--- /dev/null
+/* Common target-dependent code for ppc64 GDB, the GNU debugger.
+
+ Copyright (C) 1986-2013 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include "defs.h"
+#include "frame.h"
+#include "gdbcore.h"
+#include "ppc-tdep.h"
+#include "ppc64-tdep.h"
+
+/* Macros for matching instructions. Note that, since all the
+ operands are masked off before they're or-ed into the instruction,
+ you can use -1 to make masks. */
+
+#define insn_d(opcd, rts, ra, d) \
+ ((((opcd) & 0x3f) << 26) \
+ | (((rts) & 0x1f) << 21) \
+ | (((ra) & 0x1f) << 16) \
+ | ((d) & 0xffff))
+
+#define insn_ds(opcd, rts, ra, d, xo) \
+ ((((opcd) & 0x3f) << 26) \
+ | (((rts) & 0x1f) << 21) \
+ | (((ra) & 0x1f) << 16) \
+ | ((d) & 0xfffc) \
+ | ((xo) & 0x3))
+
+#define insn_xfx(opcd, rts, spr, xo) \
+ ((((opcd) & 0x3f) << 26) \
+ | (((rts) & 0x1f) << 21) \
+ | (((spr) & 0x1f) << 16) \
+ | (((spr) & 0x3e0) << 6) \
+ | (((xo) & 0x3ff) << 1))
+
+/* If DESC is the address of a 64-bit PowerPC FreeBSD function
+ descriptor, return the descriptor's entry point. */
+
+static CORE_ADDR
+ppc64_desc_entry_point (struct gdbarch *gdbarch, CORE_ADDR desc)
+{
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+ /* The first word of the descriptor is the entry point. */
+ return (CORE_ADDR) read_memory_unsigned_integer (desc, 8, byte_order);
+}
+
+/* Pattern for the standard linkage function. These are built by
+ build_plt_stub in elf64-ppc.c, whose GLINK argument is always
+ zero. */
+
+static struct ppc_insn_pattern ppc64_standard_linkage1[] =
+ {
+ /* addis r12, r2, <any> */
+ { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 },
+
+ /* std r2, 40(r1) */
+ { -1, insn_ds (62, 2, 1, 40, 0), 0 },
+
+ /* ld r11, <any>(r12) */
+ { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 },
+
+ /* addis r12, r12, 1 <optional> */
+ { insn_d (-1, -1, -1, -1), insn_d (15, 12, 12, 1), 1 },
+
+ /* ld r2, <any>(r12) */
+ { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 12, 0, 0), 0 },
+
+ /* addis r12, r12, 1 <optional> */
+ { insn_d (-1, -1, -1, -1), insn_d (15, 12, 12, 1), 1 },
+
+ /* mtctr r11 */
+ { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), 0 },
+
+ /* ld r11, <any>(r12) <optional> */
+ { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 1 },
+
+ /* bctr */
+ { -1, 0x4e800420, 0 },
+
+ { 0, 0, 0 }
+ };
+
+#define PPC64_STANDARD_LINKAGE1_LEN ARRAY_SIZE (ppc64_standard_linkage1)
+
+static struct ppc_insn_pattern ppc64_standard_linkage2[] =
+ {
+ /* addis r12, r2, <any> */
+ { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 },
+
+ /* std r2, 40(r1) */
+ { -1, insn_ds (62, 2, 1, 40, 0), 0 },
+
+ /* ld r11, <any>(r12) */
+ { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 },
+
+ /* addi r12, r12, <any> <optional> */
+ { insn_d (-1, -1, -1, 0), insn_d (14, 12, 12, 0), 1 },
+
+ /* mtctr r11 */
+ { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), 0 },
+
+ /* ld r2, <any>(r12) */
+ { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 12, 0, 0), 0 },
+
+ /* ld r11, <any>(r12) <optional> */
+ { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 1 },
+
+ /* bctr */
+ { -1, 0x4e800420, 0 },
+
+ { 0, 0, 0 }
+ };
+
+#define PPC64_STANDARD_LINKAGE2_LEN ARRAY_SIZE (ppc64_standard_linkage2)
+
+static struct ppc_insn_pattern ppc64_standard_linkage3[] =
+ {
+ /* std r2, 40(r1) */
+ { -1, insn_ds (62, 2, 1, 40, 0), 0 },
+
+ /* ld r11, <any>(r2) */
+ { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 2, 0, 0), 0 },
+
+ /* addi r2, r2, <any> <optional> */
+ { insn_d (-1, -1, -1, 0), insn_d (14, 2, 2, 0), 1 },
+
+ /* mtctr r11 */
+ { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), 0 },
+
+ /* ld r11, <any>(r2) <optional> */
+ { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 2, 0, 0), 1 },
+
+ /* ld r2, <any>(r2) */
+ { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 2, 0, 0), 0 },
+
+ /* bctr */
+ { -1, 0x4e800420, 0 },
+
+ { 0, 0, 0 }
+ };
+
+#define PPC64_STANDARD_LINKAGE3_LEN ARRAY_SIZE (ppc64_standard_linkage3)
