ARM: hotplug cpu: setup 1:1 map for entire kernel image for secondary CPUs

Make the entire kernel image available for secondary CPUs rather
than just the first MB of memory.  This allows the startup code
to appear in the cpuinit sections.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 55 insertions, 8 deletions

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 40dc74f2b27f..14070549e051 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -33,6 +33,7 @@
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
 #include <asm/processor.h>
+#include <asm/sections.h>
 #include <asm/tlbflush.h>
 #include <asm/ptrace.h>
 #include <asm/localtimer.h>
@@ -67,12 +68,47 @@ enum ipi_msg_type {
         IPI_CPU_STOP,
 };
 
+static inline void identity_mapping_add(pgd_t *pgd, unsigned long start,
+        unsigned long end)
+{
+        unsigned long addr, prot;
+        pmd_t *pmd;
+
+        prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE;
+        if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
+                prot |= PMD_BIT4;
+
+        for (addr = start & PGDIR_MASK; addr < end;) {
+                pmd = pmd_offset(pgd + pgd_index(addr), addr);
+                pmd[0] = __pmd(addr | prot);
+                addr += SECTION_SIZE;
+                pmd[1] = __pmd(addr | prot);
+                addr += SECTION_SIZE;
+                flush_pmd_entry(pmd);
+                outer_clean_range(__pa(pmd), __pa(pmd + 1));
+        }
+}
+
+static inline void identity_mapping_del(pgd_t *pgd, unsigned long start,
+        unsigned long end)
+{
+        unsigned long addr;
+        pmd_t *pmd;
+
+        for (addr = start & PGDIR_MASK; addr < end; addr += PGDIR_SIZE) {
+                pmd = pmd_offset(pgd + pgd_index(addr), addr);
+                pmd[0] = __pmd(0);
+                pmd[1] = __pmd(0);
+                clean_pmd_entry(pmd);
+                outer_clean_range(__pa(pmd), __pa(pmd + 1));
+        }
+}
+
 int __cpuinit __cpu_up(unsigned int cpu)
 {
         struct cpuinfo_arm *ci = &per_cpu(cpu_data, cpu);
         struct task_struct *idle = ci->idle;
         pgd_t *pgd;
-        pmd_t *pmd;
         int ret;
 
         /*
@@ -101,11 +137,16 @@ int __cpuinit __cpu_up(unsigned int cpu)
          * a 1:1 mapping for the physical address of the kernel.
          */
         pgd = pgd_alloc(&init_mm);
-        pmd = pmd_offset(pgd + pgd_index(PHYS_OFFSET), PHYS_OFFSET);
-        *pmd = __pmd((PHYS_OFFSET & PGDIR_MASK) |
-                     PMD_TYPE_SECT | PMD_SECT_AP_WRITE);
-        flush_pmd_entry(pmd);
-        outer_clean_range(__pa(pmd), __pa(pmd + 1));
+        if (!pgd)
+                return -ENOMEM;
+
+        if (PHYS_OFFSET != PAGE_OFFSET) {
+#ifndef CONFIG_HOTPLUG_CPU
+                identity_mapping_add(pgd, __pa(__init_begin), __pa(__init_end));
+#endif
+                identity_mapping_add(pgd, __pa(_stext), __pa(_etext));
+                identity_mapping_add(pgd, __pa(_sdata), __pa(_edata));
+        }
 
         /*
          * We need to tell the secondary core where to find
@@ -143,8 +184,14 @@ int __cpuinit __cpu_up(unsigned int cpu)
         secondary_data.stack = NULL;
         secondary_data.pgdir = 0;
 
-        *pmd = __pmd(0);
-        clean_pmd_entry(pmd);
+        if (PHYS_OFFSET != PAGE_OFFSET) {
+#ifndef CONFIG_HOTPLUG_CPU
+                identity_mapping_del(pgd, __pa(__init_begin), __pa(__init_end));
+#endif
+                identity_mapping_del(pgd, __pa(_stext), __pa(_etext));
+                identity_mapping_del(pgd, __pa(_sdata), __pa(_edata));
+        }
+
         pgd_free(&init_mm, pgd);
 
         if (ret) {