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authorDave Airlie <airlied@redhat.com>2015-04-20 11:32:26 +1000
committerDave Airlie <airlied@redhat.com>2015-04-20 13:05:20 +1000
commit2c33ce009ca2389dbf0535d0672214d09738e35e (patch)
tree6186a6458c3c160385d794a23eaf07c786a9e61b /arch/arm64/kernel/head.S
parentcec32a47010647e8b0603726ebb75b990a4057a4 (diff)
parent09d51602cf84a1264946711dd4ea0dddbac599a1 (diff)
Merge Linus master into drm-next
The merge is clean, but the arm build fails afterwards, due to API changes in the regulator tree. I've included the patch into the merge to fix the build. Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'arch/arm64/kernel/head.S')
-rw-r--r--arch/arm64/kernel/head.S261
1 files changed, 92 insertions, 169 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 07f930540f4a..19f915e8f6e0 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
/*
@@ -240,40 +233,43 @@ section_table:
#endif
ENTRY(stext)
- mov x21, x0 // x21=FDT
+ bl preserve_boot_args
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
- mrs x22, midr_el1 // x22=cpuid
- mov x0, x22
- bl lookup_processor_type
- mov x23, x0 // x23=current cpu_table
- /*
- * __error_p may end up out of range for cbz if text areas are
- * aligned up to section sizes.
- */
- cbnz x23, 1f // invalid processor (x23=0)?
- b __error_p
-1:
+
bl __vet_fdt
bl __create_page_tables // x25=TTBR0, x26=TTBR1
/*
- * The following calls CPU specific code in a position independent
- * manner. See arch/arm64/mm/proc.S for details. x23 = base of
- * cpu_info structure selected by lookup_processor_type above.
+ * The following calls CPU setup code, see arch/arm64/mm/proc.S for
+ * details.
* On return, the CPU will be ready for the MMU to be turned on and
* the TCR will have been set.
*/
- ldr x27, __switch_data // address to jump to after
+ ldr x27, =__mmap_switched // address to jump to after
// MMU has been enabled
- adrp lr, __enable_mmu // return (PIC) address
- add lr, lr, #:lo12:__enable_mmu
- ldr x12, [x23, #CPU_INFO_SETUP]
- add x12, x12, x28 // __virt_to_phys
- br x12 // initialise processor
+ adr_l lr, __enable_mmu // return (PIC) address
+ b __cpu_setup // initialise processor
ENDPROC(stext)
/*
+ * Preserve the arguments passed by the bootloader in x0 .. x3
+ */
+preserve_boot_args:
+ mov x21, x0 // x21=FDT
+
+ adr_l x0, boot_args // record the contents of
+ stp x21, x1, [x0] // x0 .. x3 at kernel entry
+ stp x2, x3, [x0, #16]
+
+ dmb sy // needed before dc ivac with
+ // MMU off
+
+ add x1, x0, #0x20 // 4 x 8 bytes
+ b __inval_cache_range // tail call
+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.
*/
@@ -356,7 +352,8 @@ 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
/*
@@ -385,12 +382,50 @@ __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)
+
+#ifndef CONFIG_ARM64_VA_BITS_48
+#define EXTRA_SHIFT (PGDIR_SHIFT + PAGE_SHIFT - 3)
+#define EXTRA_PTRS (1 << (48 - EXTRA_SHIFT))
+
+ /*
+ * If VA_BITS < 48, it may be too small to allow for an ID mapping to be
+ * created that covers system RAM if that is located sufficiently high
+ * in the physical address space. So for the ID map, use an extended
+ * virtual range in that case, by configuring an additional translation
+ * level.
+ * First, we have to verify our assumption that the current value of
+ * VA_BITS was chosen such that all translation levels are fully
+ * utilised, and that lowering T0SZ will always result in an additional
+ * translation level to be configured.
+ */
+#if VA_BITS != EXTRA_SHIFT
+#error "Mismatch between VA_BITS and page size/number of translation levels"
+#endif
+
+ /*
+ * Calculate the maximum allowed value for TCR_EL1.T0SZ so that the
+ * entire kernel image can be ID mapped. As T0SZ == (64 - #bits used),
+ * this number conveniently equals the number of leading zeroes in
+ * the physical address of KERNEL_END.
+ */
+ adrp x5, KERNEL_END
+ clz x5, x5
+ cmp x5, TCR_T0SZ(VA_BITS) // default T0SZ small enough?
+ b.ge 1f // .. then skip additional level
+
+ adr_l x6, idmap_t0sz
+ str x5, [x6]
+ dmb sy
+ dc ivac, x6 // Invalidate potentially stale cache line
+
+ create_table_entry x0, x3, EXTRA_SHIFT, EXTRA_PTRS, x5, x6
+1:
+#endif
+
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
/*
@@ -399,7 +434,7 @@ __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
@@ -426,6 +461,7 @@ __create_page_tables:
*/
mov x0, x25
add x1, x26, #SWAPPER_DIR_SIZE
+ dmb sy
bl __inval_cache_range
mov lr, x27
@@ -433,37 +469,22 @@ __create_page_tables:
ENDPROC(__create_page_tables)
.ltorg
- .align 3
- .type __switch_data, %object
-__switch_data:
- .quad __mmap_switched
- .quad __bss_start // x6
- .quad __bss_stop // x7
- .quad processor_id // x4
- .quad __fdt_pointer // x5
- .quad memstart_addr // x6
- .quad init_thread_union + THREAD_START_SP // sp
-
/*
- * The following fragment of code is executed with the MMU on in MMU mode, and
- * uses absolute addresses; this is not position independent.
+ * The following fragment of code is executed with the MMU enabled.