+
+/* When the dynamic linker is doing lazy symbol resolution, the first
+ call to a function in another object will go like this:
+
+ - The user's function calls the linkage function:
+
+ 100007c4: 4b ff fc d5 bl 10000498
+ 100007c8: e8 41 00 28 ld r2,40(r1)
+
+ - The linkage function loads the entry point (and other stuff) from
+ the function descriptor in the PLT, and jumps to it:
+
+ 10000498: 3d 82 00 00 addis r12,r2,0
+ 1000049c: f8 41 00 28 std r2,40(r1)
+ 100004a0: e9 6c 80 98 ld r11,-32616(r12)
+ 100004a4: e8 4c 80 a0 ld r2,-32608(r12)
+ 100004a8: 7d 69 03 a6 mtctr r11
+ 100004ac: e9 6c 80 a8 ld r11,-32600(r12)
+ 100004b0: 4e 80 04 20 bctr
+
+ - But since this is the first time that PLT entry has been used, it
+ sends control to its glink entry. That loads the number of the
+ PLT entry and jumps to the common glink0 code:
+
+ 10000c98: 38 00 00 00 li r0,0
+ 10000c9c: 4b ff ff dc b 10000c78
+
+ - The common glink0 code then transfers control to the dynamic
+ linker's fixup code:
+
+ 10000c78: e8 41 00 28 ld r2,40(r1)
+ 10000c7c: 3d 82 00 00 addis r12,r2,0
+ 10000c80: e9 6c 80 80 ld r11,-32640(r12)
+ 10000c84: e8 4c 80 88 ld r2,-32632(r12)
+ 10000c88: 7d 69 03 a6 mtctr r11
+ 10000c8c: e9 6c 80 90 ld r11,-32624(r12)
+ 10000c90: 4e 80 04 20 bctr
+
+ Eventually, this code will figure out how to skip all of this,
+ including the dynamic linker. At the moment, we just get through
+ the linkage function. */
+
+/* If the current thread is about to execute a series of instructions
+ at PC matching the ppc64_standard_linkage pattern, and INSN is the result
+ from that pattern match, return the code address to which the
+ standard linkage function will send them. (This doesn't deal with
+ dynamic linker lazy symbol resolution stubs.) */
+
+static CORE_ADDR
+ppc64_standard_linkage1_target (struct frame_info *frame,
+ CORE_ADDR pc, unsigned int *insn)
+{
+ struct gdbarch *gdbarch = get_frame_arch (frame);
+ struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+ /* The address of the function descriptor this linkage function
+ references. */
+ CORE_ADDR desc
+ = ((CORE_ADDR) get_frame_register_unsigned (frame,
+ tdep->ppc_gp0_regnum + 2)
+ + (ppc_insn_d_field (insn[0]) << 16)
+ + ppc_insn_ds_field (insn[2]));
+
+ /* The first word of the descriptor is the entry point. Return that. */
+ return ppc64_desc_entry_point (gdbarch, desc);
+}
+
+static CORE_ADDR
+ppc64_standard_linkage2_target (struct frame_info *frame,
+ CORE_ADDR pc, unsigned int *insn)
+{
+ struct gdbarch *gdbarch = get_frame_arch (frame);
+ struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+ /* The address of the function descriptor this linkage function
+ references. */
+ CORE_ADDR desc
+ = ((CORE_ADDR) get_frame_register_unsigned (frame,
+ tdep->ppc_gp0_regnum + 2)
+ + (ppc_insn_d_field (insn[0]) << 16)
+ + ppc_insn_ds_field (insn[2]));
+
+ /* The first word of the descriptor is the entry point. Return that. */
+ return ppc64_desc_entry_point (gdbarch, desc);
+}
+
+static CORE_ADDR
+ppc64_standard_linkage3_target (struct frame_info *frame,
+ CORE_ADDR pc, unsigned int *insn)
+{
+ struct gdbarch *gdbarch = get_frame_arch (frame);
+ struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+ /* The address of the function descriptor this linkage function
+ references. */
+ CORE_ADDR desc
+ = ((CORE_ADDR) get_frame_register_unsigned (frame,
+ tdep->ppc_gp0_regnum + 2)
+ + ppc_insn_ds_field (insn[1]));
+
+ /* The first word of the descriptor is the entry point. Return that. */
+ return ppc64_desc_entry_point (gdbarch, desc);
+}
+
+
+/* Given that we've begun executing a call trampoline at PC, return
+ the entry point of the function the trampoline will go to. */
+
+CORE_ADDR
+ppc64_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
+{
+ unsigned int ppc64_standard_linkage1_insn[PPC64_STANDARD_LINKAGE1_LEN];
+ unsigned int ppc64_standard_linkage2_insn[PPC64_STANDARD_LINKAGE2_LEN];
+ unsigned int ppc64_standard_linkage3_insn[PPC64_STANDARD_LINKAGE3_LEN];
