arm64: remove __calc_phys_offset

This removes the function __calc_phys_offset and all open coded
virtual to physical address translations using the offset kept
in x28.

Instead, just use absolute or PC-relative symbol references as
appropriate when referring to virtual or physical addresses,
respectively.

Tested-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 11 insertions, 36 deletions

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 750403c62928..f5ac337f9598 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -36,7 +36,7 @@
 #include <asm/page.h>
 #include <asm/virt.h>
 
-#define KERNEL_RAM_VADDR        (PAGE_OFFSET + TEXT_OFFSET)
+#define __PHYS_OFFSET   (KERNEL_START - TEXT_OFFSET)
 
 #if (TEXT_OFFSET & 0xfff) != 0
 #error TEXT_OFFSET must be at least 4KB aligned
@@ -46,13 +46,6 @@
 #error TEXT_OFFSET must be less than 2MB
 #endif
 
-        .macro  pgtbl, ttb0, ttb1, virt_to_phys
-        ldr     \ttb1, =swapper_pg_dir
-        ldr     \ttb0, =idmap_pg_dir
-        add     \ttb1, \ttb1, \virt_to_phys
-        add     \ttb0, \ttb0, \virt_to_phys
-        .endm
-
 #ifdef CONFIG_ARM64_64K_PAGES
 #define BLOCK_SHIFT     PAGE_SHIFT
 #define BLOCK_SIZE      PAGE_SIZE
@@ -63,7 +56,7 @@
 #define TABLE_SHIFT     PUD_SHIFT
 #endif
 
-#define KERNEL_START    KERNEL_RAM_VADDR
+#define KERNEL_START    _text
 #define KERNEL_END      _end
 
 /*
@@ -242,7 +235,7 @@ section_table:
 ENTRY(stext)
         mov     x21, x0                         // x21=FDT
         bl      el2_setup                       // Drop to EL1, w20=cpu_boot_mode
-        bl      __calc_phys_offset              // x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET
+        adrp    x24, __PHYS_OFFSET
         bl      set_cpu_boot_mode_flag
 
         bl      __vet_fdt
@@ -342,7 +335,8 @@ ENDPROC(__vet_fdt)
  *   - pgd entry for fixed mappings (TTBR1)
  */
 __create_page_tables:
-        pgtbl   x25, x26, x28                   // idmap_pg_dir and swapper_pg_dir addresses
+        adrp    x25, idmap_pg_dir
+        adrp    x26, swapper_pg_dir
         mov     x27, lr
 
         /*
@@ -371,12 +365,10 @@ __create_page_tables:
          * Create the identity mapping.
          */
         mov     x0, x25                         // idmap_pg_dir
-        ldr     x3, =KERNEL_START
-        add     x3, x3, x28                     // __pa(KERNEL_START)
+        adrp    x3, KERNEL_START                // __pa(KERNEL_START)
         create_pgd_entry x0, x3, x5, x6
-        ldr     x6, =KERNEL_END
         mov     x5, x3                          // __pa(KERNEL_START)
-        add     x6, x6, x28                     // __pa(KERNEL_END)
+        adr_l   x6, KERNEL_END                  // __pa(KERNEL_END)
         create_block_map x0, x7, x3, x5, x6
 
         /*
@@ -385,7 +377,7 @@ __create_page_tables:
         mov     x0, x26                         // swapper_pg_dir
         mov     x5, #PAGE_OFFSET
         create_pgd_entry x0, x5, x3, x6
-        ldr     x6, =KERNEL_END
+        ldr     x6, =KERNEL_END                 // __va(KERNEL_END)
         mov     x3, x24                         // phys offset
         create_block_map x0, x7, x3, x5, x6
 
@@ -537,8 +529,7 @@ ENDPROC(el2_setup)
  * in x20. See arch/arm64/include/asm/virt.h for more info.
  */
 ENTRY(set_cpu_boot_mode_flag)
-        ldr     x1, =__boot_cpu_mode            // Compute __boot_cpu_mode
-        add     x1, x1, x28
+        adr_l   x1, __boot_cpu_mode
         cmp     w20, #BOOT_CPU_MODE_EL2
         b.ne    1f
         add     x1, x1, #4
@@ -569,7 +560,6 @@ ENTRY(__boot_cpu_mode)
          */
 ENTRY(secondary_holding_pen)
         bl      el2_setup                       // Drop to EL1, w20=cpu_boot_mode
-        bl      __calc_phys_offset              // x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET
         bl      set_cpu_boot_mode_flag
         mrs     x0, mpidr_el1
         ldr     x1, =MPIDR_HWID_BITMASK
@@ -588,7 +578,6 @@ ENDPROC(secondary_holding_pen)
          */
 ENTRY(secondary_entry)
         bl      el2_setup                       // Drop to EL1
-        bl      __calc_phys_offset              // x24=PHYS_OFFSET, x28=PHYS_OFFSET-PAGE_OFFSET
         bl      set_cpu_boot_mode_flag
         b       secondary_startup
 ENDPROC(secondary_entry)
@@ -597,7 +586,8 @@ ENTRY(secondary_startup)
         /*
          * Common entry point for secondary CPUs.
          */
-        pgtbl   x25, x26, x28                   // x25=TTBR0, x26=TTBR1
+        adrp    x25, idmap_pg_dir
+        adrp    x26, swapper_pg_dir
         bl      __cpu_setup                     // initialise processor
 
         ldr     x21, =secondary_data
@@ -631,18 +621,3 @@ __enable_mmu:
         isb
         br      x27
 ENDPROC(__enable_mmu)
-
-/*
- * Calculate the start of physical memory.
- */
-__calc_phys_offset:
-        adr     x0, 1f
-        ldp     x1, x2, [x0]
-        sub     x28, x0, x1                     // x28 = PHYS_OFFSET - PAGE_OFFSET
-        add     x24, x2, x28                    // x24 = PHYS_OFFSET
-        ret
-ENDPROC(__calc_phys_offset)
-
-        .align 3
-1:      .quad   .
-        .quad   PAGE_OFFSET