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openwrt/target/linux/layerscape/patches-4.4/9070-Revert-arm64-use-fixma...

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From 6f7a129e59721f6d97a0f06f7078d06f19ade69e Mon Sep 17 00:00:00 2001
From: Yutang Jiang <yutang.jiang@nxp.com>
Date: Thu, 21 Jul 2016 19:37:42 +0800
Subject: [PATCH 70/70] Revert "arm64: use fixmap region for permanent FDT
mapping"
Signed-off-by: Yutang Jiang <yutang.jiang@nxp.com>
---
Documentation/arm64/booting.txt | 10 +++----
arch/arm64/include/asm/boot.h | 14 ----------
arch/arm64/include/asm/fixmap.h | 15 -----------
arch/arm64/include/asm/mmu.h | 1 -
arch/arm64/kernel/head.S | 39 ++++++++++++++++++++++++++-
arch/arm64/kernel/setup.c | 29 +++++++++++++-------
arch/arm64/mm/init.c | 1 +
arch/arm64/mm/mmu.c | 57 ---------------------------------------
8 files changed, 62 insertions(+), 104 deletions(-)
delete mode 100644 arch/arm64/include/asm/boot.h
--- a/Documentation/arm64/booting.txt
+++ b/Documentation/arm64/booting.txt
@@ -45,13 +45,11 @@ sees fit.)
Requirement: MANDATORY
-The device tree blob (dtb) must be placed on an 8-byte boundary and must
-not exceed 2 megabytes in size. Since the dtb will be mapped cacheable
-using blocks of up to 2 megabytes in size, it must not be placed within
-any 2M region which must be mapped with any specific attributes.
+The device tree blob (dtb) must be placed on an 8-byte boundary within
+the first 512 megabytes from the start of the kernel image and must not
+cross a 2-megabyte boundary. This is to allow the kernel to map the
+blob using a single section mapping in the initial page tables.
-NOTE: versions prior to v4.2 also require that the DTB be placed within
-the 512 MB region starting at text_offset bytes below the kernel Image.
3. Decompress the kernel image
------------------------------
--- a/arch/arm64/include/asm/boot.h
+++ /dev/null
@@ -1,14 +0,0 @@
-
-#ifndef __ASM_BOOT_H
-#define __ASM_BOOT_H
-
-#include <asm/sizes.h>
-
-/*
- * arm64 requires the DTB to be 8 byte aligned and
- * not exceed 2MB in size.
- */
-#define MIN_FDT_ALIGN 8
-#define MAX_FDT_SIZE SZ_2M
-
-#endif
--- a/arch/arm64/include/asm/fixmap.h
+++ b/arch/arm64/include/asm/fixmap.h
@@ -18,7 +18,6 @@
#ifndef __ASSEMBLY__
#include <linux/kernel.h>
#include <linux/sizes.h>
-#include <asm/boot.h>
#include <asm/page.h>
/*
@@ -34,20 +33,6 @@
*/
enum fixed_addresses {
FIX_HOLE,
-
- /*
- * Reserve a virtual window for the FDT that is 2 MB larger than the
- * maximum supported size, and put it at the top of the fixmap region.
- * The additional space ensures that any FDT that does not exceed
- * MAX_FDT_SIZE can be mapped regardless of whether it crosses any
- * 2 MB alignment boundaries.
- *
- * Keep this at the top so it remains 2 MB aligned.
- */
-#define FIX_FDT_SIZE (MAX_FDT_SIZE + SZ_2M)
- FIX_FDT_END,
- FIX_FDT = FIX_FDT_END + FIX_FDT_SIZE / PAGE_SIZE - 1,
-
FIX_EARLYCON_MEM_BASE,
FIX_TEXT_POKE0,
__end_of_permanent_fixed_addresses,
--- a/arch/arm64/include/asm/mmu.h
+++ b/arch/arm64/include/asm/mmu.h
@@ -34,6 +34,5 @@ extern void init_mem_pgprot(void);
extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
unsigned long virt, phys_addr_t size,
pgprot_t prot);
-extern void *fixmap_remap_fdt(phys_addr_t dt_phys);
#endif
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -212,6 +212,8 @@ ENTRY(stext)
bl el2_setup // Drop to EL1, w20=cpu_boot_mode
adrp x24, __PHYS_OFFSET
bl set_cpu_boot_mode_flag
+
+ bl __vet_fdt
bl __create_page_tables // x25=TTBR0, x26=TTBR1
/*
* The following calls CPU setup code, see arch/arm64/mm/proc.S for
@@ -243,6 +245,24 @@ preserve_boot_args:
ENDPROC(preserve_boot_args)
/*
+ * Determine validity of the x21 FDT pointer.
+ * The dtb must be 8-byte aligned and live in the first 512M of memory.
