Messages in this thread | | | From | Andy Lutomirski <> | Date | Wed, 14 Sep 2016 18:14:58 -0700 | Subject | Re: [PATCH v2 1/3] syscalls,x86 Expose arch_prctl on x86-32. |
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On Wed, Sep 14, 2016 at 2:01 PM, Kyle Huey <me@kylehuey.com> wrote: > Signed-off-by: Kyle Huey <khuey@kylehuey.com> > --- > arch/x86/entry/syscalls/syscall_32.tbl | 1 + > arch/x86/kernel/process.c | 80 ++++++++++++++++++++++++++++++++++ > arch/x86/kernel/process_64.c | 66 ---------------------------- > 3 files changed, 81 insertions(+), 66 deletions(-) > > diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl > index f848572..3b6965b 100644 > --- a/arch/x86/entry/syscalls/syscall_32.tbl > +++ b/arch/x86/entry/syscalls/syscall_32.tbl > @@ -386,3 +386,4 @@ > 377 i386 copy_file_range sys_copy_file_range > 378 i386 preadv2 sys_preadv2 compat_sys_preadv2 > 379 i386 pwritev2 sys_pwritev2 compat_sys_pwritev2 > +380 i386 arch_prctl sys_arch_prctl > diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c > index 62c0b0e..0f857c3 100644 > --- a/arch/x86/kernel/process.c > +++ b/arch/x86/kernel/process.c > @@ -20,6 +20,7 @@ > #include <linux/cpuidle.h> > #include <trace/events/power.h> > #include <linux/hw_breakpoint.h> > +#include <linux/syscalls.h> > #include <asm/cpu.h> > #include <asm/apic.h> > #include <asm/syscalls.h> > @@ -32,6 +33,7 @@ > #include <asm/tlbflush.h> > #include <asm/mce.h> > #include <asm/vm86.h> > +#include <asm/prctl.h> > > /* > * per-CPU TSS segments. Threads are completely 'soft' on Linux, > @@ -567,3 +569,81 @@ unsigned long get_wchan(struct task_struct *p) > } while (count++ < 16 && p->state != TASK_RUNNING); > return 0; > } > + > +long do_arch_prctl(struct task_struct *task, int code, unsigned long arg2) > +{ > + int ret = 0; > + int doit = task == current; > + int is_32 = IS_ENABLED(CONFIG_IA32_EMULATION) && test_thread_flag(TIF_IA32);
This should be in_compat_syscall().
Also, this code is sufficiently twisted that I think it would be better to have a common function that handles common prctls and defers to a 64-bit-specific function if needed, or vice versa. Vice versa might be easier -- have a do_arch_prctl_common() that is listed as the compat entry and have the 64-bit entry call it for unhandled prctls.
--Andy
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