[PATCH 1/2] arm64: mm: move fixmap code to its own file
Mark Rutland
mark.rutland at arm.com
Tue Mar 14 07:21:24 PDT 2023
Over time, arm64's mm/mmu.c has become increasingly large and painful to
navigate. Move the fixmap code to its own file where it can be understood in
isolation.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland at arm.com>
Cc: Anshuman Khandual <anshuman.khandual at arm.com>
Cc: Ard Biesheuvel <ardb at kernel.org>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Ryan Roberts <ryan.roberts at arm.com>
Cc: Will Deacon <will at kernel.org>
---
arch/arm64/include/asm/fixmap.h | 1 +
arch/arm64/include/asm/mmu.h | 2 +
arch/arm64/mm/Makefile | 2 +-
arch/arm64/mm/fixmap.c | 215 ++++++++++++++++++++++++++++++++
arch/arm64/mm/mmu.c | 197 +----------------------------
5 files changed, 222 insertions(+), 195 deletions(-)
create mode 100644 arch/arm64/mm/fixmap.c
diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
index 71ed5fdf718b..c153f069e9c9 100644
--- a/arch/arm64/include/asm/fixmap.h
+++ b/arch/arm64/include/asm/fixmap.h
@@ -101,6 +101,7 @@ enum fixed_addresses {
#define FIXMAP_PAGE_IO __pgprot(PROT_DEVICE_nGnRE)
void __init early_fixmap_init(void);
+void __init fixmap_copy(pgd_t *pgdir);
#define __early_set_fixmap __set_fixmap
diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h
index 48f8466a4be9..4384eaa0aeb7 100644
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -65,6 +65,8 @@ extern void paging_init(void);
extern void bootmem_init(void);
extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
extern void init_mem_pgprot(void);
+extern void create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
+ phys_addr_t size, pgprot_t prot);
extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
unsigned long virt, phys_addr_t size,
pgprot_t prot, bool page_mappings_only);
diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile
index ff1e800ba7a1..dbd1bc95967d 100644
--- a/arch/arm64/mm/Makefile
+++ b/arch/arm64/mm/Makefile
@@ -2,7 +2,7 @@
obj-y := dma-mapping.o extable.o fault.o init.o \
cache.o copypage.o flush.o \
ioremap.o mmap.o pgd.o mmu.o \
- context.o proc.o pageattr.o
+ context.o proc.o pageattr.o fixmap.o
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
obj-$(CONFIG_PTDUMP_CORE) += ptdump.o
obj-$(CONFIG_PTDUMP_DEBUGFS) += ptdump_debugfs.o
diff --git a/arch/arm64/mm/fixmap.c b/arch/arm64/mm/fixmap.c
new file mode 100644
index 000000000000..54e50552bfe3
--- /dev/null
+++ b/arch/arm64/mm/fixmap.c
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Fixmap manipulation code
+ */
+
+#include <linux/bug.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/libfdt.h>
+#include <linux/memory.h>
+#include <linux/mm.h>
+#include <linux/sizes.h>
+
+#include <asm/fixmap.h>
+#include <asm/kernel-pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+
+static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
+static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
+static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
+
+static inline pud_t *fixmap_pud(unsigned long addr)
+{
+ pgd_t *pgdp = pgd_offset_k(addr);
+ p4d_t *p4dp = p4d_offset(pgdp, addr);
+ p4d_t p4d = READ_ONCE(*p4dp);
+
+ BUG_ON(p4d_none(p4d) || p4d_bad(p4d));
+
+ return pud_offset_kimg(p4dp, addr);
+}
+
+static inline pmd_t *fixmap_pmd(unsigned long addr)
+{
+ pud_t *pudp = fixmap_pud(addr);
+ pud_t pud = READ_ONCE(*pudp);
+
+ BUG_ON(pud_none(pud) || pud_bad(pud));
+
+ return pmd_offset_kimg(pudp, addr);
+}
+
+static inline pte_t *fixmap_pte(unsigned long addr)
+{
+ return &bm_pte[pte_index(addr)];
+}
+
+/*
+ * The p*d_populate functions call virt_to_phys implicitly so they can't be used
+ * directly on kernel symbols (bm_p*d). This function is called too early to use
+ * lm_alias so __p*d_populate functions must be used to populate with the
+ * physical address from __pa_symbol.
