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Message-Id: <20220715142549.25223-2-jgross@suse.com>
Date: Fri, 15 Jul 2022 16:25:47 +0200
From: Juergen Gross <jgross@...e.com>
To: xen-devel@...ts.xenproject.org, x86@...nel.org,
linux-kernel@...r.kernel.org
Cc: brchuckz@...scape.net, jbeulich@...e.com,
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>, stable@...r.kernel.org
Subject: [PATCH 1/3] x86: move some code out of arch/x86/kernel/cpu/mtrr
Prepare making PAT and MTRR support independent from each other by
moving some code needed by both out of the MTRR specific sources.
Cc: <stable@...r.kernel.org> # 5.17
Fixes: bdd8b6c98239 ("drm/i915: replace X86_FEATURE_PAT with pat_enabled()")
Signed-off-by: Juergen Gross <jgross@...e.com>
---
arch/x86/include/asm/mtrr.h | 4 ++
arch/x86/include/asm/processor.h | 3 ++
arch/x86/kernel/cpu/common.c | 76 ++++++++++++++++++++++++++++
arch/x86/kernel/cpu/mtrr/generic.c | 80 +++---------------------------
4 files changed, 91 insertions(+), 72 deletions(-)
diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h
index 76d726074c16..12a16caed395 100644
--- a/arch/x86/include/asm/mtrr.h
+++ b/arch/x86/include/asm/mtrr.h
@@ -48,6 +48,8 @@ extern void mtrr_aps_init(void);
extern void mtrr_bp_restore(void);
extern int mtrr_trim_uncached_memory(unsigned long end_pfn);
extern int amd_special_default_mtrr(void);
+void mtrr_disable(void);
+void mtrr_enable(void);
# else
static inline u8 mtrr_type_lookup(u64 addr, u64 end, u8 *uniform)
{
@@ -87,6 +89,8 @@ static inline void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi)
#define set_mtrr_aps_delayed_init() do {} while (0)
#define mtrr_aps_init() do {} while (0)
#define mtrr_bp_restore() do {} while (0)
+#define mtrr_disable() do {} while (0)
+#define mtrr_enable() do {} while (0)
# endif
#ifdef CONFIG_COMPAT
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 356308c73951..5c934b922450 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -865,4 +865,7 @@ bool arch_is_platform_page(u64 paddr);
#define arch_is_platform_page arch_is_platform_page
#endif
+void cache_disable(void);
+void cache_enable(void);
+
#endif /* _ASM_X86_PROCESSOR_H */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 736262a76a12..e43322f8a4ef 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -61,6 +61,7 @@
#include <asm/sigframe.h>
#include <asm/traps.h>
#include <asm/sev.h>
+#include <asm/mtrr.h>
#include "cpu.h"
@@ -2327,3 +2328,78 @@ void arch_smt_update(void)
/* Check whether IPI broadcasting can be enabled */
apic_smt_update();
}
+
+/*
+ * Disable and enable caches. Needed for changing MTRRs and the PAT MSR.
+ *
+ * Since we are disabling the cache don't allow any interrupts,
+ * they would run extremely slow and would only increase the pain.
+ *
+ * The caller must ensure that local interrupts are disabled and
+ * are reenabled after cache_enable() has been called.
+ */
+static unsigned long saved_cr4;
+static DEFINE_RAW_SPINLOCK(cache_disable_lock);
+
+void cache_disable(void) __acquires(cache_disable_lock)
+{
+ unsigned long cr0;
+
+ /*
+ * Note that this is not ideal
+ * since the cache is only flushed/disabled for this CPU while the
+ * MTRRs are changed, but changing this requires more invasive
+ * changes to the way the kernel boots
+ */
+
+ raw_spin_lock(&cache_disable_lock);
+
+ /* Enter the no-fill (CD=1, NW=0) cache mode and flush caches. */
+ cr0 = read_cr0() | X86_CR0_CD;
+ write_cr0(cr0);
+
+ /*
+ * Cache flushing is the most time-consuming step when programming
+ * the MTRRs. Fortunately, as per the Intel Software Development
+ * Manual, we can skip it if the processor supports cache self-
+ * snooping.
