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authorLinus Torvalds <torvalds@linux-foundation.org>2008-04-18 08:37:01 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-18 08:37:01 -0700
commit9732b6112343df2872518ec6701c8ef729310a05 (patch)
tree9e3dcc461845038da4730c2062eee546348ca445 /mm
parent9e9abecfc0ff3a9ad2ead954b37bbfcb863c775e (diff)
parent1a9a3e76dde191f82f7a8a66059dcbb4a9f63ff3 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-kgdb
* git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-kgdb: kgdb: always use icache flush for sw breakpoints kgdb: fix SMP NMI kgdb_handle_exception exit race kgdb: documentation fixes kgdb: allow static kgdbts boot configuration kgdb: add documentation kgdb: Kconfig fix kgdb: add kgdb internal test suite kgdb: fix several kgdb regressions kgdb: kgdboc pl011 I/O module kgdb: fix optional arch functions and probe_kernel_* kgdb: add x86 HW breakpoints kgdb: print breakpoint removed on exception kgdb: clocksource watchdog kgdb: fix NMI hangs kgdb: fix kgdboc dynamic module configuration kgdb: document parameters x86: kgdb support consoles: polling support, kgdboc kgdb: core uaccess: add probe_kernel_write()
Diffstat (limited to 'mm')
-rw-r--r--mm/Makefile2
-rw-r--r--mm/maccess.c55
2 files changed, 56 insertions, 1 deletions
diff --git a/mm/Makefile b/mm/Makefile
index a5b0dd93427..18c143b3c46 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -8,7 +8,7 @@ mmu-$(CONFIG_MMU) := fremap.o highmem.o madvise.o memory.o mincore.o \
vmalloc.o
obj-y := bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \
- page_alloc.o page-writeback.o pdflush.o \
+ maccess.o page_alloc.o page-writeback.o pdflush.o \
readahead.o swap.o truncate.o vmscan.o \
prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \
page_isolation.o $(mmu-y)
diff --git a/mm/maccess.c b/mm/maccess.c
new file mode 100644
index 00000000000..ac40796cfb1
--- /dev/null
+++ b/mm/maccess.c
@@ -0,0 +1,55 @@
+/*
+ * Access kernel memory without faulting.
+ */
+#include <linux/uaccess.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+
+/**
+ * probe_kernel_read(): safely attempt to read from a location
+ * @dst: pointer to the buffer that shall take the data
+ * @src: address to read from
+ * @size: size of the data chunk
+ *
+ * Safely read from address @src to the buffer at @dst. If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+long probe_kernel_read(void *dst, void *src, size_t size)
+{
+ long ret;
+ mm_segment_t old_fs = get_fs();
+
+ set_fs(KERNEL_DS);
+ pagefault_disable();
+ ret = __copy_from_user_inatomic(dst,
+ (__force const void __user *)src, size);
+ pagefault_enable();
+ set_fs(old_fs);
+
+ return ret ? -EFAULT : 0;
+}
+EXPORT_SYMBOL_GPL(probe_kernel_read);
+
+/**
+ * probe_kernel_write(): safely attempt to write to a location
+ * @dst: address to write to
+ * @src: pointer to the data that shall be written
+ * @size: size of the data chunk
+ *
+ * Safely write to address @dst from the buffer at @src. If a kernel fault
+ * happens, handle that and return -EFAULT.
+ */
+long probe_kernel_write(void *dst, void *src, size_t size)
+{
+ long ret;
+ mm_segment_t old_fs = get_fs();
+
+ set_fs(KERNEL_DS);
+ pagefault_disable();
+ ret = __copy_to_user_inatomic((__force void __user *)dst, src, size);
+ pagefault_enable();
+ set_fs(old_fs);
+
+ return ret ? -EFAULT : 0;
+}
+EXPORT_SYMBOL_GPL(probe_kernel_write);