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abba759796
This eliminates the workaround that requires disabling -mprofile-kernel by default in Kconfig. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
841 lines
23 KiB
C
841 lines
23 KiB
C
/* Kernel module help for PPC64.
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Copyright (C) 2001, 2003 Rusty Russell IBM Corporation.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/elf.h>
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#include <linux/moduleloader.h>
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#include <linux/err.h>
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#include <linux/vmalloc.h>
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#include <linux/ftrace.h>
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#include <linux/bug.h>
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#include <linux/uaccess.h>
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#include <asm/module.h>
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#include <asm/firmware.h>
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#include <asm/code-patching.h>
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#include <linux/sort.h>
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#include <asm/setup.h>
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#include <asm/sections.h>
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/* FIXME: We don't do .init separately. To do this, we'd need to have
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a separate r2 value in the init and core section, and stub between
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them, too.
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Using a magic allocator which places modules within 32MB solves
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this, and makes other things simpler. Anton?
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--RR. */
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#ifdef PPC64_ELF_ABI_v2
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/* An address is simply the address of the function. */
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typedef unsigned long func_desc_t;
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static func_desc_t func_desc(unsigned long addr)
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{
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return addr;
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}
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static unsigned long func_addr(unsigned long addr)
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{
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return addr;
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}
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static unsigned long stub_func_addr(func_desc_t func)
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{
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return func;
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}
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/* PowerPC64 specific values for the Elf64_Sym st_other field. */
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#define STO_PPC64_LOCAL_BIT 5
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#define STO_PPC64_LOCAL_MASK (7 << STO_PPC64_LOCAL_BIT)
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#define PPC64_LOCAL_ENTRY_OFFSET(other) \
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(((1 << (((other) & STO_PPC64_LOCAL_MASK) >> STO_PPC64_LOCAL_BIT)) >> 2) << 2)
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static unsigned int local_entry_offset(const Elf64_Sym *sym)
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{
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/* sym->st_other indicates offset to local entry point
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* (otherwise it will assume r12 is the address of the start
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* of function and try to derive r2 from it). */
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return PPC64_LOCAL_ENTRY_OFFSET(sym->st_other);
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}
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#else
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/* An address is address of the OPD entry, which contains address of fn. */
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typedef struct ppc64_opd_entry func_desc_t;
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static func_desc_t func_desc(unsigned long addr)
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{
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return *(struct ppc64_opd_entry *)addr;
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}
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static unsigned long func_addr(unsigned long addr)
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{
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return func_desc(addr).funcaddr;
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}
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static unsigned long stub_func_addr(func_desc_t func)
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{
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return func.funcaddr;
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}
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static unsigned int local_entry_offset(const Elf64_Sym *sym)
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{
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return 0;
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}
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void *dereference_module_function_descriptor(struct module *mod, void *ptr)
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{
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if (ptr < (void *)mod->arch.start_opd ||
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ptr >= (void *)mod->arch.end_opd)
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return ptr;
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return dereference_function_descriptor(ptr);
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}
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#endif
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#define STUB_MAGIC 0x73747562 /* stub */
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/* Like PPC32, we need little trampolines to do > 24-bit jumps (into
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the kernel itself). But on PPC64, these need to be used for every
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jump, actually, to reset r2 (TOC+0x8000). */
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struct ppc64_stub_entry
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{
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/* 28 byte jump instruction sequence (7 instructions). We only
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* need 6 instructions on ABIv2 but we always allocate 7 so
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* so we don't have to modify the trampoline load instruction. */
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u32 jump[7];
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/* Used by ftrace to identify stubs */
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u32 magic;
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/* Data for the above code */
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func_desc_t funcdata;
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};
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/*
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* PPC64 uses 24 bit jumps, but we need to jump into other modules or
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* the kernel which may be further. So we jump to a stub.
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*
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* For ELFv1 we need to use this to set up the new r2 value (aka TOC
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* pointer). For ELFv2 it's the callee's responsibility to set up the
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* new r2, but for both we need to save the old r2.
