[Skiboot] [PATCH] asm/head.S: set POWER9 radix HID bit at entry

[Nicholas Piggin]

When running in virtual memory mode, the radix MMU hid bit should not
be changed, so set this in the initial boot SPR setup.

As a side effect, fast reboot also has HID0:RADIX bit set by the
shared spr init, so no need for an explicit call.

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 asm/head.S    |  3 +++
 core/cpu.c    | 18 ++----------------
 core/init.c   |  3 ---
 include/cpu.h |  1 -
 4 files changed, 5 insertions(+), 20 deletions(-)

diff --git a/asm/head.S b/asm/head.S
index 0ed1acddd..916b22c51 100644
--- a/asm/head.S
+++ b/asm/head.S
@@ -766,9 +766,12 @@ init_shared_sprs:
 	mtspr	SPR_TSCR, %r3
 	/* HID0: Clear bit 5 (enable core recovery)
 	 *       Clear bit 4 (HILE)
+	 *       Set bit 8 (radix)
 	 */
 	mfspr	%r3,SPR_HID0
 	li	%r0,1
+	sldi	%r4,%r0,(63-8)
+	or	%r3,%r3,%r4
 	sldi	%r4,%r0,(63-5)
 	sldi	%r5,%r0,(63-4)
 	or	%r0,%r4,%r5
diff --git a/core/cpu.c b/core/cpu.c
index d9d471337..62c020174 100644
--- a/core/cpu.c
+++ b/core/cpu.c
@@ -1433,20 +1433,6 @@ static int64_t cpu_change_all_hid0(struct hid0_change_req *req)
 	return OPAL_SUCCESS;
 }
 
-void cpu_set_radix_mode(void)
-{
-	struct hid0_change_req req;
-
-	if (!radix_supported)
-		return;
-
-	req.clr_bits = 0;
-	req.set_bits = SPR_HID0_POWER9_RADIX;
-	cleanup_global_tlb();
-	current_radix_mode = true;
-	cpu_change_all_hid0(&req);
-}
-
 static void cpu_cleanup_one(void *param __unused)
 {
 	mtspr(SPR_AMR, 0);
@@ -1488,8 +1474,8 @@ void cpu_fast_reboot_complete(void)
 	/* Fast reboot will have cleared HID0:HILE */
 	current_hile_mode = false;
 
-	/* On P9, restore radix mode */
-	cpu_set_radix_mode();
+	/* and set HID0:RADIX */
+	current_radix_mode = true;
 }
 
 static int64_t opal_reinit_cpus(uint64_t flags)
diff --git a/core/init.c b/core/init.c
index eeee2d9e9..0fe6c1682 100644
--- a/core/init.c
+++ b/core/init.c
@@ -1282,9 +1282,6 @@ void __noreturn __nomcount main_cpu_entry(const void *fdt)
 
 	prd_register_reserved_memory();
 
-	/* On P9, switch to radix mode by default */
-	cpu_set_radix_mode();
-
 	checksum_romem();
 
 	load_and_boot_kernel(false);
diff --git a/include/cpu.h b/include/cpu.h
index 39071a191..011b12bb9 100644
--- a/include/cpu.h
+++ b/include/cpu.h
@@ -313,7 +313,6 @@ extern unsigned long __attrconst cpu_emergency_stack_top(unsigned int pir);
 extern void cpu_idle_job(void);
 extern void cpu_idle_delay(unsigned long delay);
 
-extern void cpu_set_radix_mode(void);
 extern void cpu_fast_reboot_complete(void);
 
 int dctl_set_special_wakeup(struct cpu_thread *t);
-- 
2.20.1