10 files changed, 160 insertions, 0 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 8e9dbcbcf5af..cacc8d5355b3 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -2065,6 +2065,8 @@ config XIP_PHYS_ADDR
 config KEXEC
         bool "Kexec system call (EXPERIMENTAL)"
         depends on (!SMP || PM_SLEEP_SMP)
+        select CRYPTO
+        select CRYPTO_SHA256
         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/ia64/Kconfig b/arch/ia64/Kconfig
index c84c88bbbbd7..64aefb76bd69 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -549,6 +549,8 @@ source "drivers/sn/Kconfig"
 config KEXEC
         bool "kexec system call"
         depends on !IA64_HP_SIM && (!SMP || HOTPLUG_CPU)
+        select CRYPTO
+        select CRYPTO_SHA256
         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/m68k/Kconfig b/arch/m68k/Kconfig
index 87b7c7581b1d..3ff8c9a25335 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -91,6 +91,8 @@ config MMU_SUN3
 config KEXEC
         bool "kexec system call"
         depends on M68KCLASSIC
+        select CRYPTO
+        select CRYPTO_SHA256
         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/mips/Kconfig b/arch/mips/Kconfig
index 900c7e5333b6..df51e78a72cc 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2396,6 +2396,8 @@ source "kernel/Kconfig.preempt"
 
 config KEXEC
         bool "Kexec system call"
+        select CRYPTO
+        select CRYPTO_SHA256
         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/Kconfig b/arch/powerpc/Kconfig
index 4bc7b62fb4b6..a577609f8ed6 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -399,6 +399,8 @@ config PPC64_SUPPORTS_MEMORY_FAILURE
 config KEXEC
         bool "kexec system call"
         depends on (PPC_BOOK3S || FSL_BOOKE || (44x && !SMP))
+        select CRYPTO
+        select CRYPTO_SHA256
         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/s390/Kconfig b/arch/s390/Kconfig
index 05c78bb5f570..ab39ceb89ecf 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -48,6 +48,8 @@ config ARCH_SUPPORTS_DEBUG_PAGEALLOC
 
 config KEXEC
         def_bool y
+        select CRYPTO
+        select CRYPTO_SHA256
 
 config AUDIT_ARCH
         def_bool y
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index aa2df3eaeb29..453fa5c09550 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -595,6 +595,8 @@ source kernel/Kconfig.hz
 config KEXEC
         bool "kexec system call (EXPERIMENTAL)"
         depends on SUPERH32 && MMU
+        select CRYPTO
+        select CRYPTO_SHA256
         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/tile/Kconfig b/arch/tile/Kconfig
index 7fcd492adbfc..a3ffe2dd4832 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -191,6 +191,8 @@ source "kernel/Kconfig.hz"
 
 config KEXEC
         bool "kexec system call"
+        select CRYPTO
+        select CRYPTO_SHA256
         ---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/x86/Kconfig b/arch/x86/Kconfig
index 98fe3df6df82..9558b9fcafbf 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1583,6 +1583,8 @@ source kernel/Kconfig.hz
 config KEXEC
         bool "kexec system call"
         select BUILD_BIN2C
+        select CRYPTO
+        select CRYPTO_SHA256
         ---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/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index c8875b5545e1..88404c440727 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -6,6 +6,8 @@
  * Version 2.  See the file COPYING for more details.
  */
 
+#define pr_fmt(fmt)     "kexec: " fmt
+
 #include <linux/mm.h>
 #include <linux/kexec.h>
 #include <linux/string.h>
@@ -328,3 +330,143 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image)
 
