Merge tag 'dma-mapping-6.12-2024-09-19' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping updates from Christoph Hellwig:

 - support DMA zones for arm64 systems where memory starts at > 4GB
   (Baruch Siach, Catalin Marinas)

 - support direct calls into dma-iommu and thus obsolete dma_map_ops for
   many common configurations (Leon Romanovsky)

 - add DMA-API tracing (Sean Anderson)

 - remove the not very useful return value from various dma_set_* APIs
   (Christoph Hellwig)

 - misc cleanups and minor optimizations (Chen Y, Yosry Ahmed, Christoph
   Hellwig)

* tag 'dma-mapping-6.12-2024-09-19' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: reflow dma_supported
  dma-mapping: reliably inform about DMA support for IOMMU
  dma-mapping: add tracing for dma-mapping API calls
  dma-mapping: use IOMMU DMA calls for common alloc/free page calls
  dma-direct: optimize page freeing when it is not addressable
  dma-mapping: clearly mark DMA ops as an architecture feature
  vdpa_sim: don't select DMA_OPS
  arm64: mm: keep low RAM dma zone
  dma-mapping: don't return errors from dma_set_max_seg_size
  dma-mapping: don't return errors from dma_set_seg_boundary
  dma-mapping: don't return errors from dma_set_min_align_mask
  scsi: check that busses support the DMA API before setting dma parameters
  arm64: mm: fix DMA zone when dma-ranges is missing
  dma-mapping: direct calls for dma-iommu
  dma-mapping: call ->unmap_page and ->unmap_sg unconditionally
  arm64: support DMA zone above 4GB
  dma-mapping: replace zone_dma_bits by zone_dma_limit
  dma-mapping: use bit masking to check VM_DMA_COHERENT

Author: torvalds

MAINTAINERS

@@ -11841,6 +11841,7 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/iommu/linux.git
 F:	drivers/iommu/dma-iommu.c
 F:	drivers/iommu/dma-iommu.h
 F:	drivers/iommu/iova.c
+F:	include/linux/iommu-dma.h
 F:	include/linux/iova.h
 
 IOMMU SUBSYSTEM

arch/Kconfig

@@ -17,6 +17,15 @@ config CPU_MITIGATIONS
 	def_bool y
 endif
 
+#
+# Selected by architectures that need custom DMA operations for e.g. legacy
+# IOMMUs not handled by dma-iommu.  Drivers must never select this symbol.
+#
+config ARCH_HAS_DMA_OPS
+	depends on HAS_DMA
+	select DMA_OPS_HELPERS
+	bool
+
 menu "General architecture-dependent options"
 
 config ARCH_HAS_SUBPAGE_FAULTS

arch/alpha/Kconfig

@@ -4,12 +4,12 @@ config ALPHA
 	default y
 	select ARCH_32BIT_USTAT_F_TINODE
 	select ARCH_HAS_CURRENT_STACK_POINTER
+	select ARCH_HAS_DMA_OPS if PCI
 	select ARCH_MIGHT_HAVE_PC_PARPORT
 	select ARCH_MIGHT_HAVE_PC_SERIO
 	select ARCH_NO_PREEMPT
 	select ARCH_NO_SG_CHAIN
 	select ARCH_USE_CMPXCHG_LOCKREF
-	select DMA_OPS if PCI
 	select FORCE_PCI
 	select PCI_DOMAINS if PCI
 	select PCI_SYSCALL if PCI

