linux-kernel - [RFC][PATCH 2/2] ARM: ioremap: Add IO mapping space reused support.

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

Date:	Mon, 12 May 2014 10:19:55 +0800
From:	Richard Lee <superlibj8301@...il.com>
To:	<linux@....linux.org.uk>, <linux-arm-kernel@...ts.infradead.org>,
	<linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>
CC:	Richard Lee <superlibj8301@...il.com>,
	Richard Lee <superlibj@...il.com>
Subject: [RFC][PATCH 2/2] ARM: ioremap: Add IO mapping space reused support.

For the IO mapping, for the same physical address space maybe
mapped more than one time, for example, in some SoCs:
0x20000000 ~ 0x20001000: are global control IO physical map,
and this range space will be used by many drivers.
And then if each driver will do the same ioremap operation, we
will waste to much malloc virtual spaces.

This patch add IO mapping space reused support.

Signed-off-by: Richard Lee <superlibj@...il.com>
---
 arch/arm/mm/ioremap.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index f9c32ba..26a3744 100644
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -260,7 +260,7 @@ void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
 {
 	const struct mem_type *type;
 	int err;
-	unsigned long addr;
+	unsigned long addr, off;
 	struct vm_struct *area;
 	phys_addr_t paddr = __pfn_to_phys(pfn);
 
@@ -301,6 +301,12 @@ void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
 	if (WARN_ON(pfn_valid(pfn)))
 		return NULL;
 
+	area = find_vm_area_paddr(paddr, size, &off, VM_IOREMAP);
+	if (area) {
+		addr = (unsigned long)area->addr;
+		return (void __iomem *)(offset + off + addr);
+	}
+
 	area = get_vm_area_caller(size, VM_IOREMAP, caller);
  	if (!area)
  		return NULL;
@@ -410,6 +416,9 @@ void __iounmap(volatile void __iomem *io_addr)
 	if (svm)
 		return;
 
+	if (!vm_area_is_aready_to_free((unsigned long)addr))
+		return;
+
 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 	{
 		struct vm_struct *vm;
-- 
1.8.4

--
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/