linux-kernel - Re: [patch V3 12/30] x86/microcode/intel: Reuse intel_cpu_collect

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Date:   Tue, 3 Oct 2023 16:14:39 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
        "Chang S. Bae" <chang.seok.bae@...el.com>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        Nikolay Borisov <nik.borisov@...e.com>
Subject: Re: [patch V3 12/30] x86/microcode/intel: Reuse
 intel_cpu_collect_info()

On Mon, Sep 25, 2023 at 12:47:16PM +0200, Thomas Gleixner wrote:
> Eew. That's a function exposed to code outside of microcode and just
> grows that unused argument for no value and you obviously forgot to
> fixup the extern callsite :)

It's used on AMD. Adding the below to the pile.

---
From: "Borislav Petkov (AMD)" <bp@...en8.de>
Date: Tue, 3 Oct 2023 16:12:01 +0200
Subject: [PATCH] x86/microcode: Make microcode_ops.collect_cpu_info() return
 void

Simplify code flow a bit more in the process.

No functional changes.

Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
Link: https://lore.kernel.org/r/20230921104220.GHZQweDKyaJmkYdt4f@fat_crate.local
---
 arch/x86/include/asm/cpu.h               |  2 +-
 arch/x86/kernel/cpu/microcode/amd.c      |  4 +---
 arch/x86/kernel/cpu/microcode/intel.c    | 12 +++---------
 arch/x86/kernel/cpu/microcode/internal.h |  2 +-
 4 files changed, 6 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index 4066dd3734ba..581ecfbaf134 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -75,7 +75,7 @@ extern __noendbr void cet_disable(void);
 
 struct cpu_signature;
 
-void intel_collect_cpu_info(struct cpu_signature *sig);
+void intel_collect_cpu_info(int unused, struct cpu_signature *sig);
 
 static inline bool intel_cpu_signatures_match(unsigned int s1, unsigned int p1,
 					      unsigned int s2, unsigned int p2)
diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 0f15e82a536c..5d1c2a716456 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -632,7 +632,7 @@ void reload_ucode_amd(unsigned int cpu)
 	}
 }
 
-static int collect_cpu_info_amd(int cpu, struct cpu_signature *csig)
+static void collect_cpu_info_amd(int cpu, struct cpu_signature *csig)
 {
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
@@ -650,8 +650,6 @@ static int collect_cpu_info_amd(int cpu, struct cpu_signature *csig)
 		uci->mc = p->data;
 
 	pr_info("CPU%d: patch_level=0x%08x\n", cpu, csig->rev);
-
-	return 0;
 }
 
 static enum ucode_state apply_microcode_amd(int cpu)
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 3817bb2ad6ac..0eff86a5ab8f 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -66,7 +66,7 @@ static inline unsigned int exttable_size(struct extended_sigtable *et)
 	return et->count * EXT_SIGNATURE_SIZE + EXT_HEADER_SIZE;
 }
 
-void intel_collect_cpu_info(struct cpu_signature *sig)
+void intel_collect_cpu_info(int unused, struct cpu_signature *sig)
 {
 	sig->sig = cpuid_eax(1);
 	sig->pf = 0;
@@ -363,7 +363,7 @@ static __init struct microcode_intel *get_microcode_blob(struct ucode_cpu_info *
 	if (!(cp.data && cp.size))
 		return NULL;
 
-	intel_collect_cpu_info(&uci->cpu_sig);
+	intel_collect_cpu_info(0, &uci->cpu_sig);
 
 	return scan_microcode(cp.data, cp.size, uci);
 }
@@ -424,12 +424,6 @@ void reload_ucode_intel(void)
 		apply_microcode_early(&uci);
 }
 
-static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
-{
-	intel_collect_cpu_info(csig);
-	return 0;
-}
-
 static enum ucode_state apply_microcode_late(int cpu)
 {
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
@@ -592,7 +586,7 @@ static void finalize_late_load(int result)
 
 static struct microcode_ops microcode_intel_ops = {
 	.request_microcode_fw	= request_microcode_fw,
-	.collect_cpu_info	= collect_cpu_info,
+	.collect_cpu_info	= intel_collect_cpu_info,
 	.apply_microcode	= apply_microcode_late,
 	.finalize_late_load	= finalize_late_load,
 };
diff --git a/arch/x86/kernel/cpu/microcode/internal.h b/arch/x86/kernel/cpu/microcode/internal.h
index 051b7956d4fd..b3753025cd4a 100644
--- a/arch/x86/kernel/cpu/microcode/internal.h
+++ b/arch/x86/kernel/cpu/microcode/internal.h
@@ -30,7 +30,7 @@ struct microcode_ops {
 	 * See also the "Synchronization" section in microcode_core.c.
 	 */
 	enum ucode_state (*apply_microcode)(int cpu);
-	int (*collect_cpu_info)(int cpu, struct cpu_signature *csig);
+	void (*collect_cpu_info)(int cpu, struct cpu_signature *csig);
 	void (*finalize_late_load)(int result);
 };
 
-- 
2.42.0.rc0.25.ga82fb66fed25


-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette