powerpc: Handle new ELFv2 module relocations

The new ELF ABI tends to use R_PPC64_REL16_LO and R_PPC64_REL16_HA
relocations (PC-relative), so implement them.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

2 files changed, 23 insertions, 1 deletions

diff --git a/arch/powerpc/include/uapi/asm/elf.h b/arch/powerpc/include/uapi/asm/elf.h
index 0341109e4395..59dad113897b 100644
--- a/arch/powerpc/include/uapi/asm/elf.h
+++ b/arch/powerpc/include/uapi/asm/elf.h
@@ -295,8 +295,13 @@ do {									\
 #define R_PPC64_TLSLD           108
 #define R_PPC64_TOCSAVE         109
 
+#define R_PPC64_REL16           249
+#define R_PPC64_REL16_LO        250
+#define R_PPC64_REL16_HI        251
+#define R_PPC64_REL16_HA        252
+
 /* Keep this the last entry.  */
-#define R_PPC64_NUM             110
+#define R_PPC64_NUM             253
 
 /* There's actually a third entry here, but it's unused */
 struct ppc64_opd_entry
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index f6544d7071d6..34ba326ccc30 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -491,6 +491,23 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
                          */
                         break;
 
+                case R_PPC64_REL16_HA:
+                        /* Subtract location pointer */
+                        value -= (unsigned long)location;
+                        value = ((value + 0x8000) >> 16);
+                        *((uint16_t *) location)
+                                = (*((uint16_t *) location) & ~0xffff)
+                                | (value & 0xffff);
+                        break;
+
+                case R_PPC64_REL16_LO:
+                        /* Subtract location pointer */
+                        value -= (unsigned long)location;
+                        *((uint16_t *) location)
+                                = (*((uint16_t *) location) & ~0xffff)
+                                | (value & 0xffff);
+                        break;
+
                 default:
                         printk("%s: Unknown ADD relocation: %lu\n",
                                me->name,