x86/boot: Rework reserve_real_mode() to allow multiple tries

[deliverable/linux.git] / arch / x86 / realmode / init.c

diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index 747b71e8f5479da20da86d2952ea9884ad18f088..5db706f14111c7c12a55fc0731a86641fe2c4741 100644 (file)
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -1,4 +1,5 @@
 #include <linux/io.h>
+#include <linux/slab.h>
 #include <linux/memblock.h>
 
 #include <asm/cacheflush.h>
@@ -12,22 +13,34 @@ u32 *trampoline_cr4_features;
 /* Hold the pgd entry used on booting additional CPUs */
 pgd_t trampoline_pgd_entry;
 
+void __init set_real_mode_mem(phys_addr_t mem, size_t size)
+{
+       void *base = __va(mem);
+
+       real_mode_header = (struct real_mode_header *) base;
+       printk(KERN_DEBUG "Base memory trampoline at [%p] %llx size %zu\n",
+              base, (unsigned long long)mem, size);
+}
+
 void __init reserve_real_mode(void)
 {
        phys_addr_t mem;
-       unsigned char *base;
-       size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
+       size_t size = real_mode_size_needed();
+
+       if (!size)
+               return;
+
+       WARN_ON(slab_is_available());
 
        /* Has to be under 1M so we can execute real-mode AP code. */
        mem = memblock_find_in_range(0, 1<<20, size, PAGE_SIZE);
-       if (!mem)
-               panic("Cannot allocate trampoline\n");
+       if (!mem) {
+               pr_info("No sub-1M memory is available for the trampoline\n");
+               return;
+       }
 
-       base = __va(mem);
        memblock_reserve(mem, size);
-       real_mode_header = (struct real_mode_header *) base;
-       printk(KERN_DEBUG "Base memory trampoline at [%p] %llx size %zu\n",
-              base, (unsigned long long)mem, size);
+       set_real_mode_mem(mem, size);
 }
 
 static void __init setup_real_mode(void)