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SubjectRe: [PATCH] Add 32 bit VDSO time function support
On 12/17/2012 02:12 PM, stefani@seibold.net wrote:
> arch/x86/Kconfig | 4 +-
> arch/x86/include/asm/clocksource.h | 4 -
> arch/x86/include/asm/fixmap.h | 6 +-
> arch/x86/include/asm/vgtod.h | 10 ++-
> arch/x86/include/asm/vsyscall.h | 1 -
> arch/x86/include/asm/vvar.h | 5 ++
> arch/x86/kernel/Makefile | 1 +
> arch/x86/kernel/hpet.c | 11 ++-
> arch/x86/kernel/setup.c | 2 +
> arch/x86/kernel/tsc.c | 2 -
> arch/x86/kernel/vmlinux.lds.S | 4 -
> arch/x86/kernel/vsyscall_64.c | 49 -----------
> arch/x86/kernel/vsyscall_gtod.c | 93 +++++++++++++++++++++
> arch/x86/mm/init_32.c | 1 +
> arch/x86/vdso/Makefile | 6 ++
> arch/x86/vdso/vclock_gettime.c | 108 ++++++++++++++++++------
> arch/x86/vdso/vdso32-setup.c | 41 ++++++++++
> arch/x86/vdso/vdso32/vclock_gettime.c | 29 +++++++
> arch/x86/vdso/vdso32/vdso32.lds.S | 3 +
> include/linux/clocksource.h | 1 -
> include/linux/mm.h | 3 +
> include/linux/seqcount.h | 150 ++++++++++++++++++++++++++++++++++
> include/linux/seqlock.h | 145 +-------------------------------
> include/linux/time.h | 3 +-
> include/linux/timekeeper_internal.h | 1 +
> include/linux/types.h | 2 +
> mm/mmap.c | 20 ++++-
> 27 files changed, 457 insertions(+), 248 deletions(-)
> create mode 100644 arch/x86/kernel/vsyscall_gtod.c
> create mode 100644 arch/x86/vdso/vdso32/vclock_gettime.c
> create mode 100644 include/linux/seqcount.h

Please break this up in a series with the generic changes separately first.

> diff --git a/arch/x86/include/asm/vgtod.h b/arch/x86/include/asm/vgtod.h
> index 46e24d3..74c80d4 100644
> --- a/arch/x86/include/asm/vgtod.h
> +++ b/arch/x86/include/asm/vgtod.h
> @@ -1,8 +1,8 @@
> #ifndef _ASM_X86_VGTOD_H
> #define _ASM_X86_VGTOD_H
>
> -#include <asm/vsyscall.h>
> -#include <linux/clocksource.h>
> +#include <linux/seqcount.h>
> +#include <uapi/linux/time.h>
>
> struct vsyscall_gtod_data {
> seqcount_t seq;
> @@ -13,7 +13,7 @@ struct vsyscall_gtod_data {
> cycle_t mask;
> u32 mult;
> u32 shift;
> - } clock;
> + } __attribute__((aligned(4),packed)) clock;
>
> /* open coded 'struct timespec' */
> time_t wall_time_sec;
> @@ -24,7 +24,9 @@ struct vsyscall_gtod_data {
> struct timezone sys_tz;
> struct timespec wall_time_coarse;
> struct timespec monotonic_time_coarse;
> -};
> +} __attribute__((aligned(4),packed));
> +
> extern struct vsyscall_gtod_data vsyscall_gtod_data;
>
> +extern void map_vgtod(void);
> #endif /* _ASM_X86_VGTOD_H */

Please use the macros from <linux/compiler.h>. Also, aligned(4) raises
a huge red flag for me. Why??

> diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h
> index de656ac..1e71e6c 100644
> --- a/arch/x86/include/asm/vvar.h
> +++ b/arch/x86/include/asm/vvar.h
> @@ -17,7 +17,11 @@
> */
>
> /* Base address of vvars. This is not ABI. */
> +#ifdef CONFIG_X86_64
> #define VVAR_ADDRESS (-10*1024*1024 - 4096)
> +#else
> +#define VVAR_ADDRESS 0xffffd000
> +#endif
>

I thought we had agreed this was going to be part of the vdso and not a
fixmap?

> + struct vm_area_struct *vma = _install_special_mapping(mm,
> + __fix_to_virt(VSYSCALL_HPET) & 0xffffffff,
> + PAGE_SIZE, VM_READ|VM_EXEC|VM_IO|VM_LOCKED,
> + NULL);

This style is generally frowned upon; please separate the declaration
and the assignment. The & 0xffffffff there also looks... "special"...
but again, see previous statement about fixed addresses.

-hpa



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