+ */
+ if (!static_cpu_has(X86_FEATURE_SELFSNOOP))
+ wbinvd();
+
+ /* Save value of CR4 and clear Page Global Enable (bit 7) */
+ if (boot_cpu_has(X86_FEATURE_PGE)) {
+ saved_cr4 = __read_cr4();
+ __write_cr4(saved_cr4 & ~X86_CR4_PGE);
+ }
+
+ /* Flush all TLBs via a mov %cr3, %reg; mov %reg, %cr3 */
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
+ flush_tlb_local();
+
+ if (boot_cpu_has(X86_FEATURE_MTRR))
+ mtrr_disable();
+
+ /* Again, only flush caches if we have to. */
+ if (!static_cpu_has(X86_FEATURE_SELFSNOOP))
+ wbinvd();
+}
+
+void cache_enable(void) __releases(cache_disable_lock)
+{
+ /* Flush TLBs (no need to flush caches - they are disabled) */
+ count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
+ flush_tlb_local();
+
+ if (boot_cpu_has(X86_FEATURE_MTRR))
+ mtrr_enable();
+
+ /* Enable caches */
+ write_cr0(read_cr0() & ~X86_CR0_CD);
+
+ /* Restore value of CR4 */
+ if (boot_cpu_has(X86_FEATURE_PGE))
+ __write_cr4(saved_cr4);
+
+ raw_spin_unlock(&cache_disable_lock);
+}
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 558108296f3c..84732215b61d 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -396,9 +396,6 @@ print_fixed(unsigned base, unsigned step, const mtrr_type *types)
}
}
-static void prepare_set(void);
-static void post_set(void);
-
static void __init print_mtrr_state(void)
{
unsigned int i;
@@ -450,11 +447,11 @@ void __init mtrr_bp_pat_init(void)
unsigned long flags;
local_irq_save(flags);
- prepare_set();
+ cache_disable();
pat_init();
- post_set();
+ cache_enable();
local_irq_restore(flags);
}
@@ -715,80 +712,19 @@ static unsigned long set_mtrr_state(void)
return change_mask;
}
-
-static unsigned long cr4;
-static DEFINE_RAW_SPINLOCK(set_atomicity_lock);
-
-/*
- * Since we are disabling the cache don't allow any interrupts,
- * they would run extremely slow and would only increase the pain.
- *
- * The caller must ensure that local interrupts are disabled and
- * are reenabled after post_set() has been called.
- */
-static void prepare_set(void) __acquires(set_atomicity_lock)
+void mtrr_disable(void)
{
- unsigned long cr0;
-
- /*
- * Note that this is not ideal
- * since the cache is only flushed/disabled for this CPU while the
- * MTRRs are changed, but changing this requires more invasive
- * changes to the way the kernel boots
- */
-
- raw_spin_lock(&set_atomicity_lock);
-
- /* Enter the no-fill (CD=1, NW=0) cache mode and flush caches. */
- cr0 = read_cr0() | X86_CR0_CD;
- write_cr0(cr0);
-
- /*
- * Cache flushing is the most time-consuming step when programming
- * the MTRRs. Fortunately, as per the Intel Software Development
- * Manual, we can skip it if the processor supports cache self-
- * snooping.
- */
- if (!static_cpu_has(X86_FEATURE_SELFSNOOP))
- wbinvd();
-
- /* Save value of CR4 and clear Page Global Enable (bit 7) */
- if (boot_cpu_has(X86_FEATURE_PGE)) {
- cr4 = __read_cr4();
- __write_cr4(cr4 & ~X86_CR4_PGE);
- }
-
- /* Flush all TLBs via a mov %cr3, %reg; mov %reg, %cr3 */
- count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
- flush_tlb_local();
-
/* Save MTRR state */
rdmsr(MSR_MTRRdefType, deftype_lo, deftype_hi);
/* Disable MTRRs, and set the default type to uncached */
mtrr_wrmsr(MSR_MTRRdefType, deftype_lo & ~0xcff, deftype_hi);
-
- /* Again, only flush caches if we have to. */
- if (!static_cpu_has(X86_FEATURE_SELFSNOOP))
- wbinvd();
}
-static void post_set(void) __releases(set_atomicity_lock)
+void mtrr_enable(void)
{
- /* Flush TLBs (no need to flush caches - they are disabled) */
- count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
- flush_tlb_local();
-
/* Intel (P6) standard MTRRs */
mtrr_wrmsr(MSR_MTRRdefType, deftype_lo, deftype_hi);
-
- /* Enable caches */
- write_cr0(read_cr0() & ~X86_CR0_CD);
-
- /* Restore value of CR4 */
- if (boot_cpu_has(X86_FEATURE_PGE))
- __write_cr4(cr4);
- raw_spin_unlock(&set_atomicity_lock);
}
static void generic_set_all(void)
@@ -797,7 +733,7 @@ static void generic_set_all(void)
unsigned long flags;
local_irq_save(flags);
- prepare_set();
+ cache_disable();
/* Actually set the state */
mask = set_mtrr_state();
@@ -805,7 +741,7 @@ static void generic_set_all(void)
/* also set PAT */
pat_init();
- post_set();
+ cache_enable();
local_irq_restore(flags);
/* Use the atomic bitops to update the global mask */
@@ -836,7 +772,7 @@ static void generic_set_mtrr(unsigned int reg, unsigned long base,
vr = &mtrr_state.var_ranges[reg];
local_irq_save(flags);
- prepare_set();
+ cache_disable();
if (size == 0) {
/*
@@ -855,7 +791,7 @@ static void generic_set_mtrr(unsigned int reg, unsigned long base,
mtrr_wrmsr(MTRRphysMask_MSR(reg), vr->mask_lo, vr->mask_hi);
}
- post_set();
+ cache_enable();
local_irq_restore(flags);
}
--
2.35.3
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