powerpc/64s: Convert some cpu_setup() and cpu_restore() functions to C

The only thing keeping the cpu_setup() and cpu_restore() functions
used in the cputable entries for Power7, Power8, Power9 and Power10 in
assembly was cpu_restore() being called before there was a stack in
generic_secondary_smp_init(). Commit ("powerpc/64: Set up a kernel
stack for secondaries before cpu_restore()") means that it is now
possible to use C.

Rewrite the functions in C so they are a little bit easier to read.
This is not changing their functionality.

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
[mpe: Tweak copyright and authorship notes]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201014072837.24539-2-jniethe5@gmail.com

1 files changed, 271 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/cpu_setup_power.c b/arch/powerpc/kernel/cpu_setup_power.c
new file mode 100644
index 000000000000..0c2191ee139e
--- /dev/null
+++ b/arch/powerpc/kernel/cpu_setup_power.c
@@ -0,0 +1,271 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2020, Jordan Niethe, IBM Corporation.
+ *
+ * This file contains low level CPU setup functions.
+ * Originally written in assembly by Benjamin Herrenschmidt & various other
+ * authors.
+ */
+
+#include <asm/reg.h>
+#include <asm/synch.h>
+#include <linux/bitops.h>
+#include <asm/cputable.h>
+#include <asm/cpu_setup_power.h>
+
+/* Disable CPU_FTR_HVMODE and return false if MSR:HV is not set */
+static bool init_hvmode_206(struct cpu_spec *t)
+{
+	u64 msr;
+
+	msr = mfmsr();
+	if (msr & MSR_HV)
+		return true;
+
+	t->cpu_features &= ~(CPU_FTR_HVMODE | CPU_FTR_P9_TM_HV_ASSIST);
+	return false;
+}
+
+static void init_LPCR_ISA300(u64 lpcr, u64 lpes)
+{
+	/* POWER9 has no VRMASD */
+	lpcr |= (lpes << LPCR_LPES_SH) & LPCR_LPES;
+	lpcr |= LPCR_PECE0|LPCR_PECE1|LPCR_PECE2;
+	lpcr |= (4ull << LPCR_DPFD_SH) & LPCR_DPFD;
+	lpcr &= ~LPCR_HDICE;	/* clear HDICE */
+	lpcr |= (4ull << LPCR_VC_SH);
+	mtspr(SPRN_LPCR, lpcr);
+	isync();
+}
+
+/*
+ * Setup a sane LPCR:
+ *   Called with initial LPCR and desired LPES 2-bit value
+ *
+ *   LPES = 0b01 (HSRR0/1 used for 0x500)
+ *   PECE = 0b111
+ *   DPFD = 4
+ *   HDICE = 0
+ *   VC = 0b100 (VPM0=1, VPM1=0, ISL=0)
+ *   VRMASD = 0b10000 (L=1, LP=00)
+ *
+ * Other bits untouched for now
+ */
+static void init_LPCR_ISA206(u64 lpcr, u64 lpes)
+{
+	lpcr |= (0x10ull << LPCR_VRMASD_SH) & LPCR_VRMASD;
+	init_LPCR_ISA300(lpcr, lpes);
+}
+
+static void init_FSCR(void)
+{
+	u64 fscr;
+
+	fscr = mfspr(SPRN_FSCR);
+	fscr |= FSCR_TAR|FSCR_EBB;
+	mtspr(SPRN_FSCR, fscr);
+}
+
+static void init_FSCR_power9(void)
+{
+	u64 fscr;
+
+	fscr = mfspr(SPRN_FSCR);
+	fscr |= FSCR_SCV;
+	mtspr(SPRN_FSCR, fscr);
+	init_FSCR();
+}
+
+static void init_FSCR_power10(void)
+{
+	u64 fscr;
+
+	fscr = mfspr(SPRN_FSCR);
+	fscr |= FSCR_PREFIX;
+	mtspr(SPRN_FSCR, fscr);
+	init_FSCR_power9();
+}
+
+static void init_HFSCR(void)
+{
+	u64 hfscr;
+
+	hfscr = mfspr(SPRN_HFSCR);
+	hfscr |= HFSCR_TAR|HFSCR_TM|HFSCR_BHRB|HFSCR_PM|HFSCR_DSCR|\
+		 HFSCR_VECVSX|HFSCR_FP|HFSCR_EBB|HFSCR_MSGP;
+	mtspr(SPRN_HFSCR, hfscr);
+}
+
+static void init_PMU_HV(void)
+{
+	mtspr(SPRN_MMCRC, 0);
+}
+
+static void init_PMU_HV_ISA207(void)
+{
+	mtspr(SPRN_MMCRH, 0);
+}
+
