* ppc-linux-tdep.c (INSTR_SC, INSTR_LI_R0_0x6666, INSTR_LI_R0_0x7777,
INSTR_LI_R0_NR_sigreturn, INSTR_LI_R0_NR_rt_sigreturn): Remove. (PPC_LINUX_SIGNAL_FRAMESIZE, PPC_LINUX_REGS_PTR_OFFSET, PPC_LINUX_HANDLER_PTR_OFFSET): Remove. (ppc_linux_in_sigtramp, insn_is_sigreturn, ppc_linux_at_sigtramp_return_path): Remove.
This commit is contained in:
Ulrich Weigand
parent
f7c5c4b53e
commit
c3fc7e628a
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@ -1,3 +1,12 @@
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2007-06-01 Ulrich Weigand <uweigand@de.ibm.com>
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* ppc-linux-tdep.c (INSTR_SC, INSTR_LI_R0_0x6666, INSTR_LI_R0_0x7777,
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INSTR_LI_R0_NR_sigreturn, INSTR_LI_R0_NR_rt_sigreturn): Remove.
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(PPC_LINUX_SIGNAL_FRAMESIZE, PPC_LINUX_REGS_PTR_OFFSET,
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PPC_LINUX_HANDLER_PTR_OFFSET): Remove.
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(ppc_linux_in_sigtramp, insn_is_sigreturn,
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ppc_linux_at_sigtramp_return_path): Remove.
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2007-05-31 Markus Deuling <deuling@de.ibm.com>
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* xtensa-tdep.c (XTENSA_IS_ENTRY, extract_call_winsize)
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@ -40,33 +40,6 @@
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#include "frame-unwind.h"
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#include "tramp-frame.h"
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/* The following instructions are used in the signal trampoline code
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on GNU/Linux PPC. The kernel used to use magic syscalls 0x6666 and
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0x7777 but now uses the sigreturn syscalls. We check for both. */
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#define INSTR_LI_R0_0x6666 0x38006666
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#define INSTR_LI_R0_0x7777 0x38007777
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#define INSTR_LI_R0_NR_sigreturn 0x38000077
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#define INSTR_LI_R0_NR_rt_sigreturn 0x380000AC
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#define INSTR_SC 0x44000002
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/* Since the *-tdep.c files are platform independent (i.e, they may be
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used to build cross platform debuggers), we can't include system
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headers. Therefore, details concerning the sigcontext structure
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must be painstakingly rerecorded. What's worse, if these details
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ever change in the header files, they'll have to be changed here
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as well. */
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/* __SIGNAL_FRAMESIZE from <asm/ptrace.h> */
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#define PPC_LINUX_SIGNAL_FRAMESIZE 64
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/* From <asm/sigcontext.h>, offsetof(struct sigcontext_struct, regs) == 0x1c */
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#define PPC_LINUX_REGS_PTR_OFFSET (PPC_LINUX_SIGNAL_FRAMESIZE + 0x1c)
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/* From <asm/sigcontext.h>,
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offsetof(struct sigcontext_struct, handler) == 0x14 */
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#define PPC_LINUX_HANDLER_PTR_OFFSET (PPC_LINUX_SIGNAL_FRAMESIZE + 0x14)
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/* From <asm/ptrace.h>, values for PT_NIP, PT_R1, and PT_LNK */
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#define PPC_LINUX_PT_R0 0
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#define PPC_LINUX_PT_R1 1
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@ -111,116 +84,6 @@
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#define PPC_LINUX_PT_FPR31 (PPC_LINUX_PT_FPR0 + 2*31)
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#define PPC_LINUX_PT_FPSCR (PPC_LINUX_PT_FPR0 + 2*32 + 1)
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static int ppc_linux_at_sigtramp_return_path (CORE_ADDR pc);
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/* Determine if pc is in a signal trampoline...
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Ha! That's not what this does at all. wait_for_inferior in
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infrun.c calls get_frame_type() in order to detect entry into a
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signal trampoline just after delivery of a signal. But on
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GNU/Linux, signal trampolines are used for the return path only.
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The kernel sets things up so that the signal handler is called
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directly.
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If we use in_sigtramp2() in place of in_sigtramp() (see below)
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we'll (often) end up with stop_pc in the trampoline and prev_pc in
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the (now exited) handler. The code there will cause a temporary
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breakpoint to be set on prev_pc which is not very likely to get hit
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again.
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If this is confusing, think of it this way... the code in
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wait_for_inferior() needs to be able to detect entry into a signal
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trampoline just after a signal is delivered, not after the handler
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has been run.
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So, we define in_sigtramp() below to return 1 if the following is
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true:
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1) The previous frame is a real signal trampoline.
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- and -
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2) pc is at the first or second instruction of the corresponding
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handler.
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Why the second instruction? It seems that wait_for_inferior()
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never sees the first instruction when single stepping. When a
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signal is delivered while stepping, the next instruction that
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would've been stepped over isn't, instead a signal is delivered and
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the first instruction of the handler is stepped over instead. That
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puts us on the second instruction. (I added the test for the first
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instruction long after the fact, just in case the observed behavior
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is ever fixed.) */
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int
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ppc_linux_in_sigtramp (CORE_ADDR pc, char *func_name)
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{
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CORE_ADDR lr;
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CORE_ADDR sp;
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CORE_ADDR tramp_sp;
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gdb_byte buf[4];
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CORE_ADDR handler;
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lr = read_register (gdbarch_tdep (current_gdbarch)->ppc_lr_regnum);
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if (!ppc_linux_at_sigtramp_return_path (lr))
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return 0;
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sp = read_register (SP_REGNUM);
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if (target_read_memory (sp, buf, sizeof (buf)) != 0)
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return 0;
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tramp_sp = extract_unsigned_integer (buf, 4);
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if (target_read_memory (tramp_sp + PPC_LINUX_HANDLER_PTR_OFFSET, buf,
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sizeof (buf)) != 0)
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return 0;
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handler = extract_unsigned_integer (buf, 4);
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return (pc == handler || pc == handler + 4);
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}
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static int
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insn_is_sigreturn (unsigned long pcinsn)
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{
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switch(pcinsn)
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{
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case INSTR_LI_R0_0x6666:
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case INSTR_LI_R0_0x7777:
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case INSTR_LI_R0_NR_sigreturn:
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case INSTR_LI_R0_NR_rt_sigreturn:
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return 1;
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default:
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return 0;
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}
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}
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/*
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* The signal handler trampoline is on the stack and consists of exactly
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* two instructions. The easiest and most accurate way of determining
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* whether the pc is in one of these trampolines is by inspecting the
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* instructions. It'd be faster though if we could find a way to do this
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* via some simple address comparisons.
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*/
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static int
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ppc_linux_at_sigtramp_return_path (CORE_ADDR pc)
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{
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gdb_byte buf[12];
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unsigned long pcinsn;
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if (target_read_memory (pc - 4, buf, sizeof (buf)) != 0)
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return 0;
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/* extract the instruction at the pc */
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pcinsn = extract_unsigned_integer (buf + 4, 4);
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return (
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(insn_is_sigreturn (pcinsn)
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&& extract_unsigned_integer (buf + 8, 4) == INSTR_SC)
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(pcinsn == INSTR_SC
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&& insn_is_sigreturn (extract_unsigned_integer (buf, 4))));
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}
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static CORE_ADDR
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ppc_linux_skip_trampoline_code (CORE_ADDR pc)
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