[PATCH 25/27] ARM: mmu32: Use pages for early MMU setup

[Sascha Hauer <s.hauer@pengutronix.de>]

Up to now we use 1MiB sections to setup the page tables in PBL. There
are two places where this leads to problems. First is OP-TEE, we have
to map the OP-TEE area with PTE_EXT_XN to prevent the instruction
prefetcher from speculating into that area. With the current section
mapping we have to align OPTEE_SIZE to 1MiB boundaries. The second
problem comes with SRAM where the PBL might be running. This SRAM has
to be mapped executable, but at the same time we should map the
surrounding areas non executable which is not always possible with
1MiB mapping granularity.

We now have everything in place to use two level page tables from PBL,
so use arch_remap_range() for the problematic cases.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 arch/arm/cpu/mmu_32.c | 31 +++++++------------------------
 1 file changed, 7 insertions(+), 24 deletions(-)

diff --git a/arch/arm/cpu/mmu_32.c b/arch/arm/cpu/mmu_32.c
index 5ebceed89f..c52b6d3a8b 100644
--- a/arch/arm/cpu/mmu_32.c
+++ b/arch/arm/cpu/mmu_32.c
@@ -117,8 +117,10 @@ void dma_flush_range(void *ptr, size_t size)
 	unsigned long end = start + size;
 
 	__dma_flush_range(start, end);
+#ifndef __PBL__
 	if (outer_cache.flush_range)
 		outer_cache.flush_range(start, end);
+#endif
 }
 
 void dma_inv_range(void *ptr, size_t size)
@@ -126,8 +128,10 @@ void dma_inv_range(void *ptr, size_t size)
 	unsigned long start = (unsigned long)ptr;
 	unsigned long end = start + size;
 
+#ifndef __PBL__
 	if (outer_cache.inv_range)
 		outer_cache.inv_range(start, end);
+#endif
 	__dma_inv_range(start, end);
 }
 
@@ -548,16 +552,6 @@ void *dma_alloc_writecombine(size_t size, dma_addr_t *dma_handle)
 	return dma_alloc_map(size, dma_handle, ARCH_MAP_WRITECOMBINE);
 }
 
-static inline void map_region(unsigned long start, unsigned long size,
-			      uint64_t flags)
-
-{
-	start = ALIGN_DOWN(start, SZ_1M);
-	size  = ALIGN(size, SZ_1M);
-
-	create_sections(start, start + size - 1, flags);
-}
-
 void mmu_early_enable(unsigned long membase, unsigned long memsize)
 {
 	uint32_t *ttb = (uint32_t *)arm_mem_ttb(membase, membase + memsize);
@@ -578,21 +572,10 @@ void mmu_early_enable(unsigned long membase, unsigned long memsize)
 	 */
 	create_flat_mapping();
 
-	/*
-	 * There can be SoCs that have a section shared between device memory
-	 * and the on-chip RAM hosting the PBL. Thus mark this section
-	 * uncachable, but executable.
-	 * On such SoCs, executing from OCRAM could cause the instruction
-	 * prefetcher to speculatively access that device memory, triggering
-	 * potential errant behavior.
-	 *
-	 * If your SoC has such a memory layout, you should rewrite the code
-	 * here to map the OCRAM page-wise.
-	 */
-	map_region((unsigned long)_stext, _etext - _stext, PMD_SECT_DEF_UNCACHED);
-
 	/* maps main memory as cachable */
-	map_region(membase, memsize - OPTEE_SIZE, PMD_SECT_DEF_CACHED);
+	arch_remap_range((void *)membase, memsize - OPTEE_SIZE, MAP_CACHED);
+	arch_remap_range((void *)membase + memsize - OPTEE_SIZE, OPTEE_SIZE, MAP_UNCACHED);
+	arch_remap_range(_stext, PAGE_ALIGN(_etext - _stext), MAP_CACHED);
 
 	__mmu_cache_on();
 }
-- 
2.39.2