powerpc/kexec: Add support for FSL-BookE

This adds support kexec on FSL-BookE where the MMU can not be simply
switched off. The code borrows the initial MMU-setup code to create the
identical mapping mapping. The only difference to the original boot code
is the size of the mapping(s) and the executeable address.
The kexec code maps the first 2 GiB of memory in 256 MiB steps. This
should work also on e500v1 boxes.
SMP support is still not available.

(Kumar: Added minor change to build to ifdef CONFIG_PPC_STD_MMU_64 some
code that was PPC64 specific)

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

6 files changed, 74 insertions, 1 deletions

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c4c4549c22bb..5887cff16785 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -351,7 +351,7 @@ config ARCH_ENABLE_MEMORY_HOTREMOVE
 
 config KEXEC
         bool "kexec system call (EXPERIMENTAL)"
-        depends on PPC_BOOK3S && EXPERIMENTAL
+        depends on (PPC_BOOK3S || (FSL_BOOKE && !SMP)) && EXPERIMENTAL
         help
           kexec is a system call that implements the ability to shutdown your
           current kernel, and to start another kernel.  It is like a reboot
diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index a6ca6da1430b..2a9cd74a841e 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -2,6 +2,18 @@
 #define _ASM_POWERPC_KEXEC_H
 #ifdef __KERNEL__
 
+#ifdef CONFIG_FSL_BOOKE
+
+/*
+ * On FSL-BookE we setup a 1:1 mapping which covers the first 2GiB of memory
+ * and therefore we can only deal with memory within this range
+ */
+#define KEXEC_SOURCE_MEMORY_LIMIT       (2 * 1024 * 1024 * 1024UL)
+#define KEXEC_DESTINATION_MEMORY_LIMIT  (2 * 1024 * 1024 * 1024UL)
+#define KEXEC_CONTROL_MEMORY_LIMIT      (2 * 1024 * 1024 * 1024UL)
+
+#else
+
 /*
  * Maximum page that is mapped directly into kernel memory.
  * XXX: Since we copy virt we can use any page we allocate
@@ -21,6 +33,7 @@
 /* TASK_SIZE, probably left over from use_mm ?? */
 #define KEXEC_CONTROL_MEMORY_LIMIT TASK_SIZE
 #endif
+#endif
 
 #define KEXEC_CONTROL_PAGE_SIZE 4096
 
diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
index 8c066d6a8e4b..b46f2e09bd81 100644
--- a/arch/powerpc/kernel/crash.c
+++ b/arch/powerpc/kernel/crash.c
@@ -163,6 +163,7 @@ static void crash_kexec_prepare_cpus(int cpu)
 }
 
 /* wait for all the CPUs to hit real mode but timeout if they don't come in */
+#ifdef CONFIG_PPC_STD_MMU_64
 static void crash_kexec_wait_realmode(int cpu)
 {
         unsigned int msecs;
@@ -187,6 +188,7 @@ static void crash_kexec_wait_realmode(int cpu)
         }
         mb();
 }
+#endif
 
 /*
  * This function will be called by secondary cpus or by kexec cpu
@@ -445,7 +447,9 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
         crash_kexec_prepare_cpus(crashing_cpu);
         cpu_set(crashing_cpu, cpus_in_crash);
         crash_kexec_stop_spus();
+#ifdef CONFIG_PPC_STD_MMU_64
         crash_kexec_wait_realmode(crashing_cpu);
+#endif
         if (ppc_md.kexec_cpu_down)
                 ppc_md.kexec_cpu_down(1, 0);
 }
diff --git a/arch/powerpc/kernel/fsl_booke_entry_mapping.S b/arch/powerpc/kernel/fsl_booke_entry_mapping.S
index cdb1296f972d..beb4d78a2304 100644
--- a/arch/powerpc/kernel/fsl_booke_entry_mapping.S
+++ b/arch/powerpc/kernel/fsl_booke_entry_mapping.S
@@ -159,6 +159,8 @@ skpinv:	addi	r6,r6,1				/* Increment */
 #define M_IF_SMP        0
 #endif
 
+#if defined(ENTRY_MAPPING_BOOT_SETUP)
+
 /* 6. Setup KERNELBASE mapping in TLB1[0] */
         lis     r6,0x1000               /* Set MAS0(TLBSEL) = TLB1(1), ESEL = 0 */
         mtspr   SPRN_MAS0,r6
@@ -174,6 +176,41 @@ skpinv:	addi	r6,r6,1				/* Increment */
 /* 7. Jump to KERNELBASE mapping */
         lis     r6,(KERNELBASE & ~0xfff)@h
         ori     r6,r6,(KERNELBASE & ~0xfff)@l
+
+#elif defined(ENTRY_MAPPING_KEXEC_SETUP)
+/*
+ * 6. Setup a 1:1 mapping in TLB1. Esel 0 is unsued, 1 or 2 contains the tmp
+ * mapping so we start at 3. We setup 8 mappings, each 256MiB in size. This
+ * will cover the first 2GiB of memory.
+ */
+
+        lis r10, (MAS1_VALID|MAS1_IPROT)@h
+        ori r10,r10, (MAS1_TSIZE(BOOK3E_PAGESZ_256M))@l
+        li  r11, 0
+        li  r0, 8
+        mtctr   r0
+
+next_tlb_setup:
+        addi    r0, r11, 3
+        rlwinm  r0, r0, 16, 4, 15  // Compute esel
+        rlwinm  r9, r11, 28, 0, 3   // Compute [ER]PN
+        oris    r0, r0, (MAS0_TLBSEL(1))@h
+        mtspr   SPRN_MAS0,r0
+        mtspr   SPRN_MAS1,r10
+        mtspr   SPRN_MAS2,r9
+        ori r9, r9, (MAS3_SX|MAS3_SW|MAS3_SR)
+        mtspr   SPRN_MAS3,r9
+        tlbwe
+        addi    r11, r11, 1
+        bdnz+   next_tlb_setup
+
+/* 7. Jump to our 1:1 mapping */
+        li      r6, 0
+
+#else
+        #error You need to specify the mapping or not use this at all.
+#endif
+
         lis     r7,MSR_KERNEL@h
         ori     r7,r7,MSR_KERNEL@l
         bl      1f                      /* Find our address */
diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
index 6b5b1f3b6112..4faeba247854 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -95,7 +95,9 @@ _ENTRY(_start);
 
 _ENTRY(__early_start)
 
+#define ENTRY_MAPPING_BOOT_SETUP
 #include "fsl_booke_entry_mapping.S"
+#undef ENTRY_MAPPING_BOOT_SETUP
 
         /* Establish the interrupt vector offsets */
         SET_IVOR(0,  CriticalInput);
diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
index 8043d1b73cf0..dc66d52dcff5 100644
--- a/arch/powerpc/kernel/misc_32.S
+++ b/arch/powerpc/kernel/misc_32.S
@@ -711,6 +711,22 @@ relocate_new_kernel:
         /* r4 = reboot_code_buffer */
         /* r5 = start_address      */
 
+#ifdef CONFIG_FSL_BOOKE
+
+        mr      r29, r3
+        mr      r30, r4
+        mr      r31, r5
+
+#define ENTRY_MAPPING_KEXEC_SETUP
+#include "fsl_booke_entry_mapping.S"
+#undef ENTRY_MAPPING_KEXEC_SETUP
+
+        mr      r3, r29
+        mr      r4, r30
+        mr      r5, r31
+
+        li      r0, 0
+#else
         li      r0, 0
 
         /*
@@ -727,6 +743,7 @@ relocate_new_kernel:
         rfi
 
 1:
+#endif
         /* from this point address translation is turned off */
         /* and interrupts are disabled */