diff options
Diffstat (limited to 'arch/x86/realmode/rm')
| -rw-r--r-- | arch/x86/realmode/rm/trampoline_64.S | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S index c9f76fae90..14d9c7daf9 100644 --- a/arch/x86/realmode/rm/trampoline_64.S +++ b/arch/x86/realmode/rm/trampoline_64.S @@ -37,13 +37,15 @@ .text .code16 -.macro LOCK_AND_LOAD_REALMODE_ESP lock_pa=0 +.macro LOCK_AND_LOAD_REALMODE_ESP lock_pa=0 lock_rip=0 /* * Make sure only one CPU fiddles with the realmode stack */ .Llock_rm\@: .if \lock_pa lock btsl $0, pa_tr_lock + .elseif \lock_rip + lock btsl $0, tr_lock(%rip) .else lock btsl $0, tr_lock .endif @@ -220,6 +222,35 @@ SYM_CODE_START(trampoline_start64) lidt tr_idt(%rip) lgdt tr_gdt64(%rip) + /* Check if paging mode has to be changed */ + movq %cr4, %rax + xorl tr_cr4(%rip), %eax + testl $X86_CR4_LA57, %eax + jnz .L_switch_paging + + /* Paging mode is correct proceed in 64-bit mode */ + + LOCK_AND_LOAD_REALMODE_ESP lock_rip=1 + + movw $__KERNEL_DS, %dx + movl %edx, %ss + addl $pa_real_mode_base, %esp + movl %edx, %ds + movl %edx, %es + movl %edx, %fs + movl %edx, %gs + + movl $pa_trampoline_pgd, %eax + movq %rax, %cr3 + + pushq $__KERNEL_CS + pushq tr_start(%rip) + lretq +.L_switch_paging: + /* + * To switch between 4- and 5-level paging modes, it is necessary + * to disable paging. This must be done in the compatibility mode. + */ ljmpl *tr_compat(%rip) SYM_CODE_END(trampoline_start64) |