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Subject[PATCH 1/3] x86 mmiotrace: fix page-unaligned ioremaps
From c306ab1bc1f40e74f7015a498784e1a39ec6229b Mon Sep 17 00:00:00 2001
From: Pekka Paalanen <pq@iki.fi>
Date: Tue, 29 Apr 2008 22:39:40 +0300
Subject: [PATCH] x86 mmiotrace: fix page-unaligned ioremaps

mmiotrace_ioremap() expects to receive the original unaligned map phys address
and size. Also fix {un,}register_kmmio_probe() to deal properly with
unaligned size.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
---
arch/x86/mm/ioremap.c | 4 +++-
arch/x86/mm/kmmio.c | 13 +++++++++++--
arch/x86/mm/mmio-mod.c | 1 +
3 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index ce73980..923621d 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -123,6 +123,8 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
{
unsigned long pfn, offset, vaddr;
resource_size_t last_addr;
+ const resource_size_t unaligned_phys_addr = phys_addr;
+ const unsigned long unaligned_size = size;
struct vm_struct *area;
unsigned long new_prot_val;
pgprot_t prot;
@@ -235,7 +237,7 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
}

ret_addr = (void __iomem *) (vaddr + offset);
- mmiotrace_ioremap(phys_addr, size, ret_addr);
+ mmiotrace_ioremap(unaligned_phys_addr, unaligned_size, ret_addr);

return ret_addr;
}
diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c
index 40567d8..c12be07 100644
--- a/arch/x86/mm/kmmio.c
+++ b/arch/x86/mm/kmmio.c
@@ -352,11 +352,19 @@ static void release_kmmio_fault_page(unsigned long page,
}
}

+/*
+ * With page-unaligned ioremaps, one or two armed pages may contain
+ * addresses from outside the intended mapping. Events for these addresses
+ * are currently silently dropped. The events may result only from programming
+ * mistakes by accessing addresses before the beginning or past the end of a
+ * mapping.
+ */
int register_kmmio_probe(struct kmmio_probe *p)
{
unsigned long flags;
int ret = 0;
unsigned long size = 0;
+ const unsigned long size_lim = p->len + (p->addr & ~PAGE_MASK);

spin_lock_irqsave(&kmmio_lock, flags);
if (get_kmmio_probe(p->addr)) {
@@ -365,7 +373,7 @@ int register_kmmio_probe(struct kmmio_probe *p)
}
kmmio_count++;
list_add_rcu(&p->list, &kmmio_probes);
- while (size < p->len) {
+ while (size < size_lim) {
if (add_kmmio_fault_page(p->addr + size))
pr_err("kmmio: Unable to set page fault.\n");
size += PAGE_SIZE;
@@ -437,11 +445,12 @@ void unregister_kmmio_probe(struct kmmio_probe *p)
{
unsigned long flags;
unsigned long size = 0;
+ const unsigned long size_lim = p->len + (p->addr & ~PAGE_MASK);
struct kmmio_fault_page *release_list = NULL;
struct kmmio_delayed_release *drelease;

spin_lock_irqsave(&kmmio_lock, flags);
- while (size < p->len) {
+ while (size < size_lim) {
release_kmmio_fault_page(p->addr + size, &release_list);
size += PAGE_SIZE;
}
diff --git a/arch/x86/mm/mmio-mod.c b/arch/x86/mm/mmio-mod.c
index a8d2a00..278998c 100644
--- a/arch/x86/mm/mmio-mod.c
+++ b/arch/x86/mm/mmio-mod.c
@@ -280,6 +280,7 @@ static void ioremap_trace_core(unsigned long offset, unsigned long size,
{
static atomic_t next_id;
struct remap_trace *trace = kmalloc(sizeof(*trace), GFP_KERNEL);
+ /* These are page-unaligned. */
struct mmiotrace_map map = {
.phys = offset,
.virt = (unsigned long)addr,
--
1.5.3.7


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