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x86, realmode: Change EFER to a single u64 field

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Change EFER to be a single u64 field instead of two u32 fields; change
the order to maintain alignment.  Note that on x86-64 cr4 is really
also a 64-bit quantity, although we can only set the low 32 bits from
the trampoline code since it is still executing in 32-bit mode at that
point.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
This commit is contained in:
H. Peter Anvin 2012-05-16 14:02:05 -07:00
parent 1371270188
commit 638d957b51
3 changed files with 5 additions and 7 deletions
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3
arch/x86/include/asm/realmode.h
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@ -35,9 +35,8 @@ struct trampoline_header {
u32 gdt_base;
#else
u64 start;
u64 efer;
u32 cr4;
u32 efer_low;
u32 efer_high;
#endif
};

7
arch/x86/realmode/init.c
View file

@ -22,7 +22,7 @@ void __init setup_real_mode(void)
size_t size = PAGE_ALIGN(real_mode_blob_end - real_mode_blob);
#ifdef CONFIG_X86_64
u64 *trampoline_pgd;
u32 efer_low, efer_high;
u64 efer;
#endif
/* Has to be in very low memory so we can execute real-mode AP code. */
@ -70,9 +70,8 @@ void __init setup_real_mode(void)
* Some AMD processors will #GP(0) if EFER.LMA is set in WRMSR
* so we need to mask it out.
*/
rdmsr(MSR_EFER, efer_low, efer_high);
trampoline_header->efer_low = efer_low & ~EFER_LMA;
trampoline_header->efer_high = efer_high;
rdmsrl(MSR_EFER, efer);
trampoline_header->efer = efer & ~EFER_LMA;
trampoline_header->start = (u64) secondary_startup_64;
trampoline_cr4_features = &trampoline_header->cr4;

2
arch/x86/realmode/rm/trampoline_64.S
View file

@ -146,8 +146,8 @@ GLOBAL(trampoline_pgd) .space PAGE_SIZE
.balign 8
GLOBAL(trampoline_header)
tr_start: .space 8
GLOBAL(tr_cr4) .space 4
GLOBAL(tr_efer) .space 8
GLOBAL(tr_cr4) .space 4
END(trampoline_header)
#include "trampoline_common.S"