* [PATCH] mm/ioremap: Probe platform for p4d huge map support
@ 2019-06-13 6:19 Anshuman Khandual
2019-06-14 12:22 ` Thomas Gleixner
0 siblings, 1 reply; 2+ messages in thread
From: Anshuman Khandual @ 2019-06-13 6:19 UTC (permalink / raw)
To: linux-mm, linux-kernel, akpm
Cc: Anshuman Khandual, Catalin Marinas, Will Deacon, Dave Hansen,
Andy Lutomirski, Peter Zijlstra, Thomas Gleixner, Ingo Molnar,
Kirill A . Shutemov, Michal Hocko, linux-arm-kernel, x86
Finishing up what the commit c2febafc67734a ("mm: convert generic code to
5-level paging") started out while levelling up P4D huge mapping support
at par with PUD and PMD. A new arch call back arch_ioremap_p4d_supported()
is being added which just maintains status quo (P4D huge map not supported)
on x86 and arm64.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: x86@kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
- Detected this from code audit while reviewing Nicholas Piggin's proposed
ioremap changes https://patchwork.kernel.org/project/linux-mm/list/?series=129479
- Build and boot tested on x86 and arm64 platforms
- Build tested on some others
Changes in V1:
- No changes
Original RFC (https://patchwork.kernel.org/patch/10985009/)
arch/arm64/mm/mmu.c | 5 +++++
arch/x86/mm/ioremap.c | 5 +++++
include/linux/io.h | 1 +
lib/ioremap.c | 2 ++
4 files changed, 13 insertions(+)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index a1bfc44..646c829 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -953,6 +953,11 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
return dt_virt;
}
+int __init arch_ioremap_p4d_supported(void)
+{
+ return 0;
+}
+
int __init arch_ioremap_pud_supported(void)
{
/*
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 4b6423e..6cbbec8 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -440,6 +440,11 @@ void iounmap(volatile void __iomem *addr)
}
EXPORT_SYMBOL(iounmap);
+int __init arch_ioremap_p4d_supported(void)
+{
+ return 0;
+}
+
int __init arch_ioremap_pud_supported(void)
{
#ifdef CONFIG_X86_64
diff --git a/include/linux/io.h b/include/linux/io.h
index 32e30e8..58514ce 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -45,6 +45,7 @@ static inline int ioremap_page_range(unsigned long addr, unsigned long end,
#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
void __init ioremap_huge_init(void);
+int arch_ioremap_p4d_supported(void);
int arch_ioremap_pud_supported(void);
int arch_ioremap_pmd_supported(void);
#else
diff --git a/lib/ioremap.c b/lib/ioremap.c
index 0632136..c3dc213 100644
--- a/lib/ioremap.c
+++ b/lib/ioremap.c
@@ -30,6 +30,8 @@ early_param("nohugeiomap", set_nohugeiomap);
void __init ioremap_huge_init(void)
{
if (!ioremap_huge_disabled) {
+ if (arch_ioremap_p4d_supported())
+ ioremap_p4d_capable = 1;
if (arch_ioremap_pud_supported())
ioremap_pud_capable = 1;
if (arch_ioremap_pmd_supported())
--
2.7.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] mm/ioremap: Probe platform for p4d huge map support
2019-06-13 6:19 [PATCH] mm/ioremap: Probe platform for p4d huge map support Anshuman Khandual
@ 2019-06-14 12:22 ` Thomas Gleixner
0 siblings, 0 replies; 2+ messages in thread
From: Thomas Gleixner @ 2019-06-14 12:22 UTC (permalink / raw)
To: Anshuman Khandual
Cc: linux-mm, linux-kernel, akpm, Catalin Marinas, Will Deacon,
Dave Hansen, Andy Lutomirski, Peter Zijlstra, Ingo Molnar,
Kirill A . Shutemov, Michal Hocko, linux-arm-kernel, x86
On Thu, 13 Jun 2019, Anshuman Khandual wrote:
> Finishing up what the commit c2febafc67734a ("mm: convert generic code to
> 5-level paging") started out while levelling up P4D huge mapping support
> at par with PUD and PMD. A new arch call back arch_ioremap_p4d_supported()
> is being added which just maintains status quo (P4D huge map not supported)
> on x86 and arm64.
>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: x86@kernel.org
>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
^ permalink raw reply [flat|nested] 2+ messages in thread
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