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-rw-r--r--arch/arm64/kernel/head.S201
1 files changed, 178 insertions, 23 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index ffe9c2b6431b..4203d5f257bc 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -29,11 +29,14 @@
#include <asm/asm-offsets.h>
#include <asm/cache.h>
#include <asm/cputype.h>
+#include <asm/elf.h>
#include <asm/kernel-pgtable.h>
+#include <asm/kvm_arm.h>
#include <asm/memory.h>
#include <asm/pgtable-hwdef.h>
#include <asm/pgtable.h>
#include <asm/page.h>
+#include <asm/smp.h>
#include <asm/sysreg.h>
#include <asm/thread_info.h>
#include <asm/virt.h>
@@ -67,12 +70,11 @@
* in the entry routines.
*/
__HEAD
-
+_head:
/*
* DO NOT MODIFY. Image header expected by Linux boot-loaders.
*/
#ifdef CONFIG_EFI
-efi_head:
/*
* This add instruction has no meaningful effect except that
* its opcode forms the magic "MZ" signature required by UEFI.
@@ -83,9 +85,9 @@ efi_head:
b stext // branch to kernel start, magic
.long 0 // reserved
#endif
- .quad _kernel_offset_le // Image load offset from start of RAM, little-endian
- .quad _kernel_size_le // Effective size of kernel image, little-endian
- .quad _kernel_flags_le // Informative flags, little-endian
+ le64sym _kernel_offset_le // Image load offset from start of RAM, little-endian
+ le64sym _kernel_size_le // Effective size of kernel image, little-endian
+ le64sym _kernel_flags_le // Informative flags, little-endian
.quad 0 // reserved
.quad 0 // reserved
.quad 0 // reserved
@@ -94,14 +96,14 @@ efi_head:
.byte 0x4d
.byte 0x64
#ifdef CONFIG_EFI
- .long pe_header - efi_head // Offset to the PE header.
+ .long pe_header - _head // Offset to the PE header.
#else
.word 0 // reserved
#endif
#ifdef CONFIG_EFI
.globl __efistub_stext_offset
- .set __efistub_stext_offset, stext - efi_head
+ .set __efistub_stext_offset, stext - _head
.align 3
pe_header:
.ascii "PE"
@@ -124,7 +126,7 @@ optional_header:
.long _end - stext // SizeOfCode
.long 0 // SizeOfInitializedData
.long 0 // SizeOfUninitializedData
- .long __efistub_entry - efi_head // AddressOfEntryPoint
+ .long __efistub_entry - _head // AddressOfEntryPoint
.long __efistub_stext_offset // BaseOfCode
extra_header_fields:
@@ -139,7 +141,7 @@ extra_header_fields:
.short 0 // MinorSubsystemVersion
.long 0 // Win32VersionValue
- .long _end - efi_head // SizeOfImage
+ .long _end - _head // SizeOfImage
// Everything before the kernel image is considered part of the header
.long __efistub_stext_offset // SizeOfHeaders
@@ -210,6 +212,7 @@ section_table:
ENTRY(stext)
bl preserve_boot_args
bl el2_setup // Drop to EL1, w20=cpu_boot_mode
+ mov x23, xzr // KASLR offset, defaults to 0
adrp x24, __PHYS_OFFSET
bl set_cpu_boot_mode_flag
bl __create_page_tables // x25=TTBR0, x26=TTBR1
@@ -219,11 +222,13 @@ ENTRY(stext)
* On return, the CPU will be ready for the MMU to be turned on and
* the TCR will have been set.
*/
- ldr x27, =__mmap_switched // address to jump to after
+ ldr x27, 0f // address to jump to after
// MMU has been enabled
adr_l lr, __enable_mmu // return (PIC) address
b __cpu_setup // initialise processor
ENDPROC(stext)
+ .align 3
+0: .quad __mmap_switched - (_head - TEXT_OFFSET) + KIMAGE_VADDR
/*
* Preserve the arguments passed by the bootloader in x0 .. x3
@@ -311,7 +316,7 @@ ENDPROC(preserve_boot_args)
__create_page_tables:
adrp x25, idmap_pg_dir
adrp x26, swapper_pg_dir
- mov x27, lr
+ mov x28, lr
/*
* Invalidate the idmap and swapper page tables to avoid potential
@@ -389,9 +394,11 @@ __create_page_tables:
* Map the kernel image (starting with PHYS_OFFSET).
