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-rw-r--r--arch/x86/kernel/head_64.S151
1 files changed, 55 insertions, 96 deletions
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index d4918d03ef..d8198fbd70 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -26,6 +26,7 @@
#include <asm/apicdef.h>
#include <asm/fixmap.h>
#include <asm/smp.h>
+#include <asm/thread_info.h>
/*
* We are not able to switch in one step to the final KERNEL ADDRESS SPACE
@@ -39,7 +40,6 @@ L4_START_KERNEL = l4_index(__START_KERNEL_map)
L3_START_KERNEL = pud_index(__START_KERNEL_map)
- .text
__HEAD
.code64
SYM_CODE_START_NOALIGN(startup_64)
@@ -66,9 +66,7 @@ SYM_CODE_START_NOALIGN(startup_64)
mov %rsi, %r15
/* Set up the stack for verify_cpu() */
- leaq (__end_init_task - PTREGS_SIZE)(%rip), %rsp
-
- leaq _text(%rip), %rdi
+ leaq (__end_init_task - TOP_OF_KERNEL_STACK_PADDING - PTREGS_SIZE)(%rip), %rsp
/* Setup GSBASE to allow stack canary access for C code */
movl $MSR_GS_BASE, %ecx
@@ -77,7 +75,7 @@ SYM_CODE_START_NOALIGN(startup_64)
shrq $32, %rdx
wrmsr
- call startup_64_setup_env
+ call startup_64_setup_gdt_idt
/* Now switch to __KERNEL_CS so IRET works reliably */
pushq $__KERNEL_CS
@@ -113,13 +111,11 @@ SYM_CODE_START_NOALIGN(startup_64)
call __startup_64
/* Form the CR3 value being sure to include the CR3 modifier */
- addq $(early_top_pgt - __START_KERNEL_map), %rax
+ leaq early_top_pgt(%rip), %rcx
+ addq %rcx, %rax
#ifdef CONFIG_AMD_MEM_ENCRYPT
mov %rax, %rdi
- mov %rax, %r14
-
- addq phys_base(%rip), %rdi
/*
* For SEV guests: Verify that the C-bit is correct. A malicious
@@ -128,17 +124,23 @@ SYM_CODE_START_NOALIGN(startup_64)
* the next RET instruction.
*/
call sev_verify_cbit
+#endif
/*
- * Restore CR3 value without the phys_base which will be added
- * below, before writing %cr3.
+ * Switch to early_top_pgt which still has the identity mappings
+ * present.
*/
- mov %r14, %rax
-#endif
+ movq %rax, %cr3
- jmp 1f
+ /* Branch to the common startup code at its kernel virtual address */
+ ANNOTATE_RETPOLINE_SAFE
+ jmp *0f(%rip)
SYM_CODE_END(startup_64)
+ __INITRODATA
+0: .quad common_startup_64
+
+ .text
SYM_CODE_START(secondary_startup_64)
UNWIND_HINT_END_OF_STACK
ANNOTATE_NOENDBR
@@ -171,22 +173,39 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
ANNOTATE_NOENDBR
/* Clear %R15 which holds the boot_params pointer on the boot CPU */
- xorq %r15, %r15
+ xorl %r15d, %r15d
+
+ /* Derive the runtime physical address of init_top_pgt[] */
+ movq phys_base(%rip), %rax
+ addq $(init_top_pgt - __START_KERNEL_map), %rax
/*
* Retrieve the modifier (SME encryption mask if SME is active) to be
* added to the initial pgdir entry that will be programmed into CR3.
*/
#ifdef CONFIG_AMD_MEM_ENCRYPT
- movq sme_me_mask, %rax
-#else
- xorq %rax, %rax
+ addq sme_me_mask(%rip), %rax
#endif
+ /*
+ * Switch to the init_top_pgt here, away from the trampoline_pgd and
+ * unmap the identity mapped ranges.
+ */
+ movq %rax, %cr3
- /* Form the CR3 value being sure to include the CR3 modifier */
- addq $(init_top_pgt - __START_KERNEL_map), %rax
-1:
+SYM_INNER_LABEL(common_startup_64, SYM_L_LOCAL)
+ UNWIND_HINT_END_OF_STACK
+ ANNOTATE_NOENDBR
+ /*
+ * Create a mask of CR4 bits to preserve. Omit PGE in order to flush
+ * global 1:1 translations from the TLBs.
+ *
+ * From the SDM:
+ * "If CR4.PGE is changing from 0 to 1, there were no global TLB
+ * entries before the execution; if CR4.PGE is changing from 1 to 0,
+ * there will be no global TLB entries after the execution."
+ */
+ movl $(X86_CR4_PAE | X86_CR4_LA57), %edx
#ifdef CONFIG_X86_MCE
/*
* Preserve CR4.MCE if the kernel will enable #MC support.
@@ -195,52 +214,20 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
* configured will crash the system regardless of the CR4.MCE value set
* here.
