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From: Samuel Holland <samuel.holland@sifive.com>
To: Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <pjw@kernel.org>,
	linux-riscv@lists.infradead.org,
	Andrew Morton <akpm@linux-foundation.org>,
	David Hildenbrand <david@redhat.com>,
	linux-mm@kvack.org
Cc: devicetree@vger.kernel.org,
	Suren Baghdasaryan <surenb@google.com>,
	linux-kernel@vger.kernel.org, Mike Rapoport <rppt@kernel.org>,
	Michal Hocko <mhocko@suse.com>, Conor Dooley <conor@kernel.org>,
	Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Alexandre Ghiti <alex@ghiti.fr>,
	Emil Renner Berthing <kernel@esmil.dk>,
	Rob Herring <robh+dt@kernel.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	"Liam R . Howlett" <Liam.Howlett@oracle.com>,
	Samuel Holland <samuel.holland@sifive.com>
Subject: [PATCH v3 18/22] riscv: Fix logic for selecting DMA_DIRECT_REMAP
Date: Wed, 12 Nov 2025 17:45:31 -0800	[thread overview]
Message-ID: <20251113014656.2605447-19-samuel.holland@sifive.com> (raw)
In-Reply-To: <20251113014656.2605447-1-samuel.holland@sifive.com>

DMA_DIRECT_REMAP allows the kernel to make pages coherent for DMA by
remapping them in the page tables with a different pgprot_t value. On
RISC-V, this is supported by the page-based memory type extensions
(Svpbmt and Xtheadmae). It is independent from the software cache
maintenance extensions (Zicbom and Xtheadcmo).

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---

Changes in v3:
 - New patch for v3

 arch/riscv/Kconfig        | 2 +-
 arch/riscv/Kconfig.errata | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index fadec20b87a8..cf5a4b5cdcd4 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -598,6 +598,7 @@ config RISCV_ISA_SVPBMT
 	depends on 64BIT && MMU
 	depends on RISCV_ALTERNATIVE
 	default y
+	select DMA_DIRECT_REMAP
 	help
 	   Add support for the Svpbmt ISA-extension (Supervisor-mode:
 	   page-based memory types) in the kernel when it is detected at boot.
@@ -811,7 +812,6 @@ config RISCV_ISA_ZICBOM
 	depends on RISCV_ALTERNATIVE
 	default y
 	select RISCV_DMA_NONCOHERENT
-	select DMA_DIRECT_REMAP
 	help
 	   Add support for the Zicbom extension (Cache Block Management
 	   Operations) and enable its use in the kernel when it is detected
diff --git a/arch/riscv/Kconfig.errata b/arch/riscv/Kconfig.errata
index aca9b0cfcfec..46a353a266e5 100644
--- a/arch/riscv/Kconfig.errata
+++ b/arch/riscv/Kconfig.errata
@@ -108,6 +108,7 @@ config ERRATA_THEAD
 config ERRATA_THEAD_MAE
 	bool "Apply T-Head's memory attribute extension (XTheadMae) errata"
 	depends on ERRATA_THEAD && 64BIT && MMU
+	select DMA_DIRECT_REMAP
 	select RISCV_ALTERNATIVE_EARLY
 	default y
 	help
@@ -119,7 +120,6 @@ config ERRATA_THEAD_MAE
 config ERRATA_THEAD_CMO
 	bool "Apply T-Head cache management errata"
 	depends on ERRATA_THEAD && MMU
-	select DMA_DIRECT_REMAP
 	select RISCV_DMA_NONCOHERENT
 	select RISCV_NONSTANDARD_CACHE_OPS
 	default y
-- 
2.47.2



