diff options
| author |   Andy Lutomirski <luto@amacapital.net> | 2014-09-23 10:50:53 -0700 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2014-10-28 11:22:10 +0100 |
| commit | 258801563ba1be05793f2417ae30557b43a24e4e (patch) | |
| tree | 85089560726a211649a3eafa13d5fba74a80b29b /arch/x86/vdso | |
| parent | x86_64/vdso: Move getcpu code from vsyscall_64.c to vdso/vma.c (diff) | |
| download | linux-dev-258801563ba1be05793f2417ae30557b43a24e4e.tar.xz linux-dev-258801563ba1be05793f2417ae30557b43a24e4e.zip | |
x86/vdso: Change the PER_CPU segment to use struct desc_struct
This makes it easier to see what's going on. It produces
exactly the same segment descriptor as the old code.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/d492f7b55136cbc60f016adae79160707b2e03b7.1411494540.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/vdso')
| -rw-r--r-- | arch/x86/vdso/vma.c | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c index a155dca5edb5..261b1349acc9 100644 --- a/arch/x86/vdso/vma.c +++ b/arch/x86/vdso/vma.c @@ -248,7 +248,7 @@ __setup("vdso=", vdso_setup); */ static void vsyscall_set_cpu(int cpu) { - unsigned long d; + struct desc_struct d; unsigned long node = 0; #ifdef CONFIG_NUMA node = cpu_to_node(cpu); @@ -257,13 +257,18 @@ static void vsyscall_set_cpu(int cpu) write_rdtscp_aux((node << 12) | cpu); /* - * Store cpu number in limit so that it can be loaded quickly - * in user space in vgetcpu. (12 bits for the CPU and 8 bits for the node) + * Store cpu number in limit so that it can be loaded + * quickly in user space in vgetcpu. (12 bits for the CPU + * and 8 bits for the node) */ - d = 0x0f40000000000ULL; - d |= cpu; - d |= (node & 0xf) << 12; - d |= (node >> 4) << 48; + d = (struct desc_struct) { + .limit0 = cpu | ((node & 0xf) << 12), + .limit = node >> 4, + .type = 4, /* RO data, expand down */ + .dpl = 3, /* Visible to user code */ + .s = 1, /* Not a system segment */ + .p = 1, /* Present */ + }; write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_PER_CPU, &d, DESCTYPE_S); } |