         return image->fops->cleanup(image);
 }
+
+/*
+ * Apply purgatory relocations.
+ *
+ * ehdr: Pointer to elf headers
+ * sechdrs: Pointer to section headers.
+ * relsec: section index of SHT_RELA section.
+ *
+ * TODO: Some of the code belongs to generic code. Move that in kexec.c.
+ */
+int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr,
+                                     Elf64_Shdr *sechdrs, unsigned int relsec)
+{
+        unsigned int i;
+        Elf64_Rela *rel;
+        Elf64_Sym *sym;
+        void *location;
+        Elf64_Shdr *section, *symtabsec;
+        unsigned long address, sec_base, value;
+        const char *strtab, *name, *shstrtab;
+
+        /*
+         * ->sh_offset has been modified to keep the pointer to section
+         * contents in memory
+         */
+        rel = (void *)sechdrs[relsec].sh_offset;
+
+        /* Section to which relocations apply */
+        section = &sechdrs[sechdrs[relsec].sh_info];
+
+        pr_debug("Applying relocate section %u to %u\n", relsec,
+                 sechdrs[relsec].sh_info);
+
+        /* Associated symbol table */
+        symtabsec = &sechdrs[sechdrs[relsec].sh_link];
+
+        /* String table */
+        if (symtabsec->sh_link >= ehdr->e_shnum) {
+                /* Invalid strtab section number */
+                pr_err("Invalid string table section index %d\n",
+                       symtabsec->sh_link);
+                return -ENOEXEC;
+        }
+
+        strtab = (char *)sechdrs[symtabsec->sh_link].sh_offset;
+
+        /* section header string table */
+        shstrtab = (char *)sechdrs[ehdr->e_shstrndx].sh_offset;
+
+        for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
+
+                /*
+                 * rel[i].r_offset contains byte offset from beginning
+                 * of section to the storage unit affected.
+                 *
+                 * This is location to update (->sh_offset). This is temporary
+                 * buffer where section is currently loaded. This will finally
+                 * be loaded to a different address later, pointed to by
+                 * ->sh_addr. kexec takes care of moving it
+                 *  (kexec_load_segment()).
+                 */
+                location = (void *)(section->sh_offset + rel[i].r_offset);
+
+                /* Final address of the location */
+                address = section->sh_addr + rel[i].r_offset;
+
+                /*
+                 * rel[i].r_info contains information about symbol table index
+                 * w.r.t which relocation must be made and type of relocation
+                 * to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get
+                 * these respectively.
+                 */
+                sym = (Elf64_Sym *)symtabsec->sh_offset +
+                                ELF64_R_SYM(rel[i].r_info);
+
+                if (sym->st_name)
+                        name = strtab + sym->st_name;
+                else
+                        name = shstrtab + sechdrs[sym->st_shndx].sh_name;
+
+                pr_debug("Symbol: %s info: %02x shndx: %02x value=%llx size: %llx\n",
+                         name, sym->st_info, sym->st_shndx, sym->st_value,
+                         sym->st_size);
+
+                if (sym->st_shndx == SHN_UNDEF) {
+                        pr_err("Undefined symbol: %s\n", name);
+                        return -ENOEXEC;
+                }
+
+                if (sym->st_shndx == SHN_COMMON) {
+                        pr_err("symbol '%s' in common section\n", name);
+                        return -ENOEXEC;
+                }
+
+                if (sym->st_shndx == SHN_ABS)
+                        sec_base = 0;
+                else if (sym->st_shndx >= ehdr->e_shnum) {
+                        pr_err("Invalid section %d for symbol %s\n",
+                               sym->st_shndx, name);
+                        return -ENOEXEC;
+                } else
+                        sec_base = sechdrs[sym->st_shndx].sh_addr;
+
+                value = sym->st_value;
+                value += sec_base;
+                value += rel[i].r_addend;
+
+                switch (ELF64_R_TYPE(rel[i].r_info)) {
+                case R_X86_64_NONE:
+                        break;
+                case R_X86_64_64:
+                        *(u64 *)location = value;
+                        break;
+                case R_X86_64_32:
+                        *(u32 *)location = value;
+                        if (value != *(u32 *)location)
+                                goto overflow;
+                        break;
+                case R_X86_64_32S:
+                        *(s32 *)location = value;
+                        if ((s64)value != *(s32 *)location)
+                                goto overflow;
+                        break;
+                case R_X86_64_PC32:
+                        value -= (u64)address;
+                        *(u32 *)location = value;
+                        break;
+                default:
+                        pr_err("Unknown rela relocation: %llu\n",
+                               ELF64_R_TYPE(rel[i].r_info));
+                        return -ENOEXEC;
+                }
+        }
+        return 0;
+
+overflow:
+        pr_err("Overflow in relocation type %d value 0x%lx\n",
+               (int)ELF64_R_TYPE(rel[i].r_info), value);
+        return -ENOEXEC;
+}