Messages in this thread Patch in this message | | | Date | Thu, 21 Jun 2012 08:07:06 -0700 | From | "tip-bot for H. Peter Anvin" <> | Subject | [tip:x86/reboot] x86, reboot: Drop redundant write of reboot_mode |
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Commit-ID: 2b1b712f050eaf0ac576591281446dc960c0afc5 Gitweb: http://git.kernel.org/tip/2b1b712f050eaf0ac576591281446dc960c0afc5 Author: H. Peter Anvin <hpa@zytor.com> AuthorDate: Wed, 20 Jun 2012 21:18:14 -0700 Committer: H. Peter Anvin <hpa@zytor.com> CommitDate: Wed, 20 Jun 2012 21:18:14 -0700
x86, reboot: Drop redundant write of reboot_mode
We write reboot_mode to BIOS location 0x472 in native_machine_emergency_restart() (reboot.c:542) already, there is no need to then write it again in machine_real_restart().
This means nothing gets written there for MRR_APM, but the APM call is a poweroff call and doesn't use this memory location.
Link: http://lkml.kernel.org/n/tip-3i0pfh44c1e3jv5lab0cf7sc@git.kernel.org Signed-off-by: H. Peter Anvin <hpa@zytor.com> --- arch/x86/kernel/reboot.c | 8 -------- 1 files changed, 0 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index 6ddb9cd..6ef559f 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -179,14 +179,6 @@ void __noreturn machine_real_restart(unsigned int type) write_cr3(real_mode_header->trampoline_pgd); #endif - /* - * Write 0x1234 to absolute memory location 0x472. The BIOS reads - * this on booting to tell it to "Bypass memory test (also warm - * boot)". This seems like a fairly standard thing that gets set by - * REBOOT.COM programs, and the previous reset routine did this - * too. */ - *((unsigned short *)0x472) = reboot_mode; - /* Jump to the identity-mapped low memory code */ #ifdef CONFIG_X86_32 asm volatile("jmpl *%0" : :
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