From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> Now, you can use native gdb on riscv64 for rv32 app debugging. $ uname -a Linux buildroot 5.16.0-rc4-00036-gbef6b82fdf23-dirty #53 SMP Mon Dec 20 23:06:53 CST 2021 riscv64 GNU/Linux $ cat /proc/cpuinfo processor : 0 hart : 0 isa : rv64imafdcsuh mmu : sv48 $ file /bin/busybox /bin/busybox: setuid ELF 32-bit LSB shared object, UCB RISC-V, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-riscv32-ilp32d.so.1, for GNU/Linux 5.15.0, stripped $ file /usr/bin/gdb /usr/bin/gdb: ELF 32-bit LSB shared object, UCB RISC-V, version 1 (GNU/Linux), dynamically linked, interpreter /lib/ld-linux-riscv32-ilp32d.so.1, for GNU/Linux 5.15.0, stripped $ /usr/bin/gdb /bin/busybox GNU gdb (GDB) 10.2 Copyright (C) 2021 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> ... Reading symbols from /bin/busybox... (No debugging symbols found in /bin/busybox) (gdb) b main Breakpoint 1 at 0x8ddc (gdb) r Starting program: /bin/busybox Failed to read a valid object file image from memory. Breakpoint 1, 0x555a8ddc in main () (gdb) i r ra 0x77df0b74 0x77df0b74 sp 0x7fdd3d10 0x7fdd3d10 gp 0x5567e800 0x5567e800 <bb_common_bufsiz1+160> tp 0x77f64280 0x77f64280 t0 0x0 0 t1 0x555a6fac 1431990188 t2 0x77dd8db4 2011008436 fp 0x7fdd3e34 0x7fdd3e34 s1 0x7fdd3e34 2145205812 a0 0xffffffff -1 a1 0x2000 8192 a2 0x7fdd3e3c 2145205820 a3 0x0 0 a4 0x7fdd3d30 2145205552 a5 0x555a8dc0 1431997888 a6 0x77f2c170 2012397936 a7 0x6a7c7a2f 1786542639 s2 0x0 0 s3 0x0 0 s4 0x555a8dc0 1431997888 s5 0x77f8a3a8 2012783528 s6 0x7fdd3e3c 2145205820 s7 0x5567cecc 1432866508 --Type <RET> for more, q to quit, c to continue without paging-- s8 0x1 1 s9 0x0 0 s10 0x55634448 1432568904 s11 0x0 0 t3 0x77df0bb8 2011106232 t4 0x42fc 17148 t5 0x0 0 t6 0x40 64 pc 0x555a8ddc 0x555a8ddc <main+28> (gdb) si 0x555a78f0 in mallopt@plt () (gdb) c Continuing. BusyBox v1.34.1 (2021-12-19 22:39:48 CST) multi-call binary. BusyBox is copyrighted by many authors between 1998-2015. Licensed under GPLv2. See source distribution for detailed copyright notices. Usage: busybox [function [arguments]...] or: busybox --list[-full] ... [Inferior 1 (process 107) exited normally] (gdb) q Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> Signed-off-by: Guo Ren <guoren@xxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx> --- arch/riscv/kernel/ptrace.c | 87 +++++++++++++++++++++++++++++++++++--- 1 file changed, 82 insertions(+), 5 deletions(-) diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c index a89243730153..bb387593a121 100644 --- a/arch/riscv/kernel/ptrace.c +++ b/arch/riscv/kernel/ptrace.c @@ -12,6 +12,7 @@ #include <asm/thread_info.h> #include <asm/switch_to.h> #include <linux/audit.h> +#include <linux/compat.h> #include <linux/ptrace.h> #include <linux/elf.h> #include <linux/regset.h> @@ -111,11 +112,6 @@ static const struct user_regset_view riscv_user_native_view = { .n = ARRAY_SIZE(riscv_user_regset), }; -const struct user_regset_view *task_user_regset_view(struct task_struct *task) -{ - return &riscv_user_native_view; -} - struct pt_regs_offset { const char *name; int offset; @@ -273,3 +269,84 @@ __visible void do_syscall_trace_exit(struct pt_regs *regs) trace_sys_exit(regs, regs_return_value(regs)); #endif } + +#ifdef CONFIG_COMPAT +static int compat_riscv_gpr_get(struct task_struct *target, + const struct user_regset *regset, + struct membuf to) +{ + struct compat_user_regs_struct cregs; + + regs_to_cregs(&cregs, task_pt_regs(target)); + + return membuf_write(&to, &cregs, + sizeof(struct compat_user_regs_struct)); +} + +static int compat_riscv_gpr_set(struct task_struct *target, + const struct user_regset *regset, + unsigned int pos, unsigned int count, + const void *kbuf, const void __user *ubuf) +{ + int ret; + struct compat_user_regs_struct cregs; + + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &cregs, 0, -1); + + cregs_to_regs(&cregs, task_pt_regs(target)); + + return ret; +} + +static const struct user_regset compat_riscv_user_regset[] = { + [REGSET_X] = { + .core_note_type = NT_PRSTATUS, + .n = ELF_NGREG, + .size = sizeof(compat_elf_greg_t), + .align = sizeof(compat_elf_greg_t), + .regset_get = compat_riscv_gpr_get, + .set = compat_riscv_gpr_set, + }, +#ifdef CONFIG_FPU + [REGSET_F] = { + .core_note_type = NT_PRFPREG, + .n = ELF_NFPREG, + .size = sizeof(elf_fpreg_t), + .align = sizeof(elf_fpreg_t), + .regset_get = riscv_fpr_get, + .set = riscv_fpr_set, + }, +#endif +}; + +static const struct user_regset_view compat_riscv_user_native_view = { + .name = "riscv", + .e_machine = EM_RISCV, + .regsets = compat_riscv_user_regset, + .n = ARRAY_SIZE(compat_riscv_user_regset), +}; + +long compat_arch_ptrace(struct task_struct *child, compat_long_t request, + compat_ulong_t caddr, compat_ulong_t cdata) +{ + long ret = -EIO; + + switch (request) { + default: + ret = compat_ptrace_request(child, request, caddr, cdata); + break; + } + + return ret; +} +#endif /* CONFIG_COMPAT */ + +const struct user_regset_view *task_user_regset_view(struct task_struct *task) +{ +#ifdef CONFIG_COMPAT + if (test_tsk_thread_flag(task, TIF_32BIT)) + return &compat_riscv_user_native_view; + else +#endif + return &riscv_user_native_view; +} -- 2.25.1
