From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 31 Aug 2021 13:48:34 +0200
Subject: drivers: base: cacheinfo: Get rid of DEFINE_SMP_CALL_CACHE_FUNCTION()

Git-commit: 4b92d4add5f6dcf21275185c997d6ecb800054cd
Patch-mainline: v5.15-rc1
References: git-fixes

DEFINE_SMP_CALL_CACHE_FUNCTION() was usefel before the CPU hotplug rework
to ensure that the cache related functions are called on the upcoming CPU
because the notifier itself could run on any online CPU.

The hotplug state machine guarantees that the callbacks are invoked on the
upcoming CPU. So there is no need to have this SMP function call
obfuscation. That indirection was missed when the hotplug notifiers were
converted.

This also solves the problem of ARM64 init_cache_level() invoking ACPI
functions which take a semaphore in that context. That's invalid as SMP
function calls run with interrupts disabled. Running it just from the
callback in context of the CPU hotplug thread solves this.

Fixes: 8571890e1513 ("arm64: Add support for ACPI based firmware tables")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/871r69ersb.ffs@tglx
[Yousaf]: Dropped hunks in arch/riscv
Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>
---
 arch/arm64/kernel/cacheinfo.c   |    7 ++-----
 arch/mips/kernel/cacheinfo.c    |    7 ++-----
 arch/x86/kernel/cpu/cacheinfo.c |    7 ++-----
 include/linux/cacheinfo.h       |   18 ------------------
 4 files changed, 6 insertions(+), 33 deletions(-)

--- a/arch/arm64/kernel/cacheinfo.c
+++ b/arch/arm64/kernel/cacheinfo.c
@@ -45,7 +45,7 @@ static void ci_leaf_init(struct cacheinf
 	this_leaf->type = type;
 }
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	unsigned int ctype, level, leaves, fw_level;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
@@ -80,7 +80,7 @@ static int __init_cache_level(unsigned i
 	return 0;
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	unsigned int level, idx;
 	enum cache_type type;
@@ -99,6 +99,3 @@ static int __populate_cache_leaves(unsig
 	}
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)
--- a/arch/mips/kernel/cacheinfo.c
+++ b/arch/mips/kernel/cacheinfo.c
@@ -28,7 +28,7 @@ do {								\
 	leaf++;							\
 } while (0)
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
@@ -61,7 +61,7 @@ static int __init_cache_level(unsigned i
 	return 0;
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	struct cpuinfo_mips *c = &current_cpu_data;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
@@ -82,6 +82,3 @@ static int __populate_cache_leaves(unsig
 
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -981,7 +981,7 @@ static void ci_leaf_init(struct cacheinf
 	this_leaf->priv = base->nb;
 }
 
-static int __init_cache_level(unsigned int cpu)
+int init_cache_level(unsigned int cpu)
 {
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 
@@ -1010,7 +1010,7 @@ static void get_cache_id(int cpu, struct
 	id4_regs->id = c->apicid >> index_msb;
 }
 
-static int __populate_cache_leaves(unsigned int cpu)
+int populate_cache_leaves(unsigned int cpu)
 {
 	unsigned int idx, ret;
 	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
@@ -1029,6 +1029,3 @@ static int __populate_cache_leaves(unsig
 
 	return 0;
 }
-
-DEFINE_SMP_CALL_CACHE_FUNCTION(init_cache_level)
-DEFINE_SMP_CALL_CACHE_FUNCTION(populate_cache_leaves)
--- a/include/linux/cacheinfo.h
+++ b/include/linux/cacheinfo.h
@@ -75,24 +75,6 @@ struct cpu_cacheinfo {
 	bool cpu_map_populated;
 };
 
-/*
- * Helpers to make sure "func" is executed on the cpu whose cache
- * attributes are being detected
- */
-#define DEFINE_SMP_CALL_CACHE_FUNCTION(func)			\
-static inline void _##func(void *ret)				\
-{								\
-	int cpu = smp_processor_id();				\
-	*(int *)ret = __##func(cpu);				\
-}								\
-								\
-int func(unsigned int cpu)					\
-{								\
-	int ret;						\
-	smp_call_function_single(cpu, _##func, &ret, true);	\
-	return ret;						\
-}
-
 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu);
 int init_cache_level(unsigned int cpu);
 int populate_cache_leaves(unsigned int cpu);