linux-kernel - [PATCH v2] x86/resctrl: Annotate get_mem_config functions as _

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Message-Id: <20240913-x86-restctrl-get_mem_config_intel-init-v2-1-bf4b645f0246@kernel.org>
Date: Fri, 13 Sep 2024 16:27:13 -0700
From: Nathan Chancellor <nathan@...nel.org>
To: Fenghua Yu <fenghua.yu@...el.com>, 
 Reinette Chatre <reinette.chatre@...el.com>, x86@...nel.org, 
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, 
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>
Cc: linux-kernel@...r.kernel.org, llvm@...ts.linux.dev, 
 patches@...ts.linux.dev, Nathan Chancellor <nathan@...nel.org>
Subject: [PATCH v2] x86/resctrl: Annotate get_mem_config functions as
 __init

After a recent LLVM change [1] that deduces __cold on functions that
only call cold code (such as __init functions), there is a section
mismatch warning from __get_mem_config_intel(), which got moved to
.text.unlikely. as a result of that optimization:

  WARNING: modpost: vmlinux: section mismatch in reference: __get_mem_config_intel+0x77 (section: .text.unlikely.) -> thread_throttle_mode_init (section: .init.text)

Mark __get_mem_config_intel() as __init as well since it is only called
from __init code, which clears up the warning.

While __rdt_get_mem_config_amd() does not exhibit a warning because it
does not call any __init code, it is a similar function that is only
called from __init code like __get_mem_config_intel(), so mark it __init
as well to keep the code symmetrical.

Link: https://github.com/llvm/llvm-project/commit/6b11573b8c5e3d36beee099dbe7347c2a007bf53 [1]
Signed-off-by: Nathan Chancellor <nathan@...nel.org>
---
Changes in v2:
- Move position of __init within definition of __get_mem_config_intel()
  to better match coding style guidelines (Reinette).
- Apply __init to __rdt_get_mem_config_amd(), as it has the same issue
  by inspection (Reinette). Adjust commit message to reflect this
  change.
- Link to v1: https://lore.kernel.org/r/20240822-x86-restctrl-get_mem_config_intel-init-v1-1-8b0a68a8731a@kernel.org
---
 arch/x86/kernel/cpu/resctrl/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 1930fce9dfe96d5c323cb9000fb06149916a5a3c..59961618a02374a5b1639baa7034d05867884640 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -199,7 +199,7 @@ static inline bool rdt_get_mb_table(struct rdt_resource *r)
 	return false;
 }
 
-static bool __get_mem_config_intel(struct rdt_resource *r)
+static __init bool __get_mem_config_intel(struct rdt_resource *r)
 {
 	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
 	union cpuid_0x10_3_eax eax;
@@ -233,7 +233,7 @@ static bool __get_mem_config_intel(struct rdt_resource *r)
 	return true;
 }
 
-static bool __rdt_get_mem_config_amd(struct rdt_resource *r)
+static __init bool __rdt_get_mem_config_amd(struct rdt_resource *r)
 {
 	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
 	u32 eax, ebx, ecx, edx, subleaf;

---
base-commit: 7424fc6b86c8980a87169e005f5cd4438d18efe6
change-id: 20240822-x86-restctrl-get_mem_config_intel-init-3af02a5130ba

Best regards,
-- 
Nathan Chancellor <nathan@...nel.org>