*/
mov x0, x26 // swapper_pg_dir
- mov x5, #PAGE_OFFSET
+ ldr x5, =KIMAGE_VADDR
+ add x5, x5, x23 // add KASLR displacement
create_pgd_entry x0, x5, x3, x6
- ldr x6, =KERNEL_END // __va(KERNEL_END)
+ ldr w6, kernel_img_size
+ add x6, x6, x5
mov x3, x24 // phys offset
create_block_map x0, x7, x3, x5, x6
@@ -405,9 +412,11 @@ __create_page_tables:
dmb sy
bl __inval_cache_range
- mov lr, x27
- ret
+ ret x28
ENDPROC(__create_page_tables)
+
+kernel_img_size:
+ .long _end - (_head - TEXT_OFFSET)
.ltorg
/*
@@ -415,23 +424,81 @@ ENDPROC(__create_page_tables)
*/
.set initial_sp, init_thread_union + THREAD_START_SP
__mmap_switched:
+ mov x28, lr // preserve LR
+ adr_l x8, vectors // load VBAR_EL1 with virtual
+ msr vbar_el1, x8 // vector table address
+ isb
+
// Clear BSS
adr_l x0, __bss_start
mov x1, xzr
adr_l x2, __bss_stop
sub x2, x2, x0
bl __pi_memset
+ dsb ishst // Make zero page visible to PTW
+
+#ifdef CONFIG_RELOCATABLE
+
+ /*
+ * Iterate over each entry in the relocation table, and apply the
+ * relocations in place.
+ */
+ adr_l x8, __dynsym_start // start of symbol table
+ adr_l x9, __reloc_start // start of reloc table
+ adr_l x10, __reloc_end // end of reloc table
+
+0: cmp x9, x10
+ b.hs 2f
+ ldp x11, x12, [x9], #24
+ ldr x13, [x9, #-8]
+ cmp w12, #R_AARCH64_RELATIVE
+ b.ne 1f
+ add x13, x13, x23 // relocate
+ str x13, [x11, x23]
+ b 0b
+
+1: cmp w12, #R_AARCH64_ABS64
+ b.ne 0b
+ add x12, x12, x12, lsl #1 // symtab offset: 24x top word
+ add x12, x8, x12, lsr #(32 - 3) // ... shifted into bottom word
+ ldrsh w14, [x12, #6] // Elf64_Sym::st_shndx
+ ldr x15, [x12, #8] // Elf64_Sym::st_value
+ cmp w14, #-0xf // SHN_ABS (0xfff1) ?
+ add x14, x15, x23 // relocate
+ csel x15, x14, x15, ne
+ add x15, x13, x15
+ str x15, [x11, x23]
+ b 0b
+
+2: adr_l x8, kimage_vaddr // make relocated kimage_vaddr
+ dc cvac, x8 // value visible to secondaries
+ dsb sy // with MMU off
+#endif
adr_l sp, initial_sp, x4
mov x4, sp
and x4, x4, #~(THREAD_SIZE - 1)
msr sp_el0, x4 // Save thread_info
str_l x21, __fdt_pointer, x5 // Save FDT pointer
- str_l x24, memstart_addr, x6 // Save PHYS_OFFSET
+
+ ldr_l x4, kimage_vaddr // Save the offset between
+ sub x4, x4, x24 // the kernel virtual and
+ str_l x4, kimage_voffset, x5 // physical mappings
+
mov x29, #0
#ifdef CONFIG_KASAN
bl kasan_early_init
#endif
+#ifdef CONFIG_RANDOMIZE_BASE
+ cbnz x23, 0f // already running randomized?
+ mov x0, x21 // pass FDT address in x0
+ bl kaslr_early_init // parse FDT for KASLR options
+ cbz x0, 0f // KASLR disabled? just proceed
+ mov x23, x0 // record KASLR offset
+ ret x28 // we must enable KASLR, return
+ // to __enable_mmu()
+0:
+#endif
b start_kernel
ENDPROC(__mmap_switched)
@@ -440,6 +507,10 @@ ENDPROC(__mmap_switched)
* hotplug and needs to have the same protections as the text region
*/
.section ".text","ax"
+
+ENTRY(kimage_vaddr)
+ .quad _text - TEXT_OFFSET
+
/*
* If we're fortunate enough to boot at EL2, ensure that the world is
* sane before dropping to EL1.
@@ -464,9 +535,27 @@ CPU_LE( bic x0, x0, #(3 << 24) ) // Clear the EE and E0E bits for EL1
isb
ret
+2:
+#ifdef CONFIG_ARM64_VHE
+ /*
+ * Check for VHE being present. For the rest of the EL2 setup,
+ * x2 being non-zero indicates that we do have VHE, and that the
+ * kernel is intended to run at EL2.
