[patch RFC 07/15] microblaze/mm/highmem: Switch to generic kmap atomic

From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: linux-arch@vger.kernel.org,
	Linus Torvalds <torvalds@linuxfoundation.org>,
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Subject: [patch RFC 07/15] microblaze/mm/highmem: Switch to generic kmap atomic
Date: Sat, 19 Sep 2020 11:17:58 +0200	[thread overview]
Message-ID: <20200919092616.532034197@linutronix.de> (raw)
In-Reply-To: 20200919091751.011116649@linutronix.de

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Michal Simek <monstr@monstr.eu>
---
Note: Completely untested
---
 arch/microblaze/Kconfig               |    1 
 arch/microblaze/include/asm/highmem.h |    6 ++
 arch/microblaze/mm/Makefile           |    1 
 arch/microblaze/mm/highmem.c          |   78 ----------------------------------
 arch/microblaze/mm/init.c             |    6 --
 5 files changed, 6 insertions(+), 86 deletions(-)

--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -170,6 +170,7 @@ config XILINX_UNCACHED_SHADOW
 config HIGHMEM
 	bool "High memory support"
 	depends on MMU
+	select KMAP_ATOMIC_GENERIC
 	help
 	  The address space of Microblaze processors is only 4 Gigabytes large
 	  and it has to accommodate user address space, kernel address
--- a/arch/microblaze/include/asm/highmem.h
+++ b/arch/microblaze/include/asm/highmem.h
@@ -25,7 +25,6 @@
 #include <linux/uaccess.h>
 #include <asm/fixmap.h>
 
-extern pte_t *kmap_pte;
 extern pte_t *pkmap_page_table;
 
 /*
@@ -52,6 +51,11 @@ extern pte_t *pkmap_page_table;
 
 #define flush_cache_kmaps()	{ flush_icache(); flush_dcache(); }
 
+#define arch_kmap_temp_post_map(vaddr, pteval)	\
+	local_flush_tlb_page(NULL, vaddr);
+#define arch_kmap_temp_post_unmap(vaddr)	\
+	local_flush_tlb_page(NULL, vaddr);
+
 #endif /* __KERNEL__ */
 
 #endif /* _ASM_HIGHMEM_H */
--- a/arch/microblaze/mm/Makefile
+++ b/arch/microblaze/mm/Makefile
@@ -6,4 +6,3 @@
 obj-y := consistent.o init.o
 
 obj-$(CONFIG_MMU) += pgtable.o mmu_context.o fault.o
-obj-$(CONFIG_HIGHMEM) += highmem.o
--- a/arch/microblaze/mm/highmem.c
+++ /dev/null
@@ -1,78 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * highmem.c: virtual kernel memory mappings for high memory
- *
- * PowerPC version, stolen from the i386 version.
- *
- * Used in CONFIG_HIGHMEM systems for memory pages which
- * are not addressable by direct kernel virtual addresses.
- *
- * Copyright (C) 1999 Gerhard Wichert, Siemens AG
- *		      Gerhard.Wichert@pdb.siemens.de
- *
- *
- * Redesigned the x86 32-bit VM architecture to deal with
- * up to 16 Terrabyte physical memory. With current x86 CPUs
- * we now support up to 64 Gigabytes physical RAM.
- *
- * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
- *
- * Reworked for PowerPC by various contributors. Moved from
- * highmem.h by Benjamin Herrenschmidt (c) 2009 IBM Corp.
- */
-
-#include <linux/export.h>
-#include <linux/highmem.h>
-
-/*
- * The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
- * gives a more generic (and caching) interface. But kmap_atomic can
- * be used in IRQ contexts, so in some (very limited) cases we need
- * it.
- */
-#include <asm/tlbflush.h>
-
-void *kmap_atomic_high_prot(struct page *page, pgprot_t prot)
-{
-
-	unsigned long vaddr;
-	int idx, type;
-
-	type = kmap_atomic_idx_push();
-	idx = type + KM_TYPE_NR*smp_processor_id();
-	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
-#ifdef CONFIG_DEBUG_HIGHMEM
-	BUG_ON(!pte_none(*(kmap_pte-idx)));
-#endif
-	set_pte_at(&init_mm, vaddr, kmap_pte-idx, mk_pte(page, prot));
-	local_flush_tlb_page(NULL, vaddr);
-
-	return (void *) vaddr;
-}
-EXPORT_SYMBOL(kmap_atomic_high_prot);
-
-void kunmap_atomic_high(void *kvaddr)
-{
-	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
-	int type;
-	unsigned int idx;
-
-	if (vaddr < __fix_to_virt(FIX_KMAP_END))
-		return;
-
-	type = kmap_atomic_idx();
-
-	idx = type + KM_TYPE_NR * smp_processor_id();
-#ifdef CONFIG_DEBUG_HIGHMEM
-	BUG_ON(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
-#endif
-	/*
-	 * force other mappings to Oops if they'll try to access
-	 * this pte without first remap it
-	 */
-	pte_clear(&init_mm, vaddr, kmap_pte-idx);
-	local_flush_tlb_page(NULL, vaddr);
-
-	kmap_atomic_idx_pop();
-}
-EXPORT_SYMBOL(kunmap_atomic_high);
--- a/arch/microblaze/mm/init.c
+++ b/arch/microblaze/mm/init.c
@@ -49,17 +49,11 @@ unsigned long lowmem_size;
 EXPORT_SYMBOL(min_low_pfn);
 EXPORT_SYMBOL(max_low_pfn);
 
-#ifdef CONFIG_HIGHMEM
-pte_t *kmap_pte;
-EXPORT_SYMBOL(kmap_pte);
-
 static void __init highmem_init(void)
 {
 	pr_debug("%x\n", (u32)PKMAP_BASE);
 	map_page(PKMAP_BASE, 0, 0);	/* XXX gross */
 	pkmap_page_table = virt_to_kpte(PKMAP_BASE);
-
-	kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
 }
 
 static void highmem_setup(void)

