linux-kernel - [PATCH v5 08/15] x86/mtrr: have only one set

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Date:   Sat,  1 Apr 2023 08:36:45 +0200
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 v5 08/15] x86/mtrr: have only one set_mtrr() variant

Today there are two variants of set_mtrr(): one calling stop_machine()
and one calling stop_machine_cpuslocked().

The first one (set_mtrr()) has only one caller, and this caller is
always running with only one CPU online and interrupts being off.

Remove the first variant completely and replace the call of it with
a call of mtrr_if->set().

Rename the second variant set_mtrr_cpuslocked() to set_mtrr() now that
there is only one variant left.

Signed-off-by: Juergen Gross <jgross@...e.com>
---
V5:
- new patch
---
 arch/x86/kernel/cpu/mtrr/mtrr.c | 28 ++++++++--------------------
 1 file changed, 8 insertions(+), 20 deletions(-)

diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c
index 46aae69d259e..4fa3d0f94f39 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.c
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.c
@@ -192,20 +192,8 @@ static inline int types_compatible(mtrr_type type1, mtrr_type type2)
  * Note that the mechanism is the same for UP systems, too; all the SMP stuff
  * becomes nops.
  */
-static void
-set_mtrr(unsigned int reg, unsigned long base, unsigned long size, mtrr_type type)
-{
-	struct set_mtrr_data data = { .smp_reg = reg,
-				      .smp_base = base,
-				      .smp_size = size,
-				      .smp_type = type
-				    };
-
-	stop_machine(mtrr_rendezvous_handler, &data, cpu_online_mask);
-}
-
-static void set_mtrr_cpuslocked(unsigned int reg, unsigned long base,
-				unsigned long size, mtrr_type type)
+static void set_mtrr(unsigned int reg, unsigned long base, unsigned long size,
+		     mtrr_type type)
 {
 	struct set_mtrr_data data = { .smp_reg = reg,
 				      .smp_base = base,
@@ -335,7 +323,7 @@ int mtrr_add_page(unsigned long base, unsigned long size,
 	/* Search for an empty MTRR */
 	i = mtrr_if->get_free_region(base, size, replace);
 	if (i >= 0) {
-		set_mtrr_cpuslocked(i, base, size, type);
+		set_mtrr(i, base, size, type);
 		if (likely(replace < 0)) {
 			mtrr_usage_table[i] = 1;
 		} else {
@@ -343,7 +331,7 @@ int mtrr_add_page(unsigned long base, unsigned long size,
 			if (increment)
 				mtrr_usage_table[i]++;
 			if (unlikely(replace != i)) {
-				set_mtrr_cpuslocked(replace, 0, 0, 0);
+				set_mtrr(replace, 0, 0, 0);
 				mtrr_usage_table[replace] = 0;
 			}
 		}
@@ -471,7 +459,7 @@ int mtrr_del_page(int reg, unsigned long base, unsigned long size)
 		goto out;
 	}
 	if (--mtrr_usage_table[reg] < 1)
-		set_mtrr_cpuslocked(reg, 0, 0, 0);
+		set_mtrr(reg, 0, 0, 0);
 	error = reg;
  out:
 	mutex_unlock(&mtrr_mutex);
@@ -601,9 +589,9 @@ static void mtrr_restore(void)
 
 	for (i = 0; i < num_var_ranges; i++) {
 		if (mtrr_value[i].lsize) {
-			set_mtrr(i, mtrr_value[i].lbase,
-				    mtrr_value[i].lsize,
-				    mtrr_value[i].ltype);
+			mtrr_if->set(i, mtrr_value[i].lbase,
+				     mtrr_value[i].lsize,
+				     mtrr_value[i].ltype);
 		}
 	}
 }
-- 
2.35.3