Re: [PATCH -next v5 1/8] arm64: extable: add new extable type EX_TYPE_KACCESS_ERR_ZERO support

Tong Tiangen
2022-06-18T02:46:11Z

在 2022/6/17 16:23, Mark Rutland 写道:
> On Sat, May 28, 2022 at 06:50:49AM +0000, Tong Tiangen wrote:
>> Currently, The extable type EX_TYPE_UACCESS_ERR_ZERO is used by
>> __get/put_kernel_nofault(), but those helpers are not uaccess type, so we
>> add a new extable type EX_TYPE_KACCESS_ERR_ZERO which can be used by
>> __get/put_kernel_no_fault().
>>
>> This is also to prepare for distinguishing the two types in machine check
>> safe process.
>>
>> Suggested-by: Mark Rutland <mark.rutland@arm.com>
>> Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
>
> This looks good to me, so modulo one nit below:
>
> Acked-by: Mark Rutland <mark.rutland@arm.com>
>
>> ---
>> arch/arm64/include/asm/asm-extable.h | 13 ++++
>> arch/arm64/include/asm/uaccess.h | 94 ++++++++++++++--------------
>> arch/arm64/mm/extable.c | 1 +
>> 3 files changed, 61 insertions(+), 47 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/asm-extable.h b/arch/arm64/include/asm/asm-extable.h
>> index c39f2437e08e..56ebe183e78b 100644
>> --- a/arch/arm64/include/asm/asm-extable.h
>> +++ b/arch/arm64/include/asm/asm-extable.h
>> @@ -7,6 +7,7 @@
>> #define EX_TYPE_BPF 2
>> #define EX_TYPE_UACCESS_ERR_ZERO 3
>> #define EX_TYPE_LOAD_UNALIGNED_ZEROPAD 4
>> +#define EX_TYPE_KACCESS_ERR_ZERO 5
>
> Could we please renumber this so the UACCESS and KACCESS definitions are next
> to one another, i.e.
>
> #define EX_TYPE_BPF 2
> #define EX_TYPE_UACCESS_ERR_ZERO 3
> #define EX_TYPE_KACCESS_ERR_ZERO 4
> #define EX_TYPE_LOAD_UNALIGNED_ZEROPAD 5
>
> Thanks,
> Mark.

ok, It's cleaner.

Thanks,
Tong.

