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Diffstat (limited to 'arch/s390/kernel/nmi.c')
-rw-r--r--arch/s390/kernel/nmi.c205
1 files changed, 113 insertions, 92 deletions
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index 31d03a84126c..6ff169253cae 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -12,6 +12,9 @@
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/hardirq.h>
+#include <linux/log2.h>
+#include <linux/kprobes.h>
+#include <linux/slab.h>
#include <linux/time.h>
#include <linux/module.h>
#include <linux/sched/signal.h>
@@ -37,13 +40,94 @@ struct mcck_struct {
};
static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
+static struct kmem_cache *mcesa_cache;
+static unsigned long mcesa_origin_lc;
-static void s390_handle_damage(void)
+static inline int nmi_needs_mcesa(void)
{
- smp_send_stop();
+ return MACHINE_HAS_VX || MACHINE_HAS_GS;
+}
+
+static inline unsigned long nmi_get_mcesa_size(void)
+{
+ if (MACHINE_HAS_GS)
+ return MCESA_MAX_SIZE;
+ return MCESA_MIN_SIZE;
+}
+
+/*
+ * The initial machine check extended save area for the boot CPU.
+ * It will be replaced by nmi_init() with an allocated structure.
+ * The structure is required for machine check happening early in
+ * the boot process.
+ */
+static struct mcesa boot_mcesa __initdata __aligned(MCESA_MAX_SIZE);
+
+void __init nmi_alloc_boot_cpu(struct lowcore *lc)
+{
+ if (!nmi_needs_mcesa())
+ return;
+ lc->mcesad = (unsigned long) &boot_mcesa;
+ if (MACHINE_HAS_GS)
+ lc->mcesad |= ilog2(MCESA_MAX_SIZE);
+}
+
+static int __init nmi_init(void)
+{
+ unsigned long origin, cr0, size;
+
+ if (!nmi_needs_mcesa())
+ return 0;
+ size = nmi_get_mcesa_size();
+ if (size > MCESA_MIN_SIZE)
+ mcesa_origin_lc = ilog2(size);
+ /* create slab cache for the machine-check-extended-save-areas */
+ mcesa_cache = kmem_cache_create("nmi_save_areas", size, size, 0, NULL);
+ if (!mcesa_cache)
+ panic("Couldn't create nmi save area cache");
+ origin = (unsigned long) kmem_cache_alloc(mcesa_cache, GFP_KERNEL);
+ if (!origin)
+ panic("Couldn't allocate nmi save area");
+ /* The pointer is stored with mcesa_bits ORed in */
+ kmemleak_not_leak((void *) origin);
+ __ctl_store(cr0, 0, 0);
+ __ctl_clear_bit(0, 28); /* disable lowcore protection */
+ /* Replace boot_mcesa on the boot CPU */
+ S390_lowcore.mcesad = origin | mcesa_origin_lc;
+ __ctl_load(cr0, 0, 0);
+ return 0;
+}
+early_initcall(nmi_init);
+
+int nmi_alloc_per_cpu(struct lowcore *lc)
+{
+ unsigned long origin;
+
+ if (!nmi_needs_mcesa())
+ return 0;
+ origin = (unsigned long) kmem_cache_alloc(mcesa_cache, GFP_KERNEL);
+ if (!origin)
+ return -ENOMEM;
+ /* The pointer is stored with mcesa_bits ORed in */
+ kmemleak_not_leak((void *) origin);
+ lc->mcesad = origin | mcesa_origin_lc;
+ return 0;
+}
+
+void nmi_free_per_cpu(struct lowcore *lc)
+{
+ if (!nmi_needs_mcesa())
+ return;
+ kmem_cache_free(mcesa_cache, (void *)(lc->mcesad & MCESA_ORIGIN_MASK));
+}
+
+static notrace void s390_handle_damage(void)
+{
+ smp_emergency_stop();
disabled_wait((unsigned long) __builtin_return_address(0));
while (1);
}
+NOKPROBE_SYMBOL(s390_handle_damage);
/*
* Main machine check handler function. Will be called with interrupts enabled
@@ -100,18 +184,15 @@ void s390_handle_mcck(void)
EXPORT_SYMBOL_GPL(s390_handle_mcck);
/*
- * returns 0 if all registers could be validated
+ * returns 0 if all required registers are available
* returns 1 otherwise
*/
-static int notrace s390_validate_registers(union mci mci, int umode)
+static int notrace s390_check_registers(union mci mci, int umode)
{
+ union ctlreg2 cr2;
int kill_task;
- u64 zero;
- void *fpt_save_area;
- struct mcesa *mcesa;
kill_task = 0;
- zero = 0;
if (!mci.gr) {
/*
@@ -122,18 +203,13 @@ static int notrace s390_validate_registers(union mci mci, int umode)
s390_handle_damage();
kill_task = 1;
}
- /* Validate control registers */
+ /* Check control registers */
if (!mci.cr) {
/*
* Control registers have unknown contents.
* Can't recover and therefore stopping machine.
*/
s390_handle_damage();
- } else {
- asm volatile(
- " lctlg 0,15,0(%0)\n"
- " ptlb\n"
- : : "a" (&S390_lowcore.cregs_save_area) : "memory");
}
if (!mci.fp) {
/*
@@ -141,86 +217,41 @@ static int notrace s390_validate_registers(union mci mci, int umode)
* kernel currently uses floating point registers the
* system is stopped. If the process has its floating
* pointer registers loaded it is terminated.
