powerpc/64s: Move hash MMU support code under CONFIG_PPC_64S_HASH_MMU

Compiling out hash support code when CONFIG_PPC_64S_HASH_MMU=n saves
128kB kernel image size (90kB text) on powernv_defconfig minus KVM,
350kB on pseries_defconfig minus KVM, 40kB on a tiny config.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Fixup defined(ARCH_HAS_MEMREMAP_COMPAT_ALIGN), which needs CONFIG.
      Fix radix_enabled() use in setup_initial_memory_limit(). Add some
      stubs to reduce number of ifdefs.]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211201144153.2456614-18-npiggin@gmail.com

9 files changed, 44 insertions, 25 deletions

diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index cc05522f50bf..b823f484c640 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -218,10 +218,12 @@ int main(void)
 	OFFSET(PACA_EXGEN, paca_struct, exgen);
 	OFFSET(PACA_EXMC, paca_struct, exmc);
 	OFFSET(PACA_EXNMI, paca_struct, exnmi);
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	OFFSET(PACA_SLBSHADOWPTR, paca_struct, slb_shadow_ptr);
 	OFFSET(SLBSHADOW_STACKVSID, slb_shadow, save_area[SLB_NUM_BOLTED - 1].vsid);
 	OFFSET(SLBSHADOW_STACKESID, slb_shadow, save_area[SLB_NUM_BOLTED - 1].esid);
 	OFFSET(SLBSHADOW_SAVEAREA, slb_shadow, save_area);
+#endif
 	OFFSET(LPPACA_PMCINUSE, lppaca, pmcregs_in_use);
 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
 	OFFSET(PACA_PMCINUSE, paca_struct, pmcregs_in_use);
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 70cff7b49e17..9581906b5ee9 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -180,7 +180,7 @@ _GLOBAL(_switch)
 #endif
 
 	ld	r8,KSP(r4)	/* new stack pointer */
-#ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 BEGIN_MMU_FTR_SECTION
 	b	2f
 END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_RADIX)
@@ -232,7 +232,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)
 	slbmte	r7,r0
 	isync
 2:
-#endif /* CONFIG_PPC_BOOK3S_64 */
+#endif /* CONFIG_PPC_64S_HASH_MMU */
 
 	clrrdi	r7, r8, THREAD_SHIFT	/* base of new stack */
 	/* Note: this uses SWITCH_FRAME_SIZE rather than INT_FRAME_SIZE
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 2acd7e66694e..a30f563bc7a8 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -1367,11 +1367,15 @@ EXC_COMMON_BEGIN(data_access_common)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	andis.	r0,r4,DSISR_DABRMATCH@h
 	bne-	1f
+#ifdef CONFIG_PPC_64S_HASH_MMU
 BEGIN_MMU_FTR_SECTION
 	bl	do_hash_fault
 MMU_FTR_SECTION_ELSE
 	bl	do_page_fault
 ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)
+#else
+	bl	do_page_fault
+#endif
 	b	interrupt_return_srr
 
 1:	bl	do_break
@@ -1414,6 +1418,7 @@ EXC_VIRT_BEGIN(data_access_slb, 0x4380, 0x80)
 EXC_VIRT_END(data_access_slb, 0x4380, 0x80)
 EXC_COMMON_BEGIN(data_access_slb_common)
 	GEN_COMMON data_access_slb
+#ifdef CONFIG_PPC_64S_HASH_MMU
 BEGIN_MMU_FTR_SECTION
 	/* HPT case, do SLB fault */
 	addi	r3,r1,STACK_FRAME_OVERHEAD
@@ -1426,6 +1431,9 @@ MMU_FTR_SECTION_ELSE
 	/* Radix case, access is outside page table range */
 	li	r3,-EFAULT
 ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)
+#else
+	li	r3,-EFAULT
+#endif
 	std	r3,RESULT(r1)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	do_bad_segment_interrupt
@@ -1460,11 +1468,15 @@ EXC_VIRT_END(instruction_access, 0x4400, 0x80)
 EXC_COMMON_BEGIN(instruction_access_common)
 	GEN_COMMON instruction_access
 	addi	r3,r1,STACK_FRAME_OVERHEAD
+#ifdef CONFIG_PPC_64S_HASH_MMU
 BEGIN_MMU_FTR_SECTION
 	bl	do_hash_fault
 MMU_FTR_SECTION_ELSE
 	bl	do_page_fault
 ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)
+#else
+	bl	do_page_fault
+#endif
 	b	interrupt_return_srr
 
