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linux/arch/x86/realmode/rm/realmode.h

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x86, realmode: Replace open-coded ljmpw with a macro We cannot code an ljmpw to the real-mode segment directly, because gas refuses to assemble an ljmp with a symbolic segment. Instead of open-coding it everywhere, define a macro and use it for this case. This is specifically an ljmpw from a 16-bit segment. This is okay, as one should never enter real mode from a 32-bit segment: if one do, the CPU ends up in a bizarre (and useless) mode sometimes called "unreal mode" where segments behave like real mode but the default address and operand sizes is 32 bits. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1336501366-28617-15-git-send-email-jarkko.sakkinen@intel.com
2012-05-09 02:22:37 +08:00
#ifndef ARCH_X86_REALMODE_RM_REALMODE_H
#define ARCH_X86_REALMODE_RM_REALMODE_H
#ifdef __ASSEMBLY__
/*
* 16-bit ljmpw to the real_mode_seg
*
* This must be open-coded since gas will choke on using a
* relocatable symbol for the segment portion.
*/
#define LJMPW_RM(to) .byte 0xea ; .word (to), real_mode_seg
#endif /* __ASSEMBLY__ */
x86, realmode: Move end signature into header.S The end signature was defined in wakeup_asm.S as it originally came from the ACPI wakeup code. However, we rely on the existence of the .signature section to expand .bss, otherwise we would have to include code to explicitly zero the .bss depending on the configuration. Since the expanded .bss is just in .init.data anyway, it's easier to always have it expanded. This fixes failures when compiled without CONFIG_ACPI_SLEEP. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
2012-05-21 15:02:45 +08:00
/*
* Signature at the end of the realmode region
*/
#define REALMODE_END_SIGNATURE 0x65a22c82
x86, realmode: Replace open-coded ljmpw with a macro We cannot code an ljmpw to the real-mode segment directly, because gas refuses to assemble an ljmp with a symbolic segment. Instead of open-coding it everywhere, define a macro and use it for this case. This is specifically an ljmpw from a 16-bit segment. This is okay, as one should never enter real mode from a 32-bit segment: if one do, the CPU ends up in a bizarre (and useless) mode sometimes called "unreal mode" where segments behave like real mode but the default address and operand sizes is 32 bits. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1336501366-28617-15-git-send-email-jarkko.sakkinen@intel.com
2012-05-09 02:22:37 +08:00
#endif /* ARCH_X86_REALMODE_RM_REALMODE_H */