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*
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* We could simply patch the new r2 value and function pointer into
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* the stub, but it's significantly shorter to put these values at the
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* end of the stub code, and patch the stub address (32-bits relative
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* to the TOC ptr, r2) into the stub.
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*/
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static u32 ppc64_stub_insns[] = {
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0x3d620000, /* addis r11,r2, <high> */
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0x396b0000, /* addi r11,r11, <low> */
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/* Save current r2 value in magic place on the stack. */
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0xf8410000|R2_STACK_OFFSET, /* std r2,R2_STACK_OFFSET(r1) */
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0xe98b0020, /* ld r12,32(r11) */
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#ifdef PPC64_ELF_ABI_v1
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/* Set up new r2 from function descriptor */
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0xe84b0028, /* ld r2,40(r11) */
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#endif
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0x7d8903a6, /* mtctr r12 */
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0x4e800420 /* bctr */
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};
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#ifdef CONFIG_DYNAMIC_FTRACE
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int module_trampoline_target(struct module *mod, unsigned long addr,
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unsigned long *target)
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{
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struct ppc64_stub_entry *stub;
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func_desc_t funcdata;
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u32 magic;
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if (!within_module_core(addr, mod)) {
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pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name);
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return -EFAULT;
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}
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stub = (struct ppc64_stub_entry *)addr;
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if (probe_kernel_read(&magic, &stub->magic, sizeof(magic))) {
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pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name);
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return -EFAULT;
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}
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if (magic != STUB_MAGIC) {
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pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name);
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return -EFAULT;
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}
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if (probe_kernel_read(&funcdata, &stub->funcdata, sizeof(funcdata))) {
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pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name);
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return -EFAULT;
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}
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*target = stub_func_addr(funcdata);
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return 0;
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}
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#endif
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/* Count how many different 24-bit relocations (different symbol,
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different addend) */
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static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num)
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{
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unsigned int i, r_info, r_addend, _count_relocs;
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/* FIXME: Only count external ones --RR */
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_count_relocs = 0;
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r_info = 0;
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r_addend = 0;
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for (i = 0; i < num; i++)
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/* Only count 24-bit relocs, others don't need stubs */
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if (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
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(r_info != ELF64_R_SYM(rela[i].r_info) ||
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r_addend != rela[i].r_addend)) {
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_count_relocs++;
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r_info = ELF64_R_SYM(rela[i].r_info);
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r_addend = rela[i].r_addend;
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}
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return _count_relocs;
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}
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static int relacmp(const void *_x, const void *_y)
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{
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const Elf64_Rela *x, *y;
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y = (Elf64_Rela *)_x;
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x = (Elf64_Rela *)_y;
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/* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to
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* make the comparison cheaper/faster. It won't affect the sorting or
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* the counting algorithms' performance
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*/
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if (x->r_info < y->r_info)
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return -1;
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else if (x->r_info > y->r_info)
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return 1;
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else if (x->r_addend < y->r_addend)
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return -1;
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else if (x->r_addend > y->r_addend)
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return 1;
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else
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return 0;
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}
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static void relaswap(void *_x, void *_y, int size)
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{
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uint64_t *x, *y, tmp;
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int i;
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y = (uint64_t *)_x;
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x = (uint64_t *)_y;
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for (i = 0; i < sizeof(Elf64_Rela) / sizeof(uint64_t); i++) {
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tmp = x[i];
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x[i] = y[i];
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y[i] = tmp;
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}
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}
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/* Get size of potential trampolines required. */
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static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
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const Elf64_Shdr *sechdrs)
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{
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/* One extra reloc so it's always 0-funcaddr terminated */
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unsigned long relocs = 1;
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unsigned i;
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/* Every relocated section... */
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for (i = 1; i < hdr->e_shnum; i++) {
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if (sechdrs[i].sh_type == SHT_RELA) {
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pr_debug("Found relocations in section %u\n", i);
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pr_debug("Ptr: %p. Number: %Lu\n",
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(void *)sechdrs[i].sh_addr,
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sechdrs[i].sh_size / sizeof(Elf64_Rela));
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/* Sort the relocation information based on a symbol and
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* addend key. This is a stable O(n*log n) complexity
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* alogrithm but it will reduce the complexity of