arch/arm/Kconfig

@@ -10,6 +10,7 @@ config ARM
 	select ARCH_HAS_CURRENT_STACK_POINTER
 	select ARCH_HAS_DEBUG_VIRTUAL if MMU
 	select ARCH_HAS_DMA_ALLOC if MMU
+	select ARCH_HAS_DMA_OPS
 	select ARCH_HAS_DMA_WRITE_COMBINE if !ARM_DMA_MEM_BUFFERABLE
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_FORTIFY_SOURCE
@@ -54,7 +55,6 @@ config ARM
 	select DCACHE_WORD_ACCESS if HAVE_EFFICIENT_UNALIGNED_ACCESS
 	select DMA_DECLARE_COHERENT
 	select DMA_GLOBAL_POOL if !MMU
-	select DMA_OPS
 	select DMA_NONCOHERENT_MMAP if MMU
 	select EDAC_SUPPORT
 	select EDAC_ATOMIC_SCRUB

arch/arm64/Kconfig

@@ -24,6 +24,7 @@ config ARM64
 	select ARCH_HAS_CURRENT_STACK_POINTER
 	select ARCH_HAS_DEBUG_VIRTUAL
 	select ARCH_HAS_DEBUG_VM_PGTABLE
+	select ARCH_HAS_DMA_OPS if XEN
 	select ARCH_HAS_DMA_PREP_COHERENT
 	select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
 	select ARCH_HAS_FAST_MULTIPLIER

arch/arm64/mm/init.c

@@ -114,36 +114,33 @@ static void __init arch_reserve_crashkernel(void)
 				    low_size, high);
 }
 
-/*
- * Return the maximum physical address for a zone accessible by the given bits
- * limit. If DRAM starts above 32-bit, expand the zone to the maximum
- * available memory, otherwise cap it at 32-bit.
- */
-static phys_addr_t __init max_zone_phys(unsigned int zone_bits)
+static phys_addr_t __init max_zone_phys(phys_addr_t zone_limit)
 {
-	phys_addr_t zone_mask = DMA_BIT_MASK(zone_bits);
-	phys_addr_t phys_start = memblock_start_of_DRAM();
-
-	if (phys_start > U32_MAX)
-		zone_mask = PHYS_ADDR_MAX;
-	else if (phys_start > zone_mask)
-		zone_mask = U32_MAX;
+	/**
+	 * Information we get from firmware (e.g. DT dma-ranges) describe DMA
+	 * bus constraints. Devices using DMA might have their own limitations.
+	 * Some of them rely on DMA zone in low 32-bit memory. Keep low RAM
+	 * DMA zone on platforms that have RAM there.
+	 */
+	if (memblock_start_of_DRAM() < U32_MAX)
+		zone_limit = min(zone_limit, U32_MAX);
 
-	return min(zone_mask, memblock_end_of_DRAM() - 1) + 1;
+	return min(zone_limit, memblock_end_of_DRAM() - 1) + 1;
 }
 
 static void __init zone_sizes_init(void)
 {
 	unsigned long max_zone_pfns[MAX_NR_ZONES]  = {0};
-	unsigned int __maybe_unused acpi_zone_dma_bits;
-	unsigned int __maybe_unused dt_zone_dma_bits;
-	phys_addr_t __maybe_unused dma32_phys_limit = max_zone_phys(32);
+	phys_addr_t __maybe_unused acpi_zone_dma_limit;
+	phys_addr_t __maybe_unused dt_zone_dma_limit;
+	phys_addr_t __maybe_unused dma32_phys_limit =
+		max_zone_phys(DMA_BIT_MASK(32));
 
 #ifdef CONFIG_ZONE_DMA
-	acpi_zone_dma_bits = fls64(acpi_iort_dma_get_max_cpu_address());
-	dt_zone_dma_bits = fls64(of_dma_get_max_cpu_address(NULL));
-	zone_dma_bits = min3(32U, dt_zone_dma_bits, acpi_zone_dma_bits);
-	arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
+	acpi_zone_dma_limit = acpi_iort_dma_get_max_cpu_address();
+	dt_zone_dma_limit = of_dma_get_max_cpu_address(NULL);
+	zone_dma_limit = min(dt_zone_dma_limit, acpi_zone_dma_limit);
+	arm64_dma_phys_limit = max_zone_phys(zone_dma_limit);
 	max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit);
 #endif
 #ifdef CONFIG_ZONE_DMA32

