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Message-ID: <20181203160050.vebvvdiuki2iuczg@holly.lan>
Date: Mon, 3 Dec 2018 16:00:50 +0000
From: Daniel Thompson <daniel.thompson@...aro.org>
To: Douglas Anderson <dianders@...omium.org>
Cc: Jason Wessel <jason.wessel@...driver.com>,
Will Deacon <will.deacon@....com>,
kgdb-bugreport@...ts.sourceforge.net,
Peter Zijlstra <peterz@...radead.org>,
linux-mips@...ux-mips.org, linux-sh@...r.kernel.org,
Borislav Petkov <bp@...en8.de>, linux-kernel@...r.kernel.org,
sparclinux@...r.kernel.org,
Catalin Marinas <catalin.marinas@....com>,
James Hogan <jhogan@...nel.org>, linux-hexagon@...r.kernel.org,
x86@...nel.org, Vineet Gupta <vgupta@...opsys.com>,
Thomas Gleixner <tglx@...utronix.de>,
Michal Hocko <mhocko@...e.com>,
Ralf Baechle <ralf@...ux-mips.org>,
linux-snps-arc@...ts.infradead.org,
Andrew Morton <akpm@...ux-foundation.org>,
"H. Peter Anvin" <hpa@...or.com>,
Yoshinori Sato <ysato@...rs.sourceforge.jp>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Burton <paul.burton@...s.com>,
Stephen Rothwell <sfr@...b.auug.org.au>,
Ingo Molnar <mingo@...hat.com>,
Russell King <linux@...linux.org.uk>,
linux-arm-kernel@...ts.infradead.org,
Christophe Leroy <christophe.leroy@....fr>,
Huang Ying <ying.huang@...el.com>,
"David S. Miller" <davem@...emloft.net>,
Rich Felker <dalias@...c.org>,
Michael Ellerman <mpe@...erman.id.au>,
Mike Rapoport <rppt@...ux.vnet.ibm.com>,
Paul Mackerras <paulus@...ba.org>,
Richard Kuo <rkuo@...eaurora.org>,
linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v6 1/4] kgdb: Remove irq flags from roundup
On Tue, Nov 27, 2018 at 09:38:36AM -0800, Douglas Anderson wrote:
> The function kgdb_roundup_cpus() was passed a parameter that was
> documented as:
>
> > the flags that will be used when restoring the interrupts. There is
> > local_irq_save() call before kgdb_roundup_cpus().
>
> Nobody used those flags. Anyone who wanted to temporarily turn on
> interrupts just did local_irq_enable() and local_irq_disable() without
> looking at them. So we can definitely remove the flags.
>
> Signed-off-by: Douglas Anderson <dianders@...omium.org>
> Acked-by: Will Deacon <will.deacon@....com>
> ---
>
> Changes in v6: None
> Changes in v5: None
> Changes in v4: None
> Changes in v3: None
> Changes in v2:
> - Removing irq flags separated from fixing lockdep splat.
>
> arch/arc/kernel/kgdb.c | 2 +-
> arch/arm/kernel/kgdb.c | 2 +-
> arch/arm64/kernel/kgdb.c | 2 +-
> arch/hexagon/kernel/kgdb.c | 9 ++-------
> arch/mips/kernel/kgdb.c | 2 +-
> arch/powerpc/kernel/kgdb.c | 2 +-
> arch/sh/kernel/kgdb.c | 2 +-
> arch/sparc/kernel/smp_64.c | 2 +-
> arch/x86/kernel/kgdb.c | 9 ++-------
Again, please formally Cc: the arch maintainers in the patch header
(just after your Signed-off-by: if I'm not being explicitly clear).
Daniel.
