[RFC PATCH v2 13/20] powerpc/64e: Clean up impossible setups

Christophe Leroy christophe.leroy at csgroup.eu
Sat May 18 05:00:07 AEST 2024


All E500 have MMU_FTR_TYPE_FSL_E.

So remove all impossible combinations.

This leads to removing PPC_HTW_IBM and related exceptions.

Signed-off-by: Christophe Leroy <christophe.leroy at csgroup.eu>
---
 arch/powerpc/include/asm/nohash/mmu-e500.h |   1 -
 arch/powerpc/mm/nohash/tlb.c               | 148 ++++------------
 arch/powerpc/mm/nohash/tlb_low_64e.S       | 194 ---------------------
 3 files changed, 36 insertions(+), 307 deletions(-)

diff --git a/arch/powerpc/include/asm/nohash/mmu-e500.h b/arch/powerpc/include/asm/nohash/mmu-e500.h
index 6ddced0415cb..792bfaafd70b 100644
--- a/arch/powerpc/include/asm/nohash/mmu-e500.h
+++ b/arch/powerpc/include/asm/nohash/mmu-e500.h
@@ -303,7 +303,6 @@ extern unsigned long linear_map_top;
 extern int book3e_htw_mode;
 
 #define PPC_HTW_NONE	0
-#define PPC_HTW_IBM	1
 #define PPC_HTW_E6500	2
 
 /*
diff --git a/arch/powerpc/mm/nohash/tlb.c b/arch/powerpc/mm/nohash/tlb.c
index d16f1ef7516c..1caccbf4c138 100644
--- a/arch/powerpc/mm/nohash/tlb.c
+++ b/arch/powerpc/mm/nohash/tlb.c
@@ -400,13 +400,11 @@ void tlb_flush_pgtable(struct mmu_gather *tlb, unsigned long address)
 static void __init setup_page_sizes(void)
 {
 	unsigned int tlb0cfg;
-	unsigned int tlb0ps;
 	unsigned int eptcfg;
-	int i, psize;
+	int psize;
 	unsigned int mmucfg = mfspr(SPRN_MMUCFG);
-	int fsl_mmu = mmu_has_feature(MMU_FTR_TYPE_FSL_E);
 
-	if (fsl_mmu && (mmucfg & MMUCFG_MAVN) == MMUCFG_MAVN_V1) {
+	if ((mmucfg & MMUCFG_MAVN) == MMUCFG_MAVN_V1) {
 		unsigned int tlb1cfg = mfspr(SPRN_TLB1CFG);
 		unsigned int min_pg, max_pg;
 
@@ -429,11 +427,7 @@ static void __init setup_page_sizes(void)
 			if ((shift >= min_pg) && (shift <= max_pg))
 				def->flags |= MMU_PAGE_SIZE_DIRECT;
 		}
-
-		goto out;
-	}
-
-	if (fsl_mmu && (mmucfg & MMUCFG_MAVN) == MMUCFG_MAVN_V2) {
+	} else if ((mmucfg & MMUCFG_MAVN) == MMUCFG_MAVN_V2) {
 		u32 tlb1cfg, tlb1ps;
 