+ */
+void __init early_fixmap_init(void)
+{
+ pgd_t *pgdp;
+ p4d_t *p4dp, p4d;
+ pud_t *pudp;
+ pmd_t *pmdp;
+ unsigned long addr = FIXADDR_START;
+
+ pgdp = pgd_offset_k(addr);
+ p4dp = p4d_offset(pgdp, addr);
+ p4d = READ_ONCE(*p4dp);
+ if (CONFIG_PGTABLE_LEVELS > 3 &&
+ !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) {
+ /*
+ * We only end up here if the kernel mapping and the fixmap
+ * share the top level pgd entry, which should only happen on
+ * 16k/4 levels configurations.
+ */
+ BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
+ pudp = pud_offset_kimg(p4dp, addr);
+ } else {
+ if (p4d_none(p4d))
+ __p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE);
+ pudp = fixmap_pud(addr);
+ }
+ if (pud_none(READ_ONCE(*pudp)))
+ __pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE);
+ pmdp = fixmap_pmd(addr);
+ __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE);
+
+ /*
+ * The boot-ioremap range spans multiple pmds, for which
+ * we are not prepared:
+ */
+ BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
+ != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
+
+ if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
+ || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
+ WARN_ON(1);
+ pr_warn("pmdp %p != %p, %p\n",
+ pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
+ fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
+ pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
+ fix_to_virt(FIX_BTMAP_BEGIN));
+ pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n",
+ fix_to_virt(FIX_BTMAP_END));
+
+ pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END);
+ pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN);
+ }
+}
+
+/*
+ * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we
+ * ever need to use IPIs for TLB broadcasting, then we're in trouble here.
+ */
+void __set_fixmap(enum fixed_addresses idx,
+ phys_addr_t phys, pgprot_t flags)
+{
+ unsigned long addr = __fix_to_virt(idx);
+ pte_t *ptep;
+
+ BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
+
+ ptep = fixmap_pte(addr);
+
+ if (pgprot_val(flags)) {
+ set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags));
+ } else {
+ pte_clear(&init_mm, addr, ptep);
+ flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
+ }
+}
+
+void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
+{
+ const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
+ int offset;
+ void *dt_virt;
+
+ /*
+ * Check whether the physical FDT address is set and meets the minimum
+ * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
+ * at least 8 bytes so that we can always access the magic and size
+ * fields of the FDT header after mapping the first chunk, double check
+ * here if that is indeed the case.
+ */
+ BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
+ if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
+ return NULL;
+
+ /*
+ * Make sure that the FDT region can be mapped without the need to
+ * allocate additional translation table pages, so that it is safe
+ * to call create_mapping_noalloc() this early.
+ *
+ * On 64k pages, the FDT will be mapped using PTEs, so we need to
+ * be in the same PMD as the rest of the fixmap.
+ * On 4k pages, we'll use section mappings for the FDT so we only
+ * have to be in the same PUD.
+ */
+ BUILD_BUG_ON(dt_virt_base % SZ_2M);
+
+ BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
+ __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
+
+ offset = dt_phys % SWAPPER_BLOCK_SIZE;
+ dt_virt = (void *)dt_virt_base + offset;
+
+ /* map the first chunk so we can read the size from the header */
+ create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
+ dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
+
+ if (fdt_magic(dt_virt) != FDT_MAGIC)
+ return NULL;
+
+ *size = fdt_totalsize(dt_virt);
+ if (*size > MAX_FDT_SIZE)
+ return NULL;
+
+ if (offset + *size > SWAPPER_BLOCK_SIZE)
+ create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
+ round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);
+
+ return dt_virt;
+}
+
+/*
+ * Copy the fixmap region into a new pgdir.
