x86: fix spontaneous reboot with allyesconfig bzImage

[sfrench/cifs-2.6.git] / arch / x86 / kernel / head_64.S

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 09b38d539b09deb0874029b2e28fb7d5b7d2418f..b037b15be7f88b4bd1d20ea5fc54ab3a5234b127 100644 (file)
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -107,8 +107,13 @@ startup_64:
        movq    %rdx, 0(%rbx, %rax, 8)
 ident_complete:
 
-       /* Fixup the kernel text+data virtual addresses
+       /*
+        * Fixup the kernel text+data virtual addresses. Note that
+        * we might write invalid pmds, when the kernel is relocated
+        * cleanup_highmap() fixes this up along with the mappings
+        * beyond _end.
         */
+
        leaq    level2_kernel_pgt(%rip), %rdi
        leaq    4096(%rdi), %r8
        /* See if it is a valid page table entry */
@@ -250,7 +255,7 @@ ENTRY(secondary_startup_64)
        lretq
 
        /* SMP bootup changes these two */
-       __CPUINITDATA
+       __REFDATA
        .align  8
        ENTRY(initial_code)
        .quad   x86_64_start_kernel
@@ -374,18 +379,24 @@ NEXT_PAGE(level2_ident_pgt)
        /* Since I easily can, map the first 1G.
         * Don't set NX because code runs from these pages.
         */
-       PMDS(0x0000000000000000, __PAGE_KERNEL_LARGE_EXEC, PTRS_PER_PMD)
+       PMDS(0, __PAGE_KERNEL_LARGE_EXEC, PTRS_PER_PMD)
 
 NEXT_PAGE(level2_kernel_pgt)
-       /* 40MB kernel mapping. The kernel code cannot be bigger than that.
-          When you change this change KERNEL_TEXT_SIZE in page.h too. */
-       /* (2^48-(2*1024*1024*1024)-((2^39)*511)-((2^30)*510)) = 0 */
-       PMDS(0x0000000000000000, __PAGE_KERNEL_LARGE_EXEC|_PAGE_GLOBAL, KERNEL_TEXT_SIZE/PMD_SIZE)
-       /* Module mapping starts here */
-       .fill   (PTRS_PER_PMD - (KERNEL_TEXT_SIZE/PMD_SIZE)),8,0
+       /*
+        * 128 MB kernel mapping. We spend a full page on this pagetable
+        * anyway.
+        *
+        * The kernel code+data+bss must not be bigger than that.
+        *
+        * (NOTE: at +128MB starts the module area, see MODULES_VADDR.
+        *  If you want to increase this then increase MODULES_VADDR
+        *  too.)
+        */
+       PMDS(0, __PAGE_KERNEL_LARGE_EXEC|_PAGE_GLOBAL,
+               KERNEL_TEXT_SIZE/PMD_SIZE)
 
 NEXT_PAGE(level2_spare_pgt)
-       .fill   512,8,0
+       .fill   512, 8, 0
 
 #undef PMDS
 #undef NEXT_PAGE