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SubjectRe: [PATCH v3 18/20] x86/ftrace: Use vmalloc special flag
On Thu, 21 Feb 2019 15:44:49 -0800
Rick Edgecombe <rick.p.edgecombe@intel.com> wrote:

> Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special
> permissioned memory in vmalloc and remove places where memory was set NX
> and RW before freeing which is no longer needed.
>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
> ---
> arch/x86/kernel/ftrace.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
> index 13c8249b197f..93efe3955333 100644
> --- a/arch/x86/kernel/ftrace.c
> +++ b/arch/x86/kernel/ftrace.c
> @@ -692,10 +692,6 @@ static inline void *alloc_tramp(unsigned long size)
> }
> static inline void tramp_free(void *tramp, int size)

As size is no longer used within the function, can you remove that too.

Thanks,

-- Steve

> {
> - int npages = PAGE_ALIGN(size) >> PAGE_SHIFT;
> -
> - set_memory_nx((unsigned long)tramp, npages);
> - set_memory_rw((unsigned long)tramp, npages);
> module_memfree(tramp);
> }
> #else
> @@ -820,6 +816,8 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
> /* ALLOC_TRAMP flags lets us know we created it */
> ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
>
> + set_vm_flush_reset_perms(trampoline);
> +
> /*
> * Module allocation needs to be completed by making the page
> * executable. The page is still writable, which is a security hazard,

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