Commit-ID: 4d681be3c33dd74efffbe2a8f70634f7128602ec Gitweb: http://git.kernel.org/tip/4d681be3c33dd74efffbe2a8f70634f7128602ec Author: kon...@kernel.org <kon...@kernel.org> AuthorDate: Fri, 5 Apr 2013 16:42:24 -0400 Committer: H. Peter Anvin <h...@linux.intel.com> CommitDate: Thu, 11 Apr 2013 15:41:15 -0700
x86, wakeup, sleep: Use pvops functions for changing GDT entries We check the TSS descriptor before we try to dereference it. Also we document what the value '9' actually means using the AMD64 Architecture Programmer's Manual Volume 2, pg 90: "Hex value 9: Available 64-bit TSS" and pg 91: "The available 32-bit TSS (09h), which is redefined as the available 64-bit TSS." Without this, on Xen, where the GDT is available as R/O (to protect the hypervisor from the guest modifying it), we end up with a pagetable fault. Signed-off-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com> Link: http://lkml.kernel.org/r/1365194544-14648-5-git-send-email-konrad.w...@oracle.com Cc: Rafael J. Wysocki <r...@sisk.pl> Signed-off-by: H. Peter Anvin <h...@linux.intel.com> --- arch/x86/power/cpu.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c index 82c39c5..168da84 100644 --- a/arch/x86/power/cpu.c +++ b/arch/x86/power/cpu.c @@ -132,7 +132,10 @@ static void fix_processor_context(void) { int cpu = smp_processor_id(); struct tss_struct *t = &per_cpu(init_tss, cpu); - +#ifdef CONFIG_X86_64 + struct desc_struct *desc = get_cpu_gdt_table(cpu); + tss_desc tss; +#endif set_tss_desc(cpu, t); /* * This just modifies memory; should not be * necessary. But... This is necessary, because @@ -141,7 +144,9 @@ static void fix_processor_context(void) */ #ifdef CONFIG_X86_64 - get_cpu_gdt_table(cpu)[GDT_ENTRY_TSS].type = 9; + memcpy(&tss, &desc[GDT_ENTRY_TSS], sizeof(tss_desc)); + tss.type = 0x9; /* The available 64-bit TSS (see AMD vol 2, pg 91 */ + write_gdt_entry(desc, GDT_ENTRY_TSS, &tss, DESC_TSS); syscall_init(); /* This sets MSR_*STAR and related */ #endif -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
