arm: Set TTB XN bit in case DCACHE_OFF for LPAE mode

While we setup the mmu initially we mark set_section_dcache with
DCACHE_OFF flag. In case of non-LPAE mode the DCACHE_OFF macro
is rightly defined with TTB_SECT_XN_MASK set so as to mark all the
4GB XN. In case of LPAE mode  XN(Execute-never) bit is not set with
DCACHE_OFF. Hence XN bit is not set by default for DCACHE_OFF which
keeps all the regions execute okay and this leads to random speculative
fetches in random memory regions which was eventually caught by kernel
omap-l3-noc driver.

Fix this to mark the regions as XN by default.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Tom Rini <trini@konsulko.com>

diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
index c3c88d2..574a0e7 100644 (file)
--- a/arch/arm/include/asm/system.h
+++ b/arch/arm/include/asm/system.h
@@ -331,7 +331,7 @@ static inline void set_dacr(unsigned int val)
 
 /* options available for data cache on each page */
 enum dcache_option {
-       DCACHE_OFF = TTB_SECT | TTB_SECT_MAIR(0),
+       DCACHE_OFF = TTB_SECT | TTB_SECT_MAIR(0) | TTB_SECT_XN_MASK,
        DCACHE_WRITETHROUGH = TTB_SECT | TTB_SECT_MAIR(1),
        DCACHE_WRITEBACK = TTB_SECT | TTB_SECT_MAIR(2),
        DCACHE_WRITEALLOC = TTB_SECT | TTB_SECT_MAIR(3),

diff --git a/arch/arm/lib/cache-cp15.c b/arch/arm/lib/cache-cp15.c
index e9f9fc9..e9bbcf5 100644 (file)
--- a/arch/arm/lib/cache-cp15.c
+++ b/arch/arm/lib/cache-cp15.c
@@ -71,8 +71,13 @@ void mmu_set_region_dcache_behaviour(phys_addr_t start, size_t size,
 
        end = ALIGN(start + size, MMU_SECTION_SIZE) >> MMU_SECTION_SHIFT;
        start = start >> MMU_SECTION_SHIFT;
+#ifdef CONFIG_ARMV7_LPAE
+       debug("%s: start=%pa, size=%zu, option=%llx\n", __func__, &start, size,
+             option);
+#else
        debug("%s: start=%pa, size=%zu, option=0x%x\n", __func__, &start, size,
              option);
+#endif
        for (upto = start; upto < end; upto++)
                set_section_dcache(upto, option);