The patch titled
Subject: powerpc: adapt elf64_apply_relocate_add for kexec_file_load
has been added to the -mm tree. Its filename is
powerpc-adapt-elf64_apply_relocate_add-for-kexec_file_load.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/powerpc-adapt-elf64_apply_relocate_add-for-kexec_file_load.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/powerpc-adapt-elf64_apply_relocate_add-for-kexec_file_load.patch
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------------------------------------------------------
From: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx>
Subject: powerpc: adapt elf64_apply_relocate_add for kexec_file_load
Extend elf64_apply_relocate_add to support relative symbols. This is
necessary because there is a difference between how the module loading
mechanism and the kexec purgatory loading code use Elf64_Sym.st_value
at relocation time: the former changes st_value to point to the absolute
memory address before relocating the module, while the latter does that
adjustment during relocation of the purgatory.
Also, add a check_symbols argument so that the kexec code can be stricter
about undefined symbols.
Finally, add relocation types used by the purgatory.
Link: http://lkml.kernel.org/r/1471652242-14436-7-git-send-email-bauerman@xxxxxxxxxxxxxxxxxx
Signed-off-by: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Balbir Singh <bsingharora@xxxxxxxxx>
Cc: Stewart Smith <stewart@xxxxxxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Samuel Mendoza-Jonas <sam@xxxxxxxxxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/elf_util.h | 2
arch/powerpc/kernel/elf_util_64.c | 100 +++++++++++++++++++++++---
arch/powerpc/kernel/module_64.c | 6 +
3 files changed, 99 insertions(+), 9 deletions(-)
diff -puN arch/powerpc/include/asm/elf_util.h~powerpc-adapt-elf64_apply_relocate_add-for-kexec_file_load arch/powerpc/include/asm/elf_util.h
--- a/arch/powerpc/include/asm/elf_util.h~powerpc-adapt-elf64_apply_relocate_add-for-kexec_file_load
+++ a/arch/powerpc/include/asm/elf_util.h
@@ -20,6 +20,7 @@
#include <linux/elf.h>
struct elf_info {
+ const struct elfhdr *ehdr;
struct elf_shdr *sechdrs;
/* Index of stubs section. */
@@ -67,6 +68,7 @@ int elf64_apply_relocate_add(const struc
const char *strtab, const Elf64_Rela *rela,
unsigned int num_rela, void *syms_base,
void *loc_base, Elf64_Addr addr_base,
+ bool relative_symbols, bool check_symbols,
const char *obj_name);
#endif /* _ASM_POWERPC_ELF_UTIL_H */
diff -puN arch/powerpc/kernel/elf_util_64.c~powerpc-adapt-elf64_apply_relocate_add-for-kexec_file_load arch/powerpc/kernel/elf_util_64.c
--- a/arch/powerpc/kernel/elf_util_64.c~powerpc-adapt-elf64_apply_relocate_add-for-kexec_file_load
+++ a/arch/powerpc/kernel/elf_util_64.c
@@ -74,6 +74,8 @@ static void squash_toc_save_inst(const c
* @syms_base: Contents of the associated symbol table.
* @loc_base: Contents of the section to which relocations apply.
* @addr_base: The address where the section will be loaded in memory.
+ * @relative_symbols: Are the symbols' st_value members relative?
+ * @check_symbols: Fail if an unexpected symbol is found?
* @obj_name: The name of the ELF binary, for information messages.
*
* Applies RELA relocations to an ELF file already at its final location
@@ -84,12 +86,15 @@ int elf64_apply_relocate_add(const struc
const char *strtab, const Elf64_Rela *rela,
unsigned int num_rela, void *syms_base,
void *loc_base, Elf64_Addr addr_base,
+ bool relative_symbols, bool check_symbols,
const char *obj_name)
{
unsigned int i;
unsigned long *location;
unsigned long address;
+ unsigned long sec_base;
unsigned long value;
+ int reloc_type;
const char *name;
Elf64_Sym *sym;
@@ -116,15 +121,45 @@ int elf64_apply_relocate_add(const struc
else
name = "<unnamed symbol>";
- pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n",
- location, (long)ELF64_R_TYPE(rela[i].r_info),
- name, (unsigned long)sym->st_value,
+ reloc_type = ELF64_R_TYPE(rela[i].r_info);
+
+ pr_debug("RELOC at %p: %i-type as %s (0x%lx) + %li\n",
+ location, reloc_type, name, (unsigned long)sym->st_value,
(long)rela[i].r_addend);
+ if (check_symbols) {
+ /*
+ * TOC symbols appear as undefined but should be
+ * resolved as well, so allow them to be processed.
