target/linux/layerscape/patches-4.4/9070-Revert-arm64-use-fixmap-region-for-permanent-FDT-map.patch

   1 From 6f7a129e59721f6d97a0f06f7078d06f19ade69e Mon Sep 17 00:00:00 2001
   2 From: Yutang Jiang <yutang.jiang@nxp.com>
   3 Date: Thu, 21 Jul 2016 19:37:42 +0800
   4 Subject: [PATCH 70/70] Revert "arm64: use fixmap region for permanent FDT
   5  mapping"
   6
   7 Signed-off-by: Yutang Jiang <yutang.jiang@nxp.com>
   8 ---
   9  Documentation/arm64/booting.txt |   10 +++----
  10  arch/arm64/include/asm/boot.h   |   14 ----------
  11  arch/arm64/include/asm/fixmap.h |   15 -----------
  12  arch/arm64/include/asm/mmu.h    |    1 -
  13  arch/arm64/kernel/head.S        |   39 ++++++++++++++++++++++++++-
  14  arch/arm64/kernel/setup.c       |   29 +++++++++++++-------
  15  arch/arm64/mm/init.c            |    1 +
  16  arch/arm64/mm/mmu.c             |   57 ---------------------------------------
  17  8 files changed, 62 insertions(+), 104 deletions(-)
  18  delete mode 100644 arch/arm64/include/asm/boot.h
  19
  20 --- a/Documentation/arm64/booting.txt
  21 +++ b/Documentation/arm64/booting.txt
  22 @@ -45,13 +45,11 @@ sees fit.)
  23
  24  Requirement: MANDATORY
  25
  26 -The device tree blob (dtb) must be placed on an 8-byte boundary and must
  27 -not exceed 2 megabytes in size. Since the dtb will be mapped cacheable
  28 -using blocks of up to 2 megabytes in size, it must not be placed within
  29 -any 2M region which must be mapped with any specific attributes.
  30 +The device tree blob (dtb) must be placed on an 8-byte boundary within
  31 +the first 512 megabytes from the start of the kernel image and must not
  32 +cross a 2-megabyte boundary. This is to allow the kernel to map the
  33 +blob using a single section mapping in the initial page tables.
  34
  35 -NOTE: versions prior to v4.2 also require that the DTB be placed within
  36 -the 512 MB region starting at text_offset bytes below the kernel Image.
  37
  38  3. Decompress the kernel image
  39  ------------------------------
  40 --- a/arch/arm64/include/asm/boot.h
  41 +++ /dev/null
  42 @@ -1,14 +0,0 @@
  43 -
  44 -#ifndef __ASM_BOOT_H
  45 -#define __ASM_BOOT_H
  46 -
  47 -#include <asm/sizes.h>
  48 -
  49 -/*
  50 - * arm64 requires the DTB to be 8 byte aligned and
  51 - * not exceed 2MB in size.
  52 - */
  53 -#define MIN_FDT_ALIGN          8
  54 -#define MAX_FDT_SIZE           SZ_2M
  55 -
  56 -#endif
  57 --- a/arch/arm64/include/asm/fixmap.h
  58 +++ b/arch/arm64/include/asm/fixmap.h
  59 @@ -18,7 +18,6 @@
  60  #ifndef __ASSEMBLY__
  61  #include <linux/kernel.h>
  62  #include <linux/sizes.h>
  63 -#include <asm/boot.h>
  64  #include <asm/page.h>
  65
  66  /*
  67 @@ -34,20 +33,6 @@
  68   */
  69  enum fixed_addresses {
  70         FIX_HOLE,
  71 -
  72 -       /*
  73 -        * Reserve a virtual window for the FDT that is 2 MB larger than the
  74 -        * maximum supported size, and put it at the top of the fixmap region.
  75 -        * The additional space ensures that any FDT that does not exceed
  76 -        * MAX_FDT_SIZE can be mapped regardless of whether it crosses any
  77 -        * 2 MB alignment boundaries.
  78 -        *
  79 -        * Keep this at the top so it remains 2 MB aligned.