- * Otherwise just revalidate the registers.
*/
if (S390_lowcore.fpu_flags & KERNEL_VXR_V0V7)
s390_handle_damage();
if (!test_cpu_flag(CIF_FPU))
kill_task = 1;
}
- fpt_save_area = &S390_lowcore.floating_pt_save_area;
if (!mci.fc) {
/*
* Floating point control register can't be restored.
* If the kernel currently uses the floating pointer
* registers and needs the FPC register the system is
* stopped. If the process has its floating pointer
- * registers loaded it is terminated. Otherwiese the
- * FPC is just revalidated.
+ * registers loaded it is terminated.
*/
if (S390_lowcore.fpu_flags & KERNEL_FPC)
s390_handle_damage();
- asm volatile("lfpc %0" : : "Q" (zero));
if (!test_cpu_flag(CIF_FPU))
kill_task = 1;
- } else {
- asm volatile("lfpc %0"
- : : "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(
- " ld 0,0(%0)\n"
- " ld 1,8(%0)\n"
- " ld 2,16(%0)\n"
- " ld 3,24(%0)\n"
- " ld 4,32(%0)\n"
- " ld 5,40(%0)\n"
- " ld 6,48(%0)\n"
- " ld 7,56(%0)\n"
- " ld 8,64(%0)\n"
- " ld 9,72(%0)\n"
- " ld 10,80(%0)\n"
- " ld 11,88(%0)\n"
- " ld 12,96(%0)\n"
- " ld 13,104(%0)\n"
- " ld 14,112(%0)\n"
- " ld 15,120(%0)\n"
- : : "a" (fpt_save_area) : "memory");
- } else {
- /* Validate vector registers */
- union ctlreg0 cr0;
-
+ if (MACHINE_HAS_VX) {
if (!mci.vr) {
/*
* Vector registers can't be restored. If the kernel
* currently uses vector registers the system is
* stopped. If the process has its vector registers
- * loaded it is terminated. Otherwise just revalidate
- * the registers.
+ * loaded it is terminated.
*/
if (S390_lowcore.fpu_flags & KERNEL_VXR)
s390_handle_damage();
if (!test_cpu_flag(CIF_FPU))
kill_task = 1;
}
- cr0.val = S390_lowcore.cregs_save_area[0];
- cr0.afp = cr0.vx = 1;
- __ctl_load(cr0.val, 0, 0);
- asm volatile(
- " 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 *) mcesa->vector_save_area)
- : "1");
- __ctl_load(S390_lowcore.cregs_save_area[0], 0, 0);
}
- /* Validate access registers */
- asm volatile(
- " lam 0,15,0(%0)"
- : : "a" (&S390_lowcore.access_regs_save_area));
+ /* Check if access registers are valid */
if (!mci.ar) {
/*
* Access registers have unknown contents.
@@ -228,53 +259,41 @@ 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)
+ /* Check guarded storage registers */
+ cr2.val = S390_lowcore.cregs_save_area[2];
+ if (cr2.gse) {
+ 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.
- */
- /*
- * See if we can validate the TOD programmable register with its
- * old contents (should be zero) otherwise set it to zero.
- */
- if (!mci.pr)
- asm volatile(
- " sr 0,0\n"
- " sckpf"
- : : : "0", "cc");
- else
- asm volatile(
- " l 0,%0\n"
- " sckpf"
- : : "Q" (S390_lowcore.tod_progreg_save_area)
- : "0", "cc");
- /* Validate clock comparator register */
- set_clock_comparator(S390_lowcore.clock_comparator);
/* Check if old PSW is valid */
- if (!mci.wp)
+ if (!mci.wp) {
/*
* Can't tell if we come from user or kernel mode
* -> stopping machine.
*/
s390_handle_damage();
+ }
+ /* Check for invalid kernel instruction address */
+ if (!mci.ia && !umode) {
+ /*
+ * The instruction address got lost while running
+ * in the kernel -> stopping machine.
+ */
+ s390_handle_damage();
+ }
if (!mci.ms || !mci.pm || !mci.ia)
kill_task = 1;
return kill_task;
}
+NOKPROBE_SYMBOL(s390_check_registers);
/*
* Backup the guest's machine check info to its description block
@@ -300,6 +319,7 @@ static void notrace s390_backup_mcck_info(struct pt_regs *regs)
mcck_backup->failing_storage_address
= S390_lowcore.failing_storage_address;
}
+NOKPROBE_SYMBOL(s390_backup_mcck_info);
#define MAX_IPD_COUNT 29
#define MAX_IPD_TIME (5 * 60 * USEC_PER_SEC) /* 5 minutes */
@@ -372,7 +392,7 @@ void notrace s390_do_machine_check(struct pt_regs *regs)
s390_handle_damage();
}
}
- if (s390_validate_registers(mci, user_mode(regs))) {
+ if (s390_check_registers(mci, user_mode(regs))) {
/*
* Couldn't restore all register contents for the
* user space process -> mark task for termination.
@@ -443,6 +463,7 @@ void notrace s390_do_machine_check(struct pt_regs *regs)
clear_cpu_flag(CIF_MCCK_GUEST);
nmi_exit();
}
+NOKPROBE_SYMBOL(s390_do_machine_check);
static int __init machine_check_init(void)
{
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-22 03:50:45 +0100