lkml.org 
[lkml]   [2017]   [Dec]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH v1 5/6] resource: Set type of "reserve=" user-specified resources
From
Date
From: Bjorn Helgaas <bhelgaas@google.com>

When we reserve regions because the user specified a "reserve=" parameter,
set the resource type to either IORESOURCE_IO (for regions below 0x10000)
or IORESOURCE_MEM. The test for 0x10000 is just a heuristic; obviously
there can be memory below 0x10000 as well.

Improve documentation of the "reserve=" parameter.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
Documentation/admin-guide/kernel-parameters.txt | 6 +++++-
kernel/resource.c | 24 +++++++++++++++++------
2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6571fbfdb2a1..78cdf6a637fc 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3675,7 +3675,11 @@
[KNL, SMP] Set scheduler's default relax_domain_level.
See Documentation/cgroup-v1/cpusets.txt.

- reserve= [KNL,BUGS] Force the kernel to ignore some iomem area
+ reserve= [KNL,BUGS] Force kernel to ignore I/O ports or memory
+ Format: <base1>,<size1>[,<base2>,<size2>,...]
+ Reserve I/O ports or memory so the kernel won't use
+ them. If <base> is less than 0x10000, the region
+ is assumed to be I/O ports; otherwise it is memory.

reservetop= [X86-32]
Format: nn[KMG]
diff --git a/kernel/resource.c b/kernel/resource.c
index 54ba6de3757c..ba3252f7c319 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -1478,7 +1478,7 @@ void __devm_release_region(struct device *dev, struct resource *parent,
EXPORT_SYMBOL(__devm_release_region);

/*
- * Called from init/main.c to reserve IO ports.
+ * Reserve I/O ports or memory based on "reserve=" kernel parameter.
*/
#define MAXRESERVE 4
static int __init reserve_setup(char *str)
@@ -1489,26 +1489,38 @@ static int __init reserve_setup(char *str)
for (;;) {
unsigned int io_start, io_num;
int x = reserved;
+ struct resource *parent;

- if (get_option (&str, &io_start) != 2)
+ if (get_option(&str, &io_start) != 2)
break;
- if (get_option (&str, &io_num) == 0)
+ if (get_option(&str, &io_num) == 0)
break;
if (x < MAXRESERVE) {
struct resource *res = reserve + x;
+
+ /*
+ * If the region starts below 0x10000, we assume it's
+ * I/O port space; otherwise assume it's memory.
+ */
+ if (io_start < 0x10000) {
+ res->flags = IORESOURCE_IO;
+ parent = &ioport_resource;
+ } else {
+ res->flags = IORESOURCE_MEM;
+ parent = &iomem_resource;
+ }
res->name = "reserved";
res->start = io_start;
res->end = io_start + io_num - 1;
- res->flags = IORESOURCE_BUSY;
+ res->flags |= IORESOURCE_BUSY;
res->desc = IORES_DESC_NONE;
res->child = NULL;
- if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
+ if (request_resource(parent, res) == 0)
reserved = x+1;
}
}
return 1;
}
-
__setup("reserve=", reserve_setup);

/*
\
 
 \ /
  Last update: 2017-12-05 01:41    [W:0.040 / U:0.904 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site