gdb/
Fix disp-step-syscall.exp: fork: single step over fork. * i386-linux-tdep.c (-i386_linux_get_syscall_number): Rename to ... (i386_linux_get_syscall_number_from_regcache): ... here, new function comment, change parameters gdbarch and ptid to regcache. Remove parameter regcache, initialize gdbarch from regcache here. (i386_linux_get_syscall_number, i386_linux_displaced_step_copy_insn): New functions. (i386_linux_init_abi): Install i386_linux_displaced_step_copy_insn instead. * i386-tdep.c (i386_syscall_p): Check also for 'sysenter' and 'syscall'. Make the 'int' check more strict. gdb/testsuite/ Fix disp-step-syscall.exp: fork: single step over fork. * gdb.base/disp-step-syscall.exp (syscall_insn): Anchor it by whitespaces. (single step over $syscall): Remove its check. (single step over $syscall final pc): New check.
This commit is contained in:
Jan Kratochvil
parent
ffdf6de517
commit
9a7f938f93
5 changed files with 104 additions and 7 deletions
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@ -1,3 +1,17 @@
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2012-02-29 Jan Kratochvil <jan.kratochvil@redhat.com>
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Fix disp-step-syscall.exp: fork: single step over fork.
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* i386-linux-tdep.c (-i386_linux_get_syscall_number): Rename to ...
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(i386_linux_get_syscall_number_from_regcache): ... here, new function
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comment, change parameters gdbarch and ptid to regcache. Remove
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parameter regcache, initialize gdbarch from regcache here.
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(i386_linux_get_syscall_number, i386_linux_displaced_step_copy_insn):
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New functions.
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(i386_linux_init_abi): Install i386_linux_displaced_step_copy_insn
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instead.
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* i386-tdep.c (i386_syscall_p): Check also for 'sysenter' and
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'syscall'. Make the 'int' check more strict.
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2012-02-29 Jan Kratochvil <jan.kratochvil@redhat.com>
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Fix reverse mode for syscall on AMD CPUs in 32-bit mode.
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@ -491,11 +491,17 @@ i386_linux_record_signal (struct gdbarch *gdbarch,
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}
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/* Core of the implementation for gdbarch get_syscall_number. Get pending
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syscall number from REGCACHE. If there is no pending syscall -1 will be
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returned. Pending syscall means ptrace has stepped into the syscall but
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another ptrace call will step out. PC is right after the int $0x80
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/ syscall / sysenter instruction in both cases, PC does not change during
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the second ptrace step. */
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static LONGEST
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i386_linux_get_syscall_number (struct gdbarch *gdbarch,
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ptid_t ptid)
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i386_linux_get_syscall_number_from_regcache (struct regcache *regcache)
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{
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struct regcache *regcache = get_thread_regcache (ptid);
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struct gdbarch *gdbarch = get_regcache_arch (regcache);
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enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
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/* The content of a register. */
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gdb_byte buf[4];
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@ -512,6 +518,18 @@ i386_linux_get_syscall_number (struct gdbarch *gdbarch,
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return ret;
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}
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/* Wrapper for i386_linux_get_syscall_number_from_regcache to make it
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compatible with gdbarch get_syscall_number method prototype. */
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static LONGEST
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i386_linux_get_syscall_number (struct gdbarch *gdbarch,
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ptid_t ptid)
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{
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struct regcache *regcache = get_thread_regcache (ptid);
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return i386_linux_get_syscall_number_from_regcache (regcache);
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}
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/* The register sets used in GNU/Linux ELF core-dumps are identical to
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the register sets in `struct user' that are used for a.out
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core-dumps. These are also used by ptrace(2). The corresponding
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@ -643,6 +661,49 @@ i386_linux_core_read_description (struct gdbarch *gdbarch,
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return tdesc_i386_mmx_linux;
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}
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/* Linux kernel shows PC value after the 'int $0x80' instruction even if
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inferior is still inside the syscall. On next PTRACE_SINGLESTEP it will
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finish the syscall but PC will not change.
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Some vDSOs contain 'int $0x80; ret' and during stepping out of the syscall
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i386_displaced_step_fixup would keep PC at the displaced pad location.