*/
- movq %cr4, %rcx
- andl $X86_CR4_MCE, %ecx
-#else
- movl $0, %ecx
+ orl $X86_CR4_MCE, %edx
#endif
+ movq %cr4, %rcx
+ andl %edx, %ecx
- /* Enable PAE mode, PSE, PGE and LA57 */
- orl $(X86_CR4_PAE | X86_CR4_PSE | X86_CR4_PGE), %ecx
-#ifdef CONFIG_X86_5LEVEL
- testb $1, __pgtable_l5_enabled(%rip)
- jz 1f
- orl $X86_CR4_LA57, %ecx
-1:
-#endif
+ /* Even if ignored in long mode, set PSE uniformly on all logical CPUs. */
+ btsl $X86_CR4_PSE_BIT, %ecx
movq %rcx, %cr4
- /* Setup early boot stage 4-/5-level pagetables. */
- addq phys_base(%rip), %rax
-
/*
- * Switch to new page-table
- *
- * For the boot CPU this switches to early_top_pgt which still has the
- * identity mappings present. The secondary CPUs will switch to the
- * init_top_pgt here, away from the trampoline_pgd and unmap the
- * identity mapped ranges.
+ * Set CR4.PGE to re-enable global translations.
*/
- movq %rax, %cr3
-
- /*
- * Do a global TLB flush after the CR3 switch to make sure the TLB
- * entries from the identity mapping are flushed.
- */
- movq %cr4, %rcx
- movq %rcx, %rax
- xorq $X86_CR4_PGE, %rcx
+ btsl $X86_CR4_PGE_BIT, %ecx
movq %rcx, %cr4
- movq %rax, %cr4
-
- /* Ensure I am executing from virtual addresses */
- movq $1f, %rax
- ANNOTATE_RETPOLINE_SAFE
- jmp *%rax
-1:
- UNWIND_HINT_END_OF_STACK
- ANNOTATE_NOENDBR // above
#ifdef CONFIG_SMP
/*
@@ -297,7 +284,7 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
.Llookup_AP:
/* EAX contains the APIC ID of the current CPU */
- xorq %rcx, %rcx
+ xorl %ecx, %ecx
leaq cpuid_to_apicid(%rip), %rbx
.Lfind_cpunr:
@@ -428,39 +415,10 @@ SYM_INNER_LABEL(secondary_startup_64_no_verify, SYM_L_GLOBAL)
movq %r15, %rdi
.Ljump_to_C_code:
- /*
- * Jump to run C code and to be on a real kernel address.
- * Since we are running on identity-mapped space we have to jump
- * to the full 64bit address, this is only possible as indirect
- * jump. In addition we need to ensure %cs is set so we make this
- * a far return.
- *
- * Note: do not change to far jump indirect with 64bit offset.
- *
- * AMD does not support far jump indirect with 64bit offset.
- * AMD64 Architecture Programmer's Manual, Volume 3: states only
- * JMP FAR mem16:16 FF /5 Far jump indirect,
- * with the target specified by a far pointer in memory.
- * JMP FAR mem16:32 FF /5 Far jump indirect,
- * with the target specified by a far pointer in memory.
- *
- * Intel64 does support 64bit offset.
- * Software Developer Manual Vol 2: states:
- * FF /5 JMP m16:16 Jump far, absolute indirect,
- * address given in m16:16
- * FF /5 JMP m16:32 Jump far, absolute indirect,
- * address given in m16:32.
- * REX.W + FF /5 JMP m16:64 Jump far, absolute indirect,
- * address given in m16:64.
- */
- pushq $.Lafter_lret # put return address on stack for unwinder
xorl %ebp, %ebp # clear frame pointer
- movq initial_code(%rip), %rax
- pushq $__KERNEL_CS # set correct cs
- pushq %rax # target address in negative space
- lretq
-.Lafter_lret:
- ANNOTATE_NOENDBR
+ ANNOTATE_RETPOLINE_SAFE
+ callq *initial_code(%rip)
+ ud2
SYM_CODE_END(secondary_startup_64)
#include "verify_cpu.S"
@@ -477,7 +435,7 @@ SYM_CODE_START(soft_restart_cpu)
UNWIND_HINT_END_OF_STACK
/* Find the idle task stack */
- movq PER_CPU_VAR(pcpu_hot) + X86_current_task, %rcx
+ movq PER_CPU_VAR(pcpu_hot + X86_current_task), %rcx
movq TASK_threadsp(%rcx), %rsp
jmp .Ljump_to_C_code
@@ -622,7 +580,7 @@ SYM_CODE_END(vc_no_ghcb)
#define SYM_DATA_START_PAGE_ALIGNED(name) \
SYM_START(name, SYM_L_GLOBAL, .balign PAGE_SIZE)
-#ifdef CONFIG_PAGE_TABLE_ISOLATION
+#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
/*
* Each PGD needs to be 8k long and 8k aligned. We do not
* ever go out to userspace with these, so we do not
@@ -655,7 +613,8 @@ SYM_CODE_END(vc_no_ghcb)
.balign 4
SYM_DATA_START_PTI_ALIGNED(early_top_pgt)
- .fill 512,8,0
+ .fill 511,8,0
+ .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC
.fill PTI_USER_PGD_FILL,8,0
SYM_DATA_END(early_top_pgt)