From: Kees Cook <keescook@chromium.org>
To: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Russell King <linux@armlinux.org.uk>,
linux-kernel@vger.kernel.org, Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ARM/hw_breakpoint: Mark expected switch fall-throughs
Date: Mon, 29 Jul 2019 09:34:02 -0700 [thread overview]
Message-ID: <201907290934.6C8AE8C@keescook> (raw)
In-Reply-To: <20190728231651.GA22123@embeddedor>
On Sun, Jul 28, 2019 at 06:16:51PM -0500, Gustavo A. R. Silva wrote:
> Mark switch cases where we are expecting to fall through.
>
> This patch fixes the following warnings:
>
> arch/arm/kernel/hw_breakpoint.c: In function 'hw_breakpoint_arch_parse':
> arch/arm/kernel/hw_breakpoint.c:609:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
> if (hw->ctrl.len == ARM_BREAKPOINT_LEN_2)
> ^
> arch/arm/kernel/hw_breakpoint.c:611:2: note: here
> case 3:
> ^~~~
> arch/arm/kernel/hw_breakpoint.c:613:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
> if (hw->ctrl.len == ARM_BREAKPOINT_LEN_1)
> ^
> arch/arm/kernel/hw_breakpoint.c:615:2: note: here
> default:
> ^~~~~~~
> arch/arm/kernel/hw_breakpoint.c: In function 'arch_build_bp_info':
> arch/arm/kernel/hw_breakpoint.c:544:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
> if ((hw->ctrl.type != ARM_BREAKPOINT_EXECUTE)
> ^
> arch/arm/kernel/hw_breakpoint.c:547:2: note: here
> default:
> ^~~~~~~
> In file included from include/linux/kernel.h:11,
> from include/linux/list.h:9,
> from include/linux/preempt.h:11,
> from include/linux/hardirq.h:5,
> from arch/arm/kernel/hw_breakpoint.c:16:
> arch/arm/kernel/hw_breakpoint.c: In function 'hw_breakpoint_pending':
> include/linux/compiler.h:78:22: warning: this statement may fall through [-Wimplicit-fallthrough=]
> # define unlikely(x) __builtin_expect(!!(x), 0)
> ^~~~~~~~~~~~~~~~~~~~~~~~~~
> include/asm-generic/bug.h:136:2: note: in expansion of macro 'unlikely'
> unlikely(__ret_warn_on); \
> ^~~~~~~~
> arch/arm/kernel/hw_breakpoint.c:863:3: note: in expansion of macro 'WARN'
> WARN(1, "Asynchronous watchpoint exception taken. Debugging results may be unreliable\n");
> ^~~~
> arch/arm/kernel/hw_breakpoint.c:864:2: note: here
> case ARM_ENTRY_SYNC_WATCHPOINT:
> ^~~~
> arch/arm/kernel/hw_breakpoint.c: In function 'core_has_os_save_restore':
> arch/arm/kernel/hw_breakpoint.c:910:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
> if (oslsr & ARM_OSLSR_OSLM0)
> ^
> arch/arm/kernel/hw_breakpoint.c:912:2: note: here
> default:
> ^~~~~~~
>
> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
-Kees
> ---
> arch/arm/kernel/hw_breakpoint.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
> index af8b8e15f589..b0c195e3a06d 100644
> --- a/arch/arm/kernel/hw_breakpoint.c
> +++ b/arch/arm/kernel/hw_breakpoint.c
> @@ -544,6 +544,7 @@ static int arch_build_bp_info(struct perf_event *bp,
> if ((hw->ctrl.type != ARM_BREAKPOINT_EXECUTE)
> && max_watchpoint_len >= 8)
> break;
> + /* Else, fall through */
> default:
> return -EINVAL;
> }
> @@ -608,10 +609,12 @@ int hw_breakpoint_arch_parse(struct perf_event *bp,
> /* Allow halfword watchpoints and breakpoints. */
> if (hw->ctrl.len == ARM_BREAKPOINT_LEN_2)
> break;
> + /* Else, fall through */
> case 3:
> /* Allow single byte watchpoint. */
> if (hw->ctrl.len == ARM_BREAKPOINT_LEN_1)
> break;
> + /* Else, fall through */
> default:
> ret = -EINVAL;
> goto out;
> @@ -861,6 +864,7 @@ static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr,
> break;
> case ARM_ENTRY_ASYNC_WATCHPOINT:
> WARN(1, "Asynchronous watchpoint exception taken. Debugging results may be unreliable\n");
> + /* Fall through */
> case ARM_ENTRY_SYNC_WATCHPOINT:
> watchpoint_handler(addr, fsr, regs);
> break;
> @@ -909,6 +913,7 @@ static bool core_has_os_save_restore(void)
> ARM_DBG_READ(c1, c1, 4, oslsr);
> if (oslsr & ARM_OSLSR_OSLM0)
> return true;
> + /* Else, fall through */
> default:
> return false;
> }
> --
> 2.22.0
>
--
Kees Cook
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prev parent reply other threads:[~2019-07-29 16:34 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-28 23:16 [PATCH] ARM/hw_breakpoint: Mark expected switch fall-throughs Gustavo A. R. Silva
2019-07-29 16:34 ` Kees Cook [this message]
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