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

Christophe Leroy
2024-05-17T19:01:18Z

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@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