Subject: devmem, x86: fix rename of CONFIG_NONPROMISC_DEVMEM

From: Arjan van de Ven <arjan@infradead.org>
Date: Sat, 19 Jul 2008 15:47:17 -0700

CONFIG_NONPROMISC_DEVMEM was a rather confusing name - but renaming it
to CONFIG_PROMISC_DEVMEM causes problems on architectures that do not
support this feature; this patch renames it to CONFIG_STRICT_DEVMEM,
so that architectures can opt-in into it.

( the polarity of the option is still the same as it was originally; it
  needs to be for now to not break architectures that don't have the
  infastructure yet to support this feature)
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: "V.Radhakrishnan" <rk@atr-labs.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

arch/x86/Kconfig.debug

@@ -5,14 +5,15 @@ config TRACE_IRQFLAGS_SUPPORT
 
 source "lib/Kconfig.debug"
 
-config PROMISC_DEVMEM
-	bool "Allow unlimited access to /dev/mem"
-	default y
+config STRICT_DEVMEM
+	bool "Filter access to /dev/mem"
 	help
 	  If this option is left on, you allow userspace (root) access to all
 	  of memory, including kernel and userspace memory. Accidental
 	  access to this is obviously disastrous, but specific access can
-	  be used by people debugging the kernel.
+	  be used by people debugging the kernel. Note that with PAT support
+	  enabled, even in this case there are restrictions on /dev/mem
+	  use due to the cache aliasing requirements.
 
 	  If this option is switched on, the /dev/mem file only allows
 	  userspace access to PCI space and the BIOS code and data regions.

arch/x86/configs/i386_defconfig

@@ -2047,7 +2047,7 @@ CONFIG_PROVIDE_OHCI1394_DMA_INIT=y
 # CONFIG_SAMPLES is not set
 # CONFIG_KGDB is not set
 CONFIG_HAVE_ARCH_KGDB=y
-# CONFIG_NONPROMISC_DEVMEM is not set
+# CONFIG_STRICT_DEVMEM is not set
 CONFIG_EARLY_PRINTK=y
 CONFIG_DEBUG_STACKOVERFLOW=y
 CONFIG_DEBUG_STACK_USAGE=y

arch/x86/configs/x86_64_defconfig

@@ -2012,7 +2012,7 @@ CONFIG_PROVIDE_OHCI1394_DMA_INIT=y
 # CONFIG_SAMPLES is not set
 # CONFIG_KGDB is not set
 CONFIG_HAVE_ARCH_KGDB=y
-# CONFIG_NONPROMISC_DEVMEM is not set
+# CONFIG_STRICT_DEVMEM is not set
 CONFIG_EARLY_PRINTK=y
 CONFIG_DEBUG_STACKOVERFLOW=y
 CONFIG_DEBUG_STACK_USAGE=y

arch/x86/mm/pat.c

@@ -373,8 +373,8 @@ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 	return vma_prot;
 }
 
-#ifndef CONFIG_PROMISC_DEVMEM
-/* This check is done in drivers/char/mem.c in case of !PROMISC_DEVMEM*/
+#ifdef CONFIG_STRICT_DEVMEM
+/* This check is done in drivers/char/mem.c in case of STRICT_DEVMEM*/
 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
 {
 	return 1;
@@ -398,7 +398,7 @@ static inline int range_is_allowed(unsigned long pfn, unsigned long size)
 	}
 	return 1;
 }
-#endif /* CONFIG_PROMISC_DEVMEM */
+#endif /* CONFIG_STRICT_DEVMEM */
 
 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
 				unsigned long size, pgprot_t *vma_prot)

drivers/char/mem.c

@@ -80,7 +80,7 @@ static inline int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
 }
 #endif
 
-#ifndef CONFIG_PROMISC_DEVMEM
+#ifdef CONFIG_STRICT_DEVMEM
 static inline int range_is_allowed(unsigned long pfn, unsigned long size)
 {
 	u64 from = ((u64)pfn) << PAGE_SHIFT;