MIPS64 code uses rela-style relocs, and MIPS64r6 modules may include the
new R_MIPS_PC21 & R_MIPS_PC26 relocations. We thus need to support these
relocations in order to load MIPS64r6 kernel modules. They are similar
to the existing R_MIPS_PC16 relocation but applying to a wider field.
Implement support for them by genericising the existing R_MIPS_PC16
implementation such that it can be used for different field widths, and
calling it for all 3 reloc types.
Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
---
Changes in v2: None
arch/mips/include/asm/elf.h | 5 +++++
arch/mips/kernel/module-rela.c | 48 +++++++++++++++++++++++++++++++++++++++++-
2 files changed, 52 insertions(+), 1 deletion(-)
diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h
index cefb7a5..7cec234 100644
--- a/arch/mips/include/asm/elf.h
+++ b/arch/mips/include/asm/elf.h
@@ -111,6 +111,11 @@
#define R_MIPS_CALLHI16 30
#define R_MIPS_CALLLO16 31
/*
+ * Introduced for MIPSr6.
+ */
+#define R_MIPS_PC21_S2 60
+#define R_MIPS_PC26_S2 61
+/*
* This range is reserved for vendor specific relocations.
*/
#define R_MIPS_LOVENDOR 100
diff --git a/arch/mips/kernel/module-rela.c b/arch/mips/kernel/module-rela.c
index 0570676..b361142 100644
--- a/arch/mips/kernel/module-rela.c
+++ b/arch/mips/kernel/module-rela.c
@@ -16,6 +16,7 @@
* Copyright (C) 2001 Rusty Russell.
* Copyright (C) 2003, 2004 Ralf Baechle (ralf@xxxxxxxxxxxxxx)
* Copyright (C) 2005 Thiemo Seufer
+ * Copyright (C) 2015 Imagination Technologies Ltd.
*/
#include <linux/elf.h>
@@ -65,6 +66,48 @@ static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v)
return 0;
}
+static int apply_r_mips_pc_rela(struct module *me, u32 *location, Elf_Addr v,
+ unsigned bits)
+{
+ unsigned long mask = GENMASK(bits - 1, 0);
+ unsigned long se_bits;
+ long offset;
+
+ if (v % 4) {
+ pr_err("module %s: dangerous R_MIPS_PC%u RELA relocation\n",
+ me->name, bits);
+ return -ENOEXEC;
+ }
+
+ offset = ((long)v - (long)location) >> 2;
+
+ /* check the sign bit onwards are identical - ie. we didn't overflow */
+ se_bits = (offset & BIT(bits - 1)) ? ~0ul : 0;
+ if ((offset & ~mask) != (se_bits & ~mask)) {
+ pr_err("module %s: relocation overflow\n", me->name);
+ return -ENOEXEC;
+ }
+
+ *location = (*location & ~mask) | (offset & mask);
+
+ return 0;
+}
+
+static int apply_r_mips_pc16_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ return apply_r_mips_pc_rela(me, location, v, 16);
+}
+
+static int apply_r_mips_pc21_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ return apply_r_mips_pc_rela(me, location, v, 21);
+}
+
+static int apply_r_mips_pc26_rela(struct module *me, u32 *location, Elf_Addr v)
+{
+ return apply_r_mips_pc_rela(me, location, v, 26);
+}
+
static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v)
{
*(Elf_Addr *)location = v;
@@ -97,9 +140,12 @@ static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
[R_MIPS_26] = apply_r_mips_26_rela,
[R_MIPS_HI16] = apply_r_mips_hi16_rela,
[R_MIPS_LO16] = apply_r_mips_lo16_rela,
+ [R_MIPS_PC16] = apply_r_mips_pc16_rela,
[R_MIPS_64] = apply_r_mips_64_rela,
[R_MIPS_HIGHER] = apply_r_mips_higher_rela,
- [R_MIPS_HIGHEST] = apply_r_mips_highest_rela
+ [R_MIPS_HIGHEST] = apply_r_mips_highest_rela,
+ [R_MIPS_PC21_S2] = apply_r_mips_pc21_rela,
+ [R_MIPS_PC26_S2] = apply_r_mips_pc26_rela,
};
int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
--
2.7.0
