From: bob picco <bpicco@xxxxxxxxxx>
This patch attempts to restrict mmap of /dev/mem. It tightens up the bus
error (DTLB errors) issues related to mmap of /dev/mem.
A root privileged application like python using dmidecode mmap-s /dev/mem to
examine an x86 magic area which is non-existent on sparc64. This results
in a power off event within sun4v_dtlb_error_report because the HV reports
an invalid RA.
The mmap restriction of /dev/mem does introduce ARCH_HAS_VALID_PHYS_ADDR_RANGE.
This does cause us to clone the functionality of valid_phys_addr_range. A
mapper is not allowed to mmap a range which isn't kern_addr_valid true on
every 4Mb boundary.
Cc: sparclinux@xxxxxxxxxxxxxxx
Reviewed-by: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>
Signed-off-by: Bob Picco <bob.picco@xxxxxxxxxx>
---
arch/sparc/include/asm/io_64.h | 3 +++
arch/sparc/mm/init_64.c | 27 +++++++++++++++++++++++++++
2 files changed, 30 insertions(+), 0 deletions(-)
diff --git a/arch/sparc/include/asm/io_64.h b/arch/sparc/include/asm/io_64.h
index 80b54b3..3588a63 100644
--- a/arch/sparc/include/asm/io_64.h
+++ b/arch/sparc/include/asm/io_64.h
@@ -440,6 +440,9 @@ void sbus_set_sbus64(struct device *, int);
* access
*/
#define xlate_dev_mem_ptr(p) __va(p)
+#define ARCH_HAS_VALID_PHYS_ADDR_RANGE
+extern int valid_phys_addr_range(phys_addr_t addr, size_t size);
+extern int valid_mmap_phys_addr_range(unsigned long pfn, size_t size);
/*
* Convert a virtual cached pointer to an uncached pointer
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 98ac8e8..da1f051 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -169,6 +169,33 @@ unsigned long sparc64_valid_addr_bitmap[VALID_ADDR_BITMAP_BYTES /
sizeof(unsigned long)];
EXPORT_SYMBOL(sparc64_valid_addr_bitmap);
+/* This is a perfect clone of mem.c's version.*/
+int valid_phys_addr_range(phys_addr_t addr, size_t count)
+{
+ return addr + count <= __pa(high_memory);
+}
+
+/* For mmap of /dev/mem we don't permit ranges with a hole which
+ * can result in a bus error. Should a mapping be required then
+ * multiple mappings with the bus error holes avoided is necessary.
+ */
+int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
+{
+ unsigned long pa_start = pfn << PAGE_SHIFT;
+ unsigned long pa_end = pa_start + size;
+ int rc = 0;
+
+ for (pa_start = (pa_start >> ILOG2_4MB) << ILOG2_4MB;
+ pa_start < pa_end; pa_start = pa_start + (1UL << ILOG2_4MB)) {
+ unsigned long vaddr = (unsigned long) __va(pa_start);
+
+ rc = kern_addr_valid(vaddr);
+ if (!rc)
+ break;
+ }
+ return rc;
+}
+
/* Kernel physical address base and size in bytes. */
unsigned long kern_base __read_mostly;
unsigned long kern_size __read_mostly;
--
1.7.1
--
To unsubscribe from this list: send the line "unsubscribe sparclinux" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
