[PATCH v6 01/16] x86/mtrr: remove physical address size calculation

From: Juergen Gross
Date: Tue May 02 2023 - 08:09:58 EST

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The physical address width calculation in mtrr_bp_init() can easily be
replaced with using the already available value x86_phys_bits from
struct cpuinfo_x86.

The same information source can be used in mtrr/cleanup.c, removing the
need to pass that value on to mtrr_cleanup().

In print_mtrr_state() use x86_phys_bits instead of recalculating it
from size_or_mask.

Move setting of size_or_mask and size_and_mask into a dedicated new
function in mtrr/generic.c, enabling to make those 2 variables static,
as they are used in generic.c only now.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
V6:
- new patch, replacing former patches 1+2
---
arch/x86/kernel/cpu/mtrr/cleanup.c | 16 ++++----
arch/x86/kernel/cpu/mtrr/generic.c | 12 +++++-
arch/x86/kernel/cpu/mtrr/mtrr.c | 61 ++++--------------------------
arch/x86/kernel/cpu/mtrr/mtrr.h | 4 +-
4 files changed, 29 insertions(+), 64 deletions(-)

diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c
index b5f43049fa5f..70314093bb9b 100644
--- a/arch/x86/kernel/cpu/mtrr/cleanup.c
+++ b/arch/x86/kernel/cpu/mtrr/cleanup.c
@@ -173,7 +173,7 @@ early_param("mtrr_cleanup_debug", mtrr_cleanup_debug_setup);

static void __init
set_var_mtrr(unsigned int reg, unsigned long basek, unsigned long sizek,
- unsigned char type, unsigned int address_bits)
+ unsigned char type)
{
u32 base_lo, base_hi, mask_lo, mask_hi;
u64 base, mask;
@@ -183,7 +183,7 @@ set_var_mtrr(unsigned int reg, unsigned long basek, unsigned long sizek,
return;
}

- mask = (1ULL << address_bits) - 1;
+ mask = (1ULL << boot_cpu_data.x86_phys_bits) - 1;
mask &= ~((((u64)sizek) << 10) - 1);

base = ((u64)basek) << 10;
@@ -209,7 +209,7 @@ save_var_mtrr(unsigned int reg, unsigned long basek, unsigned long sizek,
range_state[reg].type = type;
}

-static void __init set_var_mtrr_all(unsigned int address_bits)
+static void __init set_var_mtrr_all(void)
{
unsigned long basek, sizek;
unsigned char type;
@@ -220,7 +220,7 @@ static void __init set_var_mtrr_all(unsigned int address_bits)
sizek = range_state[reg].size_pfn << (PAGE_SHIFT - 10);
type = range_state[reg].type;

- set_var_mtrr(reg, basek, sizek, type, address_bits);
+ set_var_mtrr(reg, basek, sizek, type);
}
}

@@ -680,7 +680,7 @@ static int __init mtrr_search_optimal_index(void)
return index_good;
}

-int __init mtrr_cleanup(unsigned address_bits)
+int __init mtrr_cleanup(void)
{
unsigned long x_remove_base, x_remove_size;
unsigned long base, size, def, dummy;
@@ -742,7 +742,7 @@ int __init mtrr_cleanup(unsigned address_bits)
mtrr_print_out_one_result(i);

if (!result[i].bad) {
- set_var_mtrr_all(address_bits);
+ set_var_mtrr_all();
pr_debug("New variable MTRRs\n");
print_out_mtrr_range_state();
return 1;
@@ -786,7 +786,7 @@ int __init mtrr_cleanup(unsigned address_bits)
gran_size = result[i].gran_sizek;
gran_size <<= 10;
x86_setup_var_mtrrs(range, nr_range, chunk_size, gran_size);
- set_var_mtrr_all(address_bits);
+ set_var_mtrr_all();
pr_debug("New variable MTRRs\n");
print_out_mtrr_range_state();
return 1;
@@ -802,7 +802,7 @@ int __init mtrr_cleanup(unsigned address_bits)
return 0;
}
#else
-int __init mtrr_cleanup(unsigned address_bits)
+int __init mtrr_cleanup(void)
{
return 0;
}
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index ee09d359e08f..3922552340b1 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -38,6 +38,16 @@ u64 mtrr_tom2;
struct mtrr_state_type mtrr_state;
EXPORT_SYMBOL_GPL(mtrr_state);