+ */
+void __init fixmap_copy(pgd_t *pgdir)
+{
+ if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdir, FIXADDR_START)))) {
+ /*
+ * The fixmap falls in a separate pgd to the kernel, and doesn't
+ * live in the carveout for the swapper_pg_dir. We can simply
+ * re-use the existing dir for the fixmap.
+ */
+ set_pgd(pgd_offset_pgd(pgdir, FIXADDR_START),
+ READ_ONCE(*pgd_offset_k(FIXADDR_START)));
+ } else if (CONFIG_PGTABLE_LEVELS > 3) {
+ pgd_t *bm_pgdp;
+ p4d_t *bm_p4dp;
+ pud_t *bm_pudp;
+ /*
+ * The fixmap shares its top level pgd entry with the kernel
+ * mapping. This can really only occur when we are running
+ * with 16k/4 levels, so we can simply reuse the pud level
+ * entry instead.
+ */
+ BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
+ bm_pgdp = pgd_offset_pgd(pgdir, FIXADDR_START);
+ bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START);
+ bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START);
+ pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd));
+ pud_clear_fixmap();
+ } else {
+ BUG();
+ }
+}
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 6f9d8898a025..f67bd80135c3 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -71,10 +71,6 @@ long __section(".mmuoff.data.write") __early_cpu_boot_status;
unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
EXPORT_SYMBOL(empty_zero_page);
-static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
-static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
-static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
-
static DEFINE_SPINLOCK(swapper_pgdir_lock);
static DEFINE_MUTEX(fixmap_lock);
@@ -450,8 +446,8 @@ static phys_addr_t pgd_pgtable_alloc(int shift)
* without allocating new levels of table. Note that this permits the
* creation of new section or page entries.
*/
-static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
- phys_addr_t size, pgprot_t prot)
+void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
+ phys_addr_t size, pgprot_t prot)
{
if ((virt >= PAGE_END) && (virt < VMALLOC_START)) {
pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
@@ -734,34 +730,7 @@ static void __init map_kernel(pgd_t *pgdp)
&vmlinux_initdata, 0, VM_NO_GUARD);
map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0);
- if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdp, FIXADDR_START)))) {
- /*
- * The fixmap falls in a separate pgd to the kernel, and doesn't
- * live in the carveout for the swapper_pg_dir. We can simply
- * re-use the existing dir for the fixmap.
- */
- set_pgd(pgd_offset_pgd(pgdp, FIXADDR_START),
- READ_ONCE(*pgd_offset_k(FIXADDR_START)));
- } else if (CONFIG_PGTABLE_LEVELS > 3) {
- pgd_t *bm_pgdp;
- p4d_t *bm_p4dp;
- pud_t *bm_pudp;
- /*
- * The fixmap shares its top level pgd entry with the kernel
- * mapping. This can really only occur when we are running
- * with 16k/4 levels, so we can simply reuse the pud level
- * entry instead.
- */
- BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
- bm_pgdp = pgd_offset_pgd(pgdp, FIXADDR_START);
- bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START);
- bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START);
- pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd));
- pud_clear_fixmap();
- } else {
- BUG();
- }
-
+ fixmap_copy(pgdp);
kasan_copy_shadow(pgdp);
}
@@ -1176,166 +1145,6 @@ void vmemmap_free(unsigned long start, unsigned long end,
}
#endif /* CONFIG_MEMORY_HOTPLUG */
-static inline pud_t *fixmap_pud(unsigned long addr)
-{
- pgd_t *pgdp = pgd_offset_k(addr);
- p4d_t *p4dp = p4d_offset(pgdp, addr);
- p4d_t p4d = READ_ONCE(*p4dp);
-
- BUG_ON(p4d_none(p4d) || p4d_bad(p4d));
-
- return pud_offset_kimg(p4dp, addr);
-}
-
-static inline pmd_t *fixmap_pmd(unsigned long addr)
-{
- pud_t *pudp = fixmap_pud(addr);
- pud_t pud = READ_ONCE(*pudp);
-
- BUG_ON(pud_none(pud) || pud_bad(pud));
-
- return pmd_offset_kimg(pudp, addr);
-}
-
-static inline pte_t *fixmap_pte(unsigned long addr)
-{
- return &bm_pte[pte_index(addr)];
-}
-
-/*
- * The p*d_populate functions call virt_to_phys implicitly so they can't be used
- * directly on kernel symbols (bm_p*d). This function is called too early to use
- * lm_alias so __p*d_populate functions must be used to populate with the
- * physical address from __pa_symbol.
