Re: [git-pull -tip V2] x86: cpu architecture debug code

Jaswinder Singh Rajput
2009-03-11T13:44:38Z

On Wed, 2009-03-11 at 14:13 +0100, Ingo Molnar wrote:
> * Ingo Molnar <mingo@elte.hu> wrote:
>
> > * Jaswinder Singh Rajput <jaswinder@kernel.org> wrote:
> >
> > > @@ -472,7 +473,7 @@ static void print_dt(void *seq)
> > > print_desc_ptr("GDT", seq, dt);
> > >
> > > /* LDT */
> > > - store_ldt(ldt);
> > > + asm volatile("sldt %0" : "=m" (ldt));
> >
> > this is still wrong.
>
> As i pointed it out before, we should not open-code an assembly
> primitive - especially since store_ldt() is available in
> arch/x86/include/asm/desc.h.
>
> True, that primitive is not available on CONFIG_PARAVIRT, but
> that is a bug: the fix is to move the store_ldt() definition
> outside the CONFIG_PARAVIRT section in desc.h, not to hack
> around the problem by open-coding assembly code.
>
> I.e. dont let an uncleanliness and incomplete primitive spread
> to other code. Fix the primitive and remove the uncleanliness
> that way.
>

The following changes since commit 259ef6fcea4046fe24495b1e3631c1b905c531c1:
Jaswinder Singh Rajput (1):
x86: cpu architecture debug code

are available in the git repository at:

git://git.kernel.org/pub/scm/linux/kernel/git/jaswinder/linux-2.6-tip-cpu.git master

Jaswinder Singh Rajput (2):
x86: cpu_debug.c cleanup
x86: move store_ldt outside the CONFIG_PARAVIRT section

arch/x86/include/asm/desc.h | 3 ++-
arch/x86/kernel/cpu/cpu_debug.c | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)

Complete diff:
diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index dc27705..ceb17cc 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -91,7 +91,6 @@ static inline int desc_empty(const void *ptr)
#define store_gdt(dtr) native_store_gdt(dtr)
#define store_idt(dtr) native_store_idt(dtr)
#define store_tr(tr) (tr = native_store_tr())
-#define store_ldt(ldt) asm("sldt %0":"=m" (ldt))

#define load_TLS(t, cpu) native_load_tls(t, cpu)
#define set_ldt native_set_ldt
@@ -112,6 +111,8 @@ static inline void paravirt_free_ldt(struct desc_struct *ldt, unsigned entries)
}
#endif /* CONFIG_PARAVIRT */

+#define store_ldt(ldt) asm("sldt %0":"=m" (ldt))
+
static inline void native_write_idt_entry(gate_desc *idt, int entry,
const gate_desc *gate)
{
diff --git a/arch/x86/kernel/cpu/cpu_debug.c b/arch/x86/kernel/cpu/cpu_debug.c
index 0bdf4da..9abbcbd 100755
--- a/arch/x86/kernel/cpu/cpu_debug.c
+++ b/arch/x86/kernel/cpu/cpu_debug.c
@@ -23,6 +23,7 @@
#include <linux/smp.h>

#include <asm/cpu_debug.h>
+#include <asm/paravirt.h>
#include <asm/system.h>
#include <asm/traps.h>
#include <asm/apic.h>
@@ -427,7 +428,7 @@ static void print_tss(void *arg)
seq_printf(seq, " CS\t: %04x\n", seg);
asm("movl %%ds,%0" : "=r" (seg));
seq_printf(seq, " DS\t: %04x\n", seg);
- seq_printf(seq, " SS\t: %04lx\n", regs->ss);
+ seq_printf(seq, " SS\t: %04lx\n", regs->ss & 0xffff);
asm("movl %%es,%0" : "=r" (seg));
seq_printf(seq, " ES\t: %04x\n", seg);
asm("movl %%fs,%0" : "=r" (seg));