powerpc: Make the 64-bit kernel as a position-independent executable

[linux-2.6-omap-h63xx.git] / arch / powerpc / kernel / prom.c

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 87d83c56b31ec1671007195ce092523535108bb9..3a2dc7e6586a392292ccf3ccbfacb39151a3f675 100644 (file)
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -888,9 +888,10 @@ static u64 __init dt_mem_next_cell(int s, cell_t **cellp)
  */
 static int __init early_init_dt_scan_drconf_memory(unsigned long node)
 {
-       cell_t *dm, *ls;
+       cell_t *dm, *ls, *usm;
        unsigned long l, n, flags;
        u64 base, size, lmb_size;
+       unsigned int is_kexec_kdump = 0, rngs;
 
        ls = (cell_t *)of_get_flat_dt_prop(node, "ibm,lmb-size", &l);
        if (ls == NULL || l < dt_root_size_cells * sizeof(cell_t))
@@ -905,6 +906,12 @@ static int __init early_init_dt_scan_drconf_memory(unsigned long node)
        if (l < (n * (dt_root_addr_cells + 4) + 1) * sizeof(cell_t))
                return 0;
 
+       /* check if this is a kexec/kdump kernel. */
+       usm = (cell_t *)of_get_flat_dt_prop(node, "linux,drconf-usable-memory",
+                                                &l);
+       if (usm != NULL)
+               is_kexec_kdump = 1;
+
        for (; n != 0; --n) {
                base = dt_mem_next_cell(dt_root_addr_cells, &dm);
                flags = dm[3];
@@ -915,13 +922,34 @@ static int __init early_init_dt_scan_drconf_memory(unsigned long node)
                if ((flags & 0x80) || !(flags & 0x8))
                        continue;
                size = lmb_size;
-               if (iommu_is_off) {
-                       if (base >= 0x80000000ul)
+               rngs = 1;
+               if (is_kexec_kdump) {
+                       /*
+                        * For each lmb in ibm,dynamic-memory, a corresponding
+                        * entry in linux,drconf-usable-memory property contains
+                        * a counter 'p' followed by 'p' (base, size) duple.
+                        * Now read the counter from
+                        * linux,drconf-usable-memory property
+                        */
+                       rngs = dt_mem_next_cell(dt_root_size_cells, &usm);
+                       if (!rngs) /* there are no (base, size) duple */
                                continue;
-                       if ((base + size) > 0x80000000ul)
-                               size = 0x80000000ul - base;
                }
-               lmb_add(base, size);
+               do {
+                       if (is_kexec_kdump) {
+                               base = dt_mem_next_cell(dt_root_addr_cells,
+                                                        &usm);
+                               size = dt_mem_next_cell(dt_root_size_cells,
+                                                        &usm);
+                       }
+                       if (iommu_is_off) {
+                               if (base >= 0x80000000ul)
+                                       continue;
+                               if ((base + size) > 0x80000000ul)
+                                       size = 0x80000000ul - base;
+                       }
+                       lmb_add(base, size);
+               } while (--rngs);
        }
        lmb_dump_all();
        return 0;
@@ -1164,6 +1192,9 @@ void __init early_init_devtree(void *params)
 
        /* Reserve LMB regions used by kernel, initrd, dt, etc... */
        lmb_reserve(PHYSICAL_START, __pa(klimit) - PHYSICAL_START);
+       /* If relocatable, reserve first 32k for interrupt vectors etc. */
+       if (PHYSICAL_START > MEMORY_START)
+               lmb_reserve(MEMORY_START, 0x8000);
        reserve_kdump_trampoline();
        reserve_crashkernel();
        early_reserve_mem();