[tip:x86/asm] x86: Introduce set_desc_base() and set_desc_limit()

tip-bot for Akinobu Mita
2009-07-20T12:02:19Z

Commit-ID: 57594742a2b545f8f114cda34f15650be8ae976d
Gitweb: http://git.kernel.org/tip/57594742a2b545f8f114cda34f15650be8ae976d
Author: Akinobu Mita <akinobu.mita@gmail.com>
AuthorDate: Sun, 19 Jul 2009 00:11:06 +0900
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Sun, 19 Jul 2009 18:27:52 +0200

x86: Introduce set_desc_base() and set_desc_limit()

Rename set_base()/set_limit to set_desc_base()/set_desc_limit()
and rewrite them in C. These are naturally introduced by the
idea of get_desc_base()/get_desc_limit().

The conversion actually found the bug in apm_32.c:
bad_bios_desc is written at run-time, but it is defined const
variable.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
LKML-Reference: <20090718151105.GC11294@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
arch/x86/include/asm/desc.h | 13 +++++++++++++
arch/x86/include/asm/stackprotector.h | 4 +---
arch/x86/include/asm/system.h | 27 ---------------------------
arch/x86/kernel/apm_32.c | 18 +++++++++---------
drivers/pnp/pnpbios/bioscalls.c | 21 +++++++++++----------
5 files changed, 34 insertions(+), 49 deletions(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index c993e9e..e8de2f6 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -291,11 +291,24 @@ static inline unsigned long get_desc_base(const struct desc_struct *desc)
return desc->base0 | ((desc->base1) << 16) | ((desc->base2) << 24);
}

+static inline void set_desc_base(struct desc_struct *desc, unsigned long base)
+{
+ desc->base0 = base & 0xffff;
+ desc->base1 = (base >> 16) & 0xff;
+ desc->base2 = (base >> 24) & 0xff;
+}
+
static inline unsigned long get_desc_limit(const struct desc_struct *desc)
{
return desc->limit0 | (desc->limit << 16);
}

+static inline void set_desc_limit(struct desc_struct *desc, unsigned long limit)
+{
+ desc->limit0 = limit & 0xffff;
+ desc->limit = (limit >> 16) & 0xf;
+}
+
static inline void _set_gate(int gate, unsigned type, void *addr,
unsigned dpl, unsigned ist, unsigned seg)
{
diff --git a/arch/x86/include/asm/stackprotector.h b/arch/x86/include/asm/stackprotector.h
index c2d742c..cdc5e0b 100644
--- a/arch/x86/include/asm/stackprotector.h
+++ b/arch/x86/include/asm/stackprotector.h
@@ -90,9 +90,7 @@ static inline void setup_stack_canary_segment(int cpu)
struct desc_struct desc;

desc = gdt_table[GDT_ENTRY_STACK_CANARY];
- desc.base0 = canary & 0xffff;
- desc.base1 = (canary >> 16) & 0xff;
- desc.base2 = (canary >> 24) & 0xff;
+ set_desc_base(&desc, canary);
write_gdt_entry(gdt_table, GDT_ENTRY_STACK_CANARY, &desc, DESCTYPE_S);
#endif
}
diff --git a/arch/x86/include/asm/system.h b/arch/x86/include/asm/system.h
index 643c59b..75c49c7 100644
--- a/arch/x86/include/asm/system.h
+++ b/arch/x86/include/asm/system.h
@@ -150,33 +150,6 @@ do { \
#endif

#ifdef __KERNEL__
-#define _set_base(addr, base) do { unsigned long __pr; \
-__asm__ __volatile__ ("movw %%dx,%1\n\t" \
- "rorl $16,%%edx\n\t" \
- "movb %%dl,%2\n\t" \
- "movb %%dh,%3" \
- :"=&d" (__pr) \
- :"m" (*((addr)+2)), \
- "m" (*((addr)+4)), \
- "m" (*((addr)+7)), \
- "0" (base) \
- ); } while (0)
-
-#define _set_limit(addr, limit) do { unsigned long __lr; \
-__asm__ __volatile__ ("movw %%dx,%1\n\t" \
- "rorl $16,%%edx\n\t" \
- "movb %2,%%dh\n\t" \
- "andb $0xf0,%%dh\n\t" \
- "orb %%dh,%%dl\n\t" \
- "movb %%dl,%2" \
- :"=&d" (__lr) \
- :"m" (*(addr)), \
- "m" (*((addr)+6)), \
- "0" (limit) \
- ); } while (0)
-
-#define set_base(ldt, base) _set_base(((char *)&(ldt)) , (base))
-#define set_limit(ldt, limit) _set_limit(((char *)&(ldt)) , ((limit)-1))

extern void native_load_gs_index(unsigned);