arch/mips/Kconfig

@@ -8,6 +8,7 @@ config MIPS
 	select ARCH_HAS_CPU_FINALIZE_INIT
 	select ARCH_HAS_CURRENT_STACK_POINTER if !CC_IS_CLANG || CLANG_VERSION >= 140000
 	select ARCH_HAS_DEBUG_VIRTUAL if !64BIT
+	select ARCH_HAS_DMA_OPS if MACH_JAZZ
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE if !EVA
@@ -393,7 +394,6 @@ config MACH_JAZZ
 	select ARC_PROMLIB
 	select ARCH_MIGHT_HAVE_PC_PARPORT
 	select ARCH_MIGHT_HAVE_PC_SERIO
-	select DMA_OPS
 	select FW_ARC
 	select FW_ARC32
 	select ARCH_MAY_HAVE_PC_FDC

arch/parisc/Kconfig

@@ -10,6 +10,7 @@ config PARISC
 	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_HAS_CPU_CACHE_ALIASING
 	select ARCH_HAS_DMA_ALLOC if PA11
+	select ARCH_HAS_DMA_OPS
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_STRICT_KERNEL_RWX
 	select ARCH_HAS_STRICT_MODULE_RWX
@@ -23,7 +24,6 @@ config PARISC
 	select ARCH_HAS_CACHE_LINE_SIZE
 	select ARCH_HAS_DEBUG_VM_PGTABLE
 	select HAVE_RELIABLE_STACKTRACE
-	select DMA_OPS
 	select RTC_CLASS
 	select RTC_DRV_GENERIC
 	select INIT_ALL_POSSIBLE

arch/powerpc/Kconfig

@@ -133,6 +133,7 @@ config PPC
 	select ARCH_HAS_DEBUG_WX		if STRICT_KERNEL_RWX
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_DMA_MAP_DIRECT 		if PPC_PSERIES
+	select ARCH_HAS_DMA_OPS			if PPC64
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_KCOV
@@ -185,7 +186,6 @@ config PPC
 	select CPUMASK_OFFSTACK			if NR_CPUS >= 8192
 	select DCACHE_WORD_ACCESS		if PPC64 && CPU_LITTLE_ENDIAN
 	select DMA_OPS_BYPASS			if PPC64
-	select DMA_OPS				if PPC64
 	select DYNAMIC_FTRACE			if FUNCTION_TRACER
 	select EDAC_ATOMIC_SCRUB
 	select EDAC_SUPPORT

arch/powerpc/mm/mem.c

@@ -216,7 +216,7 @@ static int __init mark_nonram_nosave(void)
  * everything else. GFP_DMA32 page allocations automatically fall back to
  * ZONE_DMA.
  *
- * By using 31-bit unconditionally, we can exploit zone_dma_bits to inform the
+ * By using 31-bit unconditionally, we can exploit zone_dma_limit to inform the
  * generic DMA mapping code.  32-bit only devices (if not handled by an IOMMU
  * anyway) will take a first dip into ZONE_NORMAL and get otherwise served by
  * ZONE_DMA.
@@ -230,6 +230,7 @@ void __init paging_init(void)
 {
 	unsigned long long total_ram = memblock_phys_mem_size();
 	phys_addr_t top_of_ram = memblock_end_of_DRAM();
+	int zone_dma_bits;
 
 #ifdef CONFIG_HIGHMEM
 	unsigned long v = __fix_to_virt(FIX_KMAP_END);
@@ -256,6 +257,8 @@ void __init paging_init(void)
 	else
 		zone_dma_bits = 31;
 
+	zone_dma_limit = DMA_BIT_MASK(zone_dma_bits);
+
 #ifdef CONFIG_ZONE_DMA
 	max_zone_pfns[ZONE_DMA]	= min(max_low_pfn,
 				      1UL << (zone_dma_bits - PAGE_SHIFT));