16 files changed, 181 insertions, 19 deletions

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 587da5e0990f..17c988b678d1 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -806,6 +806,19 @@ config PIN_TLB
 endmenu
 
 if PPC64
+config RELOCATABLE
+        bool "Build a relocatable kernel"
+        help
+          This builds a kernel image that is capable of running anywhere
+          in the RMA (real memory area) at any 16k-aligned base address.
+          The kernel is linked as a position-independent executable (PIE)
+          and contains dynamic relocations which are processed early
+          in the bootup process.
+
+          One use is for the kexec on panic case where the recovery kernel
+          must live at a different physical address than the primary
+          kernel.
+
 config PAGE_OFFSET
         hex
         default "0xc000000000000000"
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index c6be19e9ceae..4df38cbb4149 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -63,7 +63,9 @@ override CC	+= -m$(CONFIG_WORD_SIZE)
 override AR     := GNUTARGET=elf$(CONFIG_WORD_SIZE)-powerpc $(AR)
 endif
 
-LDFLAGS_vmlinux := -Bstatic
+LDFLAGS_vmlinux-yy := -Bstatic
+LDFLAGS_vmlinux-$(CONFIG_PPC64)$(CONFIG_RELOCATABLE) := -pie
+LDFLAGS_vmlinux := $(LDFLAGS_vmlinux-yy)
 
 CFLAGS-$(CONFIG_PPC64)  := -mminimal-toc -mtraceback=none  -mcall-aixdesc
 CFLAGS-$(CONFIG_PPC32)  := -ffixed-r2 -mmultiple
diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index 717a3bc1352e..6403275553ea 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -310,8 +310,11 @@ $(obj)/dtbImage.%: vmlinux $(wrapperbits) $(obj)/%.dtb
 $(obj)/vmlinux.strip: vmlinux
         $(STRIP) -s -R .comment $< -o $@
 
+# The iseries hypervisor won't take an ET_DYN executable, so this
+# changes the type (byte 17) in the file to ET_EXEC (2).
 $(obj)/zImage.iseries: vmlinux
         $(STRIP) -s -R .comment $< -o $@
+        printf "\x02" | dd of=$@ conv=notrunc bs=1 seek=17
 
 $(obj)/uImage: vmlinux $(wrapperbits)
         $(call if_changed,wrap,uboot)
diff --git a/arch/powerpc/boot/elf_util.c b/arch/powerpc/boot/elf_util.c
index 7454aa4cc20c..1567a0c0f05c 100644
--- a/arch/powerpc/boot/elf_util.c
+++ b/arch/powerpc/boot/elf_util.c
@@ -27,7 +27,8 @@ int parse_elf64(void *hdr, struct elf_info *info)
               elf64->e_ident[EI_MAG3]  == ELFMAG3       &&
               elf64->e_ident[EI_CLASS] == ELFCLASS64    &&
               elf64->e_ident[EI_DATA]  == ELFDATA2MSB   &&
-              elf64->e_type            == ET_EXEC       &&
+              (elf64->e_type            == ET_EXEC ||
+               elf64->e_type            == ET_DYN)      &&
               elf64->e_machine         == EM_PPC64))
                 return 0;
 
@@ -58,7 +59,8 @@ int parse_elf32(void *hdr, struct elf_info *info)
               elf32->e_ident[EI_MAG3]  == ELFMAG3       &&
               elf32->e_ident[EI_CLASS] == ELFCLASS32    &&
               elf32->e_ident[EI_DATA]  == ELFDATA2MSB   &&
-              elf32->e_type            == ET_EXEC       &&
+              (elf32->e_type            == ET_EXEC ||
+               elf32->e_type            == ET_DYN)      &&
               elf32->e_machine         == EM_PPC))
                 return 0;
 
diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index c2df53c5ceb9..5a441742ffba 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -437,7 +437,7 @@ typedef struct {
         })
 #endif /* 1 */
 
-/* This is only valid for addresses >= KERNELBASE */
+/* This is only valid for addresses >= PAGE_OFFSET */
 static inline unsigned long get_kernel_vsid(unsigned long ea, int ssize)
 {
         if (ssize == MMU_SEGSIZE_256M)
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index e088545cb3f5..64e144505f65 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -71,15 +71,21 @@
 #define PAGE_OFFSET     ASM_CONST(CONFIG_PAGE_OFFSET)
 #define LOAD_OFFSET     ASM_CONST((CONFIG_KERNEL_START-CONFIG_PHYSICAL_START))
 