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* count_relocs() to linear complexity O(n)
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*/
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sort((void *)sechdrs[i].sh_addr,
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sechdrs[i].sh_size / sizeof(Elf64_Rela),
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sizeof(Elf64_Rela), relacmp, relaswap);
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relocs += count_relocs((void *)sechdrs[i].sh_addr,
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sechdrs[i].sh_size
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/ sizeof(Elf64_Rela));
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}
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}
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#ifdef CONFIG_DYNAMIC_FTRACE
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/* make the trampoline to the ftrace_caller */
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relocs++;
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#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
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/* an additional one for ftrace_regs_caller */
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relocs++;
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#endif
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#endif
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pr_debug("Looks like a total of %lu stubs, max\n", relocs);
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return relocs * sizeof(struct ppc64_stub_entry);
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}
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/* Still needed for ELFv2, for .TOC. */
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static void dedotify_versions(struct modversion_info *vers,
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unsigned long size)
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{
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struct modversion_info *end;
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for (end = (void *)vers + size; vers < end; vers++)
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if (vers->name[0] == '.') {
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memmove(vers->name, vers->name+1, strlen(vers->name));
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}
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}
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/*
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* Undefined symbols which refer to .funcname, hack to funcname. Make .TOC.
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* seem to be defined (value set later).
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*/
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static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab)
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{
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unsigned int i;
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for (i = 1; i < numsyms; i++) {
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if (syms[i].st_shndx == SHN_UNDEF) {
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char *name = strtab + syms[i].st_name;
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if (name[0] == '.') {
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if (strcmp(name+1, "TOC.") == 0)
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syms[i].st_shndx = SHN_ABS;
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syms[i].st_name++;
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}
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}
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}
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}
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static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs,
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const char *strtab,
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unsigned int symindex)
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{
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unsigned int i, numsyms;
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Elf64_Sym *syms;
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syms = (Elf64_Sym *)sechdrs[symindex].sh_addr;
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numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym);
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for (i = 1; i < numsyms; i++) {
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if (syms[i].st_shndx == SHN_ABS
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&& strcmp(strtab + syms[i].st_name, "TOC.") == 0)
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return &syms[i];
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}
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return NULL;
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}
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int module_frob_arch_sections(Elf64_Ehdr *hdr,
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Elf64_Shdr *sechdrs,
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char *secstrings,
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struct module *me)
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{
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unsigned int i;
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/* Find .toc and .stubs sections, symtab and strtab */
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for (i = 1; i < hdr->e_shnum; i++) {
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char *p;
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if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0)
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me->arch.stubs_section = i;
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else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) {
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me->arch.toc_section = i;
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if (sechdrs[i].sh_addralign < 8)
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sechdrs[i].sh_addralign = 8;
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}
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else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0)
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dedotify_versions((void *)hdr + sechdrs[i].sh_offset,
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sechdrs[i].sh_size);
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else if (!strcmp(secstrings + sechdrs[i].sh_name, ".opd")) {
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me->arch.start_opd = sechdrs[i].sh_addr;
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me->arch.end_opd = sechdrs[i].sh_addr +
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sechdrs[i].sh_size;
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}
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/* We don't handle .init for the moment: rename to _init */
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while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init")))
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p[0] = '_';
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if (sechdrs[i].sh_type == SHT_SYMTAB)
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dedotify((void *)hdr + sechdrs[i].sh_offset,
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sechdrs[i].sh_size / sizeof(Elf64_Sym),
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(void *)hdr
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+ sechdrs[sechdrs[i].sh_link].sh_offset);
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}
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if (!me->arch.stubs_section) {
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pr_err("%s: doesn't contain .stubs.\n", me->name);
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return -ENOEXEC;
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}
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/* If we don't have a .toc, just use .stubs. We need to set r2
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to some reasonable value in case the module calls out to
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other functions via a stub, or if a function pointer escapes
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the module by some means. */
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if (!me->arch.toc_section)
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me->arch.toc_section = me->arch.stubs_section;
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/* Override the stubs size */
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sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs);
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return 0;
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}
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/*
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* r2 is the TOC pointer: it actually points 0x8000 into the TOC (this gives the
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* value maximum span in an instruction which uses a signed offset). Round down
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* to a 256 byte boundary for the odd case where we are setting up r2 without a
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* .toc section.
