From 37b05b63754e995b8cb76f4fbe7ed7219b3ca896 Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Fri, 1 Oct 2010 15:38:24 +0100
Subject: [PATCH] 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>
---
 arch/arm/kernel/smp.c | 63 +++++++++++++++++++++++++++++++++++++------
 1 file 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) {