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Message-Id: <cc13b87b0f750a538621876ecc24c22a07e7c8be.1622712515.git.christophe.leroy@csgroup.eu>
Date: Thu, 3 Jun 2021 09:29:04 +0000 (UTC)
From: Christophe Leroy <christophe.leroy@...roup.eu>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v3 3/6] powerpc/nohash: Remove CONFIG_SMP #ifdefery in
mmu_context.h
Everything can be done even when CONFIG_SMP is not selected.
Just use IS_ENABLED() where relevant and rely on GCC to
opt out unneeded code and variables when CONFIG_SMP is not set.
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
arch/powerpc/mm/nohash/mmu_context.c | 66 ++++++++++------------------
1 file changed, 24 insertions(+), 42 deletions(-)
diff --git a/arch/powerpc/mm/nohash/mmu_context.c b/arch/powerpc/mm/nohash/mmu_context.c
index 75dafec50d19..437940d191d6 100644
--- a/arch/powerpc/mm/nohash/mmu_context.c
+++ b/arch/powerpc/mm/nohash/mmu_context.c
@@ -47,6 +47,7 @@
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
+#include <asm/smp.h>
#include <mm/mmu_decl.h>
@@ -86,9 +87,7 @@ void *abatron_pteptrs[2];
static unsigned int next_context, nr_free_contexts;
static unsigned long *context_map;
-#ifdef CONFIG_SMP
static unsigned long *stale_map[NR_CPUS];
-#endif
static struct mm_struct **context_mm;
static DEFINE_RAW_SPINLOCK(context_lock);
@@ -111,7 +110,6 @@ static DEFINE_RAW_SPINLOCK(context_lock);
* the stale map as we can just flush the local CPU
* -- benh
*/
-#ifdef CONFIG_SMP
static unsigned int steal_context_smp(unsigned int id)
{
struct mm_struct *mm;
@@ -164,14 +162,11 @@ static unsigned int steal_context_smp(unsigned int id)
/* This will cause the caller to try again */
return MMU_NO_CONTEXT;
}
-#endif /* CONFIG_SMP */
static unsigned int steal_all_contexts(void)
{
struct mm_struct *mm;
-#ifdef CONFIG_SMP
int cpu = smp_processor_id();
-#endif
unsigned int id;
for (id = FIRST_CONTEXT; id <= LAST_CONTEXT; id++) {
@@ -189,9 +184,8 @@ static unsigned int steal_all_contexts(void)
mm->context.active = 0;
#endif
}
-#ifdef CONFIG_SMP
- __clear_bit(id, stale_map[cpu]);
-#endif
+ if (IS_ENABLED(CONFIG_SMP))
+ __clear_bit(id, stale_map[cpu]);
}
/* Flush the TLB for all contexts (not to be used on SMP) */
@@ -210,9 +204,7 @@ static unsigned int steal_all_contexts(void)
static unsigned int steal_context_up(unsigned int id)
{
struct mm_struct *mm;
-#ifdef CONFIG_SMP
int cpu = smp_processor_id();
-#endif
/* Pick up the victim mm */
mm = context_mm[id];
@@ -226,9 +218,8 @@ static unsigned int steal_context_up(unsigned int id)
mm->context.id = MMU_NO_CONTEXT;
/* XXX This clear should ultimately be part of local_flush_tlb_mm */
-#ifdef CONFIG_SMP
- __clear_bit(id, stale_map[cpu]);
-#endif
+ if (IS_ENABLED(CONFIG_SMP))
+ __clear_bit(id, stale_map[cpu]);
return id;
}
@@ -292,9 +283,7 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
struct task_struct *tsk)
{
unsigned int id;
-#ifdef CONFIG_SMP
unsigned int i, cpu = smp_processor_id();
-#endif
unsigned long *map;
/* No lockless fast path .. yet */
@@ -303,17 +292,17 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
