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Diffstat (limited to 'arch/x86/kernel/hw_breakpoint.c')
-rw-r--r--arch/x86/kernel/hw_breakpoint.c51
1 files changed, 36 insertions, 15 deletions
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c
index a8f1b803d2fd..a474ec37c32f 100644
--- a/arch/x86/kernel/hw_breakpoint.c
+++ b/arch/x86/kernel/hw_breakpoint.c
@@ -208,6 +208,9 @@ int arch_bp_generic_fields(int x86_len, int x86_type,
{
/* Len */
switch (x86_len) {
+ case X86_BREAKPOINT_LEN_X:
+ *gen_len = sizeof(long);
+ break;
case X86_BREAKPOINT_LEN_1:
*gen_len = HW_BREAKPOINT_LEN_1;
break;
@@ -251,6 +254,29 @@ static int arch_build_bp_info(struct perf_event *bp)
info->address = bp->attr.bp_addr;
+ /* Type */
+ switch (bp->attr.bp_type) {
+ case HW_BREAKPOINT_W:
+ info->type = X86_BREAKPOINT_WRITE;
+ break;
+ case HW_BREAKPOINT_W | HW_BREAKPOINT_R:
+ info->type = X86_BREAKPOINT_RW;
+ break;
+ case HW_BREAKPOINT_X:
+ info->type = X86_BREAKPOINT_EXECUTE;
+ /*
+ * x86 inst breakpoints need to have a specific undefined len.
+ * But we still need to check userspace is not trying to setup
+ * an unsupported length, to get a range breakpoint for example.
+ */
+ if (bp->attr.bp_len == sizeof(long)) {
+ info->len = X86_BREAKPOINT_LEN_X;
+ return 0;
+ }
+ default:
+ return -EINVAL;
+ }
+
/* Len */
switch (bp->attr.bp_len) {
case HW_BREAKPOINT_LEN_1:
@@ -271,21 +297,6 @@ static int arch_build_bp_info(struct perf_event *bp)
return -EINVAL;
}
- /* Type */
- switch (bp->attr.bp_type) {
- case HW_BREAKPOINT_W:
- info->type = X86_BREAKPOINT_WRITE;
- break;
- case HW_BREAKPOINT_W | HW_BREAKPOINT_R:
- info->type = X86_BREAKPOINT_RW;
- break;
- case HW_BREAKPOINT_X:
- info->type = X86_BREAKPOINT_EXECUTE;
- break;
- default:
- return -EINVAL;
- }
-
return 0;
}
/*
@@ -305,6 +316,9 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
ret = -EINVAL;
switch (info->len) {
+ case X86_BREAKPOINT_LEN_X:
+ align = sizeof(long) -1;
+ break;
case X86_BREAKPOINT_LEN_1:
align = 0;
break;
@@ -466,6 +480,13 @@ static int __kprobes hw_breakpoint_handler(struct die_args *args)
perf_bp_event(bp, args->regs);
+ /*
+ * Set up resume flag to avoid breakpoint recursion when
+ * returning back to origin.
+ */
+ if (bp->hw.info.type == X86_BREAKPOINT_EXECUTE)
+ args->regs->flags |= X86_EFLAGS_RF;
+
rcu_read_unlock();
}
/*