lib/ioremap.c: add huge I/O map capability interfaces

Add ioremap_pud_enabled() and ioremap_pmd_enabled(), which return 1 when
I/O mappings with pud/pmd are enabled on the kernel.

ioremap_huge_init() calls arch_ioremap_pud_supported() and
arch_ioremap_pmd_supported() to initialize the capabilities at boot-time.

A new kernel option "nohugeiomap" is also added, so that user can disable
the huge I/O map capabilities when necessary.

Signed-off-by: Toshi Kani <toshi.kani@hp.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Robert Elliott <Elliott@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index d5779bbdc9ffb6146f55c29ae1fab40856868e72..3c23ed5b7a74c7d08f82d7a5a0a6950362dbe2ed 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2322,6 +2322,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        register save and restore. The kernel will only save
                        legacy floating-point registers on task switch.
 
+       nohugeiomap     [KNL,x86] Disable kernel huge I/O mappings.
+
        noxsave         [BUGS=X86] Disables x86 extended register state save
                        and restore using xsave. The kernel will fallback to
                        enabling legacy floating-point and sse state.

diff --git a/arch/Kconfig b/arch/Kconfig
index a9c95d36ba701ce91193d3670a7fb9c5b6621f6e..c88c23f0a1da0a22f7da170b60b7f0f7b8aedf90 100644 (file)
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -446,6 +446,9 @@ config HAVE_IRQ_TIME_ACCOUNTING
 config HAVE_ARCH_TRANSPARENT_HUGEPAGE
        bool
 
+config HAVE_ARCH_HUGE_VMAP
+       bool
+
 config HAVE_ARCH_SOFT_DIRTY
        bool
 

diff --git a/include/linux/io.h b/include/linux/io.h
index fa02e55e5a2e1e2ea564829e1025a09d0722e4e2..1ce8b4e984c977df2b11d0593278fd9349dc1e35 100644 (file)
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -38,6 +38,13 @@ static inline int ioremap_page_range(unsigned long addr, unsigned long end,
 }
 #endif
 
+void __init ioremap_huge_init(void);
+
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+int arch_ioremap_pud_supported(void);
+int arch_ioremap_pmd_supported(void);
+#endif
+
 /*
  * Managed iomap interface
  */

diff --git a/init/main.c b/init/main.c
index 6f0f1c5ff8cc82c41b36f107f68732003c5b1dc3..119cdf13348ef275894dd00a38b467d4ef3bf645 100644 (file)
--- a/init/main.c
+++ b/init/main.c
@@ -80,6 +80,7 @@
 #include <linux/list.h>
 #include <linux/integrity.h>
 #include <linux/proc_ns.h>
+#include <linux/io.h>
 
 #include <asm/io.h>
 #include <asm/bugs.h>
@@ -484,6 +485,7 @@ static void __init mm_init(void)
        percpu_init_late();
        pgtable_init();
        vmalloc_init();
+       ioremap_huge_init();
 }
 
 asmlinkage __visible void __init start_kernel(void)

diff --git a/lib/ioremap.c b/lib/ioremap.c
index 0c9216c48762a0e941910f8707c0a276f62a91ba..0ce18aacd4b14ceb8592a61b6e5f68d269ce68c0 100644 (file)
--- a/lib/ioremap.c
+++ b/lib/ioremap.c
@@ -13,6 +13,44 @@
 #include <asm/cacheflush.h>
 #include <asm/pgtable.h>
 
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+int __read_mostly ioremap_pud_capable;
+int __read_mostly ioremap_pmd_capable;
+int __read_mostly ioremap_huge_disabled;
+
+static int __init set_nohugeiomap(char *str)
+{
+       ioremap_huge_disabled = 1;
+       return 0;
+}
+early_param("nohugeiomap", set_nohugeiomap);
+
+void __init ioremap_huge_init(void)
+{
+       if (!ioremap_huge_disabled) {
+               if (arch_ioremap_pud_supported())
+                       ioremap_pud_capable = 1;
+               if (arch_ioremap_pmd_supported())
+                       ioremap_pmd_capable = 1;
+       }
+}
+
+static inline int ioremap_pud_enabled(void)
+{
+       return ioremap_pud_capable;
+}
+
+static inline int ioremap_pmd_enabled(void)
+{
+       return ioremap_pmd_capable;
+}
+
+#else  /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
+void __init ioremap_huge_init(void) { }
+static inline int ioremap_pud_enabled(void) { return 0; }
+static inline int ioremap_pmd_enabled(void) { return 0; }
+#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
+
 static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
                unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
 {