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 --- arch/arm/include/asm/system.h | 2 +- arch/arm/lib/cache-cp15.c | 5 +++++ 2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h index b928bd8..2f430ad 100644 --- a/arch/arm/include/asm/system.h +++ b/arch/arm/include/asm/system.h @@ -329,7 +329,7 @@ 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 70e94f0..4d9903e 100644 --- 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=%llu\n", __func__, &start, size, + option); +#else debug("%s: start=%pa, size=%zu, option=%d\n", __func__, &start, size, option); +#endif for (upto = start; upto < end; upto++) set_section_dcache(upto, option);