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-rw-r--r--arch/s390/Kconfig.debug12
-rw-r--r--arch/s390/include/asm/page.h5
-rw-r--r--arch/s390/kernel/compat_linux.c1
-rw-r--r--arch/s390/kernel/kprobes.c70
-rw-r--r--arch/s390/kernel/nmi.c10
-rw-r--r--arch/s390/lib/delay.c14
-rw-r--r--arch/s390/mm/gup.c7
7 files changed, 86 insertions, 33 deletions
diff --git a/arch/s390/Kconfig.debug b/arch/s390/Kconfig.debug
index 45e0c6199f36..05221b13ffb1 100644
--- a/arch/s390/Kconfig.debug
+++ b/arch/s390/Kconfig.debug
@@ -6,6 +6,18 @@ config TRACE_IRQFLAGS_SUPPORT
source "lib/Kconfig.debug"
+config STRICT_DEVMEM
+ def_bool y
+ prompt "Filter access to /dev/mem"
+ ---help---
+ This option restricts access to /dev/mem. If this option is
+ disabled, you allow userspace access to all memory, including
+ kernel and userspace memory. Accidental memory access is likely
+ to be disastrous.
+ Memory access is required for experts who want to debug the kernel.
+
+ If you are unsure, say Y.
+
config DEBUG_STRICT_USER_COPY_CHECKS
bool "Strict user copy size checks"
---help---
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index a8729ea7e9ac..3c987e9ec8d6 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -130,6 +130,11 @@ struct page;
void arch_free_page(struct page *page, int order);
void arch_alloc_page(struct page *page, int order);
+static inline int devmem_is_allowed(unsigned long pfn)
+{
+ return 0;
+}
+
#define HAVE_ARCH_FREE_PAGE
#define HAVE_ARCH_ALLOC_PAGE
diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 1e6449c79ab6..53acaa86dd94 100644
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -25,7 +25,6 @@
#include <linux/resource.h>
#include <linux/times.h>
#include <linux/smp.h>
-#include <linux/smp_lock.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index d60fc4398516..2564793ec2b6 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -30,6 +30,7 @@
#include <asm/sections.h>
#include <linux/module.h>
#include <linux/slab.h>
+#include <linux/hardirq.h>
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
@@ -212,7 +213,7 @@ static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
/* Set the PER control regs, turns on single step for this address */
__ctl_load(kprobe_per_regs, 9, 11);
regs->psw.mask |= PSW_MASK_PER;
- regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK);
+ regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT);
}
static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
@@ -239,7 +240,7 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
__get_cpu_var(current_kprobe) = p;
/* Save the interrupt and per flags */
kcb->kprobe_saved_imask = regs->psw.mask &
- (PSW_MASK_PER | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK);
+ (PSW_MASK_PER | PSW_MASK_IO | PSW_MASK_EXT);
/* Save the control regs that govern PER */
__ctl_store(kcb->kprobe_saved_ctl, 9, 11);
}
@@ -316,8 +317,6 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
return 1;
ss_probe:
- if (regs->psw.mask & (PSW_MASK_PER | PSW_MASK_IO))
- local_irq_disable();
prepare_singlestep(p, regs);
kcb->kprobe_status = KPROBE_HIT_SS;
return 1;
@@ -350,6 +349,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
struct hlist_node *node, *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
+ kprobe_opcode_t *correct_ret_addr = NULL;
INIT_HLIST_HEAD(&empty_rp);
kretprobe_hash_lock(current, &head, &flags);
@@ -372,10 +372,32 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
/* another task is sharing our hash bucket */
continue;
- if (ri->rp && ri->rp->handler)
- ri->rp->handler(ri, regs);
+ orig_ret_address = (unsigned long)ri->ret_addr;
+
+ if (orig_ret_address != trampoline_address)
+ /*
+ * This is the real return address. Any other
+ * instances associated with this task are for
+ * other calls deeper on the call stack
+ */
+ break;
+ }
+
+ kretprobe_assert(ri, orig_ret_address, trampoline_address);
+
+ correct_ret_addr = ri->ret_addr;
+ hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
+ if (ri->task != current)
+ /* another task is sharing our hash bucket */
+ continue;
orig_ret_address = (unsigned long)ri->ret_addr;
+
+ if (ri->rp && ri->rp->handler) {
+ ri->ret_addr = correct_ret_addr;
+ ri->rp->handler(ri, regs);
+ }
+
recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address) {
@@ -387,7 +409,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
break;
}
}
- kretprobe_assert(ri, orig_ret_address, trampoline_address);
+
regs->psw.addr = orig_ret_address | PSW_ADDR_AMODE;
reset_current_kprobe();
@@ -465,8 +487,6 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs)
goto out;
}
reset_current_kprobe();
- if (regs->psw.mask & (PSW_MASK_PER | PSW_MASK_IO))
- local_irq_enable();
out:
preempt_enable_no_resched();
@@ -482,7 +502,7 @@ out:
return 1;
}
-int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+static int __kprobes kprobe_trap_handler(struct pt_regs *regs, int trapnr)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
@@ -508,8 +528,6 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
restore_previous_kprobe(kcb);
else {
reset_current_kprobe();
- if (regs->psw.mask & (PSW_MASK_PER | PSW_MASK_IO))
- local_irq_enable();
}
preempt_enable_no_resched();
break;
@@ -553,6 +571,18 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
return 0;
}
+int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+{
+ int ret;
+
+ if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
+ local_irq_disable();
+ ret = kprobe_trap_handler(regs, trapnr);
+ if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
+ local_irq_restore(regs->psw.mask & ~PSW_MASK_PER);
+ return ret;
+}
+
/*
* Wrapper routine to for handling exceptions.
