigned long virt, phys_addr_t phys,
 /*
  * Preload a translation in the hash table
  */
-void hash_preload(struct mm_struct *mm, unsigned long ea,
-		  bool is_exec, unsigned long trap)
+void hash_preload(struct mm_struct *mm, unsigned long ea)
 {
 	pmd_t *pmd;
 
@@ -324,34 +323,20 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
 	 * We don't need to worry about _PAGE_PRESENT here because we are
 	 * called with either mm->page_table_lock held or ptl lock held
 	 */
-	unsigned long trap;
-	bool is_exec;
 
 	/* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
 	if (!pte_young(*ptep) || address >= TASK_SIZE)
 		return;
 
-	/* We try to figure out if we are coming from an instruction
-	 * access fault and pass that down to __hash_page so we avoid
-	 * double-faulting on execution of fresh text. We have to test
-	 * for regs NULL since init will get here first thing at boot
-	 *
-	 * We also avoid filling the hash if not coming from a fault
-	 */
+	/* We have to test for regs NULL since init will get here first thing at boot */
+	if (!current->thread.regs)
+		return;
 
-	trap = current->thread.regs ? TRAP(current->thread.regs) : 0UL;
-	switch (trap) {
-	case 0x300:
-		is_exec = false;
-		break;
-	case 0x400:
-		is_exec = true;
-		break;
-	default:
+	/* We also avoid filling the hash if not coming from a fault */
+	if (TRAP(current->thread.regs) != 0x300 && TRAP(current->thread.regs) != 0x400)
 		return;
-	}
 
-	hash_preload(vma->vm_mm, address, is_exec, trap);
+	hash_preload(vma->vm_mm, address);
 }
 
 /*
diff --git a/arch/powerpc/mm/mmu_decl.h b/arch/powerpc/mm/mmu_decl.h
index 9f325a7a09cb..adbaf2167214 100644
--- a/arch/powerpc/mm/mmu_decl.h
+++ b/arch/powerpc/mm/mmu_decl.h
@@ -91,8 +91,7 @@ void print_system_hash_info(void);
 
 #ifdef CONFIG_PPC32
 
-void hash_preload(struct mm_struct *mm, unsigned long ea,
-		  bool is_exec, unsigned long trap);
+void hash_preload(struct mm_struct *mm, unsigned long ea);
 
 extern void mapin_ram(void);
 extern void setbat(int index, unsigned long virt, phys_addr_t phys,
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 35cb96cfc258..97f401a06fcc 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -252,7 +252,7 @@ static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
 		map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL);
 #ifdef CONFIG_PPC_BOOK3S_32
 		if (ktext)
-			hash_preload(&init_mm, v, false, 0x300);
+			hash_preload(&init_mm, v);
 #endif
 		v += PAGE_SIZE;
 		p += PAGE_SIZE;
-- 
2.13.3