linux-kernel - [PATCH v3 01/12] x86/mtrr: split off physical address size calculation

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Date:   Thu, 23 Feb 2023 10:32:32 +0100
From:   Juergen Gross <jgross@...e.com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org
Cc:     Juergen Gross <jgross@...e.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH v3 01/12] x86/mtrr: split off physical address size calculation

Move the calculation of the physical address size in mtrr_bp_init()
into a helper function. This will be needed later.

Do only the pure code movement without optimizing it.

Signed-off-by: Juergen Gross <jgross@...e.com>
---
V2:
- new patch
V3:
- only move code, split off optimizations (Boris Petkov)
---
 arch/x86/kernel/cpu/mtrr/mtrr.c | 57 ++++++++++++++++++---------------
 1 file changed, 32 insertions(+), 25 deletions(-)

diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c
index 783f3210d582..8310bdb111d0 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.c
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.c
@@ -620,22 +620,14 @@ static struct syscore_ops mtrr_syscore_ops = {
 int __initdata changed_by_mtrr_cleanup;
 
 #define SIZE_OR_MASK_BITS(n)  (~((1ULL << ((n) - PAGE_SHIFT)) - 1))
-/**
- * mtrr_bp_init - initialize mtrrs on the boot CPU
- *
- * This needs to be called early; before any of the other CPUs are
- * initialized (i.e. before smp_init()).
- *
- */
-void __init mtrr_bp_init(void)
+
+static unsigned int __init mtrr_calc_physbits(bool generic)
 {
-	const char *why = "(not available)";
-	u32 phys_addr;
+	unsigned int phys_addr;
 
 	phys_addr = 32;
 
-	if (boot_cpu_has(X86_FEATURE_MTRR)) {
-		mtrr_if = &generic_mtrr_ops;
+	if (generic) {
 		size_or_mask = SIZE_OR_MASK_BITS(36);
 		size_and_mask = 0x00f00000;
 		phys_addr = 36;
@@ -667,29 +659,44 @@ void __init mtrr_bp_init(void)
 			size_and_mask = 0;
 			phys_addr = 32;
 		}
+	} else {
+		size_or_mask = SIZE_OR_MASK_BITS(32);
+		size_and_mask = 0;
+	}
+
+	return phys_addr;
+}
+
+/**
+ * mtrr_bp_init - initialize mtrrs on the boot CPU
+ *
+ * This needs to be called early; before any of the other CPUs are
+ * initialized (i.e. before smp_init()).
+ *
+ */
+void __init mtrr_bp_init(void)
+{
+	const char *why = "(not available)";
+	unsigned int phys_addr;
+
+	phys_addr = mtrr_calc_physbits(boot_cpu_has(X86_FEATURE_MTRR));
+
+	if (boot_cpu_has(X86_FEATURE_MTRR)) {
+		mtrr_if = &generic_mtrr_ops;
 	} else {
 		switch (boot_cpu_data.x86_vendor) {
 		case X86_VENDOR_AMD:
-			if (cpu_feature_enabled(X86_FEATURE_K6_MTRR)) {
-				/* Pre-Athlon (K6) AMD CPU MTRRs */
+			/* Pre-Athlon (K6) AMD CPU MTRRs */
+			if (cpu_feature_enabled(X86_FEATURE_K6_MTRR))
 				mtrr_if = &amd_mtrr_ops;
-				size_or_mask = SIZE_OR_MASK_BITS(32);
-				size_and_mask = 0;
-			}
 			break;
 		case X86_VENDOR_CENTAUR:
-			if (cpu_feature_enabled(X86_FEATURE_CENTAUR_MCR)) {
+			if (cpu_feature_enabled(X86_FEATURE_CENTAUR_MCR))
 				mtrr_if = &centaur_mtrr_ops;
-				size_or_mask = SIZE_OR_MASK_BITS(32);
-				size_and_mask = 0;
-			}
 			break;
 		case X86_VENDOR_CYRIX:
-			if (cpu_feature_enabled(X86_FEATURE_CYRIX_ARR)) {
+			if (cpu_feature_enabled(X86_FEATURE_CYRIX_ARR))
 				mtrr_if = &cyrix_mtrr_ops;
-				size_or_mask = SIZE_OR_MASK_BITS(32);
-				size_and_mask = 0;
-			}
 			break;
 		default:
 			break;
-- 
2.35.3