 		tlb0cfg = mfspr(SPRN_TLB0CFG);
@@ -465,54 +459,8 @@ static void __init setup_page_sizes(void)
 					def->flags |= MMU_PAGE_SIZE_INDIRECT;
 			}
 		}
-
-		goto out;
-	}
-
-	tlb0cfg = mfspr(SPRN_TLB0CFG);
-	tlb0ps = mfspr(SPRN_TLB0PS);
-	eptcfg = mfspr(SPRN_EPTCFG);
-
-	/* Look for supported direct sizes */
-	for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
-		struct mmu_psize_def *def = &mmu_psize_defs[psize];
-
-		if (tlb0ps & (1U << (def->shift - 10)))
-			def->flags |= MMU_PAGE_SIZE_DIRECT;
-	}
-
-	/* Indirect page sizes supported ? */
-	if ((tlb0cfg & TLBnCFG_IND) == 0 ||
-	    (tlb0cfg & TLBnCFG_PT) == 0)
-		goto out;
-
-	book3e_htw_mode = PPC_HTW_IBM;
-
-	/* Now, we only deal with one IND page size for each
-	 * direct size. Hopefully all implementations today are
-	 * unambiguous, but we might want to be careful in the
-	 * future.
-	 */
-	for (i = 0; i < 3; i++) {
-		unsigned int ps, sps;
-
-		sps = eptcfg & 0x1f;
-		eptcfg >>= 5;
-		ps = eptcfg & 0x1f;
-		eptcfg >>= 5;
-		if (!ps || !sps)
-			continue;
-		for (psize = 0; psize < MMU_PAGE_COUNT; psize++) {
-			struct mmu_psize_def *def = &mmu_psize_defs[psize];
-
-			if (ps == (def->shift - 10))
-				def->flags |= MMU_PAGE_SIZE_INDIRECT;
-			if (sps == (def->shift - 10))
-				def->ind = ps + 10;
-		}
 	}
 
-out:
 	/* Cleanup array and print summary */
 	pr_info("MMU: Supported page sizes\n");
 	for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
@@ -540,10 +488,6 @@ static void __init setup_mmu_htw(void)
 	 */
 
 	switch (book3e_htw_mode) {
-	case PPC_HTW_IBM:
-		patch_exception(0x1c0, exc_data_tlb_miss_htw_book3e);
-		patch_exception(0x1e0, exc_instruction_tlb_miss_htw_book3e);
-		break;
 	case PPC_HTW_E6500:
 		extlb_level_exc = EX_TLB_SIZE;
 		patch_exception(0x1c0, exc_data_tlb_miss_e6500_book3e);
@@ -560,6 +504,8 @@ static void __init setup_mmu_htw(void)
 static void early_init_this_mmu(void)
 {
 	unsigned int mas4;
+	unsigned int num_cams;
+	bool map = true;
 
 	/* Set MAS4 based on page table setting */
 
@@ -572,12 +518,6 @@ static void early_init_this_mmu(void)
 		mmu_pte_psize = MMU_PAGE_2M;
 		break;
 
-	case PPC_HTW_IBM:
-		mas4 |= MAS4_INDD;
-		mas4 |=	BOOK3E_PAGESZ_1M << MAS4_TSIZED_SHIFT;
-		mmu_pte_psize = MMU_PAGE_1M;
-		break;
-
 	case PPC_HTW_NONE:
 		mas4 |=	BOOK3E_PAGESZ_4K << MAS4_TSIZED_SHIFT;
 		mmu_pte_psize = mmu_virtual_psize;
@@ -585,26 +525,21 @@ static void early_init_this_mmu(void)
 	}
 	mtspr(SPRN_MAS4, mas4);
 
-	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {
-		unsigned int num_cams;
-		bool map = true;
-
-		/* use a quarter of the TLBCAM for bolted linear map */
-		num_cams = (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) / 4;
+	/* use a quarter of the TLBCAM for bolted linear map */
+	num_cams = (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) / 4;
 
-		/*
-		 * Only do the mapping once per core, or else the
-		 * transient mapping would cause problems.
-		 */
+	/*
+	 * Only do the mapping once per core, or else the
+	 * transient mapping would cause problems.
+	 */
 #ifdef CONFIG_SMP
-		if (hweight32(get_tensr()) > 1)
-			map = false;
+	if (hweight32(get_tensr()) > 1)
+		map = false;
 #endif
 
-		if (map)
-			linear_map_top = map_mem_in_cams(linear_map_top,
-							 num_cams, false, true);
-	}
+	if (map)
+		linear_map_top = map_mem_in_cams(linear_map_top,
+						 num_cams, false, true);
 
 	/* A sync won't hurt us after mucking around with
 	 * the MMU configuration
@@ -620,10 +555,7 @@ static void __init early_init_mmu_global(void)
 	 *
 	 * Freescale booke only supports 4K pages in TLB0, so use that.
 	 */
-	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E))
-		mmu_vmemmap_psize = MMU_PAGE_4K;
-	else
-		mmu_vmemmap_psize = MMU_PAGE_16M;
+	mmu_vmemmap_psize = MMU_PAGE_4K;
 
