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| author | Hendrik Brueckner <brueckner@linux.vnet.ibm.com> | 2010-11-10 10:05:55 +0100 |
|---|---|---|
| committer | Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> | 2010-11-10 10:05:54 +0100 |
| commit | ec6743bb06510c7b629603ce35713d6ae9273579 (patch) | |
| tree | 6faddd2ca7b991987bafc2a7d4241ad6d141b765 | |
| parent | ca768b663131ca644689fcadc9ca092dcc96a758 (diff) | |
| download | linux-ec6743bb06510c7b629603ce35713d6ae9273579.tar.bz2 | |
[S390] mm: add devmem_is_allowed() for STRICT_DEVMEM checking
Provide the devmem_is_allowed() routine to restrict access to
kernel memory from userspace.
Set the CONFIG_STRICT_DEVMEM config option to switch on checking.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
| -rw-r--r-- | arch/s390/Kconfig.debug | 12 | ||||
| -rw-r--r-- | arch/s390/include/asm/page.h | 5 |
2 files changed, 17 insertions, 0 deletions
diff --git a/arch/s390/Kconfig.debug b/arch/s390/Kconfig.debug index 45e0c6199f36..05221b13ffb1 100644 --- a/arch/s390/Kconfig.debug +++ b/arch/s390/Kconfig.debug @@ -6,6 +6,18 @@ config TRACE_IRQFLAGS_SUPPORT source "lib/Kconfig.debug" +config STRICT_DEVMEM + def_bool y + prompt "Filter access to /dev/mem" + ---help--- + This option restricts access to /dev/mem. If this option is + disabled, you allow userspace access to all memory, including + kernel and userspace memory. Accidental memory access is likely + to be disastrous. + Memory access is required for experts who want to debug the kernel. + + If you are unsure, say Y. + config DEBUG_STRICT_USER_COPY_CHECKS bool "Strict user copy size checks" ---help--- diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h index a8729ea7e9ac..3c987e9ec8d6 100644 --- a/arch/s390/include/asm/page.h +++ b/arch/s390/include/asm/page.h @@ -130,6 +130,11 @@ struct page; void arch_free_page(struct page *page, int order); void arch_alloc_page(struct page *page, int order); +static inline int devmem_is_allowed(unsigned long pfn) +{ + return 0; +} + #define HAVE_ARCH_FREE_PAGE #define HAVE_ARCH_ALLOC_PAGE |