  80 -        */
  81 -#define FIX_FDT_SIZE           (MAX_FDT_SIZE + SZ_2M)
  82 -       FIX_FDT_END,
  83 -       FIX_FDT = FIX_FDT_END + FIX_FDT_SIZE / PAGE_SIZE - 1,
  84 -
  85         FIX_EARLYCON_MEM_BASE,
  86         FIX_TEXT_POKE0,
  87         __end_of_permanent_fixed_addresses,
  88 --- a/arch/arm64/include/asm/mmu.h
  89 +++ b/arch/arm64/include/asm/mmu.h
  90 @@ -34,6 +34,5 @@ extern void init_mem_pgprot(void);
  91  extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
  92                                unsigned long virt, phys_addr_t size,
  93                                pgprot_t prot);
  94 -extern void *fixmap_remap_fdt(phys_addr_t dt_phys);
  95
  96  #endif
  97 --- a/arch/arm64/kernel/head.S
  98 +++ b/arch/arm64/kernel/head.S
  99 @@ -212,6 +212,8 @@ ENTRY(stext)
 100         bl      el2_setup                       // Drop to EL1, w20=cpu_boot_mode
 101         adrp    x24, __PHYS_OFFSET
 102         bl      set_cpu_boot_mode_flag
 103 +
 104 +       bl      __vet_fdt
 105         bl      __create_page_tables            // x25=TTBR0, x26=TTBR1
 106         /*
 107          * The following calls CPU setup code, see arch/arm64/mm/proc.S for
 108 @@ -243,6 +245,24 @@ preserve_boot_args:
 109  ENDPROC(preserve_boot_args)
 110
 111  /*
 112 + * Determine validity of the x21 FDT pointer.
 113 + * The dtb must be 8-byte aligned and live in the first 512M of memory.
 114 + */
 115 +__vet_fdt:
 116 +       tst     x21, #0x7
 117 +       b.ne    1f
 118 +       cmp     x21, x24
 119 +       b.lt    1f
 120 +       mov     x0, #(1 << 29)
 121 +       add     x0, x0, x24
 122 +       cmp     x21, x0
 123 +       b.ge    1f
 124 +       ret
 125 +1:
 126 +       mov     x21, #0
 127 +       ret
 128 +ENDPROC(__vet_fdt)
 129 +/*
 130   * Macro to create a table entry to the next page.
 131   *
 132   *     tbl:    page table address
 133 @@ -306,7 +326,8 @@ ENDPROC(preserve_boot_args)
 134   * required to get the kernel running. The following sections are required:
 135   *   - identity mapping to enable the MMU (low address, TTBR0)
 136   *   - first few MB of the kernel linear mapping to jump to once the MMU has
 137 - *     been enabled
 138 + *     been enabled, including the FDT blob (TTBR1)
 139 + *   - pgd entry for fixed mappings (TTBR1)
 140   */
 141  __create_page_tables:
 142         adrp    x25, idmap_pg_dir
 143 @@ -396,6 +417,22 @@ __create_page_tables:
 144         create_block_map x0, x7, x3, x5, x6
 145
 146         /*
 147 +        * Map the FDT blob (maximum 2MB; must be within 512MB of
 148 +        * PHYS_OFFSET).
 149 +        */
 150 +       mov     x3, x21                         // FDT phys address
 151 +       and     x3, x3, #~((1 << 21) - 1)       // 2MB aligned
 152 +       mov     x6, #PAGE_OFFSET
 153 +       sub     x5, x3, x24                     // subtract PHYS_OFFSET
 154 +       tst     x5, #~((1 << 29) - 1)           // within 512MB?
 155 +       csel    x21, xzr, x21, ne               // zero the FDT pointer
 156 +       b.ne    1f
 157 +       add     x5, x5, x6                      // __va(FDT blob)
 158 +       add     x6, x5, #1 << 21                // 2MB for the FDT blob
 159 +       sub     x6, x6, #1                      // inclusive range
 160 +       create_block_map x0, x7, x3, x5, x6
 161 +1:
 162 +       /*
 163          * Since the page tables have been populated with non-cacheable
 164          * accesses (MMU disabled), invalidate the idmap and swapper page
 165          * tables again to remove any speculatively loaded cache lines.
 166 --- a/arch/arm64/kernel/setup.c
 167 +++ b/arch/arm64/kernel/setup.c
 168 @@ -87,6 +87,18 @@ static struct resource mem_res[] = {
 169  #define kernel_code mem_res[0]
 170  #define kernel_data mem_res[1]
 171
 172 +void __init early_print(const char *str, ...)
 173 +{
 174 +       char buf[256];
 175 +       va_list ap;
 176 +
 177 +       va_start(ap, str);
 178 +       vsnprintf(buf, sizeof(buf), str, ap);
 179 +       va_end(ap);
 180 +
 181 +       printk("%s", buf);
 182 +}
 183 +
 184  /*
 185   * The recorded values of x0 .. x3 upon kernel entry.
