From: Arnd Bergmann arnd@arndb.de
[ Upstream commit be167862ae7dd85c56d385209a4890678e1b0488 ]
Patch series "compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING", v3.
This patch (of 11):
When function tracing for IPIs is enabled, we get a warning for an overflow of the ipi_types array with the IPI_CPU_BACKTRACE type as triggered by raise_nmi():
arch/arm/kernel/smp.c: In function 'raise_nmi': arch/arm/kernel/smp.c:489:2: error: array subscript is above array bounds [-Werror=array-bounds] trace_ipi_raise(target, ipi_types[ipinr]);
This is a correct warning as we actually overflow the array here.
This patch raise_nmi() to call __smp_cross_call() instead of smp_cross_call(), to avoid calling into ftrace. For clarification, I'm also adding a two new code comments describing how this one is special.
The warning appears to have shown up after commit e7273ff49acf ("ARM: 8488/1: Make IPI_CPU_BACKTRACE a "non-secure" SGI"), which changed the number assignment from '15' to '8', but as far as I can tell has existed since the IPI tracepoints were first introduced. If we decide to backport this patch to stable kernels, we probably need to backport e7273ff49acf as well.
[yamada.masahiro@socionext.com: rebase on v5.1-rc1] Link: http://lkml.kernel.org/r/20190423034959.13525-2-yamada.masahiro@socionext.co... Fixes: e7273ff49acf ("ARM: 8488/1: Make IPI_CPU_BACKTRACE a "non-secure" SGI") Fixes: 365ec7b17327 ("ARM: add IPI tracepoints") # v3.17 Signed-off-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Masahiro Yamada yamada.masahiro@socionext.com Cc: Heiko Carstens heiko.carstens@de.ibm.com Cc: Arnd Bergmann arnd@arndb.de Cc: Ingo Molnar mingo@redhat.com Cc: Christophe Leroy christophe.leroy@c-s.fr Cc: Mathieu Malaterre malat@debian.org Cc: "H. Peter Anvin" hpa@zytor.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Benjamin Herrenschmidt benh@kernel.crashing.org Cc: Paul Mackerras paulus@samba.org Cc: Ralf Baechle ralf@linux-mips.org Cc: Stefan Agner stefan@agner.ch Cc: Boris Brezillon bbrezillon@kernel.org Cc: Miquel Raynal miquel.raynal@bootlin.com Cc: Richard Weinberger richard@nod.at Cc: David Woodhouse dwmw2@infradead.org Cc: Brian Norris computersforpeace@gmail.com Cc: Marek Vasut marek.vasut@gmail.com Cc: Russell King rmk+kernel@arm.linux.org.uk Cc: Borislav Petkov bp@suse.de Cc: Mark Rutland mark.rutland@arm.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm/include/asm/hardirq.h | 1 + arch/arm/kernel/smp.c | 6 +++++- 2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/hardirq.h b/arch/arm/include/asm/hardirq.h index 3d7351c844aac..2fd0a2619b0b3 100644 --- a/arch/arm/include/asm/hardirq.h +++ b/arch/arm/include/asm/hardirq.h @@ -5,6 +5,7 @@ #include <linux/threads.h> #include <asm/irq.h>
+/* number of IPIS _not_ including IPI_CPU_BACKTRACE */ #define NR_IPI 7
typedef struct { diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 7a5dc011c5230..deea60f01d245 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -75,6 +75,10 @@ enum ipi_msg_type { IPI_CPU_STOP, IPI_IRQ_WORK, IPI_COMPLETION, + /* + * CPU_BACKTRACE is special and not included in NR_IPI + * or tracable with trace_ipi_* + */ IPI_CPU_BACKTRACE, /* * SGI8-15 can be reserved by secure firmware, and thus may @@ -801,7 +805,7 @@ core_initcall(register_cpufreq_notifier);
static void raise_nmi(cpumask_t *mask) { - smp_cross_call(mask, IPI_CPU_BACKTRACE); + __smp_cross_call(mask, IPI_CPU_BACKTRACE); }
void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)