+ */
+ if (sym->st_shndx == SHN_UNDEF &&
+ strcmp(name, ".TOC.") != 0 &&
+ reloc_type != R_PPC64_TOC) {
+ pr_err("Undefined symbol: %s\n", name);
+ return -ENOEXEC;
+ } else if (sym->st_shndx == SHN_COMMON) {
+ pr_err("Symbol '%s' in common section.\n", name);
+ return -ENOEXEC;
+ }
+ }
+
+ if (relative_symbols && sym->st_shndx != SHN_ABS) {
+ if (sym->st_shndx >= elf_info->ehdr->e_shnum) {
+ pr_err("Invalid section %d for symbol %s\n",
+ sym->st_shndx, name);
+ return -ENOEXEC;
+ } else {
+ struct elf_shdr *sechdrs = elf_info->sechdrs;
+
+ sec_base = sechdrs[sym->st_shndx].sh_addr;
+ }
+ } else
+ sec_base = 0;
+
/* `Everything is relative'. */
- value = sym->st_value + rela[i].r_addend;
+ value = sym->st_value + sec_base + rela[i].r_addend;
- switch (ELF64_R_TYPE(rela[i].r_info)) {
+ switch (reloc_type) {
case R_PPC64_ADDR32:
/* Simply set it */
*(u32 *)location = value;
@@ -135,6 +170,10 @@ int elf64_apply_relocate_add(const struc
*(unsigned long *)location = value;
break;
+ case R_PPC64_REL32:
+ *(uint32_t *)location = value - (uint32_t)(uint64_t)location;
+ break;
+
case R_PPC64_TOC:
*(unsigned long *)location = my_r2(elf_info);
break;
@@ -186,6 +225,14 @@ int elf64_apply_relocate_add(const struc
| (value & 0xfffc);
break;
+ case R_PPC64_TOC16_HI:
+ /* Subtract TOC pointer */
+ value -= my_r2(elf_info);
+ value = value >> 16;
+ *((uint16_t *) location)
+ = (*((uint16_t *) location) & ~0xffff)
+ | (value & 0xffff);
+
case R_PPC64_TOC16_HA:
/* Subtract TOC pointer */
value -= my_r2(elf_info);
@@ -195,6 +242,21 @@ int elf64_apply_relocate_add(const struc
| (value & 0xffff);
break;
+ case R_PPC64_REL14:
+ /* Convert value to relative */
+ value -= address;
+ if (value + 0x8000 > 0xffff || (value & 3) != 0) {
+ pr_err("%s: REL14 %li out of range!\n", obj_name,
+ (long int)value);
+ return -ENOEXEC;
+ }
+
+ /* Only replace bits 2 through 16 */
+ *(uint32_t *)location
+ = (*(uint32_t *)location & ~0xfffc)
+ | (value & 0xfffc);
+ break;
+
case R_PPC_REL24:
/* FIXME: Handle weak symbols here --RR */
if (sym->st_shndx == SHN_UNDEF) {
@@ -263,6 +325,29 @@ int elf64_apply_relocate_add(const struc
((uint32_t *)location)[1] = 0x38420000 + PPC_LO(value);
break;
+ case R_PPC64_ADDR16_LO:
+ *(uint16_t *)location = value & 0xffff;
+ break;
+
+ case R_PPC64_ADDR16_HI:
+ *(uint16_t *)location = (value >> 16) & 0xffff;
+ break;
+
+ case R_PPC64_ADDR16_HA:
+ *(uint16_t *)location = (((value + 0x8000) >> 16) &
+ 0xffff);
+ break;
+
+ case R_PPC64_ADDR16_HIGHER:
+ *(uint16_t *)location = (((uint64_t)value >> 32) &
+ 0xffff);
+ break;
+
+ case R_PPC64_ADDR16_HIGHEST:
+ *(uint16_t *)location = (((uint64_t)value >> 48) &
+ 0xffff);
+ break;
+
case R_PPC64_REL16_HA:
/* Subtract location pointer */
value -= address;