 186   */
 187 @@ -180,14 +192,12 @@ static void __init smp_build_mpidr_hash(
 188
 189  static void __init setup_machine_fdt(phys_addr_t dt_phys)
 190  {
 191 -       void *dt_virt = fixmap_remap_fdt(dt_phys);
 192 -
 193 -       if (!dt_virt || !early_init_dt_scan(dt_virt)) {
 194 -               pr_crit("\n"
 195 -                       "Error: invalid device tree blob at physical address %pa (virtual address 0x%p)\n"
 196 -                       "The dtb must be 8-byte aligned and must not exceed 2 MB in size\n"
 197 -                       "\nPlease check your bootloader.",
 198 -                       &dt_phys, dt_virt);
 199 +       if (!dt_phys || !early_init_dt_scan(phys_to_virt(dt_phys))) {
 200 +               early_print("\n"
 201 +                       "Error: invalid device tree blob at physical address 0x%p (virtual address 0x%p)\n"
 202 +                       "The dtb must be 8-byte aligned and passed in the first 512MB of memory\n"
 203 +                       "\nPlease check your bootloader.\n",
 204 +                       dt_phys, phys_to_virt(dt_phys));
 205
 206                 while (true)
 207                         cpu_relax();
 208 @@ -294,6 +304,7 @@ void __init setup_arch(char **cmdline_p)
 209         pr_info("Boot CPU: AArch64 Processor [%08x]\n", read_cpuid_id());
 210
 211         sprintf(init_utsname()->machine, ELF_PLATFORM);
 212 +       setup_machine_fdt(__fdt_pointer);
 213         init_mm.start_code = (unsigned long) _text;
 214         init_mm.end_code   = (unsigned long) _etext;
 215         init_mm.end_data   = (unsigned long) _edata;
 216 @@ -304,8 +315,6 @@ void __init setup_arch(char **cmdline_p)
 217         early_fixmap_init();
 218         early_ioremap_init();
 219
 220 -       setup_machine_fdt(__fdt_pointer);
 221 -
 222         parse_early_param();
 223
 224         /*
 225 --- a/arch/arm64/mm/init.c
 226 +++ b/arch/arm64/mm/init.c
 227 @@ -175,6 +175,7 @@ void __init arm64_memblock_init(void)
 228                 memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start);
 229  #endif
 230
 231 +       early_init_fdt_reserve_self();
 232         early_init_fdt_scan_reserved_mem();
 233
 234         /* 4GB maximum for 32-bit only capable devices */
 235 --- a/arch/arm64/mm/mmu.c
 236 +++ b/arch/arm64/mm/mmu.c
 237 @@ -21,7 +21,6 @@
 238  #include <linux/kernel.h>
 239  #include <linux/errno.h>
 240  #include <linux/init.h>
 241 -#include <linux/libfdt.h>
 242  #include <linux/mman.h>
 243  #include <linux/nodemask.h>
 244  #include <linux/memblock.h>
 245 @@ -642,62 +641,6 @@ void __set_fixmap(enum fixed_addresses i
 246         }
 247  }
 248
 249 -void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
 250 -{
 251 -       const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
 252 -       pgprot_t prot = PAGE_KERNEL_RO;
 253 -       int size, offset;
 254 -       void *dt_virt;
 255 -
 256 -       /*
 257 -        * Check whether the physical FDT address is set and meets the minimum
 258 -        * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
 259 -        * at least 8 bytes so that we can always access the magic and size
 260 -        * fields of the FDT header after mapping the first chunk, double check
 261 -        * here if that is indeed the case.
 262 -        */
 263 -       BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
 264 -       if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
 265 -               return NULL;
 266 -
 267 -       /*
 268 -        * Make sure that the FDT region can be mapped without the need to
 269 -        * allocate additional translation table pages, so that it is safe
 270 -        * to call create_mapping() this early.
 271 -        *
 272 -        * On 64k pages, the FDT will be mapped using PTEs, so we need to
 273 -        * be in the same PMD as the rest of the fixmap.
 274 -        * On 4k pages, we'll use section mappings for the FDT so we only
 275 -        * have to be in the same PUD.
 276 -        */
 277 -       BUILD_BUG_ON(dt_virt_base % SZ_2M);
 278 -
 279 -       BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
 280 -                    __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
 281 -
 282 -       offset = dt_phys % SWAPPER_BLOCK_SIZE;
 283 -       dt_virt = (void *)dt_virt_base + offset;
 284 -
 285 -       /* map the first chunk so we can read the size from the header */
 286 -       create_mapping(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
 287 -                      SWAPPER_BLOCK_SIZE, prot);
 288 -
 289 -       if (fdt_magic(dt_virt) != FDT_MAGIC)
 290 -               return NULL;
 291 -
 292 -       size = fdt_totalsize(dt_virt);
 293 -       if (size > MAX_FDT_SIZE)
 294 -               return NULL;
 295 -
 296 -       if (offset + size > SWAPPER_BLOCK_SIZE)
 297 -               create_mapping(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
 298 -                              round_up(offset + size, SWAPPER_BLOCK_SIZE), prot);
 299 -
 300 -       memblock_reserve(dt_phys, size);
 301 -
 302 -       return dt_virt;
 303 -}
 304 -
 305  #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
 306  int pud_free_pmd_page(pud_t *pud, unsigned long addr)
 307  {