From: Todd Vierling <todd.vierling@oracle.com>
Date: Fri, 9 Feb 2018 21:58:34 +0000 (-0500)
Subject: kernel: on OL6 only, simulate the gcc 4.4 kABI for __stack_chk_fail()
X-Git-Tag: v4.1.12-124.31.3~1136
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=5cca067f8b78c0d8f90cd47abdec5fd3bed28e45;p=users%2Fjedix%2Flinux-maple.git

kernel: on OL6 only, simulate the gcc 4.4 kABI for __stack_chk_fail()

The __visible linkage changes st_value calculation for genksyms on newer
compilers such as OL7's 4.8 and SCL's 4.9. However, this symbol is in
the kABI whitelist and needs to retain its old st_value, even though the
guts of the compiled function have not changed.

Add a special directive, CONFIG_SIMULATE_GCC44_KABI, which will mask the
__visible qualifier at genksyms time; and use it only on OL6 builds.

Orabug: 27509351
Signed-off-by: Todd Vierling <todd.vierling@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
---

diff --git a/Kconfig b/Kconfig
index c13f48d65898..6b1ed64d6cc9 100644
--- a/Kconfig
+++ b/Kconfig
@@ -8,4 +8,9 @@ config SRCARCH
 	string
 	option env="SRCARCH"
 
+# special hack for UEK-OL6 to allow special kABI hacks
+config SIMULATE_GCC44_KABI
+	bool "Simulate the gcc 4.4 kABI"
+	default n
+
 source "arch/$SRCARCH/Kconfig"
diff --git a/kernel/panic.c b/kernel/panic.c
index e9999af53078..ec078a046b1d 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -542,7 +542,10 @@ EXPORT_SYMBOL(warn_slowpath_null);
  * Called when gcc's -fstack-protector feature is used, and
  * gcc detects corruption of the on-stack canary value
  */
-__visible void __stack_chk_fail(void)
+#if !defined(CONFIG_SIMULATE_GCC44_KABI) || !defined(__GENKSYMS__)
+__visible
+#endif
+void __stack_chk_fail(void)
 {
 	panic("stack-protector: Kernel stack is corrupted in: %p\n",
 		__builtin_return_address(0));
diff --git a/uek-rpm/ol6/config-x86_64 b/uek-rpm/ol6/config-x86_64
index 6030414dfdb8..37046a6d84c8 100644
--- a/uek-rpm/ol6/config-x86_64
+++ b/uek-rpm/ol6/config-x86_64
@@ -6371,3 +6371,4 @@ CONFIG_FONT_SUPPORT=y
 CONFIG_FONT_8x8=y
 CONFIG_FONT_8x16=y
 CONFIG_ARCH_HAS_SG_CHAIN=y
+CONFIG_SIMULATE_GCC44_KABI=y
diff --git a/uek-rpm/ol6/config-x86_64-debug b/uek-rpm/ol6/config-x86_64-debug
index 7a5ff8723015..4eaf52f033af 100644
--- a/uek-rpm/ol6/config-x86_64-debug
+++ b/uek-rpm/ol6/config-x86_64-debug
@@ -6388,3 +6388,4 @@ CONFIG_FONT_SUPPORT=y
 CONFIG_FONT_8x8=y
 CONFIG_FONT_8x16=y
 CONFIG_ARCH_HAS_SG_CHAIN=y
+CONFIG_SIMULATE_GCC44_KABI=y