[patch V2 25/44] x86: Replace access to desc_struct:a/b fields

Thomas Gleixner
2017-08-25T21:58:04Z

[-- Attachment #1: x86--Replace-access-to-desc_struct-a-b-fields.patch --]
[-- Type: text/plain, Size: 1849 bytes --]

The union inside of desc_struct which allows access to the raw u32 parts of
the descriptors. This raw access part is about to go away.

Replace the few code parts which access those fields.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
---
arch/x86/include/asm/xen/hypercall.h | 6 ++++--
arch/x86/kernel/tls.c | 2 +-
arch/x86/xen/enlighten_pv.c | 2 +-
3 files changed, 6 insertions(+), 4 deletions(-)

--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -552,6 +552,8 @@ static inline void
MULTI_update_descriptor(struct multicall_entry *mcl, u64 maddr,
struct desc_struct desc)
{
+ u32 *p = (u32 *) &desc;
+
mcl->op = __HYPERVISOR_update_descriptor;
if (sizeof(maddr) == sizeof(long)) {
mcl->args[0] = maddr;
@@ -559,8 +561,8 @@ MULTI_update_descriptor(struct multicall
} else {
mcl->args[0] = maddr;
mcl->args[1] = maddr >> 32;
- mcl->args[2] = desc.a;
- mcl->args[3] = desc.b;
+ mcl->args[2] = *p++;
+ mcl->args[3] = *p;
}

trace_xen_mc_entry(mcl, sizeof(maddr) == sizeof(long) ? 2 : 4);
--- a/arch/x86/kernel/tls.c
+++ b/arch/x86/kernel/tls.c
@@ -93,7 +93,7 @@ static void set_tls_desc(struct task_str

while (n-- > 0) {
if (LDT_empty(info) || LDT_zero(info)) {
- desc->a = desc->b = 0;
+ memset(desc, 0, sizeof(*desc));
} else {
fill_ldt(desc, info);

--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -494,7 +494,7 @@ static void __init xen_load_gdt_boot(con
static inline bool desc_equal(const struct desc_struct *d1,
const struct desc_struct *d2)
{
- return d1->a == d2->a && d1->b == d2->b;
+ return !memcmp(d1, d2, sizeof(*d1));
}

static void load_TLS_descriptor(struct thread_struct *t,