 	/* XXX This code only checks for TLB 0 capabilities and doesn't
 	 *     check what page size combos are supported by the HW. It
@@ -636,13 +568,10 @@ static void __init early_init_mmu_global(void)
 	/* Look for HW tablewalk support */
 	setup_mmu_htw();
 
-	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {
-		if (book3e_htw_mode == PPC_HTW_NONE) {
-			extlb_level_exc = EX_TLB_SIZE;
-			patch_exception(0x1c0, exc_data_tlb_miss_bolted_book3e);
-			patch_exception(0x1e0,
-				exc_instruction_tlb_miss_bolted_book3e);
-		}
+	if (book3e_htw_mode == PPC_HTW_NONE) {
+		extlb_level_exc = EX_TLB_SIZE;
+		patch_exception(0x1c0, exc_data_tlb_miss_bolted_book3e);
+		patch_exception(0x1e0, exc_instruction_tlb_miss_bolted_book3e);
 	}
 
 	/* Set the global containing the top of the linear mapping
@@ -655,16 +584,14 @@ static void __init early_init_mmu_global(void)
 
 static void __init early_mmu_set_memory_limit(void)
 {
-	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {
-		/*
-		 * Limit memory so we dont have linear faults.
-		 * Unlike memblock_set_current_limit, which limits
-		 * memory available during early boot, this permanently
-		 * reduces the memory available to Linux.  We need to
-		 * do this because highmem is not supported on 64-bit.
-		 */
-		memblock_enforce_memory_limit(linear_map_top);
-	}
+	/*
+	 * Limit memory so we dont have linear faults.
+	 * Unlike memblock_set_current_limit, which limits
+	 * memory available during early boot, this permanently
+	 * reduces the memory available to Linux.  We need to
+	 * do this because highmem is not supported on 64-bit.
+	 */
+	memblock_enforce_memory_limit(linear_map_top);
 
 	memblock_set_current_limit(linear_map_top);
 }
@@ -702,19 +629,16 @@ void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 	 * We crop it to the size of the first MEMBLOCK to
 	 * avoid going over total available memory just in case...
 	 */
-	if (early_mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {
-		unsigned long linear_sz;
-		unsigned int num_cams;
+	unsigned long linear_sz;
+	unsigned int num_cams;
 
-		/* use a quarter of the TLBCAM for bolted linear map */
-		num_cams = (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) / 4;
+	/* use a quarter of the TLBCAM for bolted linear map */
+	num_cams = (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) / 4;
 
-		linear_sz = map_mem_in_cams(first_memblock_size, num_cams,
-					    true, true);
+	linear_sz = map_mem_in_cams(first_memblock_size, num_cams,
+				    true, true);
 
-		ppc64_rma_size = min_t(u64, linear_sz, 0x40000000);
-	} else
-		ppc64_rma_size = min_t(u64, first_memblock_size, 0x40000000);
+	ppc64_rma_size = min_t(u64, linear_sz, 0x40000000);
 
 	/* Finally limit subsequent allocations */
 	memblock_set_current_limit(first_memblock_base + ppc64_rma_size);
diff --git a/arch/powerpc/mm/nohash/tlb_low_64e.S b/arch/powerpc/mm/nohash/tlb_low_64e.S
index 7e0b8fe1c279..93ecb8ec82b0 100644
--- a/arch/powerpc/mm/nohash/tlb_low_64e.S
+++ b/arch/powerpc/mm/nohash/tlb_low_64e.S
@@ -894,200 +894,6 @@ virt_page_table_tlb_miss_whacko_fault:
 	b	exc_data_storage_book3e
 