+static void init_PMU(void)
+{
+	mtspr(SPRN_MMCRA, 0);
+	mtspr(SPRN_MMCR0, 0);
+	mtspr(SPRN_MMCR1, 0);
+	mtspr(SPRN_MMCR2, 0);
+}
+
+static void init_PMU_ISA207(void)
+{
+	mtspr(SPRN_MMCRS, 0);
+}
+
+static void init_PMU_ISA31(void)
+{
+	mtspr(SPRN_MMCR3, 0);
+	mtspr(SPRN_MMCRA, MMCRA_BHRB_DISABLE);
+}
+
+/*
+ * Note that we can be called twice of pseudo-PVRs.
+ * The parameter offset is not used.
+ */
+
+void __setup_cpu_power7(unsigned long offset, struct cpu_spec *t)
+{
+	if (!init_hvmode_206(t))
+		return;
+
+	mtspr(SPRN_LPID, 0);
+	mtspr(SPRN_PCR, PCR_MASK);
+	init_LPCR_ISA206(mfspr(SPRN_LPCR), LPCR_LPES1 >> LPCR_LPES_SH);
+}
+
+void __restore_cpu_power7(void)
+{
+	u64 msr;
+
+	msr = mfmsr();
+	if (!(msr & MSR_HV))
+		return;
+
+	mtspr(SPRN_LPID, 0);
+	mtspr(SPRN_PCR, PCR_MASK);
+	init_LPCR_ISA206(mfspr(SPRN_LPCR), LPCR_LPES1 >> LPCR_LPES_SH);
+}
+
+void __setup_cpu_power8(unsigned long offset, struct cpu_spec *t)
+{
+	init_FSCR();
+	init_PMU();
+	init_PMU_ISA207();
+
+	if (!init_hvmode_206(t))
+		return;
+
+	mtspr(SPRN_LPID, 0);
+	mtspr(SPRN_PCR, PCR_MASK);
+	init_LPCR_ISA206(mfspr(SPRN_LPCR) | LPCR_PECEDH, 0); /* LPES = 0 */
+	init_HFSCR();
+	init_PMU_HV();
+	init_PMU_HV_ISA207();
+}
+
+void __restore_cpu_power8(void)
+{
+	u64 msr;
+
+	init_FSCR();
+	init_PMU();
+	init_PMU_ISA207();
+
+	msr = mfmsr();
+	if (!(msr & MSR_HV))
+		return;
+
+	mtspr(SPRN_LPID, 0);
+	mtspr(SPRN_PCR, PCR_MASK);
+	init_LPCR_ISA206(mfspr(SPRN_LPCR) | LPCR_PECEDH, 0); /* LPES = 0 */
+	init_HFSCR();
+	init_PMU_HV();
+	init_PMU_HV_ISA207();
+}
+
+void __setup_cpu_power9(unsigned long offset, struct cpu_spec *t)
+{
+	init_FSCR_power9();
+	init_PMU();
+
+	if (!init_hvmode_206(t))
+		return;
+
+	mtspr(SPRN_PSSCR, 0);
+	mtspr(SPRN_LPID, 0);
+	mtspr(SPRN_PID, 0);
+	mtspr(SPRN_PCR, PCR_MASK);
+	init_LPCR_ISA300((mfspr(SPRN_LPCR) | LPCR_PECEDH | LPCR_PECE_HVEE |\
+			 LPCR_HVICE | LPCR_HEIC) & ~(LPCR_UPRT | LPCR_HR), 0);
+	init_HFSCR();
+	init_PMU_HV();
+}
+
+void __restore_cpu_power9(void)
+{
+	u64 msr;
+
+	init_FSCR_power9();
+	init_PMU();
+
+	msr = mfmsr();
+	if (!(msr & MSR_HV))
+		return;
+
+	mtspr(SPRN_PSSCR, 0);
+	mtspr(SPRN_LPID, 0);
+	mtspr(SPRN_PID, 0);
+	mtspr(SPRN_PCR, PCR_MASK);
+	init_LPCR_ISA300((mfspr(SPRN_LPCR) | LPCR_PECEDH | LPCR_PECE_HVEE |\
+			 LPCR_HVICE | LPCR_HEIC) & ~(LPCR_UPRT | LPCR_HR), 0);
+	init_HFSCR();
+	init_PMU_HV();
+}
+
+void __setup_cpu_power10(unsigned long offset, struct cpu_spec *t)
+{
+	init_FSCR_power10();
+	init_PMU();
+	init_PMU_ISA31();
+
+	if (!init_hvmode_206(t))
+		return;
+
+	mtspr(SPRN_PSSCR, 0);
+	mtspr(SPRN_LPID, 0);
+	mtspr(SPRN_PID, 0);
+	mtspr(SPRN_PCR, PCR_MASK);
+	init_LPCR_ISA300((mfspr(SPRN_LPCR) | LPCR_PECEDH | LPCR_PECE_HVEE |\
+			 LPCR_HVICE | LPCR_HEIC) & ~(LPCR_UPRT | LPCR_HR), 0);
+	init_HFSCR();
+	init_PMU_HV();
+}
+
+void __restore_cpu_power10(void)
+{
+	u64 msr;
+
+	init_FSCR_power10();
+	init_PMU();
+	init_PMU_ISA31();
+
+	msr = mfmsr();
+	if (!(msr & MSR_HV))
+		return;
+
+	mtspr(SPRN_PSSCR, 0);
+	mtspr(SPRN_LPID, 0);
+	mtspr(SPRN_PID, 0);
+	mtspr(SPRN_PCR, PCR_MASK);
+	init_LPCR_ISA300((mfspr(SPRN_LPCR) | LPCR_PECEDH | LPCR_PECE_HVEE |\
+			 LPCR_HVICE | LPCR_HEIC) & ~(LPCR_UPRT | LPCR_HR), 0);
+	init_HFSCR();
+	init_PMU_HV();
+}