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authorLinus Torvalds <torvalds@linux-foundation.org>2017-04-09 09:05:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-04-09 09:05:25 -0700
commit462e9a355e7488fde3712c3b2585fc2f2a2c263d (patch)
tree2f1cdf7e4b72281f9fba51b6d1515c2b46f8434b
parent5b50be743f495b000891d430ecba7372cc59bb64 (diff)
parent3872fe83a2fbb7366daa93ca533a22138e2d483e (diff)
Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm
Pull ARM fixes from Russell King: "A number of ARM fixes: - prevent oopses caused by dma_get_sgtable() and declared DMA coherent memory - fix boot failure on nommu caused by ID_PFR1 access - a number of kprobes fixes from Jon Medhurst and Masami Hiramatsu" * 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 8665/1: nommu: access ID_PFR1 only if CPUID scheme ARM: dma-mapping: disallow dma_get_sgtable() for non-kernel managed memory arm: kprobes: Align stack to 8-bytes in test code arm: kprobes: Fix the return address of multiple kretprobes arm: kprobes: Skip single-stepping in recursing path if possible arm: kprobes: Allow to handle reentered kprobe on single-stepping
-rw-r--r--arch/arm/mm/dma-mapping.c20
-rw-r--r--arch/arm/mm/nommu.c5
-rw-r--r--arch/arm/probes/kprobes/core.c49
-rw-r--r--arch/arm/probes/kprobes/test-core.c11
4 files changed, 69 insertions, 16 deletions
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 63eabb06f9f1..475811f5383a 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -935,13 +935,31 @@ static void arm_coherent_dma_free(struct device *dev, size_t size, void *cpu_add
__arm_dma_free(dev, size, cpu_addr, handle, attrs, true);
}
+/*
+ * The whole dma_get_sgtable() idea is fundamentally unsafe - it seems
+ * that the intention is to allow exporting memory allocated via the
+ * coherent DMA APIs through the dma_buf API, which only accepts a
+ * scattertable. This presents a couple of problems:
+ * 1. Not all memory allocated via the coherent DMA APIs is backed by
+ * a struct page
+ * 2. Passing coherent DMA memory into the streaming APIs is not allowed
+ * as we will try to flush the memory through a different alias to that
+ * actually being used (and the flushes are redundant.)
+ */
int arm_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
void *cpu_addr, dma_addr_t handle, size_t size,
unsigned long attrs)
{
- struct page *page = pfn_to_page(dma_to_pfn(dev, handle));
+ unsigned long pfn = dma_to_pfn(dev, handle);
+ struct page *page;
int ret;
+ /* If the PFN is not valid, we do not have a struct page */
+ if (!pfn_valid(pfn))
+ return -ENXIO;
+
+ page = pfn_to_page(pfn);
+
ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
if (unlikely(ret))
return ret;
diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c
index 3b5c7aaf9c76..33a45bd96860 100644
--- a/arch/arm/mm/nommu.c
+++ b/arch/arm/mm/nommu.c
@@ -303,7 +303,10 @@ static inline void set_vbar(unsigned long val)
*/
static inline bool security_extensions_enabled(void)
{
- return !!cpuid_feature_extract(CPUID_EXT_PFR1, 4);
+ /* Check CPUID Identification Scheme before ID_PFR1 read */
+ if ((read_cpuid_id() & 0x000f0000) == 0x000f0000)
+ return !!cpuid_feature_extract(CPUID_EXT_PFR1, 4);
+ return 0;
}
static unsigned long __init setup_vectors_base(void)
diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
index b6dc9d838a9a..ad1f4e6a9e33 100644
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -266,11 +266,20 @@ void __kprobes kprobe_handler(struct pt_regs *regs)
#endif
if (p) {
- if (cur) {
+ if (!p->ainsn.insn_check_cc(regs->ARM_cpsr)) {
+ /*
+ * Probe hit but conditional execution check failed,
+ * so just skip the instruction and continue as if
+ * nothing had happened.
+ * In this case, we can skip recursing check too.
+ */
+ singlestep_skip(p, regs);
+ } else if (cur) {
/* Kprobe is pending, so we're recursing. */
switch (kcb->kprobe_status) {
case KPROBE_HIT_ACTIVE:
case KPROBE_HIT_SSDONE:
+ case KPROBE_HIT_SS:
/* A pre- or post-handler probe got us here. */
kprobes_inc_nmissed_count(p);
save_previous_kprobe(kcb);
@@ -279,11 +288,16 @@ void __kprobes kprobe_handler(struct pt_regs *regs)
singlestep(p, regs, kcb);
restore_previous_kprobe(kcb);
break;
+ case KPROBE_REENTER:
+ /* A nested probe was hit in FIQ, it is a BUG */
+ pr_warn("Unrecoverable kprobe detected at %p.\n",
+ p->addr);
+ /* fall through */
default:
/* impossible cases */
BUG();
}
- } else if (p->ainsn.insn_check_cc(regs->ARM_cpsr)) {
+ } else {
/* Probe hit and conditional execution check ok. */
set_current_kprobe(p);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
@@ -304,13 +318,6 @@ void __kprobes kprobe_handler(struct pt_regs *regs)
}
reset_current_kprobe();
}
- } else {
- /*
- * Probe hit but conditional execution check failed,
- * so just skip the instruction and continue as if
- * nothing had happened.
- */
- singlestep_skip(p, regs);
}
} else if (cur) {
/* We probably hit a jprobe. Call its break handler. */
@@ -434,6 +441,7 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
struct hlist_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);
@@ -456,14 +464,34 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
/* another task is sharing our hash bucket */
continue;
+ 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, 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) {
__this_cpu_write(current_kprobe, &ri->rp->kp);
get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
+ ri->ret_addr = correct_ret_addr;
ri->rp->handler(ri, regs);
__this_cpu_write(current_kprobe, NULL);
}
- orig_ret_address = (unsigned long)ri->ret_addr;
recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address)
@@ -475,7 +503,6 @@ static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
break;
}
- kretprobe_assert(ri, orig_ret_address, trampoline_address);
kretprobe_hash_unlock(current, &flags);
hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
diff --git a/arch/arm/probes/kprobes/test-core.c b/arch/arm/probes/kprobes/test-core.c
index c893726aa52d..1c98a87786ca 100644
--- a/arch/arm/probes/kprobes/test-core.c
+++ b/arch/arm/probes/kprobes/test-core.c
@@ -977,7 +977,10 @@ static void coverage_end(void)
void __naked __kprobes_test_case_start(void)
{
__asm__ __volatile__ (
- "stmdb sp!, {r4-r11} \n\t"
+ "mov r2, sp \n\t"
+ "bic r3, r2, #7 \n\t"
+ "mov sp, r3 \n\t"
+ "stmdb sp!, {r2-r11} \n\t"
"sub sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
"bic r0, lr, #1 @ r0 = inline data \n\t"
"mov r1, sp \n\t"
@@ -997,7 +1000,8 @@ void __naked __kprobes_test_case_end_32(void)
"movne pc, r0 \n\t"
"mov r0, r4 \n\t"
"add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
- "ldmia sp!, {r4-r11} \n\t"
+ "ldmia sp!, {r2-r11} \n\t"
+ "mov sp, r2 \n\t"
"mov pc, r0 \n\t"
);
}
@@ -1013,7 +1017,8 @@ void __naked __kprobes_test_case_end_16(void)
"bxne r0 \n\t"
"mov r0, r4 \n\t"
"add sp, sp, #"__stringify(TEST_MEMORY_SIZE)"\n\t"
- "ldmia sp!, {r4-r11} \n\t"
+ "ldmia sp!, {r2-r11} \n\t"
+ "mov sp, r2 \n\t"
"bx r0 \n\t"
);
}