Thanks for working on this! Celeste Liu <uwu@xxxxxxxxxxxxxxxxx> writes: > The orig_a0 is missing in struct user_regs_struct of riscv, and there is > no way to add it without breaking UAPI. (See Link tag below) > > Like NT_ARM_SYSTEM_CALL do, we add a new regset name NT_RISCV_ORIG_A0 to > access original a0 register from userspace via ptrace API. > > Link: https://lore.kernel.org/all/59505464-c84a-403d-972f-d4b2055eeaac@xxxxxxxxx/ > Signed-off-by: Celeste Liu <uwu@xxxxxxxxxxxxxxxxx> > --- > arch/riscv/kernel/ptrace.c | 33 +++++++++++++++++++++++++++++++++ > include/uapi/linux/elf.h | 1 + > 2 files changed, 34 insertions(+) > > diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c > index ea67e9fb7a583683b922fe2c017ea61f3bc848db..faa46de9000376eb445a32d43a40210d7b846844 100644 > --- a/arch/riscv/kernel/ptrace.c > +++ b/arch/riscv/kernel/ptrace.c > @@ -31,6 +31,7 @@ enum riscv_regset { > #ifdef CONFIG_RISCV_ISA_SUPM > REGSET_TAGGED_ADDR_CTRL, > #endif > + REGSET_ORIG_A0, > }; > > static int riscv_gpr_get(struct task_struct *target, > @@ -184,6 +185,30 @@ static int tagged_addr_ctrl_set(struct task_struct *target, > } > #endif > > +static int riscv_orig_a0_get(struct task_struct *target, > + const struct user_regset *regset, > + struct membuf to) Use full 100 chars! > +{ > + return membuf_store(&to, task_pt_regs(target)->orig_a0); > +} > + > +static int riscv_orig_a0_set(struct task_struct *target, > + const struct user_regset *regset, > + unsigned int pos, unsigned int count, > + const void *kbuf, const void __user *ubuf) Dito! > +{ > + int orig_a0 = task_pt_regs(target)->orig_a0; 64b regs on RV64. > + int ret; > + > + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &orig_a0, 0, -1); > + if (ret) > + return ret; > + > + task_pt_regs(target)->orig_a0 = orig_a0; > + return ret; > +} > + > + Multiple blanks. > static const struct user_regset riscv_user_regset[] = { > [REGSET_X] = { > .core_note_type = NT_PRSTATUS, > @@ -224,6 +249,14 @@ static const struct user_regset riscv_user_regset[] = { > .set = tagged_addr_ctrl_set, > }, > #endif > + [REGSET_ORIG_A0] = { > + .core_note_type = NT_RISCV_ORIG_A0, > + .n = 1, > + .size = sizeof(elf_greg_t), > + .align = sizeof(elf_greg_t), ...and sizeof(elf_greg_t) is 64b in RV64 -- mismatch above. Björn