+ */
+__vet_fdt:
+ tst x21, #0x7
+ b.ne 1f
+ cmp x21, x24
+ b.lt 1f
+ mov x0, #(1 << 29)
+ add x0, x0, x24
+ cmp x21, x0
+ b.ge 1f
+ ret
+1:
+ mov x21, #0
+ ret
+ENDPROC(__vet_fdt)
+/*
* Macro to create a table entry to the next page.
*
* tbl: page table address
@@ -306,7 +326,8 @@ ENDPROC(preserve_boot_args)
* required to get the kernel running. The following sections are required:
* - identity mapping to enable the MMU (low address, TTBR0)
* - first few MB of the kernel linear mapping to jump to once the MMU has
- * been enabled
+ * been enabled, including the FDT blob (TTBR1)
+ * - pgd entry for fixed mappings (TTBR1)
*/
__create_page_tables:
adrp x25, idmap_pg_dir
@@ -396,6 +417,22 @@ __create_page_tables:
create_block_map x0, x7, x3, x5, x6
/*
+ * Map the FDT blob (maximum 2MB; must be within 512MB of
+ * PHYS_OFFSET).
+ */
+ mov x3, x21 // FDT phys address
+ and x3, x3, #~((1 << 21) - 1) // 2MB aligned
+ mov x6, #PAGE_OFFSET
+ sub x5, x3, x24 // subtract PHYS_OFFSET
+ tst x5, #~((1 << 29) - 1) // within 512MB?
+ csel x21, xzr, x21, ne // zero the FDT pointer
+ b.ne 1f
+ add x5, x5, x6 // __va(FDT blob)
+ add x6, x5, #1 << 21 // 2MB for the FDT blob
+ sub x6, x6, #1 // inclusive range
+ create_block_map x0, x7, x3, x5, x6
+1:
+ /*
* Since the page tables have been populated with non-cacheable
* accesses (MMU disabled), invalidate the idmap and swapper page
* tables again to remove any speculatively loaded cache lines.
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -87,6 +87,18 @@ static struct resource mem_res[] = {
#define kernel_code mem_res[0]
#define kernel_data mem_res[1]
+void __init early_print(const char *str, ...)
+{
+ char buf[256];
+ va_list ap;
+
+ va_start(ap, str);
+ vsnprintf(buf, sizeof(buf), str, ap);
+ va_end(ap);
+
+ printk("%s", buf);
+}
+
/*
* The recorded values of x0 .. x3 upon kernel entry.
*/
@@ -180,14 +192,12 @@ static void __init smp_build_mpidr_hash(
static void __init setup_machine_fdt(phys_addr_t dt_phys)
{
- void *dt_virt = fixmap_remap_fdt(dt_phys);
-
- if (!dt_virt || !early_init_dt_scan(dt_virt)) {
- pr_crit("\n"
- "Error: invalid device tree blob at physical address %pa (virtual address 0x%p)\n"
- "The dtb must be 8-byte aligned and must not exceed 2 MB in size\n"
- "\nPlease check your bootloader.",
- &dt_phys, dt_virt);
+ if (!dt_phys || !early_init_dt_scan(phys_to_virt(dt_phys))) {
+ early_print("\n"
+ "Error: invalid device tree blob at physical address 0x%p (virtual address 0x%p)\n"
+ "The dtb must be 8-byte aligned and passed in the first 512MB of memory\n"
+ "\nPlease check your bootloader.\n",
+ dt_phys, phys_to_virt(dt_phys));
while (true)
cpu_relax();
@@ -294,6 +304,7 @@ void __init setup_arch(char **cmdline_p)
pr_info("Boot CPU: AArch64 Processor [%08x]\n", read_cpuid_id());
sprintf(init_utsname()->machine, ELF_PLATFORM);
+ setup_machine_fdt(__fdt_pointer);
init_mm.start_code = (unsigned long) _text;
init_mm.end_code = (unsigned long) _etext;
init_mm.end_data = (unsigned long) _edata;
@@ -304,8 +315,6 @@ void __init setup_arch(char **cmdline_p)
early_fixmap_init();
early_ioremap_init();
- setup_machine_fdt(__fdt_pointer);
-
parse_early_param();
/*
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -171,6 +171,7 @@ void __init arm64_memblock_init(void)
memblock_reserve(__virt_to_phys(initrd_start), initrd_end - initrd_start);
#endif
+ early_init_fdt_reserve_self();
early_init_fdt_scan_reserved_mem();
/* 4GB maximum for 32-bit only capable devices */
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -21,7 +21,6 @@
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
-#include <linux/libfdt.h>
#include <linux/mman.h>
#include <linux/nodemask.h>
#include <linux/memblock.h>
@@ -641,59 +640,3 @@ void __set_fixmap(enum fixed_addresses i
flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
}
}
-
-void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
-{
- const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
- pgprot_t prot = PAGE_KERNEL_RO;
- int size, 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() 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(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(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
- round_up(offset + size, SWAPPER_BLOCK_SIZE), prot);
-
- memblock_reserve(dt_phys, size);
-
- return dt_virt;
-}
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