[PATCH v3 04/60] arm64: mm: Move PCI I/O emulation region above the vmemmap region

Ard Biesheuvel
2023-03-07T14:07:08Z

Move the PCI I/O region above the vmemmap region in the kernel's VA
space. This will permit us to reclaim the lower part of the vmemmap
region for vmalloc/vmap allocations when running a 52-bit VA capable
build on a 48-bit VA capable system.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm64/include/asm/memory.h | 4 ++--
arch/arm64/mm/ptdump.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index a4e1d832a15a2d7a..6e321cc06a3c30f0 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -49,8 +49,8 @@
#define MODULES_VSIZE (SZ_128M)
#define VMEMMAP_START (-(UL(1) << (VA_BITS - VMEMMAP_SHIFT)))
#define VMEMMAP_END (VMEMMAP_START + VMEMMAP_SIZE)
-#define PCI_IO_END (VMEMMAP_START - SZ_8M)
-#define PCI_IO_START (PCI_IO_END - PCI_IO_SIZE)
+#define PCI_IO_START (VMEMMAP_END + SZ_8M)
+#define PCI_IO_END (PCI_IO_START + PCI_IO_SIZE)
#define FIXADDR_TOP (VMEMMAP_START - SZ_32M)

#if VA_BITS > 48
diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c
index 9bc4066c5bf33a72..9d1f4cdc6672ed5f 100644
--- a/arch/arm64/mm/ptdump.c
+++ b/arch/arm64/mm/ptdump.c
@@ -47,10 +47,10 @@ static struct addr_marker address_markers[] = {
{ VMALLOC_END, "vmalloc() end" },
{ FIXADDR_START, "Fixmap start" },
{ FIXADDR_TOP, "Fixmap end" },
- { PCI_IO_START, "PCI I/O start" },
- { PCI_IO_END, "PCI I/O end" },
{ VMEMMAP_START, "vmemmap start" },
{ VMEMMAP_START + VMEMMAP_SIZE, "vmemmap end" },
+ { PCI_IO_START, "PCI I/O start" },
+ { PCI_IO_END, "PCI I/O end" },
{ -1, NULL },
};

--
2.39.2