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SubjectRe: [PATCH] arch/tile: clean up tile-specific PTRACE_SETOPTIONS
On 12/13, Chris Metcalf wrote:
>
> Use the newer idioms for setting PTRACE_O_xxx and PT_TRACE_xxx flags.
> Only set/clear tile-specific flags if the generic routine returns
> success, since otherwise we want to avoid setting any flags at all.
> Atomically update the ptrace flags with the new values. Eliminate
> the PT_TRACE_MASK_TILE bitmask and just shift PTRACE_O_MASK_TILE.
> Add a BUILD_BUG_ON to avoid overlapping with generic bits.
>
> Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

Acked-by: Oleg Nesterov <oleg@redhat.com>

> ---
> arch/tile/include/asm/ptrace.h | 3 +--
> arch/tile/include/uapi/asm/ptrace.h | 2 +-
> arch/tile/kernel/ptrace.c | 10 +++++++---
> 3 files changed, 9 insertions(+), 6 deletions(-)
>
> diff --git a/arch/tile/include/asm/ptrace.h b/arch/tile/include/asm/ptrace.h
> index 1a4fd9a..5ce052e 100644
> --- a/arch/tile/include/asm/ptrace.h
> +++ b/arch/tile/include/asm/ptrace.h
> @@ -24,8 +24,7 @@ typedef unsigned long pt_reg_t;
> #include <uapi/asm/ptrace.h>
>
> #define PTRACE_O_MASK_TILE (PTRACE_O_TRACEMIGRATE)
> -#define PT_TRACE_MIGRATE 0x00080000
> -#define PT_TRACE_MASK_TILE (PT_TRACE_MIGRATE)
> +#define PT_TRACE_MIGRATE PT_EVENT_FLAG(PTRACE_EVENT_MIGRATE)
>
> /* Flag bits in pt_regs.flags */
> #define PT_FLAGS_DISABLE_IRQ 1 /* on return to kernel, disable irqs */
> diff --git a/arch/tile/include/uapi/asm/ptrace.h b/arch/tile/include/uapi/asm/ptrace.h
> index 0d22088..7757e19 100644
> --- a/arch/tile/include/uapi/asm/ptrace.h
> +++ b/arch/tile/include/uapi/asm/ptrace.h
> @@ -81,8 +81,8 @@ struct pt_regs {
> #define PTRACE_SETFPREGS 15
>
> /* Support TILE-specific ptrace options, with events starting at 16. */
> -#define PTRACE_O_TRACEMIGRATE 0x00010000
> #define PTRACE_EVENT_MIGRATE 16
> +#define PTRACE_O_TRACEMIGRATE (1 << PTRACE_EVENT_MIGRATE)
>
> /*
> * Flag bits in pt_regs.flags that are part of the ptrace API.
> diff --git a/arch/tile/kernel/ptrace.c b/arch/tile/kernel/ptrace.c
> index 64ba102..b32bc3f 100644
> --- a/arch/tile/kernel/ptrace.c
> +++ b/arch/tile/kernel/ptrace.c
> @@ -151,12 +151,16 @@ long arch_ptrace(struct task_struct *child, long request,
>
> case PTRACE_SETOPTIONS:
> /* Support TILE-specific ptrace options. */
> - child->ptrace &= ~PT_TRACE_MASK_TILE;
> + BUILD_BUG_ON(PTRACE_O_MASK_TILE & PTRACE_O_MASK);
> tmp = data & PTRACE_O_MASK_TILE;
> data &= ~PTRACE_O_MASK_TILE;
> ret = ptrace_request(child, request, addr, data);
> - if (tmp & PTRACE_O_TRACEMIGRATE)
> - child->ptrace |= PT_TRACE_MIGRATE;
> + if (ret == 0) {
> + unsigned int flags = child->ptrace;
> + flags &= ~(PTRACE_O_MASK_TILE << PT_OPT_FLAG_SHIFT);
> + flags |= (tmp << PT_OPT_FLAG_SHIFT);
> + child->ptrace = flags;
> + }
> break;
>
> default:
> --
> 1.7.10.3
>



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