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authorLaura Abbott <labbott@redhat.com>2017-01-10 13:35:41 -0800
committerWill Deacon <will.deacon@arm.com>2017-01-11 13:56:49 +0000
commit2dece445b6dbdaa3d94f38ef44aa1b63bc2a6bb9 (patch)
treeec3a9b45f2541d3b7e0e371b73add340dbeae0ea
parentfa5b6ec9e5274aeae2326e25995506a953e5f878 (diff)
downloadlinux-2dece445b6dbdaa3d94f38ef44aa1b63bc2a6bb9.tar.bz2
mm/cma: Cleanup highmem check
6b101e2a3ce4 ("mm/CMA: fix boot regression due to physical address of high_memory") added checks to use __pa_nodebug on x86 since CONFIG_DEBUG_VIRTUAL complains about high_memory not being linearlly mapped. arm64 is now getting support for CONFIG_DEBUG_VIRTUAL as well. Rather than add an explosion of arches to the #ifdef, switch to an alternate method to calculate the physical start of highmem using the page before highmem starts. This avoids the need for the #ifdef and extra __pa_nodebug calls. Reviewed-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
-rw-r--r--mm/cma.c15
1 files changed, 5 insertions, 10 deletions
diff --git a/mm/cma.c b/mm/cma.c
index c960459eda7e..94b3460cd608 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -235,18 +235,13 @@ int __init cma_declare_contiguous(phys_addr_t base,
phys_addr_t highmem_start;
int ret = 0;
-#ifdef CONFIG_X86
/*
- * high_memory isn't direct mapped memory so retrieving its physical
- * address isn't appropriate. But it would be useful to check the
- * physical address of the highmem boundary so it's justifiable to get
- * the physical address from it. On x86 there is a validation check for
- * this case, so the following workaround is needed to avoid it.
+ * We can't use __pa(high_memory) directly, since high_memory
+ * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly)
+ * complain. Find the boundary by adding one to the last valid
+ * address.
*/
- highmem_start = __pa_nodebug(high_memory);
-#else
- highmem_start = __pa(high_memory);
-#endif
+ highmem_start = __pa(high_memory - 1) + 1;
pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
__func__, &size, &base, &limit, &alignment);