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

Author: npiggin

arch/powerpc/Kconfig

@@ -129,7 +129,7 @@ config PPC
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_MEMBARRIER_CALLBACKS
 	select ARCH_HAS_MEMBARRIER_SYNC_CORE
-	select ARCH_HAS_MEMREMAP_COMPAT_ALIGN	if PPC_BOOK3S_64
+	select ARCH_HAS_MEMREMAP_COMPAT_ALIGN	if PPC_64S_HASH_MMU
 	select ARCH_HAS_MMIOWB			if PPC64
 	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 	select ARCH_HAS_PHYS_TO_DMA

arch/powerpc/include/asm/book3s/64/mmu-hash.h

@@ -523,8 +523,14 @@ void slb_save_contents(struct slb_entry *slb_ptr);
 void slb_dump_contents(struct slb_entry *slb_ptr);
 
 extern void slb_vmalloc_update(void);
-extern void slb_set_size(u16 size);
 void preload_new_slb_context(unsigned long start, unsigned long sp);
+
+#ifdef CONFIG_PPC_64S_HASH_MMU
+void slb_set_size(u16 size);
+#else
+static inline void slb_set_size(u16 size) { }
+#endif
+
 #endif /* __ASSEMBLY__ */
 
 /*

arch/powerpc/include/asm/book3s/64/mmu.h

@@ -105,7 +105,9 @@ typedef struct {
 		 * from EA and new context ids to build the new VAs.
 		 */
 		mm_context_id_t id;
+#ifdef CONFIG_PPC_64S_HASH_MMU
 		mm_context_id_t extended_id[TASK_SIZE_USER64/TASK_CONTEXT_SIZE];
+#endif
 	};
 
 	/* Number of bits in the mm_cpumask */
@@ -117,7 +119,9 @@ typedef struct {
 	/* Number of user space windows opened in process mm_context */
 	atomic_t vas_windows;
 
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	struct hash_mm_context *hash_context;
+#endif
 
 	void __user *vdso;
 	/*
@@ -140,6 +144,7 @@ typedef struct {
 #endif
 } mm_context_t;
 
+#ifdef CONFIG_PPC_64S_HASH_MMU
 static inline u16 mm_ctx_user_psize(mm_context_t *ctx)
 {
 	return ctx->hash_context->user_psize;
@@ -200,8 +205,15 @@ static inline struct subpage_prot_table *mm_ctx_subpage_prot(mm_context_t *ctx)
 extern int mmu_linear_psize;
 extern int mmu_virtual_psize;
 extern int mmu_vmalloc_psize;
-extern int mmu_vmemmap_psize;
 extern int mmu_io_psize;
+#else /* CONFIG_PPC_64S_HASH_MMU */
+#ifdef CONFIG_PPC_64K_PAGES
+#define mmu_virtual_psize MMU_PAGE_64K
+#else
+#define mmu_virtual_psize MMU_PAGE_4K
+#endif
+#endif
+extern int mmu_vmemmap_psize;
 
 /* MMU initialization */
 void mmu_early_init_devtree(void);
@@ -240,8 +252,9 @@ static inline void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 	 * know which translations we will pick. Hence go with hash
 	 * restrictions.
 	 */
-	return hash__setup_initial_memory_limit(first_memblock_base,
-					   first_memblock_size);
+	if (!early_radix_enabled())
+		hash__setup_initial_memory_limit(first_memblock_base,
+						 first_memblock_size);
 }
 
 #ifdef CONFIG_PPC_PSERIES
@@ -262,6 +275,7 @@ static inline void radix_init_pseries(void) { }
 void cleanup_cpu_mmu_context(void);
 #endif
 
+#ifdef CONFIG_PPC_64S_HASH_MMU
 static inline int get_user_context(mm_context_t *ctx, unsigned long ea)
 {
 	int index = ea >> MAX_EA_BITS_PER_CONTEXT;
@@ -281,6 +295,7 @@ static inline unsigned long get_user_vsid(mm_context_t *ctx,
 
 	return get_vsid(context, ea, ssize);
 }
+#endif
 
 #endif /* __ASSEMBLY__ */
 #endif /* _ASM_POWERPC_BOOK3S_64_MMU_H_ */

arch/powerpc/include/asm/book3s/64/tlbflush-hash.h

@@ -112,8 +112,14 @@ static inline void hash__flush_tlb_kernel_range(unsigned long start,
 
