From: Matthew Wilcox (Oracle) <willy@infradead.org>
Date: Thu, 26 Jan 2023 20:07:27 +0000 (+0000)
Subject: highmem: round down the address passed to kunmap_flush_on_unmap()
X-Git-Tag: baikal/aarch64/sdk6.1~38
X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=a447ba12110bf06c5be946da4870acde686bc2f8;p=kernel.git

highmem: round down the address passed to kunmap_flush_on_unmap()

commit 88d7b12068b95731c280af8ce88e8ee9561f96de upstream.

We already round down the address in kunmap_local_indexed() which is the
other implementation of __kunmap_local().  The only implementation of
kunmap_flush_on_unmap() is PA-RISC which is expecting a page-aligned
address.  This may be causing PA-RISC to be flushing the wrong addresses
currently.

Link: https://lkml.kernel.org/r/20230126200727.1680362-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Fixes: 125a79662d53 ("highmem: Provide generic variant of kmap_atomic*")
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Helge Deller <deller@gmx.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h
index 034b1106d0228..e098f38422af5 100644
--- a/include/linux/highmem-internal.h
+++ b/include/linux/highmem-internal.h
@@ -200,7 +200,7 @@ static inline void *kmap_local_pfn(unsigned long pfn)
 static inline void __kunmap_local(const void *addr)
 {
 #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
-	kunmap_flush_on_unmap(addr);
+	kunmap_flush_on_unmap(PTR_ALIGN_DOWN(addr, PAGE_SIZE));
 #endif
 }
 
@@ -227,7 +227,7 @@ static inline void *kmap_atomic_pfn(unsigned long pfn)
 static inline void __kunmap_atomic(const void *addr)
 {
 #ifdef ARCH_HAS_FLUSH_ON_KUNMAP
-	kunmap_flush_on_unmap(addr);
+	kunmap_flush_on_unmap(PTR_ALIGN_DOWN(addr, PAGE_SIZE));
 #endif
 	pagefault_enable();
 	if (IS_ENABLED(CONFIG_PREEMPT_RT))