Hi Charlie,
On 2024-09-12 9:51 PM, Charlie Jenkins wrote:
> On Wed, Aug 28, 2024 at 06:01:28PM -0700, Samuel Holland wrote:
>> This allows a tracer to control the ABI of the tracee, as on arm64.
>>
>> Signed-off-by: Samuel Holland <samuel.holland@xxxxxxxxxx>
>> ---
>
> Since this code is identical to the arm64 port, could it be extracted
> out into the generic ptrace.c and ifdef on either CONFIG_RISCV_ISA_SUPM
> or CONFIG_ARM64_TAGGED_ADDR_ABI by adding some generic flag like
> CONFIG_HAVE_ARCH_TAGGED_ADDR_ABI?
Yes, it could be factored out, though I don't know if it is worth the overhead
for these two trivial functions. I don't see any other code like this outside of
arch/.
Regards,
Samuel
>>
>> (no changes since v1)
>>
>> arch/riscv/kernel/ptrace.c | 42 ++++++++++++++++++++++++++++++++++++++
>> include/uapi/linux/elf.h | 1 +
>> 2 files changed, 43 insertions(+)
>>
>> diff --git a/arch/riscv/kernel/ptrace.c b/arch/riscv/kernel/ptrace.c
>> index 92731ff8c79a..ea67e9fb7a58 100644
>> --- a/arch/riscv/kernel/ptrace.c
>> +++ b/arch/riscv/kernel/ptrace.c
>> @@ -28,6 +28,9 @@ enum riscv_regset {
>> #ifdef CONFIG_RISCV_ISA_V
>> REGSET_V,
>> #endif
>> +#ifdef CONFIG_RISCV_ISA_SUPM
>> + REGSET_TAGGED_ADDR_CTRL,
>> +#endif
>> };
>>
>> static int riscv_gpr_get(struct task_struct *target,
>> @@ -152,6 +155,35 @@ static int riscv_vr_set(struct task_struct *target,
>> }
>> #endif
>>
>> +#ifdef CONFIG_RISCV_ISA_SUPM
>> +static int tagged_addr_ctrl_get(struct task_struct *target,
>> + const struct user_regset *regset,
>> + struct membuf to)
>> +{
>> + long ctrl = get_tagged_addr_ctrl(target);
>> +
>> + if (IS_ERR_VALUE(ctrl))
>> + return ctrl;
>> +
>> + return membuf_write(&to, &ctrl, sizeof(ctrl));
>> +}
>> +
>> +static int tagged_addr_ctrl_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;
>> + long ctrl;
>> +
>> + ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ctrl, 0, -1);
>> + if (ret)
>> + return ret;
>> +
>> + return set_tagged_addr_ctrl(target, ctrl);
>> +}
>> +#endif
>> +
>> static const struct user_regset riscv_user_regset[] = {
>> [REGSET_X] = {
>> .core_note_type = NT_PRSTATUS,
>> @@ -182,6 +214,16 @@ static const struct user_regset riscv_user_regset[] = {
>> .set = riscv_vr_set,
>> },
>> #endif
>> +#ifdef CONFIG_RISCV_ISA_SUPM
>> + [REGSET_TAGGED_ADDR_CTRL] = {
>> + .core_note_type = NT_RISCV_TAGGED_ADDR_CTRL,
>> + .n = 1,
>> + .size = sizeof(long),
>> + .align = sizeof(long),
>> + .regset_get = tagged_addr_ctrl_get,
>> + .set = tagged_addr_ctrl_set,
>> + },
>> +#endif
>> };
>>
>> static const struct user_regset_view riscv_user_native_view = {
>> diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h
>> index b54b313bcf07..9a32532d7264 100644
>> --- a/include/uapi/linux/elf.h
>> +++ b/include/uapi/linux/elf.h
>> @@ -448,6 +448,7 @@ typedef struct elf64_shdr {
>> #define NT_MIPS_MSA 0x802 /* MIPS SIMD registers */
>> #define NT_RISCV_CSR 0x900 /* RISC-V Control and Status Registers */
>> #define NT_RISCV_VECTOR 0x901 /* RISC-V vector registers */
>> +#define NT_RISCV_TAGGED_ADDR_CTRL 0x902 /* RISC-V tagged address control (prctl()) */
>> #define NT_LOONGARCH_CPUCFG 0xa00 /* LoongArch CPU config registers */
>> #define NT_LOONGARCH_CSR 0xa01 /* LoongArch control and status registers */
>> #define NT_LOONGARCH_LSX 0xa02 /* LoongArch Loongson SIMD Extension registers */
>> --
>> 2.45.1
>>
>>
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