Merge tag 'v4.20-rc7' into patchwork

Linux 4.20-rc7

* tag 'v4.20-rc7': (403 commits)
  Linux 4.20-rc7
  scripts/spdxcheck.py: always open files in binary mode
  checkstack.pl: fix for aarch64
  userfaultfd: check VM_MAYWRITE was set after verifying the uffd is registered
  fs/iomap.c: get/put the page in iomap_page_create/release()
  hugetlbfs: call VM_BUG_ON_PAGE earlier in free_huge_page()
  memblock: annotate memblock_is_reserved() with __init_memblock
  psi: fix reference to kernel commandline enable
  arch/sh/include/asm/io.h: provide prototypes for PCI I/O mapping in asm/io.h
  mm/sparse: add common helper to mark all memblocks present
  mm: introduce common STRUCT_PAGE_MAX_SHIFT define
  alpha: fix hang caused by the bootmem removal
  XArray: Fix xa_alloc when id exceeds max
  drm/vmwgfx: Protect from excessive execbuf kernel memory allocations v3
  MAINTAINERS: Daniel for drm co-maintainer
  drm/amdgpu: drop fclk/gfxclk ratio setting
  IB/core: Fix oops in netdev_next_upper_dev_rcu()
  dm thin: bump target version
  drm/vmwgfx: remove redundant return ret statement
  drm/i915: Flush GPU relocs harder for gen3
  ...

1 files changed, 17 insertions, 3 deletions

diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c
index f2701c13a66b..cf9619d4efb4 100644
--- a/arch/arc/mm/cache.c
+++ b/arch/arc/mm/cache.c
@@ -1145,6 +1145,20 @@ noinline void __init arc_ioc_setup(void)
 	unsigned int ioc_base, mem_sz;
 
 	/*
+	 * If IOC was already enabled (due to bootloader) it technically needs to
+	 * be reconfigured with aperture base,size corresponding to Linux memory map
+	 * which will certainly be different than uboot's. But disabling and
+	 * reenabling IOC when DMA might be potentially active is tricky business.
+	 * To avoid random memory issues later, just panic here and ask user to
+	 * upgrade bootloader to one which doesn't enable IOC
+	 */
+	if (read_aux_reg(ARC_REG_IO_COH_ENABLE) & ARC_IO_COH_ENABLE_BIT)
+		panic("IOC already enabled, please upgrade bootloader!\n");
+
+	if (!ioc_enable)
+		return;
+
+	/*
 	 * As for today we don't support both IOC and ZONE_HIGHMEM enabled
 	 * simultaneously. This happens because as of today IOC aperture covers
 	 * only ZONE_NORMAL (low mem) and any dma transactions outside this
@@ -1187,8 +1201,8 @@ noinline void __init arc_ioc_setup(void)
 		panic("IOC Aperture start must be aligned to the size of the aperture");
 
 	write_aux_reg(ARC_REG_IO_COH_AP0_BASE, ioc_base >> 12);
-	write_aux_reg(ARC_REG_IO_COH_PARTIAL, 1);
-	write_aux_reg(ARC_REG_IO_COH_ENABLE, 1);
+	write_aux_reg(ARC_REG_IO_COH_PARTIAL, ARC_IO_COH_PARTIAL_BIT);
+	write_aux_reg(ARC_REG_IO_COH_ENABLE, ARC_IO_COH_ENABLE_BIT);
 
 	/* Re-enable L1 dcache */
 	__dc_enable();
@@ -1265,7 +1279,7 @@ void __init arc_cache_init_master(void)
 	if (is_isa_arcv2() && l2_line_sz && !slc_enable)
 		arc_slc_disable();
 
-	if (is_isa_arcv2() && ioc_enable)
+	if (is_isa_arcv2() && ioc_exists)
 		arc_ioc_setup();
 
 	if (is_isa_arcv2() && l2_line_sz && slc_enable) {