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As PC is pointing to the 'ret' instruction before the step
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i386_displaced_step_fixup would expect inferior has just executed that 'ret'
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and PC should not be adjusted. In reality it finished syscall instead and
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PC should get relocated back to its vDSO address. Hide the 'ret'
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instruction by 'nop' so that i386_displaced_step_fixup is not confused.
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It is not fully correct as the bytes in struct displaced_step_closure will
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not match the inferior code. But we would need some new flag in
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displaced_step_closure otherwise to keep the state that syscall is finishing
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for the later i386_displaced_step_fixup execution as the syscall execution
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is already no longer detectable there. The new flag field would mean
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i386-linux-tdep.c needs to wrap all the displacement methods of i386-tdep.c
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which does not seem worth it. The same effect is achieved by patching that
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'nop' instruction there instead. */
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struct displaced_step_closure *
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i386_linux_displaced_step_copy_insn (struct gdbarch *gdbarch,
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CORE_ADDR from, CORE_ADDR to,
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struct regcache *regs)
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{
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struct displaced_step_closure *closure;
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closure = i386_displaced_step_copy_insn (gdbarch, from, to, regs);
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if (i386_linux_get_syscall_number_from_regcache (regs) != -1)
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{
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/* Since we use simple_displaced_step_copy_insn, our closure is a
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copy of the instruction. */
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gdb_byte *insn = (gdb_byte *) closure;
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/* Fake nop. */
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insn[0] = 0x90;
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}
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return closure;
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}
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static void
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i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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@ -891,7 +952,7 @@ i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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/* Displaced stepping. */
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set_gdbarch_displaced_step_copy_insn (gdbarch,
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i386_displaced_step_copy_insn);
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i386_linux_displaced_step_copy_insn);
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set_gdbarch_displaced_step_fixup (gdbarch, i386_displaced_step_fixup);
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set_gdbarch_displaced_step_free_closure (gdbarch,
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simple_displaced_step_free_closure);
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@ -521,7 +521,12 @@ i386_call_p (const gdb_byte *insn)
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static int
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i386_syscall_p (const gdb_byte *insn, int *lengthp)
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{
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if (insn[0] == 0xcd)
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/* Is it 'int $0x80'? */
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if ((insn[0] == 0xcd && insn[1] == 0x80)
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/* Or is it 'sysenter'? */
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|| (insn[0] == 0x0f && insn[1] == 0x34)
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/* Or is it 'syscall'? */
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|| (insn[0] == 0x0f && insn[1] == 0x05))
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{
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*lengthp = 2;
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return 1;
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@ -1,3 +1,11 @@
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2012-02-29 Jan Kratochvil <jan.kratochvil@redhat.com>
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Fix disp-step-syscall.exp: fork: single step over fork.
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* gdb.base/disp-step-syscall.exp (syscall_insn): Anchor it by
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whitespaces.
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(single step over $syscall): Remove its check.
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(single step over $syscall final pc): New check.
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2012-02-29 Jan Kratochvil <jan.kratochvil@redhat.com>
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Support processors without SSSE3.
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@ -25,7 +25,7 @@ set syscall_insn ""
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# Define the syscall instruction for each target.
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if { [istarget "i\[34567\]86-*-linux*"] || [istarget "x86_64-*-linux*"] } {
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set syscall_insn "(int|syscall|sysenter)"
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set syscall_insn "\[ \t\](int|syscall|sysenter)\[ \t\]"
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} else {
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return -1
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}
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@ -118,7 +118,16 @@ proc disp_step_cross_syscall { syscall } { with_test_prefix "$syscall" {
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gdb_test_no_output "set displaced-stepping on"
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# Check the address of next instruction of syscall.
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gdb_test "stepi" ".*$syscall_insn_next_addr.*" "single step over $syscall"
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gdb_test "stepi" ".*" "single step over $syscall"
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set syscall_insn_next_addr_found [get_hexadecimal_valueof "\$pc" "0"]
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set test "single step over $syscall final pc"
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if {$syscall_insn_next_addr != 0
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&& $syscall_insn_next_addr == $syscall_insn_next_addr_found} {
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pass $test
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} else {
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fail $test
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}
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# Delete breakpoint syscall insns to avoid interference to other syscalls.
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gdb_test_no_output "delete $syscall_insn_bp" "delete break $syscall insn"
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