+static u64 size_or_mask, size_and_mask;
+
+void __init mtrr_set_mask(void)
+{
+ unsigned int phys_addr = boot_cpu_data.x86_phys_bits;
+
+ size_or_mask = ~GENMASK_ULL(phys_addr - PAGE_SHIFT - 1, 0);
+ size_and_mask = ~size_or_mask & GENMASK_ULL(39, 20);
+}
+
/*
* BIOS is expected to clear MtrrFixDramModEn bit, see for example
* "BIOS and Kernel Developer's Guide for the AMD Athlon 64 and AMD
@@ -422,7 +432,7 @@ static void __init print_mtrr_state(void)
}
pr_debug("MTRR variable ranges %sabled:\n",
mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED ? "en" : "dis");
- high_width = (__ffs64(size_or_mask) - (32 - PAGE_SHIFT) + 3) / 4;
+ high_width = (boot_cpu_data.x86_phys_bits - (32 - PAGE_SHIFT) + 3) / 4;

for (i = 0; i < num_var_ranges; ++i) {
if (mtrr_state.var_ranges[i].mask_lo & (1 << 11))
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c
index 783f3210d582..1bdab16f16bd 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.c
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.c
@@ -67,8 +67,6 @@ static bool mtrr_enabled(void)
unsigned int mtrr_usage_table[MTRR_MAX_VAR_RANGES];
static DEFINE_MUTEX(mtrr_mutex);

-u64 size_or_mask, size_and_mask;
-
const struct mtrr_ops *mtrr_if;

/* Returns non-zero if we have the write-combining memory type */
@@ -619,77 +617,34 @@ 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
+ * 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)";
- u32 phys_addr;

- phys_addr = 32;
+ mtrr_set_mask();

- if (boot_cpu_has(X86_FEATURE_MTRR)) {
+ if (cpu_feature_enabled(X86_FEATURE_MTRR)) {
mtrr_if = &generic_mtrr_ops;
- size_or_mask = SIZE_OR_MASK_BITS(36);
- size_and_mask = 0x00f00000;
- phys_addr = 36;
-
- /*
- * This is an AMD specific MSR, but we assume(hope?) that
- * Intel will implement it too when they extend the address
- * bus of the Xeon.
- */
- if (cpuid_eax(0x80000000) >= 0x80000008) {
- phys_addr = cpuid_eax(0x80000008) & 0xff;
- /* CPUID workaround for Intel 0F33/0F34 CPU */
- if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
- boot_cpu_data.x86 == 0xF &&
- boot_cpu_data.x86_model == 0x3 &&
- (boot_cpu_data.x86_stepping == 0x3 ||
- boot_cpu_data.x86_stepping == 0x4))
- phys_addr = 36;
-
- size_or_mask = SIZE_OR_MASK_BITS(phys_addr);
- size_and_mask = ~size_or_mask & 0xfffff00000ULL;
- } else if (boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR &&
- boot_cpu_data.x86 == 6) {
- /*
- * VIA C* family have Intel style MTRRs,
- * but don't support PAE
- */
- size_or_mask = SIZE_OR_MASK_BITS(32);
- size_and_mask = 0;
- phys_addr = 32;
- }
} 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;
@@ -703,7 +658,7 @@ void __init mtrr_bp_init(void)
/* BIOS may override */
if (get_mtrr_state()) {
memory_caching_control |= CACHE_MTRR;
- changed_by_mtrr_cleanup = mtrr_cleanup(phys_addr);
+ changed_by_mtrr_cleanup = mtrr_cleanup();
} else {
mtrr_if = NULL;
why = "by BIOS";
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.h b/arch/x86/kernel/cpu/mtrr/mtrr.h
index 02eb5871492d..a00987e6cc1c 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.h
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.h
@@ -51,7 +51,6 @@ void fill_mtrr_var_range(unsigned int index,
u32 base_lo, u32 base_hi, u32 mask_lo, u32 mask_hi);
bool get_mtrr_state(void);

-extern u64 size_or_mask, size_and_mask;
extern const struct mtrr_ops *mtrr_if;

#define is_cpu(vnd) (mtrr_if && mtrr_if->vendor == X86_VENDOR_##vnd)
@@ -60,6 +59,7 @@ extern unsigned int num_var_ranges;
extern u64 mtrr_tom2;
extern struct mtrr_state_type mtrr_state;

+void mtrr_set_mask(void);
void mtrr_state_warn(void);
const char *mtrr_attrib_to_str(int x);
void mtrr_wrmsr(unsigned, unsigned, unsigned);
@@ -70,4 +70,4 @@ extern const struct mtrr_ops cyrix_mtrr_ops;
extern const struct mtrr_ops centaur_mtrr_ops;

extern int changed_by_mtrr_cleanup;
-extern int mtrr_cleanup(unsigned address_bits);
+extern int mtrr_cleanup(void);
--
2.35.3

Next message: Juergen Gross: "[PATCH v6 02/16] x86/mtrr: replace some constants with defines"
Previous message: Juergen Gross: "[PATCH v6 00/16] x86/mtrr: fix handling with PAT but without MTRR"
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Next in thread: Borislav Petkov: "Re: [PATCH v6 01/16] x86/mtrr: remove physical address size calculation"
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