From 25591b07033663e09f5e60355fc5ec4d4aa53e63 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Wed, 10 Nov 2010 10:05:51 +0100 Subject: [S390] fix get_user_pages_fast The check for the _PAGE_RO bit in get_user_pages_fast for write==1 is the wrong way around. It must not be set for the fast path. Signed-off-by: Martin Schwidefsky --- arch/s390/mm/gup.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'arch') 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); -- cgit v1.2.3 From ec6743bb06510c7b629603ce35713d6ae9273579 Mon Sep 17 00:00:00 2001 From: Hendrik Brueckner Date: Wed, 10 Nov 2010 10:05:55 +0100 Subject: [S390] mm: add devmem_is_allowed() for STRICT_DEVMEM checking Provide the devmem_is_allowed() routine to restrict access to kernel memory from userspace. Set the CONFIG_STRICT_DEVMEM config option to switch on checking. Signed-off-by: Hendrik Brueckner Signed-off-by: Martin Schwidefsky --- arch/s390/Kconfig.debug | 12 ++++++++++++ arch/s390/include/asm/page.h | 5 +++++ 2 files changed, 17 insertions(+) (limited to 'arch') 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 -- cgit v1.2.3 From adb45839817392102e659c19e5c19aa39530021f Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Wed, 10 Nov 2010 10:05:57 +0100 Subject: [S390] kprobes: disable interrupts throughout Execute the kprobe exception and fault handler with interrupts disabled. To disable the interrupts only while a single step is in progress is not good enough, a kprobe from interrupt context while another kprobe is handled can confuse the internal house keeping. Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/kprobes.c | 41 +++++++++++++++++++++++++++-------------- 1 file changed, 27 insertions(+), 14 deletions(-) (limited to 'arch') diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index d60fc4398516..70cf73bdba25 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -30,6 +30,7 @@ #include #include #include +#include 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; @@ -465,8 +464,6 @@ 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 +479,7 @@ 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 +505,6 @@ 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 +548,18 @@ 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 +567,12 @@ 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 +583,17 @@ 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 +607,7 @@ 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]; -- cgit v1.2.3 From 89480801a17a3069f45169d40b828c8e511aa005 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Wed, 10 Nov 2010 10:05:58 +0100 Subject: [S390] kprobes: Fix the return address of multiple kretprobes Analog to git commit 737480a0d525dae13306296da08029dff545bc72 fix the return address of subsequent kretprobes when multiple kretprobes are set on the same function. Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/kprobes.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) (limited to 'arch') diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index 70cf73bdba25..2564793ec2b6 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -349,6 +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); @@ -371,10 +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) { @@ -386,7 +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(); -- cgit v1.2.3