From 906d60cf467b2d5a20ff04dbc4805a84ef313229 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Fri, 10 Apr 2015 10:07:02 +0100 Subject: PR13858 - Can't do displaced stepping with no symbols Running break-interp.exp with the target always in non-stop mode trips on PR13858, as enabling non-stop also enables displaced stepping. The problem is that when GDB doesn't know where the entry point is, it doesn't know where to put the displaced stepping scratch pad. The test added by this commit exercises this. Without the fix, we get: (gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=on: break *$pc set displaced-stepping on (gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=on: set displaced-stepping on stepi 0x00000000004005be in ?? () Entry point address is not known. (gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=on: stepi p /x $pc $2 = 0x4005be (gdb) PASS: gdb.base/step-over-no-symbols.exp: displaced=on: get after PC FAIL: gdb.base/step-over-no-symbols.exp: displaced=on: advanced The fix switches all GNU/Linux ports to get the entry point from AT_ENTRY in the target auxiliary vector instead of from symbols. This is currently only done by PPC when Cell debugging is enabled, but I think all archs should be able to do the same. Note that ppc_linux_displaced_step_location cached the result, I'm guessing to avoid constantly re-fetching the auxv out of remote targets, but that's no longer necessary nowadays, as the auxv blob is itself cached in the inferior object. The ppc_linux_entry_point_addr global is obviously bad for multi-process too nowadays. Tested on x86-64 (-m64/-m32), PPC64 (-m64/-m32) and S/390 GNU/Linux. Yao tested the new test on ARM as well. gdb/ChangeLog: 2015-04-10 Pedro Alves PR gdb/13858 * amd64-linux-tdep.c (amd64_linux_init_abi_common): Install linux_displaced_step_location as gdbarch_displaced_step_location hook. * arm-linux-tdep.c (arm_linux_init_abi): Likewise. * i386-linux-tdep.c (i386_linux_init_abi): Likewise. * linux-tdep.c (linux_displaced_step_location): New function, based on ppc_linux_displaced_step_location. * linux-tdep.h (linux_displaced_step_location): New declaration. * ppc-linux-tdep.c (ppc_linux_entry_point_addr): Delete. (ppc_linux_inferior_created, ppc_linux_displaced_step_location): Delete. (ppc_linux_init_abi): Install linux_displaced_step_location as gdbarch_displaced_step_location hook, even without Cell/B.E.. (_initialize_ppc_linux_tdep): Don't install ppc_linux_inferior_created as inferior_created observer. * s390-linux-tdep.c (s390_gdbarch_init): Install linux_displaced_step_location as gdbarch_displaced_step_location hook. gdb/testsuite/ 2015-04-10 Pedro Alves PR gdb/13858 * gdb.base/step-over-no-symbols.exp: New file. --- gdb/i386-linux-tdep.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'gdb/i386-linux-tdep.c') diff --git a/gdb/i386-linux-tdep.c b/gdb/i386-linux-tdep.c index 4a0ce60..061ad3a 100644 --- a/gdb/i386-linux-tdep.c +++ b/gdb/i386-linux-tdep.c @@ -990,7 +990,7 @@ i386_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) set_gdbarch_displaced_step_free_closure (gdbarch, simple_displaced_step_free_closure); set_gdbarch_displaced_step_location (gdbarch, - displaced_step_at_entry_point); + linux_displaced_step_location); /* Functions for 'catch syscall'. */ set_xml_syscall_file_name (gdbarch, XML_SYSCALL_FILENAME_I386); -- cgit v1.1