Re: [PATCH 03/34] powerpc: Use CONFIG_PREEMPTION

From: Christophe Leroy
Date: Wed Oct 16 2019 - 00:58:06 EST




Le 15/10/2019 Ã 21:17, Sebastian Andrzej Siewior a ÃcritÂ:
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.

Switch the entry code over to use CONFIG_PREEMPTION. Add PREEMPT_RT
output in __die().

powerpc doesn't select ARCH_SUPPORTS_RT, so this change is useless as CONFIG_PREEMPT_RT cannot be selected.


Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
[bigeasy: +traps.c, Kconfig]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
arch/powerpc/Kconfig | 2 +-
arch/powerpc/kernel/entry_32.S | 4 ++--
arch/powerpc/kernel/entry_64.S | 4 ++--
arch/powerpc/kernel/traps.c | 7 ++++++-
4 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 3e56c9c2f16ee..8ead8d6e1cbc8 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -106,7 +106,7 @@ config LOCKDEP_SUPPORT
config GENERIC_LOCKBREAK
bool
default y
- depends on SMP && PREEMPT
+ depends on SMP && PREEMPTION
config GENERIC_HWEIGHT
bool
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index d60908ea37fb9..e1a4c39b83b86 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -897,7 +897,7 @@ user_exc_return: /* r10 contains MSR_KERNEL here */
bne- 0b
1:
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
/* check current_thread_info->preempt_count */
lwz r0,TI_PREEMPT(r2)
cmpwi 0,r0,0 /* if non-zero, just restore regs and return */
@@ -921,7 +921,7 @@ user_exc_return: /* r10 contains MSR_KERNEL here */
*/
bl trace_hardirqs_on
#endif
-#endif /* CONFIG_PREEMPT */
+#endif /* CONFIG_PREEMPTION */
restore_kuap:
kuap_restore r1, r2, r9, r10, r0
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 6467bdab8d405..83733376533e8 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -840,7 +840,7 @@ _GLOBAL(ret_from_except_lite)
bne- 0b
1:
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
/* Check if we need to preempt */
andi. r0,r4,_TIF_NEED_RESCHED
beq+ restore
@@ -871,7 +871,7 @@ _GLOBAL(ret_from_except_lite)
li r10,MSR_RI
mtmsrd r10,1 /* Update machine state */
#endif /* CONFIG_PPC_BOOK3E */
-#endif /* CONFIG_PREEMPT */
+#endif /* CONFIG_PREEMPTION */
.globl fast_exc_return_irq
fast_exc_return_irq:
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 82f43535e6867..23d2f20be4f2e 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -252,14 +252,19 @@ NOKPROBE_SYMBOL(oops_end);
static int __die(const char *str, struct pt_regs *regs, long err)
{
+ const char *pr = "";
+

Please follow the same approach as already existing. Don't add a local var for that.

printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
+ if (IS_ENABLED(CONFIG_PREEMPTION))
+ pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT";
+

drop

printk("%s PAGE_SIZE=%luK%s%s%s%s%s%s%s %s\n",

Add one %s

IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? "LE" : "BE",
PAGE_SIZE / 1024,
early_radix_enabled() ? " MMU=Radix" : "",
early_mmu_has_feature(MMU_FTR_HPTE_TABLE) ? " MMU=Hash" : "",
- IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "",

Replace by: IS_ENABLED(CONFIG_PREEMPTION) ? " PREEMPT" : ""

+ pr,

add something like: IS_ENABLED(CONFIG_PREEMPT_RT) ? "_RT" : ""

IS_ENABLED(CONFIG_SMP) ? " SMP" : "",
IS_ENABLED(CONFIG_SMP) ? (" NR_CPUS=" __stringify(NR_CPUS)) : "",
debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",


Christophe