On 2024-12-02 23:44, Björn Töpel wrote:
Thanks for working on this!
Celeste Liu uwu@coelacanthus.name 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@gmail.com/ Signed-off-by: Celeste Liu uwu@coelacanthus.name
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!
Linux code style prefer 80 limit.
+{
- 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.
Oh, my bad.
- 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.
v2 has been sent.
Björn