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From: "tip-bot2 for Thomas Gleixner" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Arnd Bergmann <arnd@arndb.de>,
	Andrew Morton <akpm@linux-foundation.org>, x86 <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: [tip: core/mm] asm-generic: Provide kmap_size.h
Date: Fri, 06 Nov 2020 23:27:26 -0000	[thread overview]
Message-ID: <160470524624.397.7764720699234410327.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20201103095857.078043987@linutronix.de>

The following commit has been merged into the core/mm branch of tip:

Commit-ID:     4f8b96cd47b06f1e3ec71c1a3216113efe8dbfb5
Gitweb:        https://git.kernel.org/tip/4f8b96cd47b06f1e3ec71c1a3216113efe8dbfb5
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Tue, 03 Nov 2020 10:27:17 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Fri, 06 Nov 2020 23:14:54 +01:00

asm-generic: Provide kmap_size.h

kmap_types.h is a misnomer because the old atomic MAP based array does not
exist anymore and the whole indirection of architectures including
kmap_types.h is inconinstent and does not allow to provide guard page
debugging for this misfeature.

Add a common header file which defines the mapping stack size for all
architectures. Will be used when converting architectures over to a
generic kmap_local/atomic implementation.

The array size is chosen with the following constraints in mind:

    - The deepest nest level in one context is 3 according to code
      inspection.

    - The worst case nesting for the upcoming reemptible version would be:

      2 maps in task context and a fault inside
      2 maps in the fault handler
      3 maps in softirq
      2 maps in interrupt

So a total of 16 is sufficient and probably overestimated.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/r/20201103095857.078043987@linutronix.de

---
 include/asm-generic/Kbuild      |  1 +
 include/asm-generic/kmap_size.h | 12 ++++++++++++
 2 files changed, 13 insertions(+)
 create mode 100644 include/asm-generic/kmap_size.h

diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild
index e78bbb9..ed62d38 100644
--- a/include/asm-generic/Kbuild
+++ b/include/asm-generic/Kbuild
@@ -31,6 +31,7 @@ mandatory-y += irq_regs.h
 mandatory-y += irq_work.h
 mandatory-y += kdebug.h
 mandatory-y += kmap_types.h
+mandatory-y += kmap_size.h
 mandatory-y += kprobes.h
 mandatory-y += linkage.h
 mandatory-y += local.h
diff --git a/include/asm-generic/kmap_size.h b/include/asm-generic/kmap_size.h
new file mode 100644
index 0000000..9d6c778
--- /dev/null
+++ b/include/asm-generic/kmap_size.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_GENERIC_KMAP_SIZE_H
+#define _ASM_GENERIC_KMAP_SIZE_H
+
+/* For debug this provides guard pages between the maps */
+#ifdef CONFIG_DEBUG_HIGHMEM
+# define KM_MAX_IDX	33
+#else
+# define KM_MAX_IDX	16
+#endif
+
+#endif

  parent reply	other threads:[~2020-11-06 23:27 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-03  9:27 [patch V3 00/37] mm/highmem: Preemptible variant of kmap_atomic & friends Thomas Gleixner
2020-11-03  9:27 ` [patch V3 01/37] mm/highmem: Un-EXPORT __kmap_atomic_idx() Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 02/37] highmem: Remove unused functions Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 03/37] fs: Remove asm/kmap_types.h includes Thomas Gleixner
2020-11-03 11:12   ` David Sterba
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 04/37] sh/highmem: Remove all traces of unused cruft Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 05/37] asm-generic: Provide kmap_size.h Thomas Gleixner
2020-11-03 12:25   ` Arnd Bergmann
2020-11-06 23:27   ` tip-bot2 for Thomas Gleixner [this message]
2020-11-03  9:27 ` [patch V3 06/37] highmem: Provide generic variant of kmap_atomic* Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 07/37] highmem: Make DEBUG_HIGHMEM functional Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 08/37] x86/mm/highmem: Use generic kmap atomic implementation Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 09/37] arc/mm/highmem: " Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 10/37] ARM: highmem: Switch to generic kmap atomic Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
     [not found]   ` <CGME20201112081036eucas1p14e135a370d3bccab311727fd2e89f4df@eucas1p1.samsung.com>
2020-11-12  8:10     ` [patch V3 10/37] " Marek Szyprowski
2020-11-12 11:03       ` Thomas Gleixner
2020-11-12 11:07       ` Sebastian Andrzej Siewior
2020-11-03  9:27 ` [patch V3 11/37] csky/mm/highmem: " Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 12/37] microblaze/mm/highmem: " Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 13/37] mips/mm/highmem: " Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 14/37] nds32/mm/highmem: " Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 15/37] powerpc/mm/highmem: " Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 16/37] sparc/mm/highmem: " Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 17/37] xtensa/mm/highmem: " Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 18/37] highmem: Get rid of kmap_types.h Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 19/37] mm/highmem: Remove the old kmap_atomic cruft Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 20/37] io-mapping: Cleanup atomic iomap Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 21/37] Documentation/io-mapping: Remove outdated blurb Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 22/37] highmem: High implementation details and document API Thomas Gleixner
2020-11-03 17:48   ` Linus Torvalds
2020-11-03 19:00     ` Thomas Gleixner
2020-11-06 23:27   ` [tip: core/mm] " tip-bot2 for Thomas Gleixner
2020-11-03  9:27 ` [patch V3 23/37] sched: Make migrate_disable/enable() independent of RT Thomas Gleixner
2020-11-03  9:27 ` [patch V3 24/37] sched: highmem: Store local kmaps in task struct Thomas Gleixner
2020-11-03 13:49   ` Thomas Gleixner
2020-11-03 13:51   ` [patch V4 " Thomas Gleixner
2020-11-03  9:27 ` [patch V3 25/37] mm/highmem: Provide kmap_local* Thomas Gleixner
2020-11-03  9:27 ` [patch V3 26/37] io-mapping: Provide iomap_local variant Thomas Gleixner
2020-11-03  9:27 ` [patch V3 27/37] x86/crashdump/32: Simplify copy_oldmem_page() Thomas Gleixner
2020-11-03  9:27 ` [patch V3 28/37] mips/crashdump: " Thomas Gleixner
2020-11-03  9:27 ` [patch V3 29/37] ARM: mm: Replace kmap_atomic_pfn() Thomas Gleixner
2020-11-03  9:27 ` [patch V3 30/37] highmem: Remove kmap_atomic_pfn() Thomas Gleixner
2020-11-03  9:27 ` [patch V3 31/37] drm/ttm: Replace kmap_atomic() usage Thomas Gleixner
2020-11-03  9:27 ` [patch V3 32/37] drm/vmgfx: Replace kmap_atomic() Thomas Gleixner
2020-11-03  9:27 ` [patch V3 33/37] highmem: Remove kmap_atomic_prot() Thomas Gleixner
2020-11-03  9:27 ` [patch V3 34/37] drm/qxl: Replace io_mapping_map_atomic_wc() Thomas Gleixner
2020-11-03  9:27 ` [patch V3 35/37] drm/nouveau/device: " Thomas Gleixner
2020-11-03  9:27 ` [patch V3 36/37] drm/i915: " Thomas Gleixner
2020-11-03  9:27 ` [patch V3 37/37] io-mapping: Remove io_mapping_map_atomic_wc() Thomas Gleixner

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