From 480af54cf68b5bb079f070b587f95620d114e87c Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Fri, 4 Dec 2020 16:43:56 -0500 Subject: gdb: make displaced stepping implementation capable of managing multiple buffers The displaced_step_buffer class, introduced in the previous patch, manages access to a single displaced step buffer. Change it into displaced_step_buffers (note the plural), which manages access to multiple displaced step buffers. When preparing a displaced step for a thread, it looks for an unused buffer. For now, all users still pass a single displaced step buffer, so no real behavior change is expected here. The following patch makes a user pass more than one buffer, so the functionality introduced by this patch is going to be useful in the next one. gdb/ChangeLog: * displaced-stepping.h (struct displaced_step_buffer): Rename to... (struct displaced_step_buffers): ... this. : Remove. : New inner class. : New. * displaced-stepping.c (displaced_step_buffer::prepare): Rename to... (displaced_step_buffers::prepare): ... this, adjust for multiple buffers. (displaced_step_buffer::finish): Rename to... (displaced_step_buffers::finish): ... this, adjust for multiple buffers. (displaced_step_buffer::copy_insn_closure_by_addr): Rename to... (displaced_step_buffers::copy_insn_closure_by_addr): ... this, adjust for multiple buffers. (displaced_step_buffer::restore_in_ptid): Rename to... (displaced_step_buffers::restore_in_ptid): ... this, adjust for multiple buffers. * linux-tdep.h (linux_init_abi): Change supports_displaced_step for num_disp_step_buffers. * linux-tdep.c (struct linux_gdbarch_data) : New field. (struct linux_info) : Rename to... : ... this, change type to displaced_step_buffers. (linux_displaced_step_prepare): Use linux_gdbarch_data::num_disp_step_buffers to create that number of buffers. (linux_displaced_step_finish): Adjust. (linux_displaced_step_copy_insn_closure_by_addr): Adjust. (linux_displaced_step_restore_all_in_ptid): Adjust. (linux_init_abi): Change supports_displaced_step parameter for num_disp_step_buffers, save it in linux_gdbarch_data. * aarch64-linux-tdep.c (aarch64_linux_init_abi): Adjust. * alpha-linux-tdep.c (alpha_linux_init_abi): Adjust. * amd64-linux-tdep.c (amd64_linux_init_abi_common): Change supports_displaced_step parameter for num_disp_step_buffers. (amd64_linux_init_abi): Adjust. (amd64_x32_linux_init_abi): Adjust. * arc-linux-tdep.c (arc_linux_init_osabi): Adjust. * arm-linux-tdep.c (arm_linux_init_abi): Adjust. * bfin-linux-tdep.c (bfin_linux_init_abi): Adjust. * cris-linux-tdep.c (cris_linux_init_abi): Adjust. * csky-linux-tdep.c (csky_linux_init_abi): Adjust. * frv-linux-tdep.c (frv_linux_init_abi): Adjust. * hppa-linux-tdep.c (hppa_linux_init_abi): Adjust. * i386-linux-tdep.c (i386_linux_init_abi): Adjust. * ia64-linux-tdep.c (ia64_linux_init_abi): Adjust. * m32r-linux-tdep.c (m32r_linux_init_abi): Adjust. * m68k-linux-tdep.c (m68k_linux_init_abi): * microblaze-linux-tdep.c (microblaze_linux_init_abi): * mips-linux-tdep.c (mips_linux_init_abi): Adjust. * mn10300-linux-tdep.c (am33_linux_init_osabi): Adjust. * nios2-linux-tdep.c (nios2_linux_init_abi): Adjust. * or1k-linux-tdep.c (or1k_linux_init_abi): Adjust. * ppc-linux-tdep.c (ppc_linux_init_abi): Adjust. * riscv-linux-tdep.c (riscv_linux_init_abi): Adjust. * rs6000-tdep.c (struct ppc_inferior_data) : Change type to displaced_step_buffers. * s390-linux-tdep.c (s390_linux_init_abi_any): Adjust. * sh-linux-tdep.c (sh_linux_init_abi): Adjust. * sparc-linux-tdep.c (sparc32_linux_init_abi): Adjust. * sparc64-linux-tdep.c (sparc64_linux_init_abi): Adjust. * tic6x-linux-tdep.c (tic6x_uclinux_init_abi): Adjust. * tilegx-linux-tdep.c (tilegx_linux_init_abi): Adjust. * xtensa-linux-tdep.c (xtensa_linux_init_abi): Adjust. Change-Id: Ia9c02f207da2c9e1d9188020139619122392bb70 --- gdb/linux-tdep.c | 54 ++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 36 insertions(+), 18 deletions(-) (limited to 'gdb/linux-tdep.c') diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c index 57ea45c..5ae28d8 100644 --- a/gdb/linux-tdep.c +++ b/gdb/linux-tdep.c @@ -166,9 +166,10 @@ enum static struct gdbarch_data *linux_gdbarch_data_handle; struct linux_gdbarch_data - { - struct type *siginfo_type; - }; +{ + struct type *siginfo_type; + int num_disp_step_buffers; +}; static void * init_linux_gdbarch_data (struct obstack *obstack) @@ -200,8 +201,8 @@ struct linux_info if we tried looking it up but failed. */ int vsyscall_range_p = 0; - /* Inferior's displaced step buffer. */ - gdb::optional disp_step_buf; + /* Inferior's displaced step buffers. */ + gdb::optional disp_step_bufs; }; /* Per-inferior data key. */ @@ -2540,15 +2541,25 @@ linux_displaced_step_prepare (gdbarch *arch, thread_info *thread, { linux_info *per_inferior = get_linux_inferior_data (thread->inf); - if (!per_inferior->disp_step_buf.has_value ()) + if (!per_inferior->disp_step_bufs.has_value ()) { + /* Figure out the location of the buffers. They are contiguous, starting + at DISP_STEP_BUF_ADDR. They are all of size BUF_LEN. */ CORE_ADDR disp_step_buf_addr = linux_displaced_step_location (thread->inf->gdbarch); + int buf_len = gdbarch_max_insn_length (arch); - per_inferior->disp_step_buf.emplace (disp_step_buf_addr); + linux_gdbarch_data *gdbarch_data = get_linux_gdbarch_data (arch); + gdb_assert (gdbarch_data->num_disp_step_buffers > 0); + + std::vector buffers; + for (int i = 0; i < gdbarch_data->num_disp_step_buffers; i++) + buffers.push_back (disp_step_buf_addr + i * buf_len); + + per_inferior->disp_step_bufs.emplace (buffers); } - return per_inferior->disp_step_buf->prepare (thread, displaced_pc); + return per_inferior->disp_step_bufs->prepare (thread, displaced_pc); } /* See linux-tdep.h. */ @@ -2558,9 +2569,9 @@ linux_displaced_step_finish (gdbarch *arch, thread_info *thread, gdb_signal sig) { linux_info *per_inferior = get_linux_inferior_data (thread->inf); - gdb_assert (per_inferior->disp_step_buf.has_value ()); + gdb_assert (per_inferior->disp_step_bufs.has_value ()); - return per_inferior->disp_step_buf->finish (arch, thread, sig); + return per_inferior->disp_step_bufs->finish (arch, thread, sig); } /* See linux-tdep.h. */ @@ -2571,10 +2582,10 @@ linux_displaced_step_copy_insn_closure_by_addr (inferior *inf, CORE_ADDR addr) linux_info *per_inferior = linux_inferior_data.get (inf); if (per_inferior == nullptr - || !per_inferior->disp_step_buf.has_value ()) + || !per_inferior->disp_step_bufs.has_value ()) return nullptr; - return per_inferior->disp_step_buf->copy_insn_closure_by_addr (addr); + return per_inferior->disp_step_bufs->copy_insn_closure_by_addr (addr); } /* See linux-tdep.h. */ @@ -2585,10 +2596,10 @@ linux_displaced_step_restore_all_in_ptid (inferior *parent_inf, ptid_t ptid) linux_info *per_inferior = linux_inferior_data.get (parent_inf); if (per_inferior == nullptr - || !per_inferior->disp_step_buf.has_value ()) + || !per_inferior->disp_step_bufs.has_value ()) return; - per_inferior->disp_step_buf->restore_in_ptid (ptid); + per_inferior->disp_step_bufs->restore_in_ptid (ptid); } /* See linux-tdep.h. */ @@ -2636,15 +2647,22 @@ show_dump_excluded_mappings (struct ui_file *file, int from_tty, } /* To be called from the various GDB_OSABI_LINUX handlers for the - various GNU/Linux architectures and machine types. */ + various GNU/Linux architectures and machine types. + + NUM_DISP_STEP_BUFFERS is the number of displaced step buffers to use. If 0, + displaced stepping is not supported. */ void linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch, - bool supports_displaced_step) + int num_disp_step_buffers) { - if (supports_displaced_step) + if (num_disp_step_buffers > 0) { - set_gdbarch_displaced_step_prepare (gdbarch, linux_displaced_step_prepare); + linux_gdbarch_data *gdbarch_data = get_linux_gdbarch_data (gdbarch); + gdbarch_data->num_disp_step_buffers = num_disp_step_buffers; + + set_gdbarch_displaced_step_prepare (gdbarch, + linux_displaced_step_prepare); set_gdbarch_displaced_step_finish (gdbarch, linux_displaced_step_finish); set_gdbarch_displaced_step_copy_insn_closure_by_addr (gdbarch, linux_displaced_step_copy_insn_closure_by_addr); -- cgit v1.1