These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / arch / x86 / kernel / hw_breakpoint.c

diff --git a/kernel/arch/x86/kernel/hw_breakpoint.c b/kernel/arch/x86/kernel/hw_breakpoint.c
index 7114ba2..50a3fad 100644 (file)
--- a/kernel/arch/x86/kernel/hw_breakpoint.c
+++ b/kernel/arch/x86/kernel/hw_breakpoint.c
@@ -32,6 +32,7 @@
 #include <linux/irqflags.h>
 #include <linux/notifier.h>
 #include <linux/kallsyms.h>
+#include <linux/kprobes.h>
 #include <linux/percpu.h>
 #include <linux/kdebug.h>
 #include <linux/kernel.h>
@@ -179,7 +180,11 @@ int arch_check_bp_in_kernelspace(struct perf_event *bp)
        va = info->address;
        len = bp->attr.bp_len;
 
-       return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE);
+       /*
+        * We don't need to worry about va + len - 1 overflowing:
+        * we already require that va is aligned to a multiple of len.
+        */
+       return (va >= TASK_SIZE_MAX) || ((va + len - 1) >= TASK_SIZE_MAX);
 }
 
 int arch_bp_generic_fields(int x86_len, int x86_type,
@@ -243,6 +248,20 @@ static int arch_build_bp_info(struct perf_event *bp)
                info->type = X86_BREAKPOINT_RW;
                break;
        case HW_BREAKPOINT_X:
+               /*
+                * We don't allow kernel breakpoints in places that are not
+                * acceptable for kprobes.  On non-kprobes kernels, we don't
+                * allow kernel breakpoints at all.
+                */
+               if (bp->attr.bp_addr >= TASK_SIZE_MAX) {
+#ifdef CONFIG_KPROBES
+                       if (within_kprobe_blacklist(bp->attr.bp_addr))
+                               return -EINVAL;
+#else
+                       return -EINVAL;
+#endif
+               }
+
                info->type = X86_BREAKPOINT_EXECUTE;
                /*
                 * x86 inst breakpoints need to have a specific undefined len.
@@ -276,8 +295,18 @@ static int arch_build_bp_info(struct perf_event *bp)
                break;
 #endif
        default:
+               /* AMD range breakpoint */
                if (!is_power_of_2(bp->attr.bp_len))
                        return -EINVAL;
+               if (bp->attr.bp_addr & (bp->attr.bp_len - 1))
+                       return -EINVAL;
+               /*
+                * It's impossible to use a range breakpoint to fake out
+                * user vs kernel detection because bp_len - 1 can't
+                * have the high bit set.  If we ever allow range instruction
+                * breakpoints, then we'll have to check for kprobe-blacklisted
+                * addresses anywhere in the range.
+                */
                if (!cpu_has_bpext)
                        return -EOPNOTSUPP;
                info->mask = bp->attr.bp_len - 1;