From 77c6f5fcdae65da0428ff75fa81059f1b5271cf0 Mon Sep 17 00:00:00 2001 From: Jim Wilson Date: Fri, 26 Oct 2018 10:32:58 -0700 Subject: [PATCH] RISC-V: Linux signal frame support. Add support for recognizing signal trampolines, parsing the signal frame, and reading register values from it. gdb/ * riscv-linux-tdep.c: Include tramp-frame.h and trad-frame.h. (riscv_linux_sigframe_init): Declare. (RISCV_INST_LI_A7_SIGRETURN, RISCV_INT_ECALL): New. (riscv_linux_sigframe): New. (SIGFRAME_SIGINFO_SIZE, UCONTEXT_MCONTEXT_OFFSET): New. (riscv_linux_sigframe_init): Define. (riscv_linux_init_abi): Call tramp_frame_prepend_unwinder. --- gdb/ChangeLog | 8 +++++ gdb/riscv-linux-tdep.c | 80 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 88 insertions(+) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 4d068ee86c..f457212dc1 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,13 @@ 2018-10-26 Jim Wilson + * riscv-linux-tdep.c: Include tramp-frame.h and trad-frame.h. + (riscv_linux_sigframe_init): Declare. + (RISCV_INST_LI_A7_SIGRETURN, RISCV_INT_ECALL): New. + (riscv_linux_sigframe): New. + (SIGFRAME_SIGINFO_SIZE, UCONTEXT_MCONTEXT_OFFSET): New. + (riscv_linux_sigframe_init): Define. + (riscv_linux_init_abi): Call tramp_frame_prepend_unwinder. + * riscv-tdep.c (riscv_isa_xlen): Refer to riscv-tdep.h comment. (riscv_isa_flen): Likewise. Drop static. * riscv-tdep.h (riscv_isa_xlen): Move riscv-tdep.c comment to here. diff --git a/gdb/riscv-linux-tdep.c b/gdb/riscv-linux-tdep.c index d072c0b754..ece75dba47 100644 --- a/gdb/riscv-linux-tdep.c +++ b/gdb/riscv-linux-tdep.c @@ -23,6 +23,8 @@ #include "linux-tdep.h" #include "solib-svr4.h" #include "regset.h" +#include "tramp-frame.h" +#include "trad-frame.h" /* Define the general register mapping. The kernel puts the PC at offset 0, gdb puts it at offset 32. Register x0 is always 0 and can be ignored. @@ -56,6 +58,82 @@ riscv_linux_iterate_over_regset_sections (struct gdbarch *gdbarch, /* TODO: Add FP register support. */ } +/* Signal trampoline support. */ + +static void riscv_linux_sigframe_init (const struct tramp_frame *self, + struct frame_info *this_frame, + struct trad_frame_cache *this_cache, + CORE_ADDR func); + +#define RISCV_INST_LI_A7_SIGRETURN 0x08b00893 +#define RISCV_INST_ECALL 0x00000073 + +static const struct tramp_frame riscv_linux_sigframe = { + SIGTRAMP_FRAME, + 4, + { + { RISCV_INST_LI_A7_SIGRETURN, ULONGEST_MAX }, + { RISCV_INST_ECALL, ULONGEST_MAX }, + { TRAMP_SENTINEL_INSN } + }, + riscv_linux_sigframe_init, + NULL +}; + +/* Runtime signal frames look like this: + struct rt_sigframe { + struct siginfo info; + struct ucontext uc; + }; + + struct ucontext { + unsigned long __uc_flags; + struct ucontext *uclink; + stack_t uc_stack; + sigset_t uc_sigmask; + char __glibc_reserved[1024 / 8 - sizeof (sigset_t)]; + mcontext_t uc_mcontext; + }; */ + +#define SIGFRAME_SIGINFO_SIZE 128 +#define UCONTEXT_MCONTEXT_OFFSET 176 + +static void +riscv_linux_sigframe_init (const struct tramp_frame *self, + struct frame_info *this_frame, + struct trad_frame_cache *this_cache, + CORE_ADDR func) +{ + struct gdbarch *gdbarch = get_frame_arch (this_frame); + int xlen = riscv_isa_xlen (gdbarch); + int flen = riscv_isa_flen (gdbarch); + CORE_ADDR frame_sp = get_frame_sp (this_frame); + CORE_ADDR mcontext_base; + CORE_ADDR regs_base; + + mcontext_base = frame_sp + SIGFRAME_SIGINFO_SIZE + UCONTEXT_MCONTEXT_OFFSET; + + /* Handle the integer registers. The first one is PC, followed by x1 + through x31. */ + regs_base = mcontext_base; + trad_frame_set_reg_addr (this_cache, RISCV_PC_REGNUM, regs_base); + for (int i = 1; i < 32; i++) + trad_frame_set_reg_addr (this_cache, RISCV_ZERO_REGNUM + i, + regs_base + (i * xlen)); + + /* Handle the FP registers. First comes the 32 FP registers, followed by + fcsr. */ + regs_base += 32 * xlen; + for (int i = 0; i < 32; i++) + trad_frame_set_reg_addr (this_cache, RISCV_FIRST_FP_REGNUM + i, + regs_base + (i * flen)); + regs_base += 32 * flen; + trad_frame_set_reg_addr (this_cache, RISCV_CSR_FCSR_REGNUM, regs_base); + + /* Choice of the bottom of the sigframe is somewhat arbitrary. */ + trad_frame_set_id (this_cache, frame_id_build (frame_sp, func)); +} + /* Initialize RISC-V Linux ABI info. */ static void @@ -82,6 +160,8 @@ riscv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) set_gdbarch_iterate_over_regset_sections (gdbarch, riscv_linux_iterate_over_regset_sections); + + tramp_frame_prepend_unwinder (gdbarch, &riscv_linux_sigframe); } /* Initialize RISC-V Linux target support. */ -- 2.34.1