  parent reply	other threads:[~2025-11-13  1:47 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-13  1:45 [PATCH v3 00/22] riscv: Memory type control for platforms with physical memory aliases Samuel Holland
2025-11-13  1:45 ` [PATCH v3 01/22] mm/ptdump: replace READ_ONCE() with standard page table accessors Samuel Holland
2025-11-13  1:45 ` [PATCH v3 02/22] mm: " Samuel Holland
2025-11-13  4:05   ` Dev Jain
2025-11-13  1:45 ` [PATCH v3 03/22] mm/dirty: replace READ_ONCE() with pudp_get() Samuel Holland
2025-11-13  1:45 ` [PATCH v3 04/22] perf/events: replace READ_ONCE() with standard page table accessors Samuel Holland
2025-11-13 19:10   ` David Hildenbrand (Red Hat)
2025-11-13  1:45 ` [PATCH v3 05/22] mm: Move the fallback definitions of pXXp_get() Samuel Holland
2025-11-13 19:11   ` David Hildenbrand (Red Hat)
2025-11-13  1:45 ` [PATCH v3 06/22] mm: Always use page table accessor functions Samuel Holland
2025-11-13  4:53   ` kernel test robot
2025-11-13  5:46   ` kernel test robot
2025-11-26 11:08   ` Christophe Leroy (CS GROUP)
2025-11-26 11:09   ` Ryan Roberts
2025-11-26 12:16     ` David Hildenbrand (Red Hat)
2025-11-26 12:19       ` David Hildenbrand (Red Hat)
2025-11-26 12:27         ` Lorenzo Stoakes
2025-11-26 12:35           ` David Hildenbrand (Red Hat)
2025-11-26 13:03             ` Ryan Roberts
2025-11-26 13:47               ` Wei Yang
2025-11-26 14:22                 ` Ryan Roberts
2025-11-26 14:37                   ` Lorenzo Stoakes
2025-11-26 14:53                     ` David Hildenbrand (Red Hat)
2025-11-26 14:46                   ` David Hildenbrand (Red Hat)
2025-11-26 14:52                     ` Lorenzo Stoakes
2025-11-26 14:56                       ` David Hildenbrand (Red Hat)
2025-11-26 15:08                         ` Lorenzo Stoakes
2025-11-26 15:12                           ` David Hildenbrand (Red Hat)
2025-11-26 16:07                             ` Ryan Roberts
2025-11-26 16:34                               ` Ryan Roberts
2025-11-26 20:31                                 ` David Hildenbrand (Red Hat)
2025-11-27  7:14                                   ` David Hildenbrand (Red Hat)
2025-11-27  7:31                                     ` David Hildenbrand (Red Hat)
2025-11-27 15:32                                       ` Ryan Roberts
2025-11-27 19:39                                 ` Christophe Leroy (CS GROUP)
2025-11-27 19:44                                 ` Christophe Leroy (CS GROUP)
2025-11-27  8:26                   ` Christophe Leroy (CS GROUP)
2025-11-27  8:35                     ` David Hildenbrand (Red Hat)
2025-11-13  1:45 ` [PATCH v3 07/22] checkpatch: Warn on page table access without accessors Samuel Holland
2025-11-13  2:21   ` Joe Perches
2025-11-13  2:36     ` Samuel Holland
2025-11-13 19:17       ` David Hildenbrand (Red Hat)
2025-11-13  1:45 ` [PATCH v3 08/22] mm: Allow page table accessors to be non-idempotent Samuel Holland
2025-11-13  7:19   ` kernel test robot
2025-11-27 16:57   ` Ryan Roberts
2025-11-27 17:47     ` David Hildenbrand (Red Hat)
2025-11-13  1:45 ` [PATCH v3 09/22] riscv: hibernate: Replace open-coded pXXp_get() Samuel Holland
2025-11-13  1:45 ` [PATCH v3 10/22] riscv: mm: Always use page table accessor functions Samuel Holland
2025-11-13  1:45 ` [PATCH v3 11/22] riscv: mm: Simplify set_p4d() and set_pgd() Samuel Holland
2025-11-13  1:45 ` [PATCH v3 12/22] riscv: mm: Deduplicate _PAGE_CHG_MASK definition Samuel Holland
2025-11-13  1:45 ` [PATCH v3 13/22] riscv: ptdump: Only show N and MT bits when enabled in the kernel Samuel Holland
2025-11-13  1:45 ` [PATCH v3 14/22] riscv: mm: Fix up memory types when writing page tables Samuel Holland
2025-11-13  1:45 ` [PATCH v3 15/22] riscv: mm: Expose all page table bits to assembly code Samuel Holland
2025-11-13  1:45 ` [PATCH v3 16/22] riscv: alternative: Add an ALTERNATIVE_3 macro Samuel Holland
2025-11-13  1:45 ` [PATCH v3 17/22] riscv: alternative: Allow calls with alternate link registers Samuel Holland
2025-11-13  1:45 ` Samuel Holland [this message]
2025-11-13  1:45 ` [PATCH v3 19/22] dt-bindings: riscv: Describe physical memory regions Samuel Holland
2025-12-04 15:12   ` Rob Herring
2025-11-13  1:45 ` [PATCH v3 20/22] riscv: mm: Use physical memory aliases to apply PMAs Samuel Holland
2025-11-13  1:45 ` [PATCH v3 21/22] riscv: dts: starfive: jh7100: Use physical memory ranges for DMA Samuel Holland
2025-11-13  1:45 ` [PATCH v3 22/22] riscv: dts: eswin: eic7700: " Samuel Holland
2025-11-13 19:13 ` [PATCH v3 00/22] riscv: Memory type control for platforms with physical memory aliases David Hildenbrand (Red Hat)

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