x86, kdump: Set crashkernel_low automatically

[karo-tx-linux.git] / arch / x86 / kernel / setup.c

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 90d8cc930f5ed134735f7697e016a83e5657dcb8..12349202cae71be073b113e49a1fc4a157642455 100644 (file)
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -521,19 +521,34 @@ static void __init reserve_crashkernel_low(void)
        unsigned long long low_base = 0, low_size = 0;
        unsigned long total_low_mem;
        unsigned long long base;
+       bool auto_set = false;
        int ret;
 
        total_low_mem = memblock_mem_size(1UL<<(32-PAGE_SHIFT));
        ret = parse_crashkernel_low(boot_command_line, total_low_mem,
                                                &low_size, &base);
-       if (ret != 0 || low_size <= 0)
-               return;
+       if (ret != 0) {
+               /*
+                * two parts from lib/swiotlb.c:
+                *      swiotlb size: user specified with swiotlb= or default.
+                *      swiotlb overflow buffer: now is hardcoded to 32k.
+                *              We round it to 8M for other buffers that
+                *              may need to stay low too.
+                */
+               low_size = swiotlb_size_or_default() + (8UL<<20);
+               auto_set = true;
+       } else {
+               /* passed with crashkernel_low=0 ? */
+               if (!low_size)
+                       return;
+       }
 
        low_base = memblock_find_in_range(low_size, (1ULL<<32),
                                        low_size, alignment);
 
        if (!low_base) {
-               pr_info("crashkernel low reservation failed - No suitable area found.\n");
+               if (!auto_set)
+                       pr_info("crashkernel low reservation failed - No suitable area found.\n");
 
                return;
        }