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[S390] Improve address space mode selection. 

Introduce user_mode to replace the two variables switch_amode and
s390_noexec. There are three valid combinations of the old values:
  1) switch_amode == 0 && s390_noexec == 0
  2) switch_amode == 1 && s390_noexec == 0
  3) switch_amode == 1 && s390_noexec == 1
They get replaced by
  1) user_mode == HOME_SPACE_MODE
  2) user_mode == PRIMARY_SPACE_MODE
  3) user_mode == SECONDARY_SPACE_MODE
The new kernel parameter user_mode=[primary,secondary,home] lets
you choose the address space mode the user space processes should
use. In addition the CONFIG_S390_SWITCH_AMODE config option
is removed.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2009-12-07 12:51:43 +01:00 committed by Martin Schwidefsky
parent 61365e132e
commit b11b533427
11 changed files with 37 additions and 57 deletions
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15
arch/s390/Kconfig
View File

@ -220,23 +220,8 @@ config AUDIT_ARCH
bool
default y
config S390_SWITCH_AMODE
bool "Switch kernel/user addressing modes"
help
This option allows to switch the addressing modes of kernel and user
space. The kernel parameter switch_amode=on will enable this feature,
default is disabled. Enabling this (via kernel parameter) on machines
earlier than IBM System z9-109 EC/BC will reduce system performance.
Note that this option will also be selected by selecting the execute
protection option below. Enabling the execute protection via the
noexec kernel parameter will also switch the addressing modes,
independent of the switch_amode kernel parameter.
config S390_EXEC_PROTECT
bool "Data execute protection"
select S390_SWITCH_AMODE
help
This option allows to enable a buffer overflow protection for user
space programs and it also selects the addressing mode option above.

1
arch/s390/defconfig
View File

@ -185,7 +185,6 @@ CONFIG_HOTPLUG_CPU=y
CONFIG_COMPAT=y
CONFIG_SYSVIPC_COMPAT=y
CONFIG_AUDIT_ARCH=y
CONFIG_S390_SWITCH_AMODE=y
CONFIG_S390_EXEC_PROTECT=y
#

4
arch/s390/include/asm/mmu_context.h
View File

@ -36,7 +36,7 @@ static inline int init_new_context(struct task_struct *tsk,
mm->context.has_pgste = 1;
mm->context.alloc_pgste = 1;
} else {
mm->context.noexec = s390_noexec;
mm->context.noexec = (user_mode == SECONDARY_SPACE_MODE);
mm->context.has_pgste = 0;
mm->context.alloc_pgste = 0;
}
@ -58,7 +58,7 @@ static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
pgd_t *pgd = mm->pgd;
S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
if (switch_amode) {
if (user_mode != HOME_SPACE_MODE) {
/* Load primary space page table origin. */
pgd = mm->context.noexec ? get_shadow_table(pgd) : pgd;
S390_lowcore.user_exec_asce = mm->context.asce_bits | __pa(pgd);

3
arch/s390/include/asm/pgalloc.h
View File

@ -143,7 +143,8 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)
spin_lock_init(&mm->context.list_lock);
INIT_LIST_HEAD(&mm->context.crst_list);
INIT_LIST_HEAD(&mm->context.pgtable_list);
return (pgd_t *) crst_table_alloc(mm, s390_noexec);
return (pgd_t *)
crst_table_alloc(mm, user_mode == SECONDARY_SPACE_MODE);
}
#define pgd_free(mm, pgd) crst_table_free(mm, (unsigned long *) pgd)

15
arch/s390/include/asm/setup.h
View File

@ -49,17 +49,12 @@ extern unsigned long memory_end;
void detect_memory_layout(struct mem_chunk chunk[]);
#ifdef CONFIG_S390_SWITCH_AMODE
extern unsigned int switch_amode;
#else
#define switch_amode (0)
#endif
#define PRIMARY_SPACE_MODE 0
#define ACCESS_REGISTER_MODE 1
#define SECONDARY_SPACE_MODE 2
#define HOME_SPACE_MODE 3
#ifdef CONFIG_S390_EXEC_PROTECT
extern unsigned int s390_noexec;
#else
#define s390_noexec (0)
#endif
extern unsigned int user_mode;
/*
* Machine features detected in head.S