*/
@@ -560,8 +590,12 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data)
{
struct die_args *args = (struct die_args *)data;
+ struct pt_regs *regs = args->regs;
int ret = NOTIFY_DONE;
+ if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
+ local_irq_disable();
+
switch (val) {
case DIE_BPT:
if (kprobe_handler(args->regs))
@@ -572,16 +606,17 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
ret = NOTIFY_STOP;
break;
case DIE_TRAP:
- /* kprobe_running() needs smp_processor_id() */
- preempt_disable();
- if (kprobe_running() &&
- kprobe_fault_handler(args->regs, args->trapnr))
+ if (!preemptible() && kprobe_running() &&
+ kprobe_trap_handler(args->regs, args->trapnr))
ret = NOTIFY_STOP;
- preempt_enable();
break;
default:
break;
}
+
+ if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
+ local_irq_restore(regs->psw.mask & ~PSW_MASK_PER);
+
return ret;
}
@@ -595,6 +630,7 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
/* setup return addr to the jprobe handler routine */
regs->psw.addr = (unsigned long)(jp->entry) | PSW_ADDR_AMODE;
+ regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT);
/* r14 is the function return address */
kcb->jprobe_saved_r14 = (unsigned long)regs->gprs[14];
diff --git a/arch/s390/kernel/nmi.c b/arch/s390/kernel/nmi.c
index ac151399ef34..1995c1712fc8 100644
--- a/arch/s390/kernel/nmi.c
+++ b/arch/s390/kernel/nmi.c
@@ -95,7 +95,6 @@ EXPORT_SYMBOL_GPL(s390_handle_mcck);
static int notrace s390_revalidate_registers(struct mci *mci)
{
int kill_task;
- u64 tmpclock;
u64 zero;
void *fpt_save_area, *fpt_creg_save_area;
@@ -214,11 +213,10 @@ static int notrace s390_revalidate_registers(struct mci *mci)
: "0", "cc");
#endif
/* Revalidate clock comparator register */
- asm volatile(
- " stck 0(%1)\n"
- " sckc 0(%1)"
- : "=m" (tmpclock) : "a" (&(tmpclock)) : "cc", "memory");
-
+ if (S390_lowcore.clock_comparator == -1)
+ set_clock_comparator(S390_lowcore.mcck_clock);
+ else
+ set_clock_comparator(S390_lowcore.clock_comparator);
/* Check if old PSW is valid */
if (!mci->wp)
/*
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index 752b362bf651..7c37ec359ec2 100644
--- a/arch/s390/lib/delay.c
+++ b/arch/s390/lib/delay.c
@@ -29,17 +29,21 @@ static void __udelay_disabled(unsigned long long usecs)
{
unsigned long mask, cr0, cr0_saved;
u64 clock_saved;
+ u64 end;
+ mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT;
+ end = get_clock() + (usecs << 12);
clock_saved = local_tick_disable();
- set_clock_comparator(get_clock() + (usecs << 12));
__ctl_store(cr0_saved, 0, 0);
cr0 = (cr0_saved & 0xffff00e0) | 0x00000800;
__ctl_load(cr0 , 0, 0);
- mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_EXT;
lockdep_off();
- trace_hardirqs_on();
- __load_psw_mask(mask);
- local_irq_disable();
+ do {
+ set_clock_comparator(end);
+ trace_hardirqs_on();
+ __load_psw_mask(mask);
+ local_irq_disable();
+ } while (get_clock() < end);
lockdep_on();
__ctl_load(cr0_saved, 0, 0);
local_tick_enable(clock_saved);
diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c
index 38e641cdd977..45b405ca2567 100644
--- a/arch/s390/mm/gup.c
+++ b/arch/s390/mm/gup.c
@@ -20,18 +20,17 @@
static inline int gup_pte_range(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
unsigned long end, int write, struct page **pages, int *nr)
{
- unsigned long mask, result;
+ unsigned long mask;
pte_t *ptep, pte;
struct page *page;
- result = write ? 0 : _PAGE_RO;
- mask = result | _PAGE_INVALID | _PAGE_SPECIAL;
+ mask = (write ? _PAGE_RO : 0) | _PAGE_INVALID | _PAGE_SPECIAL;
ptep = ((pte_t *) pmd_deref(pmd)) + pte_index(addr);
do {
pte = *ptep;
barrier();
- if ((pte_val(pte) & mask) != result)
+ if ((pte_val(pte) & mask) != 0)
return 0;
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
page = pte_page(pte);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.