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x86: add far read test to testmmiotrace 

Apparently pages far into an ioremapped region might not actually be
mapped during ioremap(). Add an optional read test to try to trigger a
multiply faulting MMIO access. Also add more messages to the kernel log
to help debugging.

This patch is based on a patch suggested by
Stuart Bennett <stuart@freedesktop.org>
who discovered bugs in mmiotrace related to normal kernel space faults.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Cc: Stuart Bennett <stuart@freedesktop.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Pekka Paalanen 2009-03-01 16:10:08 +02:00 committed by Ingo Molnar
parent fab852aaf7
commit 5ff93697fc
1 changed files with 28 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
arch/x86/mm/testmmiotrace.c
View File

@ -9,7 +9,13 @@
static unsigned long mmio_address;
module_param(mmio_address, ulong, 0);
MODULE_PARM_DESC(mmio_address, "Start address of the mapping of 16 kB.");
MODULE_PARM_DESC(mmio_address, " Start address of the mapping of 16 kB "
"(or 8 MB if read_far is non-zero).");
static unsigned long read_far = 0x400100;
module_param(read_far, ulong, 0);
MODULE_PARM_DESC(read_far, " Offset of a 32-bit read within 8 MB "
"(default: 0x400100).");
static unsigned v16(unsigned i)
{
@ -24,6 +30,7 @@ static unsigned v32(unsigned i)
static void do_write_test(void __iomem *p)
{
unsigned int i;
pr_info(MODULE_NAME ": write test.\n");
mmiotrace_printk("Write test.\n");
for (i = 0; i < 256; i++)
@ -40,6 +47,7 @@ static void do_read_test(void __iomem *p)
{
unsigned int i;
unsigned errs[3] = { 0 };
pr_info(MODULE_NAME ": read test.\n");
mmiotrace_printk("Read test.\n");
for (i = 0; i < 256; i++)
@ -58,9 +66,17 @@ static void do_read_test(void __iomem *p)
errs[0], errs[1], errs[2]);
}
static void do_test(void)
static void do_read_far_test(void __iomem *p)
{
void __iomem *p = ioremap_nocache(mmio_address, 0x4000);
pr_info(MODULE_NAME ": read far test.\n");
mmiotrace_printk("Read far test.\n");
ioread32(p + read_far);
}
static void do_test(unsigned long size)
{
void __iomem *p = ioremap_nocache(mmio_address, size);
if (!p) {
pr_err(MODULE_NAME ": could not ioremap, aborting.\n");
return;
@ -68,11 +84,15 @@ static void do_test(void)
mmiotrace_printk("ioremap returned %p.\n", p);
do_write_test(p);
do_read_test(p);
if (read_far && read_far < size - 4)
do_read_far_test(p);
iounmap(p);
}
static int __init init(void)
{
unsigned long size = (read_far) ? (8 << 20) : (16 << 10);
if (mmio_address == 0) {
pr_err(MODULE_NAME ": you have to use the module argument "
"mmio_address.\n");
@ -81,10 +101,11 @@ static int __init init(void)
return -ENXIO;
}
pr_warning(MODULE_NAME ": WARNING: mapping 16 kB @ 0x%08lx "
"in PCI address space, and writing "
"rubbish in there.\n", mmio_address);
do_test();
pr_warning(MODULE_NAME ": WARNING: mapping %lu kB @ 0x%08lx in PCI "
"address space, and writing 16 kB of rubbish in there.\n",
size >> 10, mmio_address);
do_test(size);
pr_info(MODULE_NAME ": All done.\n");
return 0;
}