pr_hard("[%d] activating context for mm @%p, active=%d, id=%d",
cpu, next, next->context.active, next->context.id);
-#ifdef CONFIG_SMP
- /* Mark us active and the previous one not anymore */
- next->context.active++;
- if (prev) {
- pr_hardcont(" (old=0x%p a=%d)", prev, prev->context.active);
- WARN_ON(prev->context.active < 1);
- prev->context.active--;
+ if (IS_ENABLED(CONFIG_SMP)) {
+ /* Mark us active and the previous one not anymore */
+ next->context.active++;
+ if (prev) {
+ pr_hardcont(" (old=0x%p a=%d)", prev, prev->context.active);
+ WARN_ON(prev->context.active < 1);
+ prev->context.active--;
+ }
}
again:
-#endif /* CONFIG_SMP */
/* If we already have a valid assigned context, skip all that */
id = next->context.id;
@@ -334,14 +323,12 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
/* No more free contexts, let's try to steal one */
if (nr_free_contexts == 0) {
-#ifdef CONFIG_SMP
if (num_online_cpus() > 1) {
id = steal_context_smp(id);
if (id == MMU_NO_CONTEXT)
goto again;
goto stolen;
}
-#endif /* CONFIG_SMP */
if (IS_ENABLED(CONFIG_PPC_8xx))
id = steal_all_contexts();
else
@@ -368,8 +355,7 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
/* If that context got marked stale on this CPU, then flush the
* local TLB for it and unmark it before we use it
*/
-#ifdef CONFIG_SMP
- if (test_bit(id, stale_map[cpu])) {
+ if (IS_ENABLED(CONFIG_SMP) && test_bit(id, stale_map[cpu])) {
pr_hardcont(" | stale flush %d [%d..%d]",
id, cpu_first_thread_sibling(cpu),
cpu_last_thread_sibling(cpu));
@@ -383,7 +369,6 @@ void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,
__clear_bit(id, stale_map[i]);
}
}
-#endif
/* Flick the MMU and release lock */
pr_hardcont(" -> %d\n", id);
@@ -442,7 +427,6 @@ void destroy_context(struct mm_struct *mm)
raw_spin_unlock_irqrestore(&context_lock, flags);
}
-#ifdef CONFIG_SMP
static int mmu_ctx_cpu_prepare(unsigned int cpu)
{
/* We don't touch CPU 0 map, it's allocated at aboot and kept
@@ -472,8 +456,6 @@ static int mmu_ctx_cpu_dead(unsigned int cpu)
return 0;
}
-#endif /* CONFIG_SMP */
-
/*
* Initialize the context management stuff.
*/
@@ -497,16 +479,16 @@ void __init mmu_context_init(void)
if (!context_mm)
panic("%s: Failed to allocate %zu bytes\n", __func__,
sizeof(void *) * (LAST_CONTEXT + 1));
-#ifdef CONFIG_SMP
- stale_map[boot_cpuid] = memblock_alloc(CTX_MAP_SIZE, SMP_CACHE_BYTES);
- if (!stale_map[boot_cpuid])
- panic("%s: Failed to allocate %zu bytes\n", __func__,
- CTX_MAP_SIZE);
-
- cpuhp_setup_state_nocalls(CPUHP_POWERPC_MMU_CTX_PREPARE,
- "powerpc/mmu/ctx:prepare",
- mmu_ctx_cpu_prepare, mmu_ctx_cpu_dead);
-#endif
+ if (IS_ENABLED(CONFIG_SMP)) {
+ stale_map[boot_cpuid] = memblock_alloc(CTX_MAP_SIZE, SMP_CACHE_BYTES);
+ if (!stale_map[boot_cpuid])
+ panic("%s: Failed to allocate %zu bytes\n", __func__,
+ CTX_MAP_SIZE);
+
+ cpuhp_setup_state_nocalls(CPUHP_POWERPC_MMU_CTX_PREPARE,
+ "powerpc/mmu/ctx:prepare",
+ mmu_ctx_cpu_prepare, mmu_ctx_cpu_dead);
+ }
printk(KERN_INFO
"MMU: Allocated %zu bytes of context maps for %d contexts\n",
--
2.25.0
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