LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Toshi Kani <toshi.kani@hp.com>
To: akpm@linux-foundation.org, hpa@zytor.com, tglx@linutronix.de,
	mingo@redhat.com, arnd@arndb.de
Cc: linux-mm@kvack.org, x86@kernel.org, linux-kernel@vger.kernel.org,
	dave.hansen@intel.com, Elliott@hp.com,
	Toshi Kani <toshi.kani@hp.com>
Subject: [PATCH v3 5/6] x86, mm: Support huge I/O mapping capability I/F
Date: Tue,  3 Mar 2015 10:44:23 -0700	[thread overview]
Message-ID: <1425404664-19675-6-git-send-email-toshi.kani@hp.com> (raw)
In-Reply-To: <1425404664-19675-1-git-send-email-toshi.kani@hp.com>

This patch implements huge I/O mapping capability interfaces
for ioremap() on x86.

IOREMAP_MAX_ORDER is defined to PUD_SHIFT on x86/64 and
PMD_SHIFT on x86/32, which overrides the default value
defined in <linux/vmalloc.h>.

Signed-off-by: Toshi Kani <toshi.kani@hp.com>
---
 arch/x86/include/asm/page_types.h |    2 ++
 arch/x86/mm/ioremap.c             |   23 +++++++++++++++++++++--
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/page_types.h b/arch/x86/include/asm/page_types.h
index 95e11f7..b526093 100644
--- a/arch/x86/include/asm/page_types.h
+++ b/arch/x86/include/asm/page_types.h
@@ -40,8 +40,10 @@
 
 #ifdef CONFIG_X86_64
 #include <asm/page_64_types.h>
+#define IOREMAP_MAX_ORDER       (PUD_SHIFT)
 #else
 #include <asm/page_32_types.h>
+#define IOREMAP_MAX_ORDER       (PMD_SHIFT)
 #endif	/* CONFIG_X86_64 */
 
 #ifndef __ASSEMBLY__
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index fdf617c..5ead4d6 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -67,8 +67,13 @@ static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
 
 /*
  * Remap an arbitrary physical address space into the kernel virtual
- * address space. Needed when the kernel wants to access high addresses
- * directly.
+ * address space. It transparently creates kernel huge I/O mapping when
+ * the physical address is aligned by a huge page size (1GB or 2MB) and
+ * the requested size is at least the huge page size.
+ *
+ * NOTE: MTRRs can override PAT memory types with a 4KB granularity.
+ * Therefore, the mapping code falls back to use a smaller page toward 4KB
+ * when a mapping range is covered by non-WB type of MTRRs.
  *
  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
  * have to convert them into an offset in a page-aligned mapping, but the
@@ -326,6 +331,20 @@ void iounmap(volatile void __iomem *addr)
 }
 EXPORT_SYMBOL(iounmap);
 
+int arch_ioremap_pud_supported(void)
+{
+#ifdef CONFIG_X86_64
+	return cpu_has_gbpages;
+#else
+	return 0;
+#endif
+}
+
+int arch_ioremap_pmd_supported(void)
+{
+	return cpu_has_pse;
+}
+
 /*
  * Convert a physical pointer to a virtual kernel pointer for /dev/mem
  * access

  parent reply	other threads:[~2015-03-03 17:45 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-03 17:44 [PATCH v3 0/6] Kernel huge I/O mapping support Toshi Kani
2015-03-03 17:44 ` [PATCH v3 1/6] mm: Change __get_vm_area_node() to use fls_long() Toshi Kani
2015-03-03 17:44 ` [PATCH v3 2/6] lib: Add huge I/O map capability interfaces Toshi Kani
2015-03-03 17:44 ` [PATCH v3 3/6] mm: Change ioremap to set up huge I/O mappings Toshi Kani
2015-03-04 22:09   ` Ingo Molnar
2015-03-04 23:15     ` Toshi Kani
2015-03-03 17:44 ` [PATCH v3 4/6] mm: Change vunmap to tear down huge KVA mappings Toshi Kani
2015-03-03 17:44 ` Toshi Kani [this message]
2015-03-03 17:44 ` [PATCH v3 6/6] x86, mm: Support huge KVA mappings on x86 Toshi Kani
2015-03-03 22:44   ` Andrew Morton
2015-03-03 23:14     ` Toshi Kani
2015-03-04  1:00       ` Andrew Morton
2015-03-04 16:23         ` Toshi Kani
2015-03-04 20:17           ` Ingo Molnar
2015-03-04 21:16             ` Toshi Kani

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1425404664-19675-6-git-send-email-toshi.kani@hp.com \
    --to=toshi.kani@hp.com \
    --cc=Elliott@hp.com \
    --cc=akpm@linux-foundation.org \
    --cc=arnd@arndb.de \
    --cc=dave.hansen@intel.com \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mingo@redhat.com \
    --cc=tglx@linutronix.de \
    --cc=x86@kernel.org \
    --subject='Re: [PATCH v3 5/6] x86, mm: Support huge I/O mapping capability I/F' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).