>
>>
>> #ifdef __ASSEMBLY__
>>
>> @@ -73,9 +74,21 @@
>> EX_DATA_REG(ZERO, zero) \
>> ")")
>>
>> +#define _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, zero) \
>> + __DEFINE_ASM_GPR_NUMS \
>> + __ASM_EXTABLE_RAW(#insn, #fixup, \
>> + __stringify(EX_TYPE_KACCESS_ERR_ZERO), \
>> + "(" \
>> + EX_DATA_REG(ERR, err) " | " \
>> + EX_DATA_REG(ZERO, zero) \
>> + ")")
>> +
>> #define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err) \
>> _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
>>
>> +#define _ASM_EXTABLE_KACCESS_ERR(insn, fixup, err) \
>> + _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, wzr)
>> +
>> #define EX_DATA_REG_DATA_SHIFT 0
>> #define EX_DATA_REG_DATA GENMASK(4, 0)
>> #define EX_DATA_REG_ADDR_SHIFT 5
>> diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
>> index 63f9c828f1a7..2fc9f0861769 100644
>> --- a/arch/arm64/include/asm/uaccess.h
>> +++ b/arch/arm64/include/asm/uaccess.h
>> @@ -232,34 +232,34 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
>> * The "__xxx_error" versions set the third argument to -EFAULT if an error
>> * occurs, and leave it unchanged on success.
>> */
>> -#define __get_mem_asm(load, reg, x, addr, err) \
>> +#define __get_mem_asm(load, reg, x, addr, err, type) \
>> asm volatile( \
>> "1: " load " " reg "1, [%2]\n" \
>> "2:\n" \
>> - _ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 2b, %w0, %w1) \
>> + _ASM_EXTABLE_##type##ACCESS_ERR_ZERO(1b, 2b, %w0, %w1) \
>> : "+r" (err), "=&r" (x) \
>> : "r" (addr))
>>
>> -#define __raw_get_mem(ldr, x, ptr, err) \
>> -do { \
>> - unsigned long __gu_val; \
>> - switch (sizeof(*(ptr))) { \
>> - case 1: \
>> - __get_mem_asm(ldr "b", "%w", __gu_val, (ptr), (err)); \
>> - break; \
>> - case 2: \
>> - __get_mem_asm(ldr "h", "%w", __gu_val, (ptr), (err)); \
>> - break; \
>> - case 4: \
>> - __get_mem_asm(ldr, "%w", __gu_val, (ptr), (err)); \
>> - break; \
>> - case 8: \
>> - __get_mem_asm(ldr, "%x", __gu_val, (ptr), (err)); \
>> - break; \
>> - default: \
>> - BUILD_BUG(); \
>> - } \
>> - (x) = (__force __typeof__(*(ptr)))__gu_val; \
>> +#define __raw_get_mem(ldr, x, ptr, err, type) \
>> +do { \
>> + unsigned long __gu_val; \
>> + switch (sizeof(*(ptr))) { \
>> + case 1: \
>> + __get_mem_asm(ldr "b", "%w", __gu_val, (ptr), (err), type); \
>> + break; \
>> + case 2: \
>> + __get_mem_asm(ldr "h", "%w", __gu_val, (ptr), (err), type); \
>> + break; \
>> + case 4: \
>> + __get_mem_asm(ldr, "%w", __gu_val, (ptr), (err), type); \
>> + break; \
>> + case 8: \
>> + __get_mem_asm(ldr, "%x", __gu_val, (ptr), (err), type); \
>> + break; \
>> + default: \
>> + BUILD_BUG(); \
>> + } \
>> + (x) = (__force __typeof__(*(ptr)))__gu_val; \
>> } while (0)
>>
>> /*
>> @@ -274,7 +274,7 @@ do { \
>> __chk_user_ptr(ptr); \
>> \
>> uaccess_ttbr0_enable(); \
>> - __raw_get_mem("ldtr", __rgu_val, __rgu_ptr, err); \
>> + __raw_get_mem("ldtr", __rgu_val, __rgu_ptr, err, U); \
>> uaccess_ttbr0_disable(); \
>> \
>> (x) = __rgu_val; \
>> @@ -314,40 +314,40 @@ do { \
>> \
>> __uaccess_enable_tco_async(); \
>> __raw_get_mem("ldr", *((type *)(__gkn_dst)), \
>> - (__force type *)(__gkn_src), __gkn_err); \
>> + (__force type *)(__gkn_src), __gkn_err, K); \
>> __uaccess_disable_tco_async(); \
>> \
>> if (unlikely(__gkn_err)) \
>> goto err_label; \
>> } while (0)
>>
>> -#define __put_mem_asm(store, reg, x, addr, err) \
>> +#define __put_mem_asm(store, reg, x, addr, err, type) \
>> asm volatile( \
>> "1: " store " " reg "1, [%2]\n" \
>> "2:\n" \
>> - _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %w0) \
>> + _ASM_EXTABLE_##type##ACCESS_ERR(1b, 2b, %w0) \
>> : "+r" (err) \
>> : "r" (x), "r" (addr))
>>
>> -#define __raw_put_mem(str, x, ptr, err) \
>> -do { \
>> - __typeof__(*(ptr)) __pu_val = (x); \
>> - switch (sizeof(*(ptr))) { \
>> - case 1: \
>> - __put_mem_asm(str "b", "%w", __pu_val, (ptr), (err)); \
>> - break; \
>> - case 2: \
>> - __put_mem_asm(str "h", "%w", __pu_val, (ptr), (err)); \
>> - break; \
>> - case 4: \
>> - __put_mem_asm(str, "%w", __pu_val, (ptr), (err)); \
>> - break; \
>> - case 8: \
>> - __put_mem_asm(str, "%x", __pu_val, (ptr), (err)); \
>> - break; \
>> - default: \
>> - BUILD_BUG(); \
>> - } \
>> +#define __raw_put_mem(str, x, ptr, err, type) \
>> +do { \
>> + __typeof__(*(ptr)) __pu_val = (x); \
>> + switch (sizeof(*(ptr))) { \
>> + case 1: \
>> + __put_mem_asm(str "b", "%w", __pu_val, (ptr), (err), type); \
>> + break; \
>> + case 2: \
>> + __put_mem_asm(str "h", "%w", __pu_val, (ptr), (err), type); \
>> + break; \
>> + case 4: \
>> + __put_mem_asm(str, "%w", __pu_val, (ptr), (err), type); \
>> + break; \
>> + case 8: \
>> + __put_mem_asm(str, "%x", __pu_val, (ptr), (err), type); \
>> + break; \
>> + default: \
>> + BUILD_BUG(); \
>> + } \
>> } while (0)
>>
>> /*
>> @@ -362,7 +362,7 @@ do { \
>> __chk_user_ptr(__rpu_ptr); \
>> \
>> uaccess_ttbr0_enable(); \
>> - __raw_put_mem("sttr", __rpu_val, __rpu_ptr, err); \
>> + __raw_put_mem("sttr", __rpu_val, __rpu_ptr, err, U); \
>> uaccess_ttbr0_disable(); \
>> } while (0)
>>
>> @@ -400,7 +400,7 @@ do { \
>> \
>> __uaccess_enable_tco_async(); \
>> __raw_put_mem("str", *((type *)(__pkn_src)), \
>> - (__force type *)(__pkn_dst), __pkn_err); \
>> + (__force type *)(__pkn_dst), __pkn_err, K); \
>> __uaccess_disable_tco_async(); \
>> \
>> if (unlikely(__pkn_err)) \
>> diff --git a/arch/arm64/mm/extable.c b/arch/arm64/mm/extable.c
>> index 489455309695..056591e5ca80 100644
>> --- a/arch/arm64/mm/extable.c
>> +++ b/arch/arm64/mm/extable.c
>> @@ -77,6 +77,7 @@ bool fixup_exception(struct pt_regs *regs)
>> case EX_TYPE_BPF:
>> return ex_handler_bpf(ex, regs);
>> case EX_TYPE_UACCESS_ERR_ZERO:
>> + case EX_TYPE_KACCESS_ERR_ZERO:
>> return ex_handler_uaccess_err_zero(ex, regs);
>> case EX_TYPE_LOAD_UNALIGNED_ZEROPAD:
>> return ex_handler_load_unaligned_zeropad(ex, regs);
>> --
>> 2.25.1
>>
>
> .