+ */
+ mrs x2, id_aa64mmfr1_el1
+ ubfx x2, x2, #8, #4
+#else
+ mov x2, xzr
+#endif
+
/* Hyp configuration. */
-2: mov x0, #(1 << 31) // 64-bit EL1
+ mov x0, #HCR_RW // 64-bit EL1
+ cbz x2, set_hcr
+ orr x0, x0, #HCR_TGE // Enable Host Extensions
+ orr x0, x0, #HCR_E2H
+set_hcr:
msr hcr_el2, x0
+ isb
/* Generic timers. */
mrs x0, cnthctl_el2
@@ -514,13 +603,25 @@ CPU_LE( movk x0, #0x30d0, lsl #16 ) // Clear EE and E0E on LE systems
#endif
/* EL2 debug */
+ mrs x0, id_aa64dfr0_el1 // Check ID_AA64DFR0_EL1 PMUVer
+ sbfx x0, x0, #8, #4
+ cmp x0, #1
+ b.lt 4f // Skip if no PMU present
mrs x0, pmcr_el0 // Disable debug access traps
ubfx x0, x0, #11, #5 // to EL2 and allow access to
msr mdcr_el2, x0 // all PMU counters from EL1
+4:
/* Stage-2 translation */
msr vttbr_el2, xzr
+ cbz x2, install_el2_stub
+
+ mov w20, #BOOT_CPU_MODE_EL2 // This CPU booted in EL2
+ isb
+ ret
+
+install_el2_stub:
/* Hypervisor stub */
adrp x0, __hyp_stub_vectors
add x0, x0, #:lo12:__hyp_stub_vectors
@@ -600,13 +701,20 @@ ENTRY(secondary_startup)
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
+ ldr x8, kimage_vaddr
+ ldr w9, 0f
+ sub x27, x8, w9, sxtw // address to jump to after enabling the MMU
b __enable_mmu
ENDPROC(secondary_startup)
+0: .long (_text - TEXT_OFFSET) - __secondary_switched
ENTRY(__secondary_switched)
- ldr x0, [x21] // get secondary_data.stack
+ adr_l x5, vectors
+ msr vbar_el1, x5
+ isb
+
+ adr_l x0, secondary_data
+ ldr x0, [x0, #CPU_BOOT_STACK] // get secondary_data.stack
mov sp, x0
and x0, x0, #~(THREAD_SIZE - 1)
msr sp_el0, x0 // save thread_info
@@ -615,6 +723,29 @@ ENTRY(__secondary_switched)
ENDPROC(__secondary_switched)
/*
+ * The booting CPU updates the failed status @__early_cpu_boot_status,
+ * with MMU turned off.
+ *
+ * update_early_cpu_boot_status tmp, status
+ * - Corrupts tmp1, tmp2
+ * - Writes 'status' to __early_cpu_boot_status and makes sure
+ * it is committed to memory.
+ */
+
+ .macro update_early_cpu_boot_status status, tmp1, tmp2
+ mov \tmp2, #\status
+ str_l \tmp2, __early_cpu_boot_status, \tmp1
+ dmb sy
+ dc ivac, \tmp1 // Invalidate potentially stale cache line
+ .endm
+
+ .pushsection .data..cacheline_aligned
+ .align L1_CACHE_SHIFT
+ENTRY(__early_cpu_boot_status)
+ .long 0
+ .popsection
+
+/*
* Enable the MMU.
*
* x0 = SCTLR_EL1 value for turning on the MMU.
@@ -627,12 +758,12 @@ ENDPROC(__secondary_switched)
*/
.section ".idmap.text", "ax"
__enable_mmu:
+ mrs x22, sctlr_el1 // preserve old SCTLR_EL1 value
mrs x1, ID_AA64MMFR0_EL1
ubfx x2, x1, #ID_AA64MMFR0_TGRAN_SHIFT, 4
cmp x2, #ID_AA64MMFR0_TGRAN_SUPPORTED
b.ne __no_granule_support
- ldr x5, =vectors
- msr vbar_el1, x5
+ update_early_cpu_boot_status 0, x1, x2
msr ttbr0_el1, x25 // load TTBR0
msr ttbr1_el1, x26 // load TTBR1
isb
@@ -646,10 +777,34 @@ __enable_mmu:
ic iallu
dsb nsh
isb
+#ifdef CONFIG_RANDOMIZE_BASE
+ mov x19, x0 // preserve new SCTLR_EL1 value
+ blr x27
+
+ /*
+ * If we return here, we have a KASLR displacement in x23 which we need
+ * to take into account by discarding the current kernel mapping and
+ * creating a new one.
+ */
+ msr sctlr_el1, x22 // disable the MMU
+ isb
+ bl __create_page_tables // recreate kernel mapping
+
+ msr sctlr_el1, x19 // re-enable the MMU
+ isb
+ ic iallu // flush instructions fetched
+ dsb nsh // via old mapping
+ isb
+ add x27, x27, x23 // relocated __mmap_switched
+#endif
br x27
ENDPROC(__enable_mmu)
__no_granule_support:
+ /* Indicate that this CPU can't boot and is stuck in the kernel */
+ update_early_cpu_boot_status CPU_STUCK_IN_KERNEL, x1, x2
+1:
wfe
- b __no_granule_support
+ wfi
+ b 1b
ENDPROC(__no_granule_support)