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*/
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static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me)
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{
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return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000;
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}
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/* Both low and high 16 bits are added as SIGNED additions, so if low
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16 bits has high bit set, high 16 bits must be adjusted. These
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macros do that (stolen from binutils). */
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#define PPC_LO(v) ((v) & 0xffff)
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#define PPC_HI(v) (((v) >> 16) & 0xffff)
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#define PPC_HA(v) PPC_HI ((v) + 0x8000)
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/* Patch stub to reference function and correct r2 value. */
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static inline int create_stub(const Elf64_Shdr *sechdrs,
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struct ppc64_stub_entry *entry,
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unsigned long addr,
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struct module *me)
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{
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long reladdr;
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memcpy(entry->jump, ppc64_stub_insns, sizeof(ppc64_stub_insns));
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/* Stub uses address relative to r2. */
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reladdr = (unsigned long)entry - my_r2(sechdrs, me);
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if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
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pr_err("%s: Address %p of stub out of range of %p.\n",
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me->name, (void *)reladdr, (void *)my_r2);
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return 0;
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}
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pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr);
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entry->jump[0] |= PPC_HA(reladdr);
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entry->jump[1] |= PPC_LO(reladdr);
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entry->funcdata = func_desc(addr);
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entry->magic = STUB_MAGIC;
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return 1;
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}
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/* Create stub to jump to function described in this OPD/ptr: we need the
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stub to set up the TOC ptr (r2) for the function. */
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static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs,
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unsigned long addr,
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struct module *me)
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{
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struct ppc64_stub_entry *stubs;
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unsigned int i, num_stubs;
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num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs);
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/* Find this stub, or if that fails, the next avail. entry */
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stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr;
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for (i = 0; stub_func_addr(stubs[i].funcdata); i++) {
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if (WARN_ON(i >= num_stubs))
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return 0;
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if (stub_func_addr(stubs[i].funcdata) == func_addr(addr))
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return (unsigned long)&stubs[i];
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}
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if (!create_stub(sechdrs, &stubs[i], addr, me))
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return 0;
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return (unsigned long)&stubs[i];
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}
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#ifdef CONFIG_MPROFILE_KERNEL
|
|
static bool is_mprofile_mcount_callsite(const char *name, u32 *instruction)
|
|
{
|
|
if (strcmp("_mcount", name))
|
|
return false;
|
|
|
|
/*
|
|
* Check if this is one of the -mprofile-kernel sequences.
|
|
*/
|
|
if (instruction[-1] == PPC_INST_STD_LR &&
|
|
instruction[-2] == PPC_INST_MFLR)
|
|
return true;
|
|
|
|
if (instruction[-1] == PPC_INST_MFLR)
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* In case of _mcount calls, do not save the current callee's TOC (in r2) into
|
|
* the original caller's stack frame. If we did we would clobber the saved TOC
|
|
* value of the original caller.
