Messages in this thread | | | Date | Sat, 8 Feb 2014 23:21:23 -0800 | From | Andi Kleen <> | Subject | Re: [PATCH v13 8/9] Add 32 bit VDSO time support for 32 bit kernel |
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On Sat, Feb 08, 2014 at 09:22:30PM -0800, Andi Kleen wrote: > > +notrace static long vdso_fallback_gettime(long clock, struct timespec *ts) > > +{ > > + long ret; > > + > > + asm( > > + "push %%ebx \n" > > + "mov %2,%%ebx \n" > > + "call VDSO32_vsyscall \n" > > + "pop %%ebx \n" > > + : "=a" (ret) > > + : "0" (__NR_clock_gettime), "d" (clock), "c" (ts) > > + : "memory"); > > The push/mov/pop could be just replaced with "b"?
Actually thinking about it more you likely did that to avoid errors with -fPIC right? In this case you still need to supply correct dwarf2 unwind annotations.
Also this change is still needed:
> Also I if this calls syscall.S:__kernel_vsyscall it clobbers more registers > (ecx at least?) and you need to describe that to gcc with a + > > Same in the other sys calls. > > > @@ -310,6 +311,11 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) > > unsigned long addr; > > int ret = 0; > > bool compat; > > + struct vm_area_struct *vma; > > + extern char __vvar_page; > > +#ifdef CONFIG_HPET_TIMER > > + extern unsigned long hpet_address; > > +#endif > > Put this into a header. > > > +++ b/arch/x86/vdso/vdso32/vclock_gettime.c > > @@ -0,0 +1,16 @@ > > +#define BUILD_VDSO32 > > + > > +#ifdef CONFIG_X86_64 > > + > > +#define _ASM_X86_PAGE_H > > + > > +#define __pa(x) 0 > > +#define __va(x) 0 > > + > > +#undef CONFIG_ILLEGAL_POINTER_VALUE > > +#define CONFIG_ILLEGAL_POINTER_VALUE 0 > > This needs some comments. > > Why are the __pa/__va defines safe? > > The rest of the patchkit looks reasonable to me from a quick read. > Much better than the first version. > > -Andi > > -- > ak@linux.intel.com -- Speaking for myself only
-- ak@linux.intel.com -- Speaking for myself only
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