 
-/**************************************************************
- *                                                            *
- * TLB miss handling for Book3E with hw page table support    *
- *                                                            *
- **************************************************************/
-
-
-/* Data TLB miss */
-	START_EXCEPTION(data_tlb_miss_htw)
-	TLB_MISS_PROLOG
-
-	/* Now we handle the fault proper. We only save DEAR in normal
-	 * fault case since that's the only interesting values here.
-	 * We could probably also optimize by not saving SRR0/1 in the
-	 * linear mapping case but I'll leave that for later
-	 */
-	mfspr	r14,SPRN_ESR
-	mfspr	r16,SPRN_DEAR		/* get faulting address */
-	srdi	r11,r16,44		/* get region */
-	xoris	r11,r11,0xc
-	cmpldi	cr0,r11,0		/* linear mapping ? */
-	beq	tlb_load_linear		/* yes -> go to linear map load */
-	cmpldi	cr1,r11,1		/* vmalloc mapping ? */
-
-	/* We do the user/kernel test for the PID here along with the RW test
-	 */
-	srdi.	r11,r16,60		/* Check for user region */
-	ld	r15,PACAPGD(r13)	/* Load user pgdir */
-	beq	htw_tlb_miss
-
-	/* XXX replace the RMW cycles with immediate loads + writes */
-1:	mfspr	r10,SPRN_MAS1
-	rlwinm	r10,r10,0,16,1		/* Clear TID */
-	mtspr	SPRN_MAS1,r10
-	ld	r15,PACA_KERNELPGD(r13)	/* Load kernel pgdir */
-	beq+	cr1,htw_tlb_miss
-
-	/* We got a crappy address, just fault with whatever DEAR and ESR
-	 * are here
-	 */
-	TLB_MISS_EPILOG_ERROR
-	b	exc_data_storage_book3e
-
-/* Instruction TLB miss */
-	START_EXCEPTION(instruction_tlb_miss_htw)
-	TLB_MISS_PROLOG
-
-	/* If we take a recursive fault, the second level handler may need
-	 * to know whether we are handling a data or instruction fault in
-	 * order to get to the right store fault handler. We provide that
-	 * info by keeping a crazy value for ESR in r14
-	 */
-	li	r14,-1	/* store to exception frame is done later */
-
-	/* Now we handle the fault proper. We only save DEAR in the non
-	 * linear mapping case since we know the linear mapping case will
-	 * not re-enter. We could indeed optimize and also not save SRR0/1
-	 * in the linear mapping case but I'll leave that for later
-	 *
-	 * Faulting address is SRR0 which is already in r16
-	 */
-	srdi	r11,r16,44		/* get region */
-	xoris	r11,r11,0xc
-	cmpldi	cr0,r11,0		/* linear mapping ? */
-	beq	tlb_load_linear		/* yes -> go to linear map load */
-	cmpldi	cr1,r11,1		/* vmalloc mapping ? */
-
-	/* We do the user/kernel test for the PID here along with the RW test
-	 */
-	srdi.	r11,r16,60		/* Check for user region */
-	ld	r15,PACAPGD(r13)		/* Load user pgdir */
-	beq	htw_tlb_miss
-
-	/* XXX replace the RMW cycles with immediate loads + writes */
-1:	mfspr	r10,SPRN_MAS1
-	rlwinm	r10,r10,0,16,1			/* Clear TID */
-	mtspr	SPRN_MAS1,r10
-	ld	r15,PACA_KERNELPGD(r13)		/* Load kernel pgdir */
-	beq+	htw_tlb_miss
-
-	/* We got a crappy address, just fault */
-	TLB_MISS_EPILOG_ERROR
-	b	exc_instruction_storage_book3e
-
-
-/*
- * This is the guts of the second-level TLB miss handler for direct
- * misses. We are entered with:
- *
- * r16 = virtual page table faulting address