diff --git a/arch/x86/kernel/apm_32.c b/arch/x86/kernel/apm_32.c
index 79302e9..b5e841b 100644
--- a/arch/x86/kernel/apm_32.c
+++ b/arch/x86/kernel/apm_32.c
@@ -403,7 +403,7 @@ static DECLARE_WAIT_QUEUE_HEAD(apm_waitqueue);
static DECLARE_WAIT_QUEUE_HEAD(apm_suspend_waitqueue);
static struct apm_user *user_list;
static DEFINE_SPINLOCK(user_list_lock);
-static const struct desc_struct bad_bios_desc = { { { 0, 0x00409200 } } };
+static struct desc_struct bad_bios_desc = { { { 0, 0x00409200 } } };

static const char driver_version[] = "1.16ac"; /* no spaces */

@@ -2337,8 +2337,8 @@ static int __init apm_init(void)
* This is for buggy BIOS's that refer to (real mode) segment 0x40
* even though they are called in protected mode.
*/
- set_base(bad_bios_desc, __va((unsigned long)0x40 << 4));
- _set_limit((char *)&bad_bios_desc, 4095 - (0x40 << 4));
+ set_desc_base(&bad_bios_desc, (unsigned long)__va(0x40UL << 4));
+ set_desc_limit(&bad_bios_desc, 4095 - (0x40 << 4));

/*
* Set up the long jump entry point to the APM BIOS, which is called
@@ -2358,12 +2358,12 @@ static int __init apm_init(void)
* code to that CPU.
*/
gdt = get_cpu_gdt_table(0);
- set_base(gdt[APM_CS >> 3],
- __va((unsigned long)apm_info.bios.cseg << 4));
- set_base(gdt[APM_CS_16 >> 3],
- __va((unsigned long)apm_info.bios.cseg_16 << 4));
- set_base(gdt[APM_DS >> 3],
- __va((unsigned long)apm_info.bios.dseg << 4));
+ set_desc_base(&gdt[APM_CS >> 3],
+ (unsigned long)__va((unsigned long)apm_info.bios.cseg << 4));
+ set_desc_base(&gdt[APM_CS_16 >> 3],
+ (unsigned long)__va((unsigned long)apm_info.bios.cseg_16 << 4));
+ set_desc_base(&gdt[APM_DS >> 3],
+ (unsigned long)__va((unsigned long)apm_info.bios.dseg << 4));

proc_create("apm", 0, NULL, &apm_file_ops);

diff --git a/drivers/pnp/pnpbios/bioscalls.c b/drivers/pnp/pnpbios/bioscalls.c
index 7e6b5a3..45ad3e9 100644
--- a/drivers/pnp/pnpbios/bioscalls.c
+++ b/drivers/pnp/pnpbios/bioscalls.c
@@ -55,9 +55,9 @@ __asm__(".text \n"

#define Q2_SET_SEL(cpu, selname, address, size) \
do { \
-struct desc_struct *gdt = get_cpu_gdt_table((cpu)); \
-set_base(gdt[(selname) >> 3], (u32)(address)); \
-set_limit(gdt[(selname) >> 3], size); \
+ struct desc_struct *gdt = get_cpu_gdt_table((cpu)); \
+ set_desc_base(&gdt[(selname) >> 3], (u32)(address)); \
+ set_desc_limit(&gdt[(selname) >> 3], (size) - 1); \
} while(0)

static struct desc_struct bad_bios_desc;
@@ -479,16 +479,17 @@ void pnpbios_calls_init(union pnp_bios_install_struct *header)
bad_bios_desc.a = 0;
bad_bios_desc.b = 0x00409200;

- set_base(bad_bios_desc, __va((unsigned long)0x40 << 4));
- _set_limit((char *)&bad_bios_desc, 4095 - (0x40 << 4));
+ set_desc_base(&bad_bios_desc, (unsigned long)__va(0x40UL << 4));
+ set_desc_limit(&bad_bios_desc, 4095 - (0x40 << 4));
for_each_possible_cpu(i) {
struct desc_struct *gdt = get_cpu_gdt_table(i);
if (!gdt)
continue;
- set_base(gdt[GDT_ENTRY_PNPBIOS_CS32], &pnp_bios_callfunc);
- set_base(gdt[GDT_ENTRY_PNPBIOS_CS16],
- __va(header->fields.pm16cseg));
- set_base(gdt[GDT_ENTRY_PNPBIOS_DS],
- __va(header->fields.pm16dseg));
+ set_desc_base(&gdt[GDT_ENTRY_PNPBIOS_CS32],
+ (unsigned long)&pnp_bios_callfunc);
+ set_desc_base(&gdt[GDT_ENTRY_PNPBIOS_CS16],
+ (unsigned long)__va(header->fields.pm16cseg));
+ set_desc_base(&gdt[GDT_ENTRY_PNPBIOS_DS],
+ (unsigned long)__va(header->fields.pm16dseg));
}
}