36
arch/s390/kernel/setup.c
View File

@ -305,9 +305,8 @@ static int __init early_parse_mem(char *p)
}
early_param("mem", early_parse_mem);
#ifdef CONFIG_S390_SWITCH_AMODE
unsigned int switch_amode = 0;
EXPORT_SYMBOL_GPL(switch_amode);
unsigned int user_mode = HOME_SPACE_MODE;
EXPORT_SYMBOL_GPL(user_mode);
static int set_amode_and_uaccess(unsigned long user_amode,
unsigned long user32_amode)
@ -340,23 +339,29 @@ static int set_amode_and_uaccess(unsigned long user_amode,
*/
static int __init early_parse_switch_amode(char *p)
{
switch_amode = 1;
if (user_mode != SECONDARY_SPACE_MODE)
user_mode = PRIMARY_SPACE_MODE;
return 0;
}
early_param("switch_amode", early_parse_switch_amode);
#else /* CONFIG_S390_SWITCH_AMODE */
static inline int set_amode_and_uaccess(unsigned long user_amode,
unsigned long user32_amode)
static int __init early_parse_user_mode(char *p)
{
if (p && strcmp(p, "primary") == 0)
user_mode = PRIMARY_SPACE_MODE;
#ifdef CONFIG_S390_EXEC_PROTECT
else if (p && strcmp(p, "secondary") == 0)
user_mode = SECONDARY_SPACE_MODE;
#endif
else if (!p || strcmp(p, "home") == 0)
user_mode = HOME_SPACE_MODE;
else
return 1;
return 0;
}
#endif /* CONFIG_S390_SWITCH_AMODE */
early_param("user_mode", early_parse_user_mode);
#ifdef CONFIG_S390_EXEC_PROTECT
unsigned int s390_noexec = 0;
EXPORT_SYMBOL_GPL(s390_noexec);
/*
* Enable execute protection?
*/
@ -364,8 +369,7 @@ static int __init early_parse_noexec(char *p)
{
if (!strncmp(p, "off", 3))
return 0;
switch_amode = 1;
s390_noexec = 1;
user_mode = SECONDARY_SPACE_MODE;
return 0;
}
early_param("noexec", early_parse_noexec);
@ -373,7 +377,7 @@ early_param("noexec", early_parse_noexec);
static void setup_addressing_mode(void)
{
if (s390_noexec) {
if (user_mode == SECONDARY_SPACE_MODE) {
if (set_amode_and_uaccess(PSW_ASC_SECONDARY,
PSW32_ASC_SECONDARY))
pr_info("Execute protection active, "
@ -381,7 +385,7 @@ static void setup_addressing_mode(void)
else
pr_info("Execute protection active, "
"mvcos not available\n");
} else if (switch_amode) {
} else if (user_mode == PRIMARY_SPACE_MODE) {
if (set_amode_and_uaccess(PSW_ASC_PRIMARY, PSW32_ASC_PRIMARY))
pr_info("Address spaces switched, "
"mvcos available\n");
@ -411,7 +415,7 @@ setup_lowcore(void)
lc->restart_psw.mask = PSW_BASE_BITS | PSW_DEFAULT_KEY;
lc->restart_psw.addr =
PSW_ADDR_AMODE | (unsigned long) restart_int_handler;
if (switch_amode)
if (user_mode != HOME_SPACE_MODE)
lc->restart_psw.mask |= PSW_ASC_HOME;
lc->external_new_psw.mask = psw_kernel_bits;
lc->external_new_psw.addr =

9
arch/s390/kernel/vdso.c
View File

@ -86,7 +86,8 @@ static void vdso_init_data(struct vdso_data *vd)
unsigned int facility_list;
facility_list = stfl();
vd->ectg_available = switch_amode && (facility_list & 1);
vd->ectg_available =
user_mode != HOME_SPACE_MODE && (facility_list & 1);
}
#ifdef CONFIG_64BIT
@ -114,7 +115,7 @@ int vdso_alloc_per_cpu(int cpu, struct _lowcore *lowcore)
lowcore->vdso_per_cpu_data = __LC_PASTE;
if (!switch_amode || !vdso_enabled)
if (user_mode == HOME_SPACE_MODE || !vdso_enabled)
return 0;
segment_table = __get_free_pages(GFP_KERNEL, SEGMENT_ORDER);
@ -160,7 +161,7 @@ void vdso_free_per_cpu(int cpu, struct _lowcore *lowcore)
unsigned long segment_table, page_table, page_frame;
u32 *psal, *aste;
if (!switch_amode || !vdso_enabled)
if (user_mode == HOME_SPACE_MODE || !vdso_enabled)
return;
psal = (u32 *)(addr_t) lowcore->paste[4];
@ -184,7 +185,7 @@ static void __vdso_init_cr5(void *dummy)
static void vdso_init_cr5(void)
{
if (switch_amode && vdso_enabled)
if (user_mode != HOME_SPACE_MODE && vdso_enabled)
on_each_cpu(__vdso_init_cr5, NULL, 1);
}
#endif /* CONFIG_64BIT */

1
arch/s390/kvm/Kconfig
View File

@ -20,7 +20,6 @@ config KVM
depends on HAVE_KVM && EXPERIMENTAL
select PREEMPT_NOTIFIERS
select ANON_INODES
select S390_SWITCH_AMODE
---help---
Support hosting paravirtualized guest machines using the SIE
virtualization capability on the mainframe. This should work

4
arch/s390/lib/uaccess_mvcos.c
View File

@ -162,7 +162,6 @@ static size_t clear_user_mvcos(size_t size, void __user *to)
return size;
}
#ifdef CONFIG_S390_SWITCH_AMODE
static size_t strnlen_user_mvcos(size_t count, const char __user *src)
{
char buf[256];
@ -200,7 +199,6 @@ static size_t strncpy_from_user_mvcos(size_t count, const char __user *src,
} while ((len_str == len) && (done < count));
return done;
}
#endif /* CONFIG_S390_SWITCH_AMODE */
struct uaccess_ops uaccess_mvcos = {
.copy_from_user = copy_from_user_mvcos_check,
@ -215,7 +213,6 @@ struct uaccess_ops uaccess_mvcos = {
.futex_atomic_cmpxchg = futex_atomic_cmpxchg_std,
};
#ifdef CONFIG_S390_SWITCH_AMODE
struct uaccess_ops uaccess_mvcos_switch = {
.copy_from_user = copy_from_user_mvcos,
.copy_from_user_small = copy_from_user_mvcos,
@ -228,4 +225,3 @@ struct uaccess_ops uaccess_mvcos_switch = {
.futex_atomic_op = futex_atomic_op_pt,
.futex_atomic_cmpxchg = futex_atomic_cmpxchg_pt,
};
#endif

4
arch/s390/mm/fault.c
View File

@ -112,7 +112,7 @@ static inline int user_space_fault(unsigned long trans_exc_code)
if (trans_exc_code == 2)
/* Access via secondary space, set_fs setting decides */
return current->thread.mm_segment.ar4;
if (!switch_amode)
if (user_mode == HOME_SPACE_MODE)
/* User space if the access has been done via home space. */
return trans_exc_code == 3;
/*
@ -168,7 +168,7 @@ static void do_no_context(struct pt_regs *regs, unsigned long error_code,
* terminate things with extreme prejudice.
*/
address = trans_exc_code & __FAIL_ADDR_MASK;
if (user_space_fault(trans_exc_code) == 0)
if (!user_space_fault(trans_exc_code))
printk(KERN_ALERT "Unable to handle kernel pointer dereference"
" at virtual kernel address %p\n", (void *)address);
else

2
arch/s390/mm/pgtable.c
View File

@ -269,7 +269,7 @@ int s390_enable_sie(void)
struct mm_struct *mm, *old_mm;
/* Do we have switched amode? If no, we cannot do sie */
if (!switch_amode)
if (user_mode == HOME_SPACE_MODE)
return -EINVAL;
/* Do we have pgstes? if yes, we are done */