+ CORE_ADDR target;
+
+ if (ppc_insns_match_pattern (pc, ppc64_standard_linkage1,
+ ppc64_standard_linkage1_insn))
+ pc = ppc64_standard_linkage1_target (frame, pc,
+ ppc64_standard_linkage1_insn);
+ else if (ppc_insns_match_pattern (pc, ppc64_standard_linkage2,
+ ppc64_standard_linkage2_insn))
+ pc = ppc64_standard_linkage2_target (frame, pc,
+ ppc64_standard_linkage2_insn);
+ else if (ppc_insns_match_pattern (pc, ppc64_standard_linkage3,
+ ppc64_standard_linkage3_insn))
+ pc = ppc64_standard_linkage3_target (frame, pc,
+ ppc64_standard_linkage3_insn);
+ else
+ return 0;
+
+ /* The PLT descriptor will either point to the already resolved target
+ address, or else to a glink stub. As the latter carry synthetic @plt
+ symbols, find_solib_trampoline_target should be able to resolve them. */
+ target = find_solib_trampoline_target (frame, pc);
+ return target ? target : pc;
+}
+
+/* Support for convert_from_func_ptr_addr (ARCH, ADDR, TARG) on PPC64
+ GNU/Linux.
+
+ Usually a function pointer's representation is simply the address
+ of the function. On GNU/Linux on the PowerPC however, a function
+ pointer may be a pointer to a function descriptor.
+
+ For PPC64, a function descriptor is a TOC entry, in a data section,
+ which contains three words: the first word is the address of the
+ function, the second word is the TOC pointer (r2), and the third word
+ is the static chain value.
+
+ Throughout GDB it is currently assumed that a function pointer contains
+ the address of the function, which is not easy to fix. In addition, the
+ conversion of a function address to a function pointer would
+ require allocation of a TOC entry in the inferior's memory space,
+ with all its drawbacks. To be able to call C++ virtual methods in
+ the inferior (which are called via function pointers),
+ find_function_addr uses this function to get the function address
+ from a function pointer.
+
+ If ADDR points at what is clearly a function descriptor, transform
+ it into the address of the corresponding function, if needed. Be
+ conservative, otherwise GDB will do the transformation on any
+ random addresses such as occur when there is no symbol table. */
+
+CORE_ADDR
+ppc64_convert_from_func_ptr_addr (struct gdbarch *gdbarch,
+ CORE_ADDR addr,
+ struct target_ops *targ)
+{
+ enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+ struct target_section *s = target_section_by_addr (targ, addr);
+
+ /* Check if ADDR points to a function descriptor. */
+ if (s && strcmp (s->the_bfd_section->name, ".opd") == 0)
+ {
+ /* There may be relocations that need to be applied to the .opd
+ section. Unfortunately, this function may be called at a time
+ where these relocations have not yet been performed -- this can
+ happen for example shortly after a library has been loaded with
+ dlopen, but ld.so has not yet applied the relocations.
+
+ To cope with both the case where the relocation has been applied,
+ and the case where it has not yet been applied, we do *not* read
+ the (maybe) relocated value from target memory, but we instead
+ read the non-relocated value from the BFD, and apply the relocation
+ offset manually.
+
+ This makes the assumption that all .opd entries are always relocated
+ by the same offset the section itself was relocated. This should
+ always be the case for GNU/Linux executables and shared libraries.
+ Note that other kind of object files (e.g. those added via
+ add-symbol-files) will currently never end up here anyway, as this
+ function accesses *target* sections only; only the main exec and
+ shared libraries are ever added to the target. */
+
+ gdb_byte buf[8];
+ int res;
+
+ res = bfd_get_section_contents (s->bfd, s->the_bfd_section,
+ &buf, addr - s->addr, 8);
+ if (res != 0)
+ return extract_unsigned_integer (buf, 8, byte_order)
+ - bfd_section_vma (s->bfd, s->the_bfd_section) + s->addr;
+ }
+
+ return addr;
+}
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