- * r15 = PGD pointer
- * r14 = ESR
- * r13 = PACA
- * r12 = TLB exception frame in PACA
- * r11 = crap (free to use)
- * r10 = crap (free to use)
- *
- * It can be re-entered by the linear mapping miss handler. However, to
- * avoid too much complication, it will save/restore things for us
- */
-htw_tlb_miss:
-#ifdef CONFIG_PPC_KUAP
-	mfspr	r10,SPRN_MAS1
-	rlwinm.	r10,r10,0,0x3fff0000
-	beq-	htw_tlb_miss_fault /* KUAP fault */
-#endif
-	/* Search if we already have a TLB entry for that virtual address, and
-	 * if we do, bail out.
-	 *
-	 * MAS1:IND should be already set based on MAS4
-	 */
-	PPC_TLBSRX_DOT(0,R16)
-	beq	htw_tlb_miss_done
-
-	/* Now, we need to walk the page tables. First check if we are in
-	 * range.
-	 */
-	rldicl.	r10,r16,64-PGTABLE_EADDR_SIZE,PGTABLE_EADDR_SIZE+4
-	bne-	htw_tlb_miss_fault
-
-	/* Get the PGD pointer */
-	cmpldi	cr0,r15,0
-	beq-	htw_tlb_miss_fault
-
-	/* Get to PGD entry */
-	rldicl	r11,r16,64-(PGDIR_SHIFT-3),64-PGD_INDEX_SIZE-3
-	clrrdi	r10,r11,3
-	ldx	r15,r10,r15
-	cmpdi	cr0,r15,0
-	bge	htw_tlb_miss_fault
-
-	/* Get to PUD entry */
-	rldicl	r11,r16,64-(PUD_SHIFT-3),64-PUD_INDEX_SIZE-3
-	clrrdi	r10,r11,3
-	ldx	r15,r10,r15
-	cmpdi	cr0,r15,0
-	bge	htw_tlb_miss_fault
-
-	/* Get to PMD entry */
-	rldicl	r11,r16,64-(PMD_SHIFT-3),64-PMD_INDEX_SIZE-3
-	clrrdi	r10,r11,3
-	ldx	r15,r10,r15
-	cmpdi	cr0,r15,0
-	bge	htw_tlb_miss_fault
-
-	/* Ok, we're all right, we can now create an indirect entry for
-	 * a 1M or 256M page.
-	 *
-	 * The last trick is now that because we use "half" pages for
-	 * the HTW (1M IND is 2K and 256M IND is 32K) we need to account
-	 * for an added LSB bit to the RPN. For 64K pages, there is no
-	 * problem as we already use 32K arrays (half PTE pages), but for
-	 * 4K page we need to extract a bit from the virtual address and
-	 * insert it into the "PA52" bit of the RPN.
-	 */
-	rlwimi	r15,r16,32-9,20,20
-	/* Now we build the MAS:
-	 *
-	 * MAS 0   :	Fully setup with defaults in MAS4 and TLBnCFG
-	 * MAS 1   :	Almost fully setup
-	 *               - PID already updated by caller if necessary
-	 *               - TSIZE for now is base ind page size always
-	 * MAS 2   :	Use defaults
-	 * MAS 3+7 :	Needs to be done
-	 */
-	ori	r10,r15,(BOOK3E_PAGESZ_4K << MAS3_SPSIZE_SHIFT)
-
-	srdi	r16,r10,32
-	mtspr	SPRN_MAS3,r10
-	mtspr	SPRN_MAS7,r16
-
-	tlbwe
-
-htw_tlb_miss_done:
-	/* We don't bother with restoring DEAR or ESR since we know we are
-	 * level 0 and just going back to userland. They are only needed
-	 * if you are going to take an access fault
-	 */
-	TLB_MISS_EPILOG_SUCCESS
-	rfi
-
-htw_tlb_miss_fault:
-	/* We need to check if it was an instruction miss. We know this
-	 * though because r14 would contain -1
-	 */
-	cmpdi	cr0,r14,-1
-	beq	1f
-	mtspr	SPRN_DEAR,r16
-	mtspr	SPRN_ESR,r14
-	TLB_MISS_EPILOG_ERROR
-	b	exc_data_storage_book3e
-1:	TLB_MISS_EPILOG_ERROR
-	b	exc_instruction_storage_book3e
-
 /*
  * This is the guts of "any" level TLB miss handler for kernel linear
  * mapping misses. We are entered with:
-- 
2.44.0



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