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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2016-01-26 14:10:34 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2017-03-22 08:14:25 +0100
commit916cda1aa1b412d7cf2991c3af7479544942d121 (patch)
tree51e373acacf962c1635899f1567484be0baed745 /arch/s390/kernel/nmi.c
parent093b995e3b55a0ae0670226ddfcb05bfbf0099ae (diff)
downloadlinux-916cda1aa1b412d7cf2991c3af7479544942d121.tar.bz2
s390: add a system call for guarded storage
This adds a new system call to enable the use of guarded storage for user space processes. The system call takes two arguments, a command and pointer to a guarded storage control block: s390_guarded_storage(int command, struct gs_cb *gs_cb); The second argument is relevant only for the GS_SET_BC_CB command. The commands in detail: 0 - GS_ENABLE Enable the guarded storage facility for the current task. The initial content of the guarded storage control block will be all zeros. After the enablement the user space code can use load-guarded-storage-controls instruction (LGSC) to load an arbitrary control block. While a task is enabled the kernel will save and restore the current content of the guarded storage registers on context switch. 1 - GS_DISABLE Disables the use of the guarded storage facility for the current task. The kernel will cease to save and restore the content of the guarded storage registers, the task specific content of these registers is lost. 2 - GS_SET_BC_CB Set a broadcast guarded storage control block. This is called per thread and stores a specific guarded storage control block in the task struct of the current task. This control block will be used for the broadcast event GS_BROADCAST. 3 - GS_CLEAR_BC_CB Clears the broadcast guarded storage control block. The guarded- storage control block is removed from the task struct that was established by GS_SET_BC_CB. 4 - GS_BROADCAST Sends a broadcast to all thread siblings of the current task. Every sibling that has established a broadcast guarded storage control block will load this control block and will be enabled for guarded storage. The broadcast guarded storage control block is used up, a second broadcast without a refresh of the stored control block with GS_SET_BC_CB will not have any effect. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/nmi.c')
-rw-r--r--arch/s390/kernel/nmi.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index 9bf8327154ee..985589523970 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -106,6 +106,7 @@ static int notrace s390_validate_registers(union mci mci, int umode)
int kill_task;
u64 zero;
void *fpt_save_area;
+ struct mcesa *mcesa;
kill_task = 0;
zero = 0;
@@ -165,6 +166,7 @@ static int notrace s390_validate_registers(union mci mci, int umode)
: : "Q" (S390_lowcore.fpt_creg_save_area));
}
+ mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK);
if (!MACHINE_HAS_VX) {
/* Validate floating point registers */
asm volatile(
@@ -209,8 +211,8 @@ static int notrace s390_validate_registers(union mci mci, int umode)
" la 1,%0\n"
" .word 0xe70f,0x1000,0x0036\n" /* vlm 0,15,0(1) */
" .word 0xe70f,0x1100,0x0c36\n" /* vlm 16,31,256(1) */
- : : "Q" (*(struct vx_array *)
- &S390_lowcore.vector_save_area) : "1");
+ : : "Q" (*(struct vx_array *) mcesa->vector_save_area)
+ : "1");
__ctl_load(S390_lowcore.cregs_save_area[0], 0, 0);
}
/* Validate access registers */
@@ -224,6 +226,19 @@ static int notrace s390_validate_registers(union mci mci, int umode)
*/
kill_task = 1;
}
+ /* Validate guarded storage registers */
+ if (MACHINE_HAS_GS && (S390_lowcore.cregs_save_area[2] & (1UL << 4))) {
+ if (!mci.gs)
+ /*
+ * Guarded storage register can't be restored and
+ * the current processes uses guarded storage.
+ * It has to be terminated.
+ */
+ kill_task = 1;
+ else
+ load_gs_cb((struct gs_cb *)
+ mcesa->guarded_storage_save_area);
+ }
/*
* We don't even try to validate the TOD register, since we simply
* can't write something sensible into that register.