Re: [PATCH v4 09/29] arm64: disable recordmcount with DYNAMIC_FTRACE_WITH_REGS
From: Mark Rutland <mark.rutland@arm.com>
Date: 2020-09-30 09:59:15
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Hi Sami, On Tue, Sep 29, 2020 at 02:46:11PM -0700, Sami Tolvanen wrote:
Select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY to disable recordmcount when DYNAMIC_FTRACE_WITH_REGS is selected.
Could you please add an explanation as to /why/ this is necessary in the commit message? I couldn't figure this out form the commit message alone, and reading the cover letter also didn't help. If the minimum required GCC version supports patchable-function-entry I'd be happy to make that a requirement for dynamic ftrace on arm64, as then we'd only need to support one mechanism, and can get rid of some redundant code. We already default to it when present anyhow.
quoted hunk ↗ jump to hunk
Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- arch/arm64/Kconfig | 2 ++ 1 file changed, 2 insertions(+)diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 6d232837cbee..ad522b021f35 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig@@ -155,6 +155,8 @@ config ARM64 select HAVE_DYNAMIC_FTRACE select HAVE_DYNAMIC_FTRACE_WITH_REGS \ if $(cc-option,-fpatchable-function-entry=2) + select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \ + if DYNAMIC_FTRACE_WITH_REGS
This doesn't look quite right to me. Presumably we shouldn't allow DYNAMIC_FTRACE_WITH_REGS to be selected if HAVE_DYNAMIC_FTRACE_WITH_REGS isn't. Thanks, Mark. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel