Re: [PATCH RFC v1 4/6] swiotlb: enable 64-bit swiotlb

[kernel test robot <lkp@intel.com>]

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Hi Dongli,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on powerpc/next]
[also build test WARNING on linus/master v5.11-rc6 next-20210125]
[cannot apply to swiotlb/linux-next xen-tip/linux-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Dongli-Zhang/swiotlb-64-bit-DMA-buffer/20210204-074426
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc64-randconfig-r036-20210202 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 275c6af7d7f1ed63a03d05b4484413e447133269)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install powerpc64 cross compiling tool for clang build
        # apt-get install binutils-powerpc64-linux-gnu
        # https://github.com/0day-ci/linux/commit/bb094f75bbb66bf693fc13a9990702b3a88ae93f
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Dongli-Zhang/swiotlb-64-bit-DMA-buffer/20210204-074426
        git checkout bb094f75bbb66bf693fc13a9990702b3a88ae93f
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> kernel/dma/swiotlb.c:524:33: warning: result of comparison of constant 18446744073709551615 with expression of type 'unsigned long' is always false [-Wtautological-constant-out-of-range-compare]
           if (swiotlb_nr > 1 && dma_mask == DMA_BIT_MASK(64))
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:56:47: note: expanded from macro 'if'
   #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
                              ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:58:86: note: expanded from macro '__trace_if_var'
   #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
                                                                       ~~~~~~~~~~~~~~~~~^~~~~
   include/linux/compiler.h:69:3: note: expanded from macro '__trace_if_value'
           (cond) ?                                        \
            ^~~~
>> kernel/dma/swiotlb.c:524:33: warning: result of comparison of constant 18446744073709551615 with expression of type 'unsigned long' is always false [-Wtautological-constant-out-of-range-compare]
           if (swiotlb_nr > 1 && dma_mask == DMA_BIT_MASK(64))
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:56:47: note: expanded from macro 'if'
   #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
                              ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:58:52: note: expanded from macro '__trace_if_var'
   #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
                                                      ^~~~
>> kernel/dma/swiotlb.c:524:33: warning: result of comparison of constant 18446744073709551615 with expression of type 'unsigned long' is always false [-Wtautological-constant-out-of-range-compare]
           if (swiotlb_nr > 1 && dma_mask == DMA_BIT_MASK(64))
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:56:47: note: expanded from macro 'if'
   #define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
                              ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/compiler.h:58:61: note: expanded from macro '__trace_if_var'
   #define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
                                                               ^~~~
   3 warnings generated.

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for HOTPLUG_CPU
   Depends on SMP && (PPC_PSERIES || PPC_PMAC || PPC_POWERNV || FSL_SOC_BOOKE
   Selected by
   - PM_SLEEP_SMP && SMP && (ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE && PM_SLEEP


vim +524 kernel/dma/swiotlb.c

   506	
   507	phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t orig_addr,
   508			size_t mapping_size, size_t alloc_size,
   509			enum dma_data_direction dir, unsigned long attrs)
   510	{
   511		dma_addr_t tbl_dma_addr;
   512		unsigned long flags;
   513		phys_addr_t tlb_addr;
   514		unsigned int nslots, stride, index, wrap;
   515		int i;
   516		unsigned long mask;
   517		unsigned long offset_slots;
   518		unsigned long max_slots;
   519		unsigned long tmp_io_tlb_used;
   520		unsigned long dma_mask = min_not_zero(*hwdev->dma_mask,
   521						      hwdev->bus_dma_limit);
   522		int type;
   523	
 > 524		if (swiotlb_nr > 1 && dma_mask == DMA_BIT_MASK(64))
   525			type = SWIOTLB_HI;
   526		else
   527			type = SWIOTLB_LO;
   528	
   529		if (no_iotlb_memory[type])
   530			panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
   531	
   532		if (mem_encrypt_active())
   533			pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
   534	
   535		if (mapping_size > alloc_size) {
   536			dev_warn_once(hwdev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)",
   537				      mapping_size, alloc_size);
   538			return (phys_addr_t)DMA_MAPPING_ERROR;
   539		}
   540	
   541		tbl_dma_addr = phys_to_dma_unencrypted(hwdev, io_tlb_start[type]);
   542	
   543		mask = dma_get_seg_boundary(hwdev);
   544	
   545		tbl_dma_addr &= mask;
   546	
   547		offset_slots = ALIGN(tbl_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
   548	
   549		/*
   550		 * Carefully handle integer overflow which can occur when mask == ~0UL.
   551		 */
   552		max_slots = mask + 1
   553			    ? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT
   554			    : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);
   555	
   556		/*
   557		 * For mappings greater than or equal to a page, we limit the stride
   558		 * (and hence alignment) to a page size.
   559		 */
   560		nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
   561		if (alloc_size >= PAGE_SIZE)
   562			stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
   563		else
   564			stride = 1;
   565	
   566		BUG_ON(!nslots);
   567	
   568		/*
   569		 * Find suitable number of IO TLB entries size that will fit this
   570		 * request and allocate a buffer from that IO TLB pool.
   571		 */
   572		spin_lock_irqsave(&io_tlb_lock, flags);
   573	
   574		if (unlikely(nslots > io_tlb_nslabs[type] - io_tlb_used[type]))
   575			goto not_found;
   576	
   577		index = ALIGN(io_tlb_index[type], stride);
   578		if (index >= io_tlb_nslabs[type])
   579			index = 0;
   580		wrap = index;
   581	
   582		do {
   583			while (iommu_is_span_boundary(index, nslots, offset_slots,
   584						      max_slots)) {
   585				index += stride;
   586				if (index >= io_tlb_nslabs[type])
   587					index = 0;
   588				if (index == wrap)
   589					goto not_found;
   590			}
   591	
   592			/*
   593			 * If we find a slot that indicates we have 'nslots' number of
   594			 * contiguous buffers, we allocate the buffers from that slot
   595			 * and mark the entries as '0' indicating unavailable.
   596			 */
   597			if (io_tlb_list[type][index] >= nslots) {
   598				int count = 0;
   599	
   600				for (i = index; i < (int) (index + nslots); i++)
   601					io_tlb_list[type][i] = 0;
   602				for (i = index - 1;
   603				     (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) &&
   604				     io_tlb_list[type][i];
   605				     i--)
   606					io_tlb_list[type][i] = ++count;
   607				tlb_addr = io_tlb_start[type] + (index << IO_TLB_SHIFT);
   608	
   609				/*
   610				 * Update the indices to avoid searching in the next
   611				 * round.
   612				 */
   613				io_tlb_index[type] = ((index + nslots) < io_tlb_nslabs[type]
   614						? (index + nslots) : 0);
   615	
   616				goto found;
   617			}
   618			index += stride;
   619			if (index >= io_tlb_nslabs[type])
   620				index = 0;
   621		} while (index != wrap);
   622	
   623	not_found:
   624		tmp_io_tlb_used = io_tlb_used[type];
   625	
   626		spin_unlock_irqrestore(&io_tlb_lock, flags);
   627		if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
   628			dev_warn(hwdev, "%s swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
   629				 swiotlb_name[type], alloc_size, io_tlb_nslabs[type], tmp_io_tlb_used);
   630		return (phys_addr_t)DMA_MAPPING_ERROR;
   631	found:
   632		io_tlb_used[type] += nslots;
   633		spin_unlock_irqrestore(&io_tlb_lock, flags);
   634	
   635		/*
   636		 * Save away the mapping from the original address to the DMA address.
   637		 * This is needed when we sync the memory.  Then we sync the buffer if
   638		 * needed.
   639		 */
   640		for (i = 0; i < nslots; i++)
   641			io_tlb_orig_addr[type][index+i] = orig_addr + (i << IO_TLB_SHIFT);
   642		if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
   643		    (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
   644			swiotlb_bounce(orig_addr, tlb_addr, mapping_size, DMA_TO_DEVICE);
   645	
   646		return tlb_addr;
   647	}
   648	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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