- */
-void __init early_fixmap_init(void)
-{
- pgd_t *pgdp;
- p4d_t *p4dp, p4d;
- pud_t *pudp;
- pmd_t *pmdp;
- unsigned long addr = FIXADDR_START;
-
- pgdp = pgd_offset_k(addr);
- p4dp = p4d_offset(pgdp, addr);
- p4d = READ_ONCE(*p4dp);
- if (CONFIG_PGTABLE_LEVELS > 3 &&
- !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) {
- /*
- * We only end up here if the kernel mapping and the fixmap
- * share the top level pgd entry, which should only happen on
- * 16k/4 levels configurations.
- */
- BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
- pudp = pud_offset_kimg(p4dp, addr);
- } else {
- if (p4d_none(p4d))
- __p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE);
- pudp = fixmap_pud(addr);
- }
- if (pud_none(READ_ONCE(*pudp)))
- __pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE);
- pmdp = fixmap_pmd(addr);
- __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE);
-
- /*
- * The boot-ioremap range spans multiple pmds, for which
- * we are not prepared:
- */
- BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
- != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
-
- if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
- || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
- WARN_ON(1);
- pr_warn("pmdp %p != %p, %p\n",
- pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
- fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
- pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
- fix_to_virt(FIX_BTMAP_BEGIN));
- pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n",
- fix_to_virt(FIX_BTMAP_END));
-
- pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END);
- pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN);
- }
-}
-
-/*
- * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we
- * ever need to use IPIs for TLB broadcasting, then we're in trouble here.
- */
-void __set_fixmap(enum fixed_addresses idx,
- phys_addr_t phys, pgprot_t flags)
-{
- unsigned long addr = __fix_to_virt(idx);
- pte_t *ptep;
-
- BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
-
- ptep = fixmap_pte(addr);
-
- if (pgprot_val(flags)) {
- set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags));
- } else {
- pte_clear(&init_mm, addr, ptep);
- flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
- }
-}
-
-void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
-{
- const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
- int offset;
- void *dt_virt;
-
- /*
- * Check whether the physical FDT address is set and meets the minimum
- * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
- * at least 8 bytes so that we can always access the magic and size
- * fields of the FDT header after mapping the first chunk, double check
- * here if that is indeed the case.
- */
- BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
- if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
- return NULL;
-
- /*
- * Make sure that the FDT region can be mapped without the need to
- * allocate additional translation table pages, so that it is safe
- * to call create_mapping_noalloc() this early.
- *
- * On 64k pages, the FDT will be mapped using PTEs, so we need to
- * be in the same PMD as the rest of the fixmap.
- * On 4k pages, we'll use section mappings for the FDT so we only
- * have to be in the same PUD.
- */
- BUILD_BUG_ON(dt_virt_base % SZ_2M);
-
- BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
- __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
-
- offset = dt_phys % SWAPPER_BLOCK_SIZE;
- dt_virt = (void *)dt_virt_base + offset;
-
- /* map the first chunk so we can read the size from the header */
- create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
- dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
-
- if (fdt_magic(dt_virt) != FDT_MAGIC)
- return NULL;
-
- *size = fdt_totalsize(dt_virt);
- if (*size > MAX_FDT_SIZE)
- return NULL;
-
- if (offset + *size > SWAPPER_BLOCK_SIZE)
- create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
- round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);
-
- return dt_virt;
-}
-
int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
{
pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot));
--
2.30.2
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