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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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7
arch/x86/realmode/init.c
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@@ -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;