|
|
*/
|
|
static void squash_toc_save_inst(const char *name, unsigned long addr)
|
|
{
|
|
struct ppc64_stub_entry *stub = (struct ppc64_stub_entry *)addr;
|
|
|
|
/* Only for calls to _mcount */
|
|
if (strcmp("_mcount", name) != 0)
|
|
return;
|
|
|
|
stub->jump[2] = PPC_INST_NOP;
|
|
}
|
|
#else
|
|
static void squash_toc_save_inst(const char *name, unsigned long addr) { }
|
|
|
|
static bool is_mprofile_mcount_callsite(const char *name, u32 *instruction)
|
|
{
|
|
return false;
|
|
}
|
|
#endif
|
|
|
|
/* We expect a noop next: if it is, replace it with instruction to
|
|
restore r2. */
|
|
static int restore_r2(const char *name, u32 *instruction, struct module *me)
|
|
{
|
|
u32 *prev_insn = instruction - 1;
|
|
|
|
if (is_mprofile_mcount_callsite(name, prev_insn))
|
|
return 1;
|
|
|
|
/*
|
|
* Make sure the branch isn't a sibling call. Sibling calls aren't
|
|
* "link" branches and they don't return, so they don't need the r2
|
|
* restore afterwards.
|
|
*/
|
|
if (!instr_is_relative_link_branch(*prev_insn))
|
|
return 1;
|
|
|
|
if (*instruction != PPC_INST_NOP) {
|
|
pr_err("%s: Expected nop after call, got %08x at %pS\n",
|
|
me->name, *instruction, instruction);
|
|
return 0;
|
|
}
|
|
/* ld r2,R2_STACK_OFFSET(r1) */
|
|
*instruction = PPC_INST_LD_TOC;
|
|
return 1;
|
|
}
|
|
|
|
int apply_relocate_add(Elf64_Shdr *sechdrs,
|
|
const char *strtab,
|
|
unsigned int symindex,
|
|
unsigned int relsec,
|
|
struct module *me)
|
|
{
|
|
unsigned int i;
|
|
Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr;
|
|
Elf64_Sym *sym;
|
|
unsigned long *location;
|
|
unsigned long value;
|
|
|
|
pr_debug("Applying ADD relocate section %u to %u\n", relsec,
|
|
sechdrs[relsec].sh_info);
|
|
|
|
/* First time we're called, we can fix up .TOC. */
|
|
if (!me->arch.toc_fixed) {
|
|
sym = find_dot_toc(sechdrs, strtab, symindex);
|
|
/* It's theoretically possible that a module doesn't want a
|
|
* .TOC. so don't fail it just for that. */
|
|
if (sym)
|
|
sym->st_value = my_r2(sechdrs, me);
|
|
me->arch.toc_fixed = true;
|
|
}
|
|
|
|
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
|
|
/* This is where to make the change */
|
|
location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
|
|
+ rela[i].r_offset;
|
|
/* This is the symbol it is referring to */
|
|
sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
|
|
+ ELF64_R_SYM(rela[i].r_info);
|
|
|
|
pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n",
|
|
location, (long)ELF64_R_TYPE(rela[i].r_info),
|
|
strtab + sym->st_name, (unsigned long)sym->st_value,
|
|
(long)rela[i].r_addend);
|
|
|
|
/* `Everything is relative'. */
|
|
value = sym->st_value + rela[i].r_addend;
|
|
|
|
switch (ELF64_R_TYPE(rela[i].r_info)) {
|
|
case R_PPC64_ADDR32:
|
|
/* Simply set it */
|
|
*(u32 *)location = value;
|
|
break;
|
|
|
|
case R_PPC64_ADDR64:
|
|
/* Simply set it */
|
|
*(unsigned long *)location = value;
