kernel 5.7.8

1 files changed, 86 insertions, 0 deletions

diff --git a/SOURCES/0001-ARM-fix-__get_user_check-in-case-uaccess_-calls-are-.patch b/SOURCES/0001-ARM-fix-__get_user_check-in-case-uaccess_-calls-are-.patch
new file mode 100644
index 0000000..c5a4360
--- /dev/null
+++ b/SOURCES/0001-ARM-fix-__get_user_check-in-case-uaccess_-calls-are-.patch
@@ -0,0 +1,86 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Masahiro Yamada <yamada.masahiro@socionext.com>
+Date: Mon, 30 Sep 2019 14:59:25 +0900
+Subject: [PATCH] ARM: fix __get_user_check() in case uaccess_* calls are not
+ inlined
+
+KernelCI reports that bcm2835_defconfig is no longer booting since
+commit ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING
+forcibly"):
+
+  https://lkml.org/lkml/2019/9/26/825
+
+I also received a regression report from Nicolas Saenz Julienne:
+
+  https://lkml.org/lkml/2019/9/27/263
+
+This problem has cropped up on arch/arm/config/bcm2835_defconfig
+because it enables CONFIG_CC_OPTIMIZE_FOR_SIZE. The compiler tends
+to prefer not inlining functions with -Os. I was able to reproduce
+it with other boards and defconfig files by manually enabling
+CONFIG_CC_OPTIMIZE_FOR_SIZE.
+
+The __get_user_check() specifically uses r0, r1, r2 registers.
+So, uaccess_save_and_enable() and uaccess_restore() must be inlined
+in order to avoid those registers being overwritten in the callees.
+
+Prior to commit 9012d011660e ("compiler: allow all arches to enable
+CONFIG_OPTIMIZE_INLINING"), the 'inline' marker was always enough for
+inlining functions, except on x86.
+
+Since that commit, all architectures can enable CONFIG_OPTIMIZE_INLINING.
+So, __always_inline is now the only guaranteed way of forcible inlining.
+
+I want to keep as much compiler's freedom as possible about the inlining
+decision. So, I changed the function call order instead of adding
+__always_inline around.
+
+Call uaccess_save_and_enable() before assigning the __p ("r0"), and
+uaccess_restore() after evacuating the __e ("r0").
+
+Fixes: 9012d011660e ("compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING")
+Reported-by: "kernelci.org bot" <bot@kernelci.org>
+Reported-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
+Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
+Acked-by: Arnd Bergmann <arnd@arndb.de>
+Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
+Tested-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
+Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
+---
+ arch/arm/include/asm/uaccess.h | 8 +++++---
+ 1 file changed, 5 insertions(+), 3 deletions(-)
+
+diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
+index 98c6b91be4a8..60055827dddc 100644
+--- a/arch/arm/include/asm/uaccess.h
++++ b/arch/arm/include/asm/uaccess.h
+@@ -191,11 +191,12 @@ extern int __get_user_64t_4(void *);
+ #define __get_user_check(x, p)						\
+ 	({								\
+ 		unsigned long __limit = current_thread_info()->addr_limit - 1; \
++		unsigned int __ua_flags = uaccess_save_and_enable();	\
+ 		register typeof(*(p)) __user *__p asm("r0") = (p);	\
+ 		register __inttype(x) __r2 asm("r2");			\
+ 		register unsigned long __l asm("r1") = __limit;		\
+ 		register int __e asm("r0");				\
+-		unsigned int __ua_flags = uaccess_save_and_enable();	\
++		unsigned int __err;					\
+ 		switch (sizeof(*(__p))) {				\
+ 		case 1:							\
+ 			if (sizeof((x)) >= 8)				\
+@@ -223,9 +224,10 @@ extern int __get_user_64t_4(void *);
+ 			break;						\
+ 		default: __e = __get_user_bad(); break;			\
+ 		}							\
+-		uaccess_restore(__ua_flags);				\
++		__err = __e;						\
+ 		x = (typeof(*(p))) __r2;				\
+-		__e;							\
++		uaccess_restore(__ua_flags);				\
++		__err;							\
+ 	})
+
+ #define get_user(x, p)							\
+-- 
+2.26.2
+