 struct mmu_gather;
 extern void hash__tlb_flush(struct mmu_gather *tlb);
+void flush_tlb_pmd_range(struct mm_struct *mm, pmd_t *pmd, unsigned long addr);
+
+#ifdef CONFIG_PPC_64S_HASH_MMU
 /* Private function for use by PCI IO mapping code */
 extern void __flush_hash_table_range(unsigned long start, unsigned long end);
 extern void flush_tlb_pmd_range(struct mm_struct *mm, pmd_t *pmd,
 				unsigned long addr);
+#else
+static inline void __flush_hash_table_range(unsigned long start, unsigned long end) { }
+#endif
 #endif /*  _ASM_POWERPC_BOOK3S_64_TLBFLUSH_HASH_H */

arch/powerpc/include/asm/book3s/pgtable.h

@@ -25,6 +25,7 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 				     unsigned long size, pgprot_t vma_prot);
 #define __HAVE_PHYS_MEM_ACCESS_PROT
 
+#if defined(CONFIG_PPC32) || defined(CONFIG_PPC_64S_HASH_MMU)
 /*
  * This gets called at the end of handling a page fault, when
  * the kernel has put a new PTE into the page table for the process.
@@ -35,6 +36,9 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
  * waiting for the inevitable extra hash-table miss exception.
  */
 void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep);
+#else
+static inline void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) {}
+#endif
 
 #endif /* __ASSEMBLY__ */
 #endif

arch/powerpc/include/asm/mmu_context.h

@@ -75,6 +75,7 @@ extern void hash__reserve_context_id(int id);
 extern void __destroy_context(int context_id);
 static inline void mmu_context_init(void) { }
 
+#ifdef CONFIG_PPC_64S_HASH_MMU
 static inline int alloc_extended_context(struct mm_struct *mm,
 					 unsigned long ea)
 {
@@ -100,6 +101,7 @@ static inline bool need_extra_context(struct mm_struct *mm, unsigned long ea)
 		return true;
 	return false;
 }
+#endif
 
 #else
 extern void switch_mmu_context(struct mm_struct *prev, struct mm_struct *next,

arch/powerpc/include/asm/paca.h

@@ -97,7 +97,9 @@ struct paca_struct {
 					/* this becomes non-zero. */
 	u8 kexec_state;		/* set when kexec down has irqs off */
 #ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	struct slb_shadow *slb_shadow_ptr;
+#endif
 	struct dtl_entry *dispatch_log;
 	struct dtl_entry *dispatch_log_end;
 #endif
@@ -110,6 +112,7 @@ struct paca_struct {
 	/* used for most interrupts/exceptions */
 	u64 exgen[EX_SIZE] __attribute__((aligned(0x80)));
 
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	/* SLB related definitions */
 	u16 vmalloc_sllp;
 	u8 slb_cache_ptr;
@@ -120,6 +123,7 @@ struct paca_struct {
 	u32 slb_used_bitmap;		/* Bitmaps for first 32 SLB entries. */
 	u32 slb_kern_bitmap;
 	u32 slb_cache[SLB_CACHE_ENTRIES];
+#endif
 #endif /* CONFIG_PPC_BOOK3S_64 */
 
 #ifdef CONFIG_PPC_BOOK3E
@@ -149,13 +153,15 @@ struct paca_struct {
 #endif /* CONFIG_PPC_BOOK3E */
 
 #ifdef CONFIG_PPC_BOOK3S
+#ifdef CONFIG_PPC_64S_HASH_MMU
 #ifdef CONFIG_PPC_MM_SLICES
 	unsigned char mm_ctx_low_slices_psize[BITS_PER_LONG / BITS_PER_BYTE];
 	unsigned char mm_ctx_high_slices_psize[SLICE_ARRAY_SIZE];
 #else
 	u16 mm_ctx_user_psize;
 	u16 mm_ctx_sllp;
 #endif
+#endif
 #endif
 
 	/*
@@ -268,9 +274,11 @@ struct paca_struct {
 #endif /* CONFIG_PPC_PSERIES */
 
 #ifdef CONFIG_PPC_BOOK3S_64
+#ifdef CONFIG_PPC_64S_HASH_MMU
 	/* Capture SLB related old contents in MCE handler. */
 	struct slb_entry *mce_faulty_slbs;
 	u16 slb_save_cache_ptr;
+#endif
 #endif /* CONFIG_PPC_BOOK3S_64 */
 #ifdef CONFIG_STACKPROTECTOR
 	unsigned long canary;

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);

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

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