* [PATCH AUTOSEL 4.14 01/46] powerpc/powernv/smp: Fix spurious DBG() warning
@ 2020-10-27 0:09 Sasha Levin
2020-10-27 0:09 ` [PATCH AUTOSEL 4.14 02/46] powerpc: select ARCH_WANT_IRQS_OFF_ACTIVATE_MM Sasha Levin
0 siblings, 1 reply; 2+ messages in thread
From: Sasha Levin @ 2020-10-27 0:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Sasha Levin, linuxppc-dev, Oliver O'Halloran, Joel Stanley
From: Oliver O'Halloran <oohall@gmail.com>
[ Upstream commit f6bac19cf65c5be21d14a0c9684c8f560f2096dd ]
When building with W=1 we get the following warning:
arch/powerpc/platforms/powernv/smp.c: In function ‘pnv_smp_cpu_kill_self’:
arch/powerpc/platforms/powernv/smp.c:276:16: error: suggest braces around
empty body in an ‘if’ statement [-Werror=empty-body]
276 | cpu, srr1);
| ^
cc1: all warnings being treated as errors
The full context is this block:
if (srr1 && !generic_check_cpu_restart(cpu))
DBG("CPU%d Unexpected exit while offline srr1=%lx!\n",
cpu, srr1);
When building with DEBUG undefined DBG() expands to nothing and GCC emits
the warning due to the lack of braces around an empty statement.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200804005410.146094-2-oohall@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/platforms/powernv/smp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index c17f81e433f7d..11d8fde770c38 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -44,7 +44,7 @@
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
-#define DBG(fmt...)
+#define DBG(fmt...) do { } while (0)
#endif
static void pnv_smp_setup_cpu(int cpu)
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH AUTOSEL 4.14 02/46] powerpc: select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
2020-10-27 0:09 [PATCH AUTOSEL 4.14 01/46] powerpc/powernv/smp: Fix spurious DBG() warning Sasha Levin
@ 2020-10-27 0:09 ` Sasha Levin
0 siblings, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2020-10-27 0:09 UTC (permalink / raw)
To: linux-kernel, stable; +Cc: Sasha Levin, linuxppc-dev, Nicholas Piggin
From: Nicholas Piggin <npiggin@gmail.com>
[ Upstream commit 66acd46080bd9e5ad2be4b0eb1d498d5145d058e ]
powerpc uses IPIs in some situations to switch a kernel thread away
from a lazy tlb mm, which is subject to the TLB flushing race
described in the changelog introducing ARCH_WANT_IRQS_OFF_ACTIVATE_MM.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200914045219.3736466-3-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/mmu_context.h | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 679e1e3c16953..7cc91d7f893cf 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -154,6 +154,7 @@ config PPC
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF if PPC64
select ARCH_WANT_IPC_PARSE_VERSION
+ select ARCH_WANT_IRQS_OFF_ACTIVATE_MM
select ARCH_WEAK_RELEASE_ACQUIRE
select BINFMT_ELF
select BUILDTIME_EXTABLE_SORT
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 6f67ff5a52672..5f9ad4f4b9c0f 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -101,7 +101,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
*/
static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
{
- switch_mm(prev, next, current);
+ switch_mm_irqs_off(prev, next, current);
}
/* We don't currently use enter_lazy_tlb() for anything */
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
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