@@ -295,6 +295,8 @@ do { \
#define R_PPC64_TLSLD 108
#define R_PPC64_TOCSAVE 109
+#define R_PPC64_ENTRY 118
+
#define R_PPC64_REL16 249
#define R_PPC64_REL16_LO 250
#define R_PPC64_REL16_HI 251
@@ -637,6 +637,33 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
*/
break;
+ case R_PPC64_ENTRY:
+ /*
+ * Optimize ELFv2 large code model entry point if
+ * the TOC is within 2GB range of current location.
+ */
+ value = my_r2(sechdrs, me) - (unsigned long)location;
+ if (value + 0x80008000 > 0xffffffff)
+ break;
+ /*
+ * Check for the large code model prolog sequence:
+ * ld r2, ...(r12)
+ * add r2, r2, r12
+ */
+ if ((((uint32_t *)location)[0] & ~0xfffc)
+ != 0xe84c0000)
+ break;
+ if (((uint32_t *)location)[1] != 0x7c426214)
+ break;
+ /*
+ * If found, replace it with:
+ * addis r2, r12, (.TOC.-func)@ha
+ * addi r2, r12, (.TOC.-func)@l
+ */
+ ((uint32_t *)location)[0] = 0x3c4c0000 + PPC_HA(value);
+ ((uint32_t *)location)[1] = 0x38420000 + PPC_LO(value);
+ break;
+
case R_PPC64_REL16_HA:
/* Subtract location pointer */
value -= (unsigned long)location;
This is a note to let you know that I have just added a patch titled powerpc/module: Handle R_PPC64_ENTRY relocations to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt24. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ---8<------------------------------------------------------------ From cd8014be9326512bcbee335d559befd3fcfed615 Mon Sep 17 00:00:00 2001 From: Ulrich Weigand <ulrich.weigand@de.ibm.com> Date: Tue, 12 Jan 2016 23:14:23 +1100 Subject: powerpc/module: Handle R_PPC64_ENTRY relocations commit a61674bdfc7c2bf909c4010699607b62b69b7bec upstream. GCC 6 will include changes to generated code with -mcmodel=large, which is used to build kernel modules on powerpc64le. This was necessary because the large model is supposed to allow arbitrary sizes and locations of the code and data sections, but the ELFv2 global entry point prolog still made the unconditional assumption that the TOC associated with any particular function can be found within 2 GB of the function entry point: func: addis r2,r12,(.TOC.-func)@ha addi r2,r2,(.TOC.-func)@l .localentry func, .-func To remove this assumption, GCC will now generate instead this global entry point prolog sequence when using -mcmodel=large: .quad .TOC.-func func: .reloc ., R_PPC64_ENTRY ld r2, -8(r12) add r2, r2, r12 .localentry func, .-func The new .reloc triggers an optimization in the linker that will replace this new prolog with the original code (see above) if the linker determines that the distance between .TOC. and func is in range after all. Since this new relocation is now present in module object files, the kernel module loader is required to handle them too. This patch adds support for the new relocation and implements the same optimization done by the GNU linker. Signed-off-by: Ulrich Weigand <ulrich.weigand@de.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- arch/powerpc/include/uapi/asm/elf.h | 2 ++ arch/powerpc/kernel/module_64.c | 27 +++++++++++++++++++++++++++ 2 files changed, 29 insertions(+)