@@ -281,9 +366,8 @@ int elf64_apply_relocate_add(const struc
break;
default:
- pr_err("%s: Unknown ADD relocation: %lu\n",
- obj_name,
- (unsigned long)ELF64_R_TYPE(rela[i].r_info));
+ pr_err("%s: Unknown ADD relocation: %d\n", obj_name,
+ reloc_type);
return -ENOEXEC;
}
}
diff -puN arch/powerpc/kernel/module_64.c~powerpc-adapt-elf64_apply_relocate_add-for-kexec_file_load arch/powerpc/kernel/module_64.c
--- a/arch/powerpc/kernel/module_64.c~powerpc-adapt-elf64_apply_relocate_add-for-kexec_file_load
+++ a/arch/powerpc/kernel/module_64.c
@@ -341,6 +341,7 @@ int module_frob_arch_sections(Elf64_Ehdr
sechdrs[me->arch.elf_info.stubs_section].sh_size = get_stubs_size(hdr, sechdrs);
/* For the elf_util functions. */
+ me->arch.elf_info.ehdr = hdr;
me->arch.elf_info.sechdrs = sechdrs;
return 0;
@@ -443,6 +444,9 @@ int restore_r2(u32 *instruction, const c
* When this function is called, the module is already at its final location in
* memory, so Elf64_Shdr.sh_addr can be used for accessing the section
* contents as well as the base address for relocations.
+ *
+ * Also, simplify_symbols already changed all symbols' st_value members
+ * to absolute addresses.
*/
int apply_relocate_add(Elf64_Shdr *sechdrs,
const char *strtab,
@@ -472,7 +476,7 @@ int apply_relocate_add(Elf64_Shdr *sechd
return elf64_apply_relocate_add(&me->arch.elf_info, strtab, rela,
num_rela, syms_base, (void *) addr_base,
- addr_base, me->name);
+ addr_base, false, false, me->name);
}
#ifdef CONFIG_DYNAMIC_FTRACE
_
Patches currently in -mm which might be from bauerman@xxxxxxxxxxxxxxxxxx are
kexec_file-allow-arch-specific-memory-walking-for-kexec_add_buffer.patch
kexec_file-change-kexec_add_buffer-to-take-kexec_buf-as-argument.patch
kexec_file-factor-out-kexec_locate_mem_hole-from-kexec_add_buffer.patch
powerpc-factor-out-relocation-code-from-module_64c-to-elf_util_64c.patch
powerpc-generalize-elf64_apply_relocate_add.patch
powerpc-adapt-elf64_apply_relocate_add-for-kexec_file_load.patch
powerpc-add-functions-to-read-elf-files-of-any-endianness.patch
powerpc-implement-kexec_file_load.patch
powerpc-add-code-to-work-with-device-trees-in-kexec_file_load.patch
powerpc-add-support-for-loading-elf-kernels-with-kexec_file_load.patch
powerpc-add-purgatory-for-kexec_file_load-implementation.patch
powerpc-enable-config_kexec_file-in-powerpc-server-defconfigs.patch
kexec_file-add-buffer-hand-over-support-for-the-next-kernel.patch
powerpc-kexec_file-add-buffer-hand-over-support-for-the-next-kernel.patch
kexec_file-allow-skipping-checksum-calculation-for-some-segments.patch
kexec_file-add-mechanism-to-update-kexec-segments.patch
ima-demonstration-code-for-kexec-buffer-passing.patch
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