 
@@ -1494,6 +1506,7 @@ EXC_VIRT_BEGIN(instruction_access_slb, 0x4480, 0x80)
 EXC_VIRT_END(instruction_access_slb, 0x4480, 0x80)
 EXC_COMMON_BEGIN(instruction_access_slb_common)
 	GEN_COMMON instruction_access_slb
+#ifdef CONFIG_PPC_64S_HASH_MMU
 BEGIN_MMU_FTR_SECTION
 	/* HPT case, do SLB fault */
 	addi	r3,r1,STACK_FRAME_OVERHEAD
@@ -1506,6 +1519,9 @@ MMU_FTR_SECTION_ELSE
 	/* Radix case, access is outside page table range */
 	li	r3,-EFAULT
 ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)
+#else
+	li	r3,-EFAULT
+#endif
 	std	r3,RESULT(r1)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	do_bad_segment_interrupt
diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
index fd829f7f25a4..2503dd4713b9 100644
--- a/arch/powerpc/kernel/mce.c
+++ b/arch/powerpc/kernel/mce.c
@@ -586,7 +586,7 @@ void machine_check_print_event_info(struct machine_check_event *evt,
 		mc_error_class[evt->error_class] : "Unknown";
 	printk("%sMCE: CPU%d: %s\n", level, evt->cpu, subtype);
 
-#ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	/* Display faulty slb contents for SLB errors. */
 	if (evt->error_type == MCE_ERROR_TYPE_SLB && !in_guest)
 		slb_dump_contents(local_paca->mce_faulty_slbs);
diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c
index cf5263b648fc..a48ff18d6d65 100644
--- a/arch/powerpc/kernel/mce_power.c
+++ b/arch/powerpc/kernel/mce_power.c
@@ -77,7 +77,7 @@ static bool mce_in_guest(void)
 }
 
 /* flush SLBs and reload */
-#ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 void flush_and_reload_slb(void)
 {
 	if (early_radix_enabled())
@@ -99,7 +99,7 @@ void flush_and_reload_slb(void)
 
 void flush_erat(void)
 {
-#ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	if (!early_cpu_has_feature(CPU_FTR_ARCH_300)) {
 		flush_and_reload_slb();
 		return;
@@ -114,7 +114,7 @@ void flush_erat(void)
 
 static int mce_flush(int what)
 {
-#ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	if (what == MCE_FLUSH_SLB) {
 		flush_and_reload_slb();
 		return 1;
@@ -499,8 +499,10 @@ static int mce_handle_ierror(struct pt_regs *regs, unsigned long srr1,
 			/* attempt to correct the error */
 			switch (table[i].error_type) {
 			case MCE_ERROR_TYPE_SLB:
+#ifdef CONFIG_PPC_64S_HASH_MMU
 				if (local_paca->in_mce == 1)
 					slb_save_contents(local_paca->mce_faulty_slbs);
+#endif
 				handled = mce_flush(MCE_FLUSH_SLB);
 				break;
 			case MCE_ERROR_TYPE_ERAT:
@@ -588,8 +590,10 @@ static int mce_handle_derror(struct pt_regs *regs,
 			/* attempt to correct the error */
 			switch (table[i].error_type) {
 			case MCE_ERROR_TYPE_SLB:
+#ifdef CONFIG_PPC_64S_HASH_MMU
 				if (local_paca->in_mce == 1)
 					slb_save_contents(local_paca->mce_faulty_slbs);
+#endif
 				if (mce_flush(MCE_FLUSH_SLB))
 					handled = 1;
 				break;
diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index 4208b4044d12..39da688a9455 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -139,8 +139,7 @@ static struct lppaca * __init new_lppaca(int cpu, unsigned long limit)
 }
 #endif /* CONFIG_PPC_PSERIES */
 
-#ifdef CONFIG_PPC_BOOK3S_64
-
+#ifdef CONFIG_PPC_64S_HASH_MMU
 /*
  * 3 persistent SLBs are allocated here.  The buffer will be zero
  * initially, hence will all be invaild until we actually write them.
@@ -169,8 +168,7 @@ static struct slb_shadow * __init new_slb_shadow(int cpu, unsigned long limit)
 
 	return s;
 }
-
-#endif /* CONFIG_PPC_BOOK3S_64 */
+#endif /* CONFIG_PPC_64S_HASH_MMU */
 
 #ifdef CONFIG_PPC_PSERIES
 /**
@@ -226,7 +224,7 @@ void __init initialise_paca(struct paca_struct *new_paca, int cpu)
 	new_paca->kexec_state = KEXEC_STATE_NONE;
 	new_paca->__current = &init_task;
 	new_paca->data_offset = 0xfeeeeeeeeeeeeeeeULL;
-#ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	new_paca->slb_shadow_ptr = NULL;
 #endif
 
