diff options
Diffstat (limited to 'arch/x86/realmode/rm')
| -rw-r--r-- | arch/x86/realmode/rm/header.S | 1 | ||||
| -rw-r--r-- | arch/x86/realmode/rm/trampoline_64.S | 57 | ||||
| -rw-r--r-- | arch/x86/realmode/rm/trampoline_common.S | 12 | ||||
| -rw-r--r-- | arch/x86/realmode/rm/wakemain.c | 4 |
4 files changed, 69 insertions, 5 deletions
diff --git a/arch/x86/realmode/rm/header.S b/arch/x86/realmode/rm/header.S index 8c1db5bf5d78..2eb62be6d256 100644 --- a/arch/x86/realmode/rm/header.S +++ b/arch/x86/realmode/rm/header.S @@ -24,6 +24,7 @@ SYM_DATA_START(real_mode_header) .long pa_sev_es_trampoline_start #endif #ifdef CONFIG_X86_64 + .long pa_trampoline_start64 .long pa_trampoline_pgd; #endif /* ACPI S3 wakeup */ diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S index cc8391f86cdb..e38d61d6562e 100644 --- a/arch/x86/realmode/rm/trampoline_64.S +++ b/arch/x86/realmode/rm/trampoline_64.S @@ -70,7 +70,7 @@ SYM_CODE_START(trampoline_start) movw $__KERNEL_DS, %dx # Data segment descriptor # Enable protected mode - movl $X86_CR0_PE, %eax # protected mode (PE) bit + movl $(CR0_STATE & ~X86_CR0_PG), %eax movl %eax, %cr0 # into protected mode # flush prefetch and jump to startup_32 @@ -143,13 +143,24 @@ SYM_CODE_START(startup_32) movl %eax, %cr3 # Set up EFER + movl $MSR_EFER, %ecx + rdmsr + /* + * Skip writing to EFER if the register already has desired + * value (to avoid #VE for the TDX guest). + */ + cmp pa_tr_efer, %eax + jne .Lwrite_efer + cmp pa_tr_efer + 4, %edx + je .Ldone_efer +.Lwrite_efer: movl pa_tr_efer, %eax movl pa_tr_efer + 4, %edx - movl $MSR_EFER, %ecx wrmsr - # Enable paging and in turn activate Long Mode - movl $(X86_CR0_PG | X86_CR0_WP | X86_CR0_PE), %eax +.Ldone_efer: + # Enable paging and in turn activate Long Mode. + movl $CR0_STATE, %eax movl %eax, %cr0 /* @@ -161,6 +172,19 @@ SYM_CODE_START(startup_32) ljmpl $__KERNEL_CS, $pa_startup_64 SYM_CODE_END(startup_32) +SYM_CODE_START(pa_trampoline_compat) + /* + * In compatibility mode. Prep ESP and DX for startup_32, then disable + * paging and complete the switch to legacy 32-bit mode. + */ + movl $rm_stack_end, %esp + movw $__KERNEL_DS, %dx + + movl $(CR0_STATE & ~X86_CR0_PG), %eax + movl %eax, %cr0 + ljmpl $__KERNEL32_CS, $pa_startup_32 +SYM_CODE_END(pa_trampoline_compat) + .section ".text64","ax" .code64 .balign 4 @@ -169,6 +193,20 @@ SYM_CODE_START(startup_64) jmpq *tr_start(%rip) SYM_CODE_END(startup_64) +SYM_CODE_START(trampoline_start64) + /* + * APs start here on a direct transfer from 64-bit BIOS with identity + * mapped page tables. Load the kernel's GDT in order to gear down to + * 32-bit mode (to handle 4-level vs. 5-level paging), and to (re)load + * segment registers. Load the zero IDT so any fault triggers a + * shutdown instead of jumping back into BIOS. + */ + lidt tr_idt(%rip) + lgdt tr_gdt64(%rip) + + ljmpl *tr_compat(%rip) +SYM_CODE_END(trampoline_start64) + .section ".rodata","a" # Duplicate the global descriptor table # so the kernel can live anywhere @@ -182,6 +220,17 @@ SYM_DATA_START(tr_gdt) .quad 0x00cf93000000ffff # __KERNEL_DS SYM_DATA_END_LABEL(tr_gdt, SYM_L_LOCAL, tr_gdt_end) +SYM_DATA_START(tr_gdt64) + .short tr_gdt_end - tr_gdt - 1 # gdt limit + .long pa_tr_gdt + .long 0 +SYM_DATA_END(tr_gdt64) + +SYM_DATA_START(tr_compat) + .long pa_trampoline_compat + .short __KERNEL32_CS +SYM_DATA_END(tr_compat) + .bss .balign PAGE_SIZE SYM_DATA(trampoline_pgd, .space PAGE_SIZE) diff --git a/arch/x86/realmode/rm/trampoline_common.S b/arch/x86/realmode/rm/trampoline_common.S index 5033e640f957..4331c32c47f8 100644 --- a/arch/x86/realmode/rm/trampoline_common.S +++ b/arch/x86/realmode/rm/trampoline_common.S @@ -1,4 +1,14 @@ /* SPDX-License-Identifier: GPL-2.0 */ .section ".rodata","a" .balign 16 -SYM_DATA_LOCAL(tr_idt, .fill 1, 6, 0) + +/* + * When a bootloader hands off to the kernel in 32-bit mode an + * IDT with a 2-byte limit and 4-byte base is needed. When a boot + * loader hands off to a kernel 64-bit mode the base address + * extends to 8-bytes. Reserve enough space for either scenario. + */ +SYM_DATA_START_LOCAL(tr_idt) + .short 0 + .quad 0 +SYM_DATA_END(tr_idt) diff --git a/arch/x86/realmode/rm/wakemain.c b/arch/x86/realmode/rm/wakemain.c index 1d6437e6d2ba..a6f4d8388ad8 100644 --- a/arch/x86/realmode/rm/wakemain.c +++ b/arch/x86/realmode/rm/wakemain.c @@ -62,8 +62,12 @@ static void send_morse(const char *pattern) } } +struct port_io_ops pio_ops; + void main(void) { + init_default_io_ops(); + /* Kill machine if structures are wrong */ if (wakeup_header.real_magic != 0x12345678) while (1) |