linux-kernel - [PATCH 1/2] NOMMU: new vcoalesce helper function

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 12 Jan 2011 00:08:08 -0500
From:	Mike Frysinger <vapier@...too.org>
To:	uclinux-dev@...inux.org, David Howells <dhowells@...hat.com>,
	David McCullough <davidm@...pgear.com>,
	Greg Ungerer <gerg@...inux.org>,
	Paul Mundt <lethal@...ux-sh.org>
Cc:	uclinux-dist-devel@...ckfin.uclinux.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] NOMMU: new vcoalesce helper function

We can't support vmap on NOMMU systems, so add a new vcoalesce function
which combines maps via kmalloc.  A bit more overhead, but at least it
works.  For MMU systems, vcoalesce simply redirects to vmap.

Signed-off-by: Mike Frysinger <vapier@...too.org>
---
 include/linux/vmalloc.h |    3 +++
 mm/nommu.c              |   22 +++++++++++++++++++++-
 2 files changed, 24 insertions(+), 1 deletions(-)

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 44b54f6..1dec450 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -44,10 +44,13 @@ extern void vm_unmap_aliases(void);
 
 #ifdef CONFIG_MMU
 extern void __init vmalloc_init(void);
+#define vcoalesce(...) vmap(...)
 #else
 static inline void vmalloc_init(void)
 {
 }
+extern void *vcoalesce(struct page **pages, unsigned int count,
+			unsigned long flags, pgprot_t prot);
 #endif
 
 extern void *vmalloc(unsigned long size);
diff --git a/mm/nommu.c b/mm/nommu.c
index ef4045d..c1b8e39 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -402,6 +402,26 @@ void *vmalloc_32_user(unsigned long size)
 }
 EXPORT_SYMBOL(vmalloc_32_user);
 
+void *vcoalesce(struct page **pages, unsigned int count,
+	unsigned long flags, pgprot_t prot)
+{
+	unsigned int i;
+	void *new_map, *page_data;
+
+	new_map = kmalloc(count << PAGE_SHIFT, GFP_KERNEL);
+	if (!new_map)
+		return NULL;
+
+	for (i = 0; i < count; ++i) {
+		page_data = kmap(pages[i]);
+		memcpy(new_map + (i << PAGE_SHIFT), page_data, PAGE_SIZE);
+		kunmap(page_data);
+	}
+
+	return new_map;
+}
+EXPORT_SYMBOL(vcoalesce);
+
 void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
 {
 	BUG();
@@ -411,7 +431,7 @@ EXPORT_SYMBOL(vmap);
 
 void vunmap(const void *addr)
 {
-	BUG();
+	kfree(addr);
 }
 EXPORT_SYMBOL(vunmap);
 
-- 
1.7.4.rc1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/