> include/linux/kgdb.h | 9 ++-------
> kernel/debug/debug_core.c | 2 +-
> 11 files changed, 14 insertions(+), 29 deletions(-)
>
> diff --git a/arch/arc/kernel/kgdb.c b/arch/arc/kernel/kgdb.c
> index 9a3c34af2ae8..0932851028e0 100644
> --- a/arch/arc/kernel/kgdb.c
> +++ b/arch/arc/kernel/kgdb.c
> @@ -197,7 +197,7 @@ static void kgdb_call_nmi_hook(void *ignored)
> kgdb_nmicallback(raw_smp_processor_id(), NULL);
> }
>
> -void kgdb_roundup_cpus(unsigned long flags)
> +void kgdb_roundup_cpus(void)
> {
> local_irq_enable();
> smp_call_function(kgdb_call_nmi_hook, NULL, 0);
> diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c
> index caa0dbe3dc61..f21077b077be 100644
> --- a/arch/arm/kernel/kgdb.c
> +++ b/arch/arm/kernel/kgdb.c
> @@ -175,7 +175,7 @@ static void kgdb_call_nmi_hook(void *ignored)
> kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
> }
>
> -void kgdb_roundup_cpus(unsigned long flags)
> +void kgdb_roundup_cpus(void)
> {
> local_irq_enable();
> smp_call_function(kgdb_call_nmi_hook, NULL, 0);
> diff --git a/arch/arm64/kernel/kgdb.c b/arch/arm64/kernel/kgdb.c
> index a20de58061a8..12c339ff6e75 100644
> --- a/arch/arm64/kernel/kgdb.c
> +++ b/arch/arm64/kernel/kgdb.c
> @@ -289,7 +289,7 @@ static void kgdb_call_nmi_hook(void *ignored)
> kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
> }
>
> -void kgdb_roundup_cpus(unsigned long flags)
> +void kgdb_roundup_cpus(void)
> {
> local_irq_enable();
> smp_call_function(kgdb_call_nmi_hook, NULL, 0);
> diff --git a/arch/hexagon/kernel/kgdb.c b/arch/hexagon/kernel/kgdb.c
> index 16c24b22d0b2..012e0e230ac2 100644
> --- a/arch/hexagon/kernel/kgdb.c
> +++ b/arch/hexagon/kernel/kgdb.c
> @@ -119,17 +119,12 @@ void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
>
> /**
> * kgdb_roundup_cpus - Get other CPUs into a holding pattern
> - * @flags: Current IRQ state
> *
> * On SMP systems, we need to get the attention of the other CPUs
> * and get them be in a known state. This should do what is needed
> * to get the other CPUs to call kgdb_wait(). Note that on some arches,
> * the NMI approach is not used for rounding up all the CPUs. For example,
> - * in case of MIPS, smp_call_function() is used to roundup CPUs. In
> - * this case, we have to make sure that interrupts are enabled before
> - * calling smp_call_function(). The argument to this function is
> - * the flags that will be used when restoring the interrupts. There is
> - * local_irq_save() call before kgdb_roundup_cpus().
> + * in case of MIPS, smp_call_function() is used to roundup CPUs.
> *
> * On non-SMP systems, this is not called.
> */
> @@ -139,7 +134,7 @@ static void hexagon_kgdb_nmi_hook(void *ignored)
> kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
> }
>
> -void kgdb_roundup_cpus(unsigned long flags)
> +void kgdb_roundup_cpus(void)
> {
> local_irq_enable();
> smp_call_function(hexagon_kgdb_nmi_hook, NULL, 0);
> diff --git a/arch/mips/kernel/kgdb.c b/arch/mips/kernel/kgdb.c
> index eb6c0d582626..2b05effc17b4 100644
> --- a/arch/mips/kernel/kgdb.c
> +++ b/arch/mips/kernel/kgdb.c
> @@ -219,7 +219,7 @@ static void kgdb_call_nmi_hook(void *ignored)
> set_fs(old_fs);
> }
>
> -void kgdb_roundup_cpus(unsigned long flags)
> +void kgdb_roundup_cpus(void)
> {
> local_irq_enable();
> smp_call_function(kgdb_call_nmi_hook, NULL, 0);
> diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
> index 59c578f865aa..b0e804844be0 100644
> --- a/arch/powerpc/kernel/kgdb.c
> +++ b/arch/powerpc/kernel/kgdb.c
> @@ -124,7 +124,7 @@ static int kgdb_call_nmi_hook(struct pt_regs *regs)
> }
>
> #ifdef CONFIG_SMP
> -void kgdb_roundup_cpus(unsigned long flags)
> +void kgdb_roundup_cpus(void)
> {
> smp_send_debugger_break();
> }
> diff --git a/arch/sh/kernel/kgdb.c b/arch/sh/kernel/kgdb.c
> index 4f04c6638a4d..cc57630f6bf2 100644
