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/ Cc: stable@vger.kernel.org Signed-off-by: Celeste Liu uwu@coelacanthus.name
arch/riscv/kernel/ptrace.c | 32 ++++++++++++++++++++++++++++++++ include/uapi/linux/elf.h | 1 + 2 files changed, 33 insertions(+)
diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c index ea67e9fb7a583683b922fe2c017ea61f3bc848db..18ce07ffb27bb1180667769eed800f6fdf96c083 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 +185,29 @@ 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)+{
- 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)+{
- unsigned long orig_a0 = task_pt_regs(target)->orig_a0;
- 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;
Nit: Could be return 0, for readability.
Regardless, Reviewed-by: Björn Töpel bjorn@rivosinc.com