From: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Subject: mm/ioremap: probe platform for p4d huge map support
Finish up what c2febafc67734a ("mm: convert generic code to 5-level
paging") started while levelling up P4D huge mapping support at par with
PUD and PMD. A new arch call back arch_ioremap_p4d_supported() is added
which just maintains status quo (P4D huge map not supported) on x86, arm64
and powerpc.
When HAVE_ARCH_HUGE_VMAP is enabled its just a simple check from the
arch about the support, hence runtime effects are minimal.
Link: http://lkml.kernel.org/r/1561699231-20991-1-git-send-email-anshuman.khandual@xxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> (powerpc)
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/mm/mmu.c | 5 +++++
arch/powerpc/mm/book3s64/radix_pgtable.c | 5 +++++
arch/x86/mm/ioremap.c | 5 +++++
include/linux/io.h | 1 +
lib/ioremap.c | 2 ++
5 files changed, 18 insertions(+)
--- a/arch/arm64/mm/mmu.c~mm-ioremap-probe-platform-for-p4d-huge-map-support
+++ a/arch/arm64/mm/mmu.c
@@ -942,6 +942,11 @@ void *__init fixmap_remap_fdt(phys_addr_
return dt_virt;
}
+int __init arch_ioremap_p4d_supported(void)
+{
+ return 0;
+}
+
int __init arch_ioremap_pud_supported(void)
{
/*
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c~mm-ioremap-probe-platform-for-p4d-huge-map-support
+++ a/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -1237,3 +1237,8 @@ int radix__ioremap_range(unsigned long e
return 0;
}
}
+
+int __init arch_ioremap_p4d_supported(void)
+{
+ return 0;
+}
--- a/arch/x86/mm/ioremap.c~mm-ioremap-probe-platform-for-p4d-huge-map-support
+++ a/arch/x86/mm/ioremap.c
@@ -459,6 +459,11 @@ 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
--- a/include/linux/io.h~mm-ioremap-probe-platform-for-p4d-huge-map-support
+++ a/include/linux/io.h
@@ -33,6 +33,7 @@ static inline int ioremap_page_range(uns
#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
--- a/lib/ioremap.c~mm-ioremap-probe-platform-for-p4d-huge-map-support
+++ a/lib/ioremap.c
@@ -30,6 +30,8 @@ early_param("nohugeiomap", set_nohugeiom
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())
_
