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Message-Id: <20221004081023.32402-8-jgross@suse.com>
Date: Tue, 4 Oct 2022 10:10:14 +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 v4 07/16] x86/mtrr: split generic_set_all()
Split generic_set_all() into multiple parts, while moving the main
function body into cacheinfo.c.
Prepare the support of PAT without needing MTRR support by
moving the main function body of generic_set_all() into cacheinfo.c
while renaming it to cache_cpu_init(). The MTRR specific parts are
moved into a dedicated small function called by cache_cpu_init() in
order to make cache_cpu_init() as MTRR agnostic as possible.
The setting of smp_changes_mask is merged into the (new) function
mtrr_generic_set_state() used to call set_mtrr_state(). It was
probably split in ancient times, as atomic operations while running
uncached might be quite expensive, but OTOH only systems with a
broken BIOS should ever require to set any bit in smp_changes_mask,
so just hurting those devices with a penalty of a few microseconds
during boot shouldn't be a real issue.
Signed-off-by: Juergen Gross <jgross@...e.com>
---
V2:
- new patch
V4:
- remove some comments (Borislav Petkov)
---
arch/x86/include/asm/cacheinfo.h | 1 +
arch/x86/include/asm/mtrr.h | 2 ++
arch/x86/kernel/cpu/cacheinfo.c | 17 +++++++++++++++++
arch/x86/kernel/cpu/mtrr/generic.c | 15 ++-------------
4 files changed, 22 insertions(+), 13 deletions(-)
diff --git a/arch/x86/include/asm/cacheinfo.h b/arch/x86/include/asm/cacheinfo.h
index 6159874b4183..978bac70fd49 100644
--- a/arch/x86/include/asm/cacheinfo.h
+++ b/arch/x86/include/asm/cacheinfo.h
@@ -12,5 +12,6 @@ void cacheinfo_hygon_init_llc_id(struct cpuinfo_x86 *c, int cpu);
void cache_disable(void);
void cache_enable(void);
+void cache_cpu_init(void);
#endif /* _ASM_X86_CACHEINFO_H */
diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h
index 12a16caed395..986249a2b9b6 100644
--- a/arch/x86/include/asm/mtrr.h
+++ b/arch/x86/include/asm/mtrr.h
@@ -50,6 +50,7 @@ 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);
+void mtrr_generic_set_state(void);
# else
static inline u8 mtrr_type_lookup(u64 addr, u64 end, u8 *uniform)
{
@@ -91,6 +92,7 @@ static inline void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi)
#define mtrr_bp_restore() do {} while (0)
#define mtrr_disable() do {} while (0)
#define mtrr_enable() do {} while (0)
+#define mtrr_generic_set_state() do {} while (0)
# endif
#ifdef CONFIG_COMPAT
diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index ff32b2b1ca23..49b60a427fc9 100644
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -1120,3 +1120,20 @@ void cache_enable(void) __releases(cache_disable_lock)
raw_spin_unlock(&cache_disable_lock);
}
+
+void cache_cpu_init(void)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ cache_disable();
+
+ if (memory_caching_control & CACHE_MTRR)
+ mtrr_generic_set_state();
+
+ if (memory_caching_control & CACHE_PAT)
+ pat_init();
+
+ cache_enable();
+ local_irq_restore(flags);
+}
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index bfe13eedaca8..32aebed25e3f 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -731,30 +731,19 @@ void mtrr_enable(void)
mtrr_wrmsr(MSR_MTRRdefType, deftype_lo, deftype_hi);
}
-static void generic_set_all(void)
+void mtrr_generic_set_state(void)
{
unsigned long mask, count;
- unsigned long flags;
-
- local_irq_save(flags);
- cache_disable();
/* Actually set the state */
mask = set_mtrr_state();
- /* also set PAT */
- pat_init();
-
- cache_enable();
- local_irq_restore(flags);
-
/* Use the atomic bitops to update the global mask */
for (count = 0; count < sizeof(mask) * 8; ++count) {
if (mask & 0x01)
set_bit(count, &smp_changes_mask);
mask >>= 1;
}
-
}
/**
@@ -854,7 +843,7 @@ int positive_have_wrcomb(void)
* Generic structure...
*/
const struct mtrr_ops generic_mtrr_ops = {
- .set_all = generic_set_all,
+ .set_all = cache_cpu_init,
.get = generic_get_mtrr,
.get_free_region = generic_get_free_region,
.set = generic_set_mtrr,
--
2.35.3
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