> diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
> index 9f5bd9c69c24..1a14eb2a51dc 100644
> --- a/arch/arm64/include/asm/uaccess.h
> +++ b/arch/arm64/include/asm/uaccess.h
> @@ -270,28 +270,43 @@ do { \
> #define get_user __get_user
>
> /*
> - * We must not call into the scheduler between __mte_enable_tco_async() and
> - * __mte_disable_tco_async(). As `dst` and `src` may contain blocking
> - * functions, we must evaluate these outside of the critical section.
> + * Nofault load without TCO management for use inside a
> + * __begin/__end_kernel_nofault_bare() region.
> */
> -#define __get_kernel_nofault(dst, src, type, err_label) \
> +#define __get_kernel_nofault_bare(dst, src, type, err_label) \
> do { \
> __typeof__(dst) __gkn_dst = (dst); \
> __typeof__(src) __gkn_src = (src); \
> do { \
> __label__ __gkn_label; \
> - \
> - __mte_enable_tco_async(); \
> __raw_get_mem("ldr", *((type *)(__gkn_dst)), \
> (__force type *)(__gkn_src), __gkn_label, K); \
> - __mte_disable_tco_async(); \
> break; \
> __gkn_label: \
> - __mte_disable_tco_async(); \
> goto err_label; \
> } while (0); \
> } while (0)
>
> /*
> + * We must not call into the scheduler between __mte_enable_tco_async() and
> + * __mte_disable_tco_async(). As dst and src may contain blocking functions,
> + * evaluate them before overriding TCO.
> + */
> +#define __get_kernel_nofault(dst, src, type, err_label) \
> +do { \
> + __label__ __gkn_tco_err; \
> + __typeof__(dst) __gkn_tco_dst = (dst); \
> + __typeof__(src) __gkn_tco_src = (src); \
> + __mte_enable_tco_async(); \
> + __get_kernel_nofault_bare(__gkn_tco_dst, __gkn_tco_src, type, \
> + __gkn_tco_err); \
> + __mte_disable_tco_async(); \
> + break; \
> +__gkn_tco_err: \
> + __mte_disable_tco_async(); \
> + goto err_label; \
> +} while (0)
This isn't a bug, but the get and put variants now carry the same rule
in two different wordings - would it read better to keep the two
comments identical, or to have the put side just point at the get side?
The comment above __get_kernel_nofault says "As dst and src may contain
blocking functions, evaluate them before overriding TCO," while the
comment above __put_kernel_nofault keeps the original "As `dst` and
`src` may contain blocking functions, we must evaluate these outside of
the critical section" - including the backticks that the get variant
dropped.
Also, should the wrapped argument line up under the open paren here
(four tabs plus two spaces rather than five)?
> + __get_kernel_nofault_bare(__gkn_tco_dst, __gkn_tco_src, type, \
> + __gkn_tco_err); \
The continuation line sits at column 37, while the open parenthesis of
__get_kernel_nofault_bare( sits at column 34. The same three-column
offset appears in __put_kernel_nofault at line 412.
[ ... ]
> @@ -366,28 +381,48 @@ do { \
>
> #define put_user __put_user
>
> -/*
> - * We must not call into the scheduler between __mte_enable_tco_async() and
> - * __mte_disable_tco_async(). As `dst` and `src` may contain blocking
> - * functions, we must evaluate these outside of the critical section.
> - */
> -#define __put_kernel_nofault(dst, src, type, err_label) \
> +/* Nofault store without TCO management; see __get_kernel_nofault_bare. */
> +#define __put_kernel_nofault_bare(dst, src, type, err_label) \
> do { \
> __typeof__(dst) __pkn_dst = (dst); \
> __typeof__(src) __pkn_src = (src); \
> \
> do { \
> __label__ __pkn_err; \
> - __mte_enable_tco_async(); \
> __raw_put_mem("str", *((type *)(__pkn_src)), \
> (__force type *)(__pkn_dst), __pkn_err, K); \
> - __mte_disable_tco_async(); \
> break; \
> __pkn_err: \
> - __mte_disable_tco_async(); \
> goto err_label; \
> } while (0); \
> -} while(0)
> +} while (0)
> +
> +/*
> + * We must not call into the scheduler between __mte_enable_tco_async() and
> + * __mte_disable_tco_async(). As `dst` and `src` may contain blocking
> + * functions, we must evaluate these outside of the critical section.
> + */
[ ... ]
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/32751368606
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