> --- a/arch/sh/kernel/kgdb.c
> +++ b/arch/sh/kernel/kgdb.c
> @@ -319,7 +319,7 @@ static void kgdb_call_nmi_hook(void *ignored)
> kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
> }
>
> -void kgdb_roundup_cpus(unsigned long flags)
> +void kgdb_roundup_cpus(void)
> {
> local_irq_enable();
> smp_call_function(kgdb_call_nmi_hook, NULL, 0);
> diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
> index 4792e08ad36b..f45d876983f1 100644
> --- a/arch/sparc/kernel/smp_64.c
> +++ b/arch/sparc/kernel/smp_64.c
> @@ -1014,7 +1014,7 @@ void flush_dcache_page_all(struct mm_struct *mm, struct page *page)
> }
>
> #ifdef CONFIG_KGDB
> -void kgdb_roundup_cpus(unsigned long flags)
> +void kgdb_roundup_cpus(void)
> {
> smp_cross_call(&xcall_kgdb_capture, 0, 0, 0);
> }
> diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
> index 8e36f249646e..ac6291a4178d 100644
> --- a/arch/x86/kernel/kgdb.c
> +++ b/arch/x86/kernel/kgdb.c
> @@ -422,21 +422,16 @@ static void kgdb_disable_hw_debug(struct pt_regs *regs)
> #ifdef CONFIG_SMP
> /**
> * kgdb_roundup_cpus - Get other CPUs into a holding pattern
> - * @flags: Current IRQ state
> *
> * On SMP systems, we need to get the attention of the other CPUs
> * and get them be in a known state. This should do what is needed
> * to get the other CPUs to call kgdb_wait(). Note that on some arches,
> * the NMI approach is not used for rounding up all the CPUs. For example,
> - * in case of MIPS, smp_call_function() is used to roundup CPUs. In
> - * this case, we have to make sure that interrupts are enabled before
> - * calling smp_call_function(). The argument to this function is
> - * the flags that will be used when restoring the interrupts. There is
> - * local_irq_save() call before kgdb_roundup_cpus().
> + * in case of MIPS, smp_call_function() is used to roundup CPUs.
> *
> * On non-SMP systems, this is not called.
> */
> -void kgdb_roundup_cpus(unsigned long flags)
> +void kgdb_roundup_cpus(void)
> {
> apic->send_IPI_allbutself(APIC_DM_NMI);
> }
> diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
> index e465bb15912d..05e5b2eb0d32 100644
> --- a/include/linux/kgdb.h
> +++ b/include/linux/kgdb.h
> @@ -178,21 +178,16 @@ kgdb_arch_handle_exception(int vector, int signo, int err_code,
>
> /**
> * kgdb_roundup_cpus - Get other CPUs into a holding pattern
> - * @flags: Current IRQ state
> *
> * On SMP systems, we need to get the attention of the other CPUs
> * and get them into a known state. This should do what is needed
> * to get the other CPUs to call kgdb_wait(). Note that on some arches,
> * the NMI approach is not used for rounding up all the CPUs. For example,
> - * in case of MIPS, smp_call_function() is used to roundup CPUs. In
> - * this case, we have to make sure that interrupts are enabled before
> - * calling smp_call_function(). The argument to this function is
> - * the flags that will be used when restoring the interrupts. There is
> - * local_irq_save() call before kgdb_roundup_cpus().
> + * in case of MIPS, smp_call_function() is used to roundup CPUs.
> *
> * On non-SMP systems, this is not called.
> */
> -extern void kgdb_roundup_cpus(unsigned long flags);
> +extern void kgdb_roundup_cpus(void);
>
> /**
> * kgdb_arch_set_pc - Generic call back to the program counter
> diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
> index 65c0f1363788..f3cadda45f07 100644
> --- a/kernel/debug/debug_core.c
> +++ b/kernel/debug/debug_core.c
> @@ -593,7 +593,7 @@ static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs,
>
> /* Signal the other CPUs to enter kgdb_wait() */
> else if ((!kgdb_single_step) && kgdb_do_roundup)
> - kgdb_roundup_cpus(flags);
> + kgdb_roundup_cpus();
> #endif
>
> /*
> --
> 2.20.0.rc0.387.gc7a69e6b6c-goog
>
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