|
|
break;
|
|
|
|
case R_PPC64_TOC:
|
|
*(unsigned long *)location = my_r2(sechdrs, me);
|
|
break;
|
|
|
|
case R_PPC64_TOC16:
|
|
/* Subtract TOC pointer */
|
|
value -= my_r2(sechdrs, me);
|
|
if (value + 0x8000 > 0xffff) {
|
|
pr_err("%s: bad TOC16 relocation (0x%lx)\n",
|
|
me->name, value);
|
|
return -ENOEXEC;
|
|
}
|
|
*((uint16_t *) location)
|
|
= (*((uint16_t *) location) & ~0xffff)
|
|
| (value & 0xffff);
|
|
break;
|
|
|
|
case R_PPC64_TOC16_LO:
|
|
/* Subtract TOC pointer */
|
|
value -= my_r2(sechdrs, me);
|
|
*((uint16_t *) location)
|
|
= (*((uint16_t *) location) & ~0xffff)
|
|
| (value & 0xffff);
|
|
break;
|
|
|
|
case R_PPC64_TOC16_DS:
|
|
/* Subtract TOC pointer */
|
|
value -= my_r2(sechdrs, me);
|
|
if ((value & 3) != 0 || value + 0x8000 > 0xffff) {
|
|
pr_err("%s: bad TOC16_DS relocation (0x%lx)\n",
|
|
me->name, value);
|
|
return -ENOEXEC;
|
|
}
|
|
*((uint16_t *) location)
|
|
= (*((uint16_t *) location) & ~0xfffc)
|
|
| (value & 0xfffc);
|
|
break;
|
|
|
|
case R_PPC64_TOC16_LO_DS:
|
|
/* Subtract TOC pointer */
|
|
value -= my_r2(sechdrs, me);
|
|
if ((value & 3) != 0) {
|
|
pr_err("%s: bad TOC16_LO_DS relocation (0x%lx)\n",
|
|
me->name, value);
|
|
return -ENOEXEC;
|
|
}
|
|
*((uint16_t *) location)
|
|
= (*((uint16_t *) location) & ~0xfffc)
|
|
| (value & 0xfffc);
|
|
break;
|
|
|
|
case R_PPC64_TOC16_HA:
|
|
/* Subtract TOC pointer */
|
|
value -= my_r2(sechdrs, me);
|
|
value = ((value + 0x8000) >> 16);
|
|
*((uint16_t *) location)
|
|
= (*((uint16_t *) location) & ~0xffff)
|
|
| (value & 0xffff);
|
|
break;
|
|
|
|
case R_PPC_REL24:
|
|
/* FIXME: Handle weak symbols here --RR */
|
|
if (sym->st_shndx == SHN_UNDEF ||
|
|
sym->st_shndx == SHN_LIVEPATCH) {
|
|
/* External: go via stub */
|
|
value = stub_for_addr(sechdrs, value, me);
|
|
if (!value)
|
|
return -ENOENT;
|
|
if (!restore_r2(strtab + sym->st_name,
|
|
(u32 *)location + 1, me))
|
|
return -ENOEXEC;
|
|
|
|
squash_toc_save_inst(strtab + sym->st_name, value);
|
|
} else
|
|
value += local_entry_offset(sym);
|
|
|
|
/* Convert value to relative */
|
|
value -= (unsigned long)location;
|
|
if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){
|
|
pr_err("%s: REL24 %li out of range!\n",
|
|
me->name, (long int)value);
|
|
return -ENOEXEC;
|
|
}
|
|
|
|
/* Only replace bits 2 through 26 */
|
|
*(uint32_t *)location
|
|
= (*(uint32_t *)location & ~0x03fffffc)
|
|
| (value & 0x03fffffc);
|
|
break;
|
|
|
|
case R_PPC64_REL64:
|
|
/* 64 bits relative (used by features fixups) */
|
|
*location = value - (unsigned long)location;
|
|
break;
|
|
|
|
case R_PPC64_REL32:
|
|
/* 32 bits relative (used by relative exception tables) */
|
|
*(u32 *)location = value - (unsigned long)location;
|
|
break;
|
|
|
|
case R_PPC64_TOCSAVE:
|
|
/*
|
|
* Marker reloc indicates we don't have to save r2.
|
|
* That would only save us one instruction, so ignore
|
|
* it.
|
|
*/
|
|
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;
|
|
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:
|
|
pr_err("%s: Unknown ADD relocation: %lu\n",
|
|
me->name,
|
|
(unsigned long)ELF64_R_TYPE(rela[i].r_info));
|
|
return -ENOEXEC;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_DYNAMIC_FTRACE
|
|
|
|
#ifdef CONFIG_MPROFILE_KERNEL
|
|
|
|
#define PACATOC offsetof(struct paca_struct, kernel_toc)
|
|
|
|
/*
|
|
* For mprofile-kernel we use a special stub for ftrace_caller() because we
|
|
* can't rely on r2 containing this module's TOC when we enter the stub.
|
|
*
|
|
* That can happen if the function calling us didn't need to use the toc. In
|
|
* that case it won't have setup r2, and the r2 value will be either the
|
|
* kernel's toc, or possibly another modules toc.
|
|
*
|
|
* To deal with that this stub uses the kernel toc, which is always accessible
|
|
* via the paca (in r13). The target (ftrace_caller()) is responsible for
|
|
* saving and restoring the toc before returning.
|
|
*/
|
|
static unsigned long create_ftrace_stub(const Elf64_Shdr *sechdrs,
|
|
struct module *me, unsigned long addr)
|
|
{
|
|
struct ppc64_stub_entry *entry;
|
|
unsigned int i, num_stubs;
|
|
static u32 stub_insns[] = {
|
|
0xe98d0000 | PACATOC, /* ld r12,PACATOC(r13) */
|
|
0x3d8c0000, /* addis r12,r12,<high> */
|
|
0x398c0000, /* addi r12,r12,<low> */
|
|
0x7d8903a6, /* mtctr r12 */
|
|
0x4e800420, /* bctr */
|
|
};
|
|
long reladdr;
|
|
|
|
num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*entry);
|
|
|
|
/* Find the next available stub entry */
|
|
entry = (void *)sechdrs[me->arch.stubs_section].sh_addr;
|
|
for (i = 0; i < num_stubs && stub_func_addr(entry->funcdata); i++, entry++);
|
|
|
|
if (i >= num_stubs) {
|
|
pr_err("%s: Unable to find a free slot for ftrace stub.\n", me->name);
|
|
return 0;
|
|
}
|
|
|
|
memcpy(entry->jump, stub_insns, sizeof(stub_insns));
|
|
|
|
/* Stub uses address relative to kernel toc (from the paca) */
|
|
reladdr = addr - kernel_toc_addr();
|
|
if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
|
|
pr_err("%s: Address of %ps out of range of kernel_toc.\n",
|
|
me->name, (void *)addr);
|
|
return 0;
|
|
}
|
|
|
|
entry->jump[1] |= PPC_HA(reladdr);
|
|
entry->jump[2] |= PPC_LO(reladdr);
|
|
|
|
/* Eventhough we don't use funcdata in the stub, it's needed elsewhere. */
|
|
entry->funcdata = func_desc(addr);
|
|
entry->magic = STUB_MAGIC;
|
|
|
|
return (unsigned long)entry;
|
|
}
|
|
#else
|
|
static unsigned long create_ftrace_stub(const Elf64_Shdr *sechdrs,
|
|
struct module *me, unsigned long addr)
|
|
{
|
|
return stub_for_addr(sechdrs, addr, me);
|
|
}
|
|
#endif
|
|
|
|
int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs)
|
|
{
|
|
mod->arch.tramp = create_ftrace_stub(sechdrs, mod,
|
|
(unsigned long)ftrace_caller);
|
|
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
|
|
mod->arch.tramp_regs = create_ftrace_stub(sechdrs, mod,
|
|
(unsigned long)ftrace_regs_caller);
|
|
if (!mod->arch.tramp_regs)
|
|
return -ENOENT;
|
|
#endif
|
|
|
|
if (!mod->arch.tramp)
|
|
return -ENOENT;
|
|
|
|
return 0;
|
|
}
|
|
#endif
|