[PATCH 5/5] ppc64: support CONFIG_DEBUG_PREEMPT
Hugh Dickins
hugh at veritas.com
Wed Nov 1 05:44:54 EST 2006
Add CONFIG_DEBUG_PREEMPT support to ppc64: it was useful for testing
get_paca() preemption. Cheat a little, just use debug_smp_processor_id()
in the debug version of get_paca(): it contains all the right checks and
reporting, though get_paca() doesn't really use smp_processor_id().
Use local_paca for what might have been called __raw_get_paca().
Silence harmless warnings from io.h and lparcfg.c with local_paca - I
assume it is okay for iseries_lparcfg_data to be referencing shared_proc
with preemption enabled: all cpus show the same value for shared_proc?
Why do other architectures need TRACE_IRQFLAGS_SUPPORT for DEBUG_PREEMPT?
I don't know, ppc64 appears to get along fine without it.
Signed-off-by: Hugh Dickins <hugh at veritas.com>
---
I've only tested this on one particular PowerMac G5 configuration:
it's quite likely that once integrated, defaulting to y when PREEMPT,
it'll show up a bunch of noisy warnings on other configurations:
not something to rush into mainline.
arch/powerpc/kernel/lparcfg.c | 2 +-
include/asm-powerpc/io.h | 14 +++++++-------
include/asm-powerpc/paca.h | 11 +++++++++++
include/asm-powerpc/percpu.h | 2 +-
include/asm-powerpc/smp.h | 2 +-
lib/Kconfig.debug | 2 +-
6 files changed, 22 insertions(+), 11 deletions(-)
--- git-powerpc/arch/powerpc/kernel/lparcfg.c 2006-10-24 04:34:08.000000000 +0100
+++ linux/arch/powerpc/kernel/lparcfg.c 2006-10-30 19:50:54.000000000 +0000
@@ -77,7 +77,7 @@ static int iseries_lparcfg_data(struct s
int processors, max_processors;
unsigned long purr = get_purr();
- shared = (int)(get_lppaca()->shared_proc);
+ shared = (int)(local_paca->lppaca_ptr->shared_proc);
seq_printf(m, "system_active_processors=%d\n",
(int)HvLpConfig_getSystemPhysicalProcessors());
--- git-powerpc/include/asm-powerpc/io.h 2006-10-24 04:34:33.000000000 +0100
+++ linux/include/asm-powerpc/io.h 2006-10-30 19:50:54.000000000 +0000
@@ -282,7 +282,7 @@ static inline void __out_8(volatile unsi
{
__asm__ __volatile__("sync; stb%U0%X0 %1,%0"
: "=m" (*addr) : "r" (val));
- get_paca()->io_sync = 1;
+ local_paca->io_sync = 1;
}
static inline int __in_le16(const volatile unsigned short __iomem *addr)
@@ -307,14 +307,14 @@ static inline void __out_le16(volatile u
{
__asm__ __volatile__("sync; sthbrx %1,0,%2"
: "=m" (*addr) : "r" (val), "r" (addr));
- get_paca()->io_sync = 1;
+ local_paca->io_sync = 1;
}
static inline void __out_be16(volatile unsigned short __iomem *addr, int val)
{
__asm__ __volatile__("sync; sth%U0%X0 %1,%0"
: "=m" (*addr) : "r" (val));
- get_paca()->io_sync = 1;
+ local_paca->io_sync = 1;
}
static inline unsigned __in_le32(const volatile unsigned __iomem *addr)
@@ -339,14 +339,14 @@ static inline void __out_le32(volatile u
{
__asm__ __volatile__("sync; stwbrx %1,0,%2" : "=m" (*addr)
: "r" (val), "r" (addr));
- get_paca()->io_sync = 1;
+ local_paca->io_sync = 1;
}
static inline void __out_be32(volatile unsigned __iomem *addr, int val)
{
__asm__ __volatile__("sync; stw%U0%X0 %1,%0"
: "=m" (*addr) : "r" (val));
- get_paca()->io_sync = 1;
+ local_paca->io_sync = 1;
}
static inline unsigned long __in_le64(const volatile unsigned long __iomem *addr)
@@ -393,13 +393,13 @@ static inline void __out_le64(volatile u
"sync\n"
"std %0,0(%3)"
: "=&r" (tmp) , "=&r" (val) : "1" (val) , "b" (addr) , "m" (*addr));
- get_paca()->io_sync = 1;
+ local_paca->io_sync = 1;
}
static inline void __out_be64(volatile unsigned long __iomem *addr, unsigned long val)
{
__asm__ __volatile__("sync; std%U0%X0 %1,%0" : "=m" (*addr) : "r" (val));
- get_paca()->io_sync = 1;
+ local_paca->io_sync = 1;
}
#include <asm/eeh.h>
--- git-powerpc/include/asm-powerpc/paca.h 2006-10-30 19:30:57.000000000 +0000
+++ linux/include/asm-powerpc/paca.h 2006-10-30 19:50:54.000000000 +0000
@@ -21,7 +21,18 @@
#include <asm/mmu.h>
register struct paca_struct *local_paca asm("r13");
+
+#if defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_SMP)
+extern unsigned int debug_smp_processor_id(void); /* from linux/smp.h */
+/*
+ * Add standard checks that preemption cannot occur when using get_paca():
+ * otherwise the paca_struct it points to may be the wrong one just after.
+ */
+#define get_paca() ((void) debug_smp_processor_id(), local_paca)
+#else
#define get_paca() local_paca
+#endif
+
#define get_lppaca() (get_paca()->lppaca_ptr)
#define get_slb_shadow() (get_paca()->slb_shadow_ptr)
--- git-powerpc/include/asm-powerpc/percpu.h 2006-09-20 04:42:06.000000000 +0100
+++ linux/include/asm-powerpc/percpu.h 2006-10-30 19:50:54.000000000 +0000
@@ -23,7 +23,7 @@
/* var is in discarded region: offset to particular copy we want */
#define per_cpu(var, cpu) (*RELOC_HIDE(&per_cpu__##var, __per_cpu_offset(cpu)))
#define __get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()))
-#define __raw_get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()))
+#define __raw_get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, local_paca->data_offset))
/* A macro to avoid #include hell... */
#define percpu_modcopy(pcpudst, src, size) \
--- git-powerpc/include/asm-powerpc/smp.h 2006-10-24 04:34:33.000000000 +0100
+++ linux/include/asm-powerpc/smp.h 2006-10-30 19:50:54.000000000 +0000
@@ -45,7 +45,7 @@ void generic_mach_cpu_die(void);
#endif
#ifdef CONFIG_PPC64
-#define raw_smp_processor_id() (get_paca()->paca_index)
+#define raw_smp_processor_id() (local_paca->paca_index)
#define hard_smp_processor_id() (get_paca()->hw_cpu_id)
#else
/* 32-bit */
--- git-powerpc/lib/Kconfig.debug 2006-10-30 19:15:49.000000000 +0000
+++ linux/lib/Kconfig.debug 2006-10-30 19:50:54.000000000 +0000
@@ -114,7 +114,7 @@ config DEBUG_SLAB_LEAK
config DEBUG_PREEMPT
bool "Debug preemptible kernel"
- depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
+ depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)
default y
help
If you say Y here then the kernel will use a debug variant of the
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