-#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_FLATMEM)
+#if defined(CONFIG_RELOCATABLE)
 #ifndef __ASSEMBLY__
 extern phys_addr_t memstart_addr;
 extern phys_addr_t kernstart_addr;
 #endif
 #define PHYSICAL_START  kernstart_addr
-#define MEMORY_START    memstart_addr
 #else
 #define PHYSICAL_START  ASM_CONST(CONFIG_PHYSICAL_START)
+#endif
+
+#ifdef CONFIG_PPC64
+#define MEMORY_START    0UL
+#elif defined(CONFIG_RELOCATABLE)
+#define MEMORY_START    memstart_addr
+#else
 #define MEMORY_START    (PHYSICAL_START + PAGE_OFFSET - KERNELBASE)
 #endif
 
@@ -92,8 +98,8 @@ extern phys_addr_t kernstart_addr;
 #define pfn_to_kaddr(pfn)       __va((pfn) << PAGE_SHIFT)
 #define virt_addr_valid(kaddr)  pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
 
-#define __va(x) ((void *)((unsigned long)(x) - PHYSICAL_START + KERNELBASE))
-#define __pa(x) ((unsigned long)(x) + PHYSICAL_START - KERNELBASE)
+#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET - MEMORY_START))
+#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET + MEMORY_START)
 
 /*
  * Unfortunately the PLT is in the BSS in the PPC32 ELF ABI,
diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h
index 7710e9e6660f..baf318aec533 100644
--- a/arch/powerpc/include/asm/sections.h
+++ b/arch/powerpc/include/asm/sections.h
@@ -16,6 +16,12 @@ static inline int in_kernel_text(unsigned long addr)
         return 0;
 }
 
+static inline int overlaps_kernel_text(unsigned long start, unsigned long end)
+{
+        return start < (unsigned long)__init_end &&
+                (unsigned long)_stext < end;
+}
+
 #undef dereference_function_descriptor
 void *dereference_function_descriptor(void *);
 
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 49b49c0707f0..16326fd92f99 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_PPC64)		+= setup_64.o sys_ppc32.o \
                                    paca.o cpu_setup_ppc970.o \
                                    cpu_setup_pa6t.o \
                                    firmware.o nvram_64.o
+obj64-$(CONFIG_RELOCATABLE)     += reloc_64.o
 obj-$(CONFIG_PPC64)             += vdso64/
 obj-$(CONFIG_ALTIVEC)           += vecemu.o vector.o
 obj-$(CONFIG_PPC_970_NAP)       += idle_power4.o
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 6cdfd44d8efe..84856bee33a5 100644
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -1360,6 +1360,12 @@ _INIT_STATIC(__boot_from_prom)
          */
         rldicr  r1,r1,0,59
 
+#ifdef CONFIG_RELOCATABLE
+        /* Relocate code for where we are now */
+        mr      r3,r26
+        bl      .relocate
+#endif
+
         /* Restore parameters */
         mr      r3,r31
         mr      r4,r30
@@ -1368,11 +1374,19 @@ _INIT_STATIC(__boot_from_prom)
         mr      r7,r27
 
         /* Do all of the interaction with OF client interface */
+        mr      r8,r26
         bl      .prom_init
         /* We never return */
         trap
 
 _STATIC(__after_prom_start)
+#ifdef CONFIG_RELOCATABLE
+        /* process relocations for the final address of the kernel */
+        lis     r25,PAGE_OFFSET@highest /* compute virtual base of kernel */
+        sldi    r25,r25,32
+        mr      r3,r25
+        bl      .relocate
+#endif
 
 /*
  * We need to run with _stext at physical address PHYSICAL_START.
@@ -1381,10 +1395,9 @@ _STATIC(__after_prom_start)
  *
  * Note: This process overwrites the OF exception vectors.
  */
-        LOAD_REG_IMMEDIATE(r3, PHYSICAL_START)  /* target addr */
-        cmpd    r3,r26                  /* In some cases the loader may  */
+        li      r3,0                    /* target addr */
+        mr.     r4,r26                  /* In some cases the loader may  */
         beq     9f                      /* have already put us at zero */
-        mr      r4,r26                  /* source address */
         lis     r5,(copy_to_here - _stext)@ha
         addi    r5,r5,(copy_to_here - _stext)@l /* # bytes of memory to copy */
         li      r6,0x100                /* Start offset, the first 0x100 */
@@ -1617,6 +1630,13 @@ _INIT_STATIC(start_here_multiplatform)
         ori     r6,r6,MSR_RI
         mtmsrd  r6                      /* RI on */
 
