On Fri, Aug 16, 2019 at 02:57:43PM +0100, Will Deacon wrote:
> The initial support for dynamic ftrace trampolines in modules made use
> of an indirect branch which loaded its target from the beginning of
> a special section (e71a4e1bebaf7 ("arm64: ftrace: add support for far
> branches to dynamic ftrace")). Since no instructions were being patched,
> no cache maintenance was needed. However, later in be0f272bfc83 ("arm64:
> ftrace: emit ftrace-mod.o contents through code") this code was reworked
> to output the trampoline instructions directly into the PLT entry but,
> unfortunately, the necessary cache maintenance was overlooked.
>
> Add a call to __flush_icache_range() after writing the new trampoline
> instructions but before patching in the branch to the trampoline.
>
> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: James Morse <james.morse@xxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Fixes: be0f272bfc83 ("arm64: ftrace: emit ftrace-mod.o contents through code")
> Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Queued for 5.3. Thanks.
--
Catalin
