diff options
| -rw-r--r-- | gdb/ChangeLog | 14 | ||||
| -rw-r--r-- | gdb/i386-linux-tdep.c | 69 | ||||
| -rw-r--r-- | gdb/i386-tdep.c | 7 | ||||
| -rw-r--r-- | gdb/testsuite/ChangeLog | 8 | ||||
| -rw-r--r-- | gdb/testsuite/gdb.base/disp-step-syscall.exp | 13 |
5 files changed, 104 insertions, 7 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 3c59ad9..387ce79 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,19 @@ 2012-02-29 Jan Kratochvil <jan.kratochvil@redhat.com> + 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. + +2012-02-29 Jan Kratochvil <jan.kratochvil@redhat.com> + Fix reverse mode for syscall on AMD CPUs in 32-bit mode. * i386-linux-tdep.c (i386_linux_intx80_sysenter_record): Rename to ... (i386_linux_intx80_sysenter_syscall_record): ... here. diff --git a/gdb/i386-linux-tdep.c b/gdb/i386-linux-tdep.c index 13857e5..bfb0e1c 100644 --- a/gdb/i386-linux-tdep.c +++ b/gdb/i386-linux-tdep.c @@ -491,11 +491,17 @@ i386_linux_record_signal (struct gdbarch *gdbarch, } +/* Core of the implementation for gdbarch get_syscall_number. Get pending + syscall number from REGCACHE. If there is no pending syscall -1 will be + returned. Pending syscall means ptrace has stepped into the syscall but + another ptrace call will step out. PC is right after the int $0x80 + / syscall / sysenter instruction in both cases, PC does not change during + the second ptrace step. */ + static LONGEST -i386_linux_get_syscall_number (struct gdbarch *gdbarch, - ptid_t ptid) +i386_linux_get_syscall_number_from_regcache (struct regcache *regcache) { - struct regcache *regcache = get_thread_regcache (ptid); + struct gdbarch *gdbarch = get_regcache_arch (regcache); enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); /* The content of a register. */ gdb_byte buf[4]; @@ -512,6 +518,18 @@ i386_linux_get_syscall_number (struct gdbarch *gdbarch, return ret; } +/* Wrapper for i386_linux_get_syscall_number_from_regcache to make it + compatible with gdbarch get_syscall_number method prototype. */ + +static LONGEST +i386_linux_get_syscall_number (struct gdbarch *gdbarch, + ptid_t ptid) +{ + struct regcache *regcache = get_thread_regcache (ptid); + + return i386_linux_get_syscall_number_from_regcache (regcache); +} + /* The register sets used in GNU/Linux ELF core-dumps are identical to the register sets in `struct user' that are used for a.out core-dumps. These are also used by ptrace(2). The corresponding @@ -643,6 +661,49 @@ i386_linux_core_read_description (struct gdbarch *gdbarch, return tdesc_i386_mmx_linux; } +/* Linux kernel shows PC value after the 'int $0x80' instruction even if + inferior is still inside the syscall. On next PTRACE_SINGLESTEP it will + finish the syscall but PC will not change. + + Some vDSOs contain 'int $0x80; ret' and during stepping out of the syscall + i386_displaced_step_fixup would keep PC at the displaced pad location. + As PC is pointing to the 'ret' instruction before the step + i386_displaced_step_fixup would expect inferior has just executed that 'ret' + and PC should not be adjusted. In reality it finished syscall instead and + PC should get relocated back to its vDSO address. Hide the 'ret' + instruction by 'nop' so that i386_displaced_step_fixup is not confused. + + It is not fully correct as the bytes in struct displaced_step_closure will + not match the inferior code. But we would need some new flag in + displaced_step_closure otherwise to keep the state that syscall is finishing + for the later i386_displaced_step_fixup execution as the syscall execution + is already no longer detectable there. The new flag field would mean + i386-linux-tdep.c needs to wrap all the displacement methods of i386-tdep.c + which does not seem worth it. The same effect is achieved by patching that + 'nop' instruction there instead. */ + +struct displaced_step_closure * +i386_linux_displaced_step_copy_insn (struct gdbarch *gdbarch, + CORE_ADDR from, CORE_ADDR to, + struct regcache *regs) +{ + struct displaced_step_closure *closure; + + closure = i386_displaced_step_copy_insn (gdbarch, from, to, regs); + + if (i386_linux_get_syscall_number_from_regcache (regs) != -1) + { + /* Since we use simple_displaced_step_copy_insn, our closure is a + copy of the instruction. */ + gdb_byte *insn = (gdb_byte *) closure; + + /* Fake nop. */ + insn[0] = 0x90; + } + + return closure; +} + static void i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) { @@ -891,7 +952,7 @@ i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) /* Displaced stepping. */ set_gdbarch_displaced_step_copy_insn (gdbarch, - i386_displaced_step_copy_insn); + i386_linux_displaced_step_copy_insn); set_gdbarch_displaced_step_fixup (gdbarch, i386_displaced_step_fixup); set_gdbarch_displaced_step_free_closure (gdbarch, simple_displaced_step_free_closure); diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c index 56e375e..d18aa99 100644 --- a/gdb/i386-tdep.c +++ b/gdb/i386-tdep.c @@ -521,7 +521,12 @@ i386_call_p (const gdb_byte *insn) static int i386_syscall_p (const gdb_byte *insn, int *lengthp) { - if (insn[0] == 0xcd) + /* Is it 'int $0x80'? */ + if ((insn[0] == 0xcd && insn[1] == 0x80) + /* Or is it 'sysenter'? */ + || (insn[0] == 0x0f && insn[1] == 0x34) + /* Or is it 'syscall'? */ + || (insn[0] == 0x0f && insn[1] == 0x05)) { *lengthp = 2; return 1; diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index ba1ef51..f8bd318 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,5 +1,13 @@ 2012-02-29 Jan Kratochvil <jan.kratochvil@redhat.com> + 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. + +2012-02-29 Jan Kratochvil <jan.kratochvil@redhat.com> + Support processors without SSSE3. * gdb.reverse/i386-sse-reverse.c (sse_test): Move pabsb, pabsw and pabsd into ... diff --git a/gdb/testsuite/gdb.base/disp-step-syscall.exp b/gdb/testsuite/gdb.base/disp-step-syscall.exp index c62938c..4cf5529 100644 --- a/gdb/testsuite/gdb.base/disp-step-syscall.exp +++ b/gdb/testsuite/gdb.base/disp-step-syscall.exp @@ -25,7 +25,7 @@ set syscall_insn "" # Define the syscall instruction for each target. if { [istarget "i\[34567\]86-*-linux*"] || [istarget "x86_64-*-linux*"] } { - set syscall_insn "(int|syscall|sysenter)" + set syscall_insn "\[ \t\](int|syscall|sysenter)\[ \t\]" } else { return -1 } @@ -118,7 +118,16 @@ proc disp_step_cross_syscall { syscall } { with_test_prefix "$syscall" { gdb_test_no_output "set displaced-stepping on" # Check the address of next instruction of syscall. - gdb_test "stepi" ".*$syscall_insn_next_addr.*" "single step over $syscall" + gdb_test "stepi" ".*" "single step over $syscall" + set syscall_insn_next_addr_found [get_hexadecimal_valueof "\$pc" "0"] + + set test "single step over $syscall final pc" + if {$syscall_insn_next_addr != 0 + && $syscall_insn_next_addr == $syscall_insn_next_addr_found} { + pass $test + } else { + fail $test + } # Delete breakpoint syscall insns to avoid interference to other syscalls. gdb_test_no_output "delete $syscall_insn_bp" "delete break $syscall insn" |