x86, realmode: read cr4 and EFER from kernel for 64-bit trampoline

This patch changes 64-bit trampoline so that CR4 and
EFER are provided by the kernel instead of using fixed
values.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-24-git-send-email-jarkko.sakkinen@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Jarkko Sakkinen 2012-05-08 21:22:46 +03:00 committed by H. Peter Anvin
parent bf8b88e977
commit cda846f101
7 changed files with 49 additions and 28 deletions

View File

@ -544,13 +544,16 @@ static inline void load_sp0(struct tss_struct *tss,
* enable), so that any CPU's that boot up
* after us can get the correct flags.
*/
extern unsigned long mmu_cr4_features;
extern unsigned long mmu_cr4_features;
extern u32 *trampoline_cr4_features;
static inline void set_in_cr4(unsigned long mask)
{
unsigned long cr4;
mmu_cr4_features |= mask;
if (trampoline_cr4_features)
*trampoline_cr4_features = mmu_cr4_features;
cr4 = read_cr4();
cr4 |= mask;
write_cr4(cr4);
@ -561,6 +564,8 @@ static inline void clear_in_cr4(unsigned long mask)
unsigned long cr4;
mmu_cr4_features &= ~mask;
if (trampoline_cr4_features)
*trampoline_cr4_features = mmu_cr4_features;
cr4 = read_cr4();
cr4 &= ~mask;
write_cr4(cr4);

View File

@ -24,18 +24,22 @@ struct real_mode_header {
#ifdef CONFIG_X86_32
u32 machine_real_restart_asm;
#endif
} __attribute__((__packed__));
};
/* This must match data at trampoline_32/64.S */
struct trampoline_header {
#ifdef CONFIG_X86_32
u32 start;
u16 gdt_pad;
u16 gdt_limit;
u32 gdt_base;
#else
u64 start;
u32 cr4;
u32 efer_low;
u32 efer_high;
#endif
} __attribute__((__packed__));
};
extern struct real_mode_header *real_mode_header;
extern unsigned char real_mode_blob_end[];

View File

@ -6,6 +6,7 @@
#include <asm/realmode.h>
struct real_mode_header *real_mode_header;
u32 *trampoline_cr4_features;
void __init setup_real_mode(void)
{
@ -64,7 +65,14 @@ void __init setup_real_mode(void)
trampoline_header->gdt_limit = __BOOT_DS + 7;
trampoline_header->gdt_base = __pa(boot_gdt);
#else
if (rdmsr_safe(MSR_EFER, &trampoline_header->efer_low,
&trampoline_header->efer_high))
BUG();
trampoline_header->start = (u64) secondary_startup_64;
trampoline_cr4_features = &trampoline_header->cr4;
*trampoline_cr4_features = read_cr4();
trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
trampoline_pgd[0] = __pa(level3_ident_pgt) + _KERNPG_TABLE;
trampoline_pgd[511] = __pa(level3_kernel_pgt) + _KERNPG_TABLE;

View File

@ -975,6 +975,8 @@ void __init setup_arch(char **cmdline_p)
if (boot_cpu_data.cpuid_level >= 0) {
/* A CPU has %cr4 if and only if it has CPUID */
mmu_cr4_features = read_cr4();
if (trampoline_cr4_features)
*trampoline_cr4_features = mmu_cr4_features;
}
#ifdef CONFIG_X86_32

View File

@ -9,6 +9,7 @@
.section ".header", "a"
.balign 16
GLOBAL(real_mode_header)
.long pa_text_start
.long pa_ro_end

View File

@ -34,9 +34,9 @@
#include "realmode.h"
.text
.balign PAGE_SIZE
.code16
.balign PAGE_SIZE
ENTRY(trampoline_start)
cli # We should be safe anyway
wbinvd
@ -65,8 +65,8 @@ ENTRY(trampoline_start)
* to 32 bit.
*/
lidtl tidt # load idt with 0, 0
lgdtl tgdt # load gdt with whatever is appropriate
lidtl tr_idt # load idt with 0, 0
lgdtl tr_gdt # load gdt with whatever is appropriate
movw $__KERNEL_DS, %dx # Data segment descriptor
@ -93,16 +93,17 @@ ENTRY(startup_32)
movl %edx, %fs
movl %edx, %gs
movl $X86_CR4_PAE, %eax
movl pa_tr_cr4, %eax
movl %eax, %cr4 # Enable PAE mode
# Setup trampoline 4 level pagetables
movl $pa_trampoline_pgd, %eax
movl %eax, %cr3
# Set up EFER
movl pa_tr_efer, %eax
movl pa_tr_efer + 4, %edx
movl $MSR_EFER, %ecx
movl $((1 << _EFER_LME) | (1 << _EFER_NX)), %eax # Enable Long Mode
xorl %edx, %edx
wrmsr
# Enable paging and in turn activate Long Mode
@ -124,23 +125,4 @@ ENTRY(startup_64)
# Now jump into the kernel using virtual addresses
jmpq *tr_start(%rip)
.section ".rodata","a"
.balign 16
tidt:
.word 0 # idt limit = 0
.word 0, 0 # idt base = 0L
# Duplicate the global descriptor table
# so the kernel can live anywhere
.balign 16
.globl tgdt
tgdt:
.short tgdt_end - tgdt - 1 # gdt limit
.long pa_tgdt
.short 0
.quad 0x00cf9b000000ffff # __KERNEL32_CS
.quad 0x00af9b000000ffff # __KERNEL_CS
.quad 0x00cf93000000ffff # __KERNEL_DS
tgdt_end:
#include "trampoline_common.S"

View File

@ -1,5 +1,20 @@
.section ".rodata","a"
#ifdef CONFIG_X86_64
# Duplicate the global descriptor table
# so the kernel can live anywhere
.balign 16
.globl tr_gdt
tr_gdt:
.short tr_gdt_end - tr_gdt - 1 # gdt limit
.long pa_tr_gdt
.short 0
.quad 0x00cf9b000000ffff # __KERNEL32_CS
.quad 0x00af9b000000ffff # __KERNEL_CS
.quad 0x00cf93000000ffff # __KERNEL_DS
tr_gdt_end:
#endif
.balign 4
tr_idt: .fill 1, 6, 0
@ -8,12 +23,16 @@ tr_idt: .fill 1, 6, 0
.balign 4
GLOBAL(trampoline_status) .space 4
.balign 8
GLOBAL(trampoline_header)
#ifdef CONFIG_X86_32
tr_start: .space 4
tr_gdt_pad: .space 2
tr_gdt: .space 6
#else
tr_start: .space 8
GLOBAL(tr_cr4) .space 4
GLOBAL(tr_efer) .space 8
#endif
END(trampoline_header)