powerpc/64s: Improve local TLB flush for boot and MCE on POWER9

There are several cases outside the normal address space management
where a CPU's entire local TLB is to be flushed:

  1. Booting the kernel, in case something has left stale entries in
     the TLB (e.g., kexec).

  2. Machine check, to clean corrupted TLB entries.

One other place where the TLB is flushed, is waking from deep idle
states. The flush is a side-effect of calling ->cpu_restore with the
intention of re-setting various SPRs. The flush itself is unnecessary
because in the first case, the TLB should not acquire new corrupted
TLB entries as part of sleep/wake (though they may be lost).

This type of TLB flush is coded inflexibly, several times for each CPU
type, and they have a number of problems with ISA v3.0B:

- The current radix mode of the MMU is not taken into account, it is
  always done as a hash flushn For IS=2 (LPID-matching flush from host)
  and IS=3 with HV=0 (guest kernel flush), tlbie(l) is undefined if
  the R field does not match the current radix mode.

- ISA v3.0B hash must flush the partition and process table caches as
  well.

- ISA v3.0B radix must flush partition and process scoped translations,
  partition and process table caches, and also the page walk cache.

So consolidate the flushing code and implement it in C and inline asm
under the mm/ directory with the rest of the flush code. Add ISA v3.0B
cases for radix and hash, and use the radix flush in radix environment.

Provide a way for IS=2 (LPID flush) to specify the radix mode of the
partition. Have KVM pass in the radix mode of the guest.

Take out the flushes from early cputable/dt_cpu_ftrs detection hooks,
and move it later in the boot process after, the MMU registers are set
up and before relocation is first turned on.

The TLB flush is no longer called when restoring from deep idle states.
This was not be done as a separate step because booting secondaries
uses the same cpu_restore as idle restore, which needs the TLB flush.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 0 insertions, 30 deletions

diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c
index 8bdc2f96c5d6..945e2c29ad2d 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c
@@ -77,8 +77,6 @@ struct dt_cpu_feature {
  * Set up the base CPU
  */
 
-extern void __flush_tlb_power8(unsigned int action);
-extern void __flush_tlb_power9(unsigned int action);
 extern long __machine_check_early_realmode_p8(struct pt_regs *regs);
 extern long __machine_check_early_realmode_p9(struct pt_regs *regs);
 
@@ -92,27 +90,6 @@ static struct {
 
 static void (*init_pmu_registers)(void);
 
-static void cpufeatures_flush_tlb(void)
-{
-	/*
-	 * This is a temporary measure to keep equivalent TLB flush as the
-	 * cputable based setup code.
-	 */
-	switch (PVR_VER(mfspr(SPRN_PVR))) {
-	case PVR_POWER8:
-	case PVR_POWER8E:
-	case PVR_POWER8NVL:
-		__flush_tlb_power8(TLB_INVAL_SCOPE_GLOBAL);
-		break;
-	case PVR_POWER9:
-		__flush_tlb_power9(TLB_INVAL_SCOPE_GLOBAL);
-		break;
-	default:
-		pr_err("unknown CPU version for boot TLB flush\n");
-		break;
-	}
-}
-
 static void __restore_cpu_cpufeatures(void)
 {
 	/*
@@ -137,8 +114,6 @@ static void __restore_cpu_cpufeatures(void)
 
 	if (init_pmu_registers)
 		init_pmu_registers();
-
-	cpufeatures_flush_tlb();
 }
 
 static char dt_cpu_name[64];
@@ -157,7 +132,6 @@ static struct cpu_spec __initdata base_cpu_spec = {
 	.oprofile_type		= PPC_OPROFILE_INVALID,
 	.cpu_setup		= NULL,
 	.cpu_restore		= __restore_cpu_cpufeatures,
-	.flush_tlb		= NULL,
 	.machine_check_early	= NULL,
 	.platform		= NULL,
 };
@@ -412,7 +386,6 @@ static void init_pmu_power8(void)
 static int __init feat_enable_mce_power8(struct dt_cpu_feature *f)
 {
 	cur_cpu_spec->platform = "power8";
-	cur_cpu_spec->flush_tlb = __flush_tlb_power8;
 	cur_cpu_spec->machine_check_early = __machine_check_early_realmode_p8;
 
 	return 1;
@@ -451,7 +424,6 @@ static void init_pmu_power9(void)
 static int __init feat_enable_mce_power9(struct dt_cpu_feature *f)
 {
 	cur_cpu_spec->platform = "power9";
-	cur_cpu_spec->flush_tlb = __flush_tlb_power9;
 	cur_cpu_spec->machine_check_early = __machine_check_early_realmode_p9;
 
 	return 1;
@@ -752,8 +724,6 @@ static void __init cpufeatures_setup_finished(void)
 	system_registers.hfscr = mfspr(SPRN_HFSCR);
 	system_registers.fscr = mfspr(SPRN_FSCR);
 
-	cpufeatures_flush_tlb();
-
 	pr_info("final cpu/mmu features = 0x%016lx 0x%08x\n",
 		cur_cpu_spec->cpu_features, cur_cpu_spec->mmu_features);
 }