@@ -307,7 +305,7 @@ void __init allocate_paca(int cpu)
 #ifdef CONFIG_PPC_PSERIES
 	paca->lppaca_ptr = new_lppaca(cpu, limit);
 #endif
-#ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	paca->slb_shadow_ptr = new_slb_shadow(cpu, limit);
 #endif
 #ifdef CONFIG_PPC_PSERIES
@@ -328,7 +326,7 @@ void __init free_unused_pacas(void)
 	paca_nr_cpu_ids = nr_cpu_ids;
 	paca_ptrs_size = new_ptrs_size;
 
-#ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	if (early_radix_enabled()) {
 		/* Ugly fixup, see new_slb_shadow() */
 		memblock_phys_free(__pa(paca_ptrs[boot_cpuid]->slb_shadow_ptr),
@@ -341,9 +339,9 @@ void __init free_unused_pacas(void)
 			paca_ptrs_size + paca_struct_size, nr_cpu_ids);
 }
 
+#ifdef CONFIG_PPC_64S_HASH_MMU
 void copy_mm_to_paca(struct mm_struct *mm)
 {
-#ifdef CONFIG_PPC_BOOK3S
 	mm_context_t *context = &mm->context;
 
 #ifdef CONFIG_PPC_MM_SLICES
@@ -356,7 +354,5 @@ void copy_mm_to_paca(struct mm_struct *mm)
 	get_paca()->mm_ctx_user_psize = context->user_psize;
 	get_paca()->mm_ctx_sllp = context->sllp;
 #endif
-#else /* !CONFIG_PPC_BOOK3S */
-	return;
-#endif
 }
+#endif /* CONFIG_PPC_64S_HASH_MMU */
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 5d2333d2a283..a64cfbb85ca2 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1240,7 +1240,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
 {
 	struct thread_struct *new_thread, *old_thread;
 	struct task_struct *last;
-#ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	struct ppc64_tlb_batch *batch;
 #endif
 
@@ -1249,7 +1249,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
 
 	WARN_ON(!irqs_disabled());
 
-#ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	batch = this_cpu_ptr(&ppc64_tlb_batch);
 	if (batch->active) {
 		current_thread_info()->local_flags |= _TLF_LAZY_MMU;
@@ -1328,6 +1328,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
 	 */
 
 #ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	/*
 	 * This applies to a process that was context switched while inside
 	 * arch_enter_lazy_mmu_mode(), to re-activate the batch that was
@@ -1339,6 +1340,7 @@ struct task_struct *__switch_to(struct task_struct *prev,
 		batch = this_cpu_ptr(&ppc64_tlb_batch);
 		batch->active = 1;
 	}
+#endif
 
 	/*
 	 * Math facilities are masked out of the child MSR in copy_thread.
@@ -1689,7 +1691,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 
 static void setup_ksp_vsid(struct task_struct *p, unsigned long sp)
 {
-#ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	unsigned long sp_vsid;
 	unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 
@@ -2333,10 +2335,9 @@ unsigned long arch_randomize_brk(struct mm_struct *mm)
 	 * the heap, we can put it above 1TB so it is backed by a 1TB
 	 * segment. Otherwise the heap will be in the bottom 1TB
 	 * which always uses 256MB segments and this may result in a
-	 * performance penalty. We don't need to worry about radix. For
-	 * radix, mmu_highuser_ssize remains unchanged from 256MB.
+	 * performance penalty.
 	 */
-	if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
+	if (!radix_enabled() && !is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
 		base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
 #endif
 
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 2e67588f6f6e..75678ff04dd7 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -231,7 +231,7 @@ static void __init check_cpu_pa_features(unsigned long node)
 		      ibm_pa_features, ARRAY_SIZE(ibm_pa_features));
 }
 
-#ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 static void __init init_mmu_slb_size(unsigned long node)
 {
 	const __be32 *slb_size_ptr;
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 9a493796ce66..703a2e6ab08d 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -886,7 +886,7 @@ void __init setup_per_cpu_areas(void)
 		atom_size = SZ_1M;
 	} else if (radix_enabled()) {
 		atom_size = PAGE_SIZE;
-	} else {
+	} else if (IS_ENABLED(CONFIG_PPC_64S_HASH_MMU)) {
 		/*
 		 * Linear mapping is one of 4K, 1M and 16M.  For 4K, no need
 		 * to group units.  For larger mappings, use 1M atom which