diff options
| author | Dave Hansen <dave.hansen@linux.intel.com> | 2017-08-30 16:23:00 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-05 15:44:25 +0100 |
| commit | eb82151d0b1df53d1ad8d060ecd554ca12eb552a (patch) | |
| tree | f84284e5399a5caee2e11a9d0cc4a774f3c6685f /arch/x86/kernel/cpu/common.c | |
| parent | 3e3d38fd9832e82a8cb1a5b1154acfa43ac08d15 (diff) | |
kaiser: enhanced by kernel and user PCIDs
Merged performance improvements to Kaiser, using distinct kernel
and user Process Context Identifiers to minimize the TLB flushing.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/kernel/cpu/common.c')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index e5ba9701ee6c..07b7f2816567 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -321,11 +321,45 @@ static __always_inline void setup_smap(struct cpuinfo_x86 *c) } } +/* + * These can have bit 63 set, so we can not just use a plain "or" + * instruction to get their value or'd into CR3. It would take + * another register. So, we use a memory reference to these + * instead. + * + * This is also handy because systems that do not support + * PCIDs just end up or'ing a 0 into their CR3, which does + * no harm. + */ +__aligned(PAGE_SIZE) unsigned long X86_CR3_PCID_KERN_VAR = 0; +__aligned(PAGE_SIZE) unsigned long X86_CR3_PCID_USER_VAR = 0; + static void setup_pcid(struct cpuinfo_x86 *c) { if (cpu_has(c, X86_FEATURE_PCID)) { if (cpu_has(c, X86_FEATURE_PGE)) { cr4_set_bits(X86_CR4_PCIDE); + /* + * These variables are used by the entry/exit + * code to change PCIDs. + */ +#ifdef CONFIG_KAISER + X86_CR3_PCID_KERN_VAR = X86_CR3_PCID_KERN_NOFLUSH; + X86_CR3_PCID_USER_VAR = X86_CR3_PCID_USER_NOFLUSH; +#endif + /* + * INVPCID has two "groups" of types: + * 1/2: Invalidate an individual address + * 3/4: Invalidate all contexts + * + * 1/2 take a PCID, but 3/4 do not. So, 3/4 + * ignore the PCID argument in the descriptor. + * But, we have to be careful not to call 1/2 + * with an actual non-zero PCID in them before + * we do the above cr4_set_bits(). + */ + if (cpu_has(c, X86_FEATURE_INVPCID)) + set_cpu_cap(c, X86_FEATURE_INVPCID_SINGLE); } else { /* * flush_tlb_all(), as currently implemented, won't |