From: Mark Rutland <mark.rutland@arm.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org, LKML <linux-kernel@vger.kernel.org>,
Sven Schnelle <svens@linux.ibm.com>
Subject: Re: [PATCH v3 08/11] entry: Make CONFIG_DEBUG_ENTRY available outside x86
Date: Mon, 8 Mar 2021 10:13:47 +0000 [thread overview]
Message-ID: <20210308101347.GD7951@C02TD0UTHF1T.local> (raw)
In-Reply-To: <d5b13da88adf4e732a07fe709263e572cb5ca8de.1614884673.git.luto@kernel.org>
On Thu, Mar 04, 2021 at 11:06:01AM -0800, Andy Lutomirski wrote:
> In principle, the generic entry code is generic, and the goal is to use it
> in many architectures once it settles down more. Move CONFIG_DEBUG_ENTRY
> to the generic config so that it can be used in the generic entry code and
> not just in arch/x86.
>
> Disable it on arm64. arm64 uses some but not all of the kentry
> code, and trying to debug the resulting state machine will be painful.
> arm64 can turn it back on when it starts using the entire generic
> path.
Can we make this depend on CONFIG_GENERIC_ENTRY instead of !ARM64?
That'd be more in line with "use the generic entry code, get the generic
functionality". Note that arm64 doesn't select CONFIG_GENERIC_ENTRY
today.
I see that s390 selects CONFIG_GENERIC_ENTRY, and either way this will
enable DEBUG_ENTRY for them, so it'd ve worth checking whether this is
ok for them.
Sven, thoughts?
Thanks,
Mark.
>
> Signed-off-by: Andy Lutomirski <luto@kernel.org>
> ---
> arch/x86/Kconfig.debug | 10 ----------
> lib/Kconfig.debug | 11 +++++++++++
> 2 files changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
> index 80b57e7f4947..a5a52133730c 100644
> --- a/arch/x86/Kconfig.debug
> +++ b/arch/x86/Kconfig.debug
> @@ -170,16 +170,6 @@ config CPA_DEBUG
> help
> Do change_page_attr() self-tests every 30 seconds.
>
> -config DEBUG_ENTRY
> - bool "Debug low-level entry code"
> - depends on DEBUG_KERNEL
> - help
> - This option enables sanity checks in x86's low-level entry code.
> - Some of these sanity checks may slow down kernel entries and
> - exits or otherwise impact performance.
> -
> - If unsure, say N.
> -
> config DEBUG_NMI_SELFTEST
> bool "NMI Selftest"
> depends on DEBUG_KERNEL && X86_LOCAL_APIC
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 7937265ef879..76549c8afa8a 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1411,6 +1411,17 @@ config CSD_LOCK_WAIT_DEBUG
>
> endmenu # lock debugging
>
> +config DEBUG_ENTRY
> + bool "Debug low-level entry code"
> + depends on DEBUG_KERNEL
> + depends on !ARM64
> + help
> + This option enables sanity checks in the low-level entry code.
> + Some of these sanity checks may slow down kernel entries and
> + exits or otherwise impact performance.
> +
> + If unsure, say N.
> +
> config TRACE_IRQFLAGS
> depends on TRACE_IRQFLAGS_SUPPORT
> bool
> --
> 2.29.2
>
next prev parent reply other threads:[~2021-03-08 10:14 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-04 19:05 [PATCH v3 00/11] kentry: A stable bugfix and a bunch of improvements Andy Lutomirski
2021-03-04 19:05 ` [PATCH v3 01/11] x86/entry: Fix entry/exit mismatch on failed fast 32-bit syscalls Andy Lutomirski
2021-03-05 10:16 ` [tip: x86/urgent] " tip-bot2 for Andy Lutomirski
2021-03-06 10:44 ` tip-bot2 for Andy Lutomirski
2021-03-06 12:18 ` tip-bot2 for Andy Lutomirski
2021-03-04 19:05 ` [PATCH v3 02/11] kentry: Rename irqentry to kentry Andy Lutomirski
2021-03-08 9:45 ` Mark Rutland
2021-03-04 19:05 ` [PATCH v3 03/11] x86/dumpstack: Remove unnecessary range check fetching opcode bytes Andy Lutomirski
2021-03-04 19:05 ` [PATCH v3 04/11] x86/kthread,dumpstack: Set task_pt_regs->cs.RPL=3 for kernel threads Andy Lutomirski
2021-03-04 20:19 ` Ira Weiny
2021-03-04 19:05 ` [PATCH v3 05/11] x86/entry: Convert ret_from_fork to C Andy Lutomirski
2021-03-05 0:55 ` Brian Gerst
2021-03-04 19:05 ` [PATCH v3 06/11] kentry: Simplify the common syscall API Andy Lutomirski
2021-03-08 9:49 ` Mark Rutland
2021-03-04 19:06 ` [PATCH v3 07/11] kentry: Make entry/exit_to_user_mode() arm64-only Andy Lutomirski
2021-03-08 10:06 ` Mark Rutland
2021-03-14 1:18 ` Andy Lutomirski
2021-03-04 19:06 ` [PATCH v3 08/11] entry: Make CONFIG_DEBUG_ENTRY available outside x86 Andy Lutomirski
2021-03-08 10:13 ` Mark Rutland [this message]
2021-03-29 11:50 ` Sven Schnelle
2021-03-04 19:06 ` [PATCH v3 09/11] kentry: Add debugging checks for proper kentry API usage Andy Lutomirski
2021-03-04 19:06 ` [PATCH v3 10/11] kentry: Check that syscall entries and syscall exits match Andy Lutomirski
2021-03-04 19:06 ` [PATCH v3 11/11] kentry: Verify kentry state in instrumentation_begin/end() Andy Lutomirski
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