+#ifdef CONFIG_RELOCATABLE
+        /* Save the physical address we're running at in kernstart_addr */
+        LOAD_REG_ADDR(r4, kernstart_addr)
+        clrldi  r0,r25,2
+        std     r0,0(r4)
+#endif
+
         /* The following gets the stack set up with the regs */
         /* pointing to the real addr of the kernel stack.  This is   */
         /* all done to support the C function call below which sets  */
diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index 623e8c3c57f9..48a347133f41 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -12,6 +12,7 @@
 
 #include <asm/lppaca.h>
 #include <asm/paca.h>
+#include <asm/sections.h>
 
 /* This symbol is provided by the linker - let it fill in the paca
  * field correctly */
@@ -79,7 +80,7 @@ void __init initialise_pacas(void)
                 new_paca->lock_token = 0x8000;
                 new_paca->paca_index = cpu;
                 new_paca->kernel_toc = kernel_toc;
-                new_paca->kernelbase = KERNELBASE;
+                new_paca->kernelbase = (unsigned long) _stext;
                 new_paca->kernel_msr = MSR_KERNEL;
                 new_paca->hw_cpu_id = 0xffff;
                 new_paca->slb_shadow_ptr = &slb_shadow[cpu];
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 09455e1c27c5..3a2dc7e6586a 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -1192,6 +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();
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 1f8988585054..7cf274a2b334 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -2309,13 +2309,14 @@ static void __init prom_check_initrd(unsigned long r3, unsigned long r4)
 
 unsigned long __init prom_init(unsigned long r3, unsigned long r4,
                                unsigned long pp,
-                               unsigned long r6, unsigned long r7)
+                               unsigned long r6, unsigned long r7,
+                               unsigned long kbase)
 {       
         struct prom_t *_prom;
         unsigned long hdr;
-        unsigned long offset = reloc_offset();
 
 #ifdef CONFIG_PPC32
+        unsigned long offset = reloc_offset();
         reloc_got2(offset);
 #endif
 
@@ -2349,9 +2350,11 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
          */
         RELOC(of_platform) = prom_find_machine_type();
 
+#ifndef CONFIG_RELOCATABLE
         /* Bail if this is a kdump kernel. */
         if (PHYSICAL_START > 0)
                 prom_panic("Error: You can't boot a kdump kernel from OF!\n");
+#endif
 
         /*
          * Check for an initrd
@@ -2371,7 +2374,7 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
          * Copy the CPU hold code
          */
         if (RELOC(of_platform) != PLATFORM_POWERMAC)
-                copy_and_flush(0, KERNELBASE + offset, 0x100, 0);
+                copy_and_flush(0, kbase, 0x100, 0);
 
         /*
          * Do early parsing of command line
@@ -2474,7 +2477,7 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
         reloc_got2(-offset);
 #endif
 
-        __start(hdr, KERNELBASE + offset, 0);
+        __start(hdr, kbase, 0);
 