*/
+ .set initial_sp, init_thread_union + THREAD_START_SP
__mmap_switched:
- adr x3, __switch_data + 8
+ adr_l x6, __bss_start
+ adr_l x7, __bss_stop
- ldp x6, x7, [x3], #16
1: cmp x6, x7
b.hs 2f
str xzr, [x6], #8 // Clear BSS
b 1b
2:
- ldp x4, x5, [x3], #16
- ldr x6, [x3], #8
- ldr x16, [x3]
- mov sp, x16
- str x22, [x4] // Save processor ID
- str x21, [x5] // Save FDT pointer
- str x24, [x6] // Save PHYS_OFFSET
+ adr_l sp, initial_sp, x4
+ str_l x21, __fdt_pointer, x5 // Save FDT pointer
+ str_l x24, memstart_addr, x6 // Save PHYS_OFFSET
mov x29, #0
b start_kernel
ENDPROC(__mmap_switched)
@@ -566,8 +587,7 @@ 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
@@ -588,29 +608,21 @@ ENDPROC(set_cpu_boot_mode_flag)
.align L1_CACHE_SHIFT
ENTRY(__boot_cpu_mode)
.long BOOT_CPU_MODE_EL2
- .long 0
+ .long BOOT_CPU_MODE_EL1
.popsection
#ifdef CONFIG_SMP
- .align 3
-1: .quad .
- .quad secondary_holding_pen_release
-
/*
* This provides a "holding pen" for platforms to hold all secondary
* cores are held until we're ready for them to initialise.
*/
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
and x0, x0, x1
- adr x1, 1b
- ldp x2, x3, [x1]
- sub x1, x1, x2
- add x3, x3, x1
+ adr_l x3, secondary_holding_pen_release
pen: ldr x4, [x3]
cmp x4, x0
b.eq secondary_startup
@@ -624,7 +636,6 @@ 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)
@@ -633,16 +644,9 @@ ENTRY(secondary_startup)
/*
* Common entry point for secondary CPUs.
*/
- mrs x22, midr_el1 // x22=cpuid
- mov x0, x22
- bl lookup_processor_type
- mov x23, x0 // x23=current cpu_table
- cbz x23, __error_p // invalid processor (x23=0)?
-
- pgtbl x25, x26, x28 // x25=TTBR0, x26=TTBR1
- ldr x12, [x23, #CPU_INFO_SETUP]
- add x12, x12, x28 // __virt_to_phys
- blr x12 // initialise processor
+ adrp x25, idmap_pg_dir
+ adrp x26, swapper_pg_dir
+ bl __cpu_setup // initialise processor
ldr x21, =secondary_data
ldr x27, =__secondary_switched // address to jump to after enabling the MMU
@@ -658,11 +662,12 @@ ENDPROC(__secondary_switched)
#endif /* CONFIG_SMP */
/*
- * Setup common bits before finally enabling the MMU. Essentially this is just
- * loading the page table pointer and vector base registers.
+ * Enable the MMU.
*
- * On entry to this code, x0 must contain the SCTLR_EL1 value for turning on
- * the MMU.
+ * x0 = SCTLR_EL1 value for turning on the MMU.
+ * x27 = *virtual* address to jump to upon completion
+ *
+ * other registers depend on the function called upon completion
*/
__enable_mmu:
ldr x5, =vectors
@@ -670,89 +675,7 @@ __enable_mmu:
msr ttbr0_el1, x25 // load TTBR0
msr ttbr1_el1, x26 // load TTBR1
isb
- b __turn_mmu_on
-ENDPROC(__enable_mmu)
-
-/*
- * Enable the MMU. This completely changes the structure of the visible memory
- * space. You will not be able to trace execution through this.
- *
- * x0 = system control register
- * x27 = *virtual* address to jump to upon completion
- *
- * other registers depend on the function called upon completion
- *
- * We align the entire function to the smallest power of two larger than it to
- * ensure it fits within a single block map entry. Otherwise were PHYS_OFFSET
- * close to the end of a 512MB or 1GB block we might require an additional
- * table to map the entire function.
- */
- .align 4
-__turn_mmu_on:
msr sctlr_el1, x0
isb
br x27
-ENDPROC(__turn_mmu_on)
-
-/*
- * 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
-
-/*
- * Exception handling. Something went wrong and we can't proceed. We ought to
- * tell the user, but since we don't have any guarantee that we're even
- * running on the right architecture, we do virtually nothing.
- */
-__error_p:
-ENDPROC(__error_p)
-
-__error:
-1: nop
- b 1b
-ENDPROC(__error)
-
-/*
- * This function gets the processor ID in w0 and searches the cpu_table[] for
- * a match. It returns a pointer to the struct cpu_info it found. The
- * cpu_table[] must end with an empty (all zeros) structure.
- *
- * This routine can be called via C code and it needs to work with the MMU
- * both disabled and enabled (the offset is calculated automatically).
- */
-ENTRY(lookup_processor_type)
- adr x1, __lookup_processor_type_data
- ldp x2, x3, [x1]
- sub x1, x1, x2 // get offset between VA and PA
- add x3, x3, x1 // convert VA to PA
-1:
- ldp w5, w6, [x3] // load cpu_id_val and cpu_id_mask
- cbz w5, 2f // end of list?
- and w6, w6, w0
- cmp w5, w6
- b.eq 3f
- add x3, x3, #CPU_INFO_SZ
- b 1b
-2:
- mov x3, #0 // unknown processor
-3:
- mov x0, x3
- ret
-ENDPROC(lookup_processor_type)
-
- .align 3
- .type __lookup_processor_type_data, %object
-__lookup_processor_type_data:
- .quad .
- .quad cpu_table
- .size __lookup_processor_type_data, . - __lookup_processor_type_data
+ENDPROC(__enable_mmu)