[tip:x86/extable] x86, extable: Add early_fixup_exception()

tip-bot for H. Peter Anvin
2012-04-20T00:27:26Z

Commit-ID: 6a1ea279c210e7dc05de86dc29c0d4f577f484fb
Gitweb: http://git.kernel.org/tip/6a1ea279c210e7dc05de86dc29c0d4f577f484fb
Author: H. Peter Anvin <hpa@linux.intel.com>
AuthorDate: Thu, 19 Apr 2012 15:24:20 -0700
Committer: H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Thu, 19 Apr 2012 15:31:04 -0700

x86, extable: Add early_fixup_exception()

Add a restricted version of fixup_exception() to be used during early
boot only. In particular, this doesn't support the try..catch variant
since we may not have a thread_info set up yet.

This relies on the exception table being sorted already at build time.

Link: http://lkml.kernel.org/r/1334794610-5546-1-git-send-email-hpa@zytor.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
arch/x86/mm/extable.c | 17 +++++++++++++++++
1 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 1fb85db..5555675 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -35,3 +35,20 @@ int fixup_exception(struct pt_regs *regs)

return 0;
}
+
+/* Restricted version used during very early boot */
+int __init early_fixup_exception(unsigned long *ip)
+{
+ const struct exception_table_entry *fixup;
+
+ fixup = search_exception_tables(*ip);
+ if (fixup) {
+ if (fixup->fixup < 16)
+ return 0; /* Not supported during early boot */
+
+ *ip = fixup->fixup;
+ return 1;
+ }
+
+ return 0;
+}