         return 0;
 }
diff --git a/arch/powerpc/kernel/reloc_64.S b/arch/powerpc/kernel/reloc_64.S
new file mode 100644
index 000000000000..b47a0e1ab001
--- /dev/null
+++ b/arch/powerpc/kernel/reloc_64.S
@@ -0,0 +1,87 @@
+/*
+ * Code to process dynamic relocations in the kernel.
+ *
+ * Copyright 2008 Paul Mackerras, IBM Corp.
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ */
+
+#include <asm/ppc_asm.h>
+
+RELA = 7
+RELACOUNT = 0x6ffffff9
+R_PPC64_RELATIVE = 22
+
+/*
+ * r3 = desired final address of kernel
+ */
+_GLOBAL(relocate)
+        mflr    r0
+        bcl     20,31,$+4
+0:      mflr    r12             /* r12 has runtime addr of label 0 */
+        mtlr    r0
+        ld      r11,(p_dyn - 0b)(r12)
+        add     r11,r11,r12     /* r11 has runtime addr of .dynamic section */
+        ld      r9,(p_rela - 0b)(r12)
+        add     r9,r9,r12       /* r9 has runtime addr of .rela.dyn section */
+        ld      r10,(p_st - 0b)(r12)
+        add     r10,r10,r12     /* r10 has runtime addr of _stext */
+
+        /*
+         * Scan the dynamic section for the RELA and RELACOUNT entries.
+         */
+        li      r7,0
+        li      r8,0
+1:      ld      r6,0(r11)       /* get tag */
+        cmpdi   r6,0
+        beq     4f              /* end of list */
+        cmpdi   r6,RELA
+        bne     2f
+        ld      r7,8(r11)       /* get RELA pointer in r7 */
+        b       3f
+2:      addis   r6,r6,(-RELACOUNT)@ha
+        cmpdi   r6,RELACOUNT@l
+        bne     3f
+        ld      r8,8(r11)       /* get RELACOUNT value in r8 */
+3:      addi    r11,r11,16
+        b       1b
+4:      cmpdi   r7,0            /* check we have both RELA and RELACOUNT */
+        cmpdi   cr1,r8,0
+        beq     6f
+        beq     cr1,6f
+
+        /*
+         * Work out linktime address of _stext and hence the
+         * relocation offset to be applied.
+         * cur_offset [r7] = rela.run [r9] - rela.link [r7]
+         * _stext.link [r10] = _stext.run [r10] - cur_offset [r7]
+         * final_offset [r3] = _stext.final [r3] - _stext.link [r10]
+         */
+        subf    r7,r7,r9        /* cur_offset */
+        subf    r10,r7,r10
+        subf    r3,r10,r3       /* final_offset */
+
+        /*
+         * Run through the list of relocations and process the
+         * R_PPC64_RELATIVE ones.
+         */
+        mtctr   r8
+5:      lwz     r0,12(9)        /* ELF64_R_TYPE(reloc->r_info) */
+        cmpwi   r0,R_PPC64_RELATIVE
+        bne     6f
+        ld      r6,0(r9)        /* reloc->r_offset */
+        ld      r0,16(r9)       /* reloc->r_addend */
+        add     r0,r0,r3
+        stdx    r0,r7,r6
+        addi    r9,r9,24
+        bdnz    5b
+
+6:      blr
+
+p_dyn:  .llong  __dynamic_start - 0b
+p_rela: .llong  __rela_dyn_start - 0b
+p_st:   .llong  _stext - 0b
+
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 9f6c1ca1739e..e6927fb2e655 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -187,6 +187,21 @@ SECTIONS
                 *(.machine.desc)
                 __machine_desc_end = . ;
         }
+        . = ALIGN(8);
+        .dynsym : AT(ADDR(.dynsym) - LOAD_OFFSET) { *(.dynsym) }
+        .dynstr : AT(ADDR(.dynstr) - LOAD_OFFSET) { *(.dynstr) }
+        .dynamic : AT(ADDR(.dynamic) - LOAD_OFFSET)
+        {
+                __dynamic_start = .;
+                *(.dynamic)
+        }
+        .hash : AT(ADDR(.hash) - LOAD_OFFSET) { *(.hash) }
+        .interp : AT(ADDR(.interp) - LOAD_OFFSET) { *(.interp) }
+        .rela.dyn : AT(ADDR(.rela.dyn) - LOAD_OFFSET)
+        {
+                __rela_dyn_start = .;
+                *(.rela*)
+        }
 
         /* freed after init ends here */
         . = ALIGN(PAGE_SIZE);
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index d666f71f1f30..09db4efe1921 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -194,7 +194,7 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
                 unsigned long tprot = prot;
 
                 /* Make kernel text executable */
-                if (in_kernel_text(vaddr))
+                if (overlaps_kernel_text(vaddr, vaddr + step))
                         tprot &= ~HPTE_R_N;
 
                 hash = hpt_hash(va, shift, ssize);
diff --git a/arch/powerpc/platforms/powermac/smp.c b/arch/powerpc/platforms/powermac/smp.c
index 4ae3d00e0bdd..40f72c2a4699 100644
--- a/arch/powerpc/platforms/powermac/smp.c
+++ b/arch/powerpc/platforms/powermac/smp.c
@@ -787,7 +787,7 @@ static void __devinit smp_core99_kick_cpu(int nr)
 {
         unsigned int save_vector;
         unsigned long target, flags;
-        unsigned int *vector = (unsigned int *)(KERNELBASE+0x100);
+        unsigned int *vector = (unsigned int *)(PAGE_OFFSET+0x100);
 
         if (nr < 0 || nr > 3)
                 return;
@@ -801,7 +801,7 @@ static void __devinit smp_core99_kick_cpu(int nr)
         save_vector = *vector;
 
         /* Setup fake reset vector that does
-         *   b __secondary_start_pmac_0 + nr*8 - KERNELBASE
+         *   b __secondary_start_pmac_0 + nr*8
          */
         target = (unsigned long) __secondary_start_pmac_0 + nr * 8;
         patch_branch(vector, target, BRANCH_SET_LINK);