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 <[email protected]> Cc: Will Deacon <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Michal Hocko <[email protected]> Cc: [email protected] Cc: [email protected] Signed-off-by: Anshuman Khandual <[email protected]> --- - Detected this from code audit while reviewing Nicholas Piggin's 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 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 a1bfc4413982..646c82922d77 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 4b6423e7bd21..6cbbec83991d 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 32e30e8fb9db..58514cebfce6 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 063213685563..c3dc213b6980 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()) -- 2.20.1
