[GIT pull] x86/urgent for 5.3-rc4

From: Thomas Gleixner
Date: Sat Aug 10 2019 - 16:08:17 EST


Linus,

please pull the latest x86-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-urgent-for-linus

up to: 04f5bda84b07: x86/lib/cpu: Address missing prototypes warning

A few fixes for x86:

- Don't reset the carefully adjusted build flags for the purgatory and
remove the unwanted flags instead. The 'reset all' approach led to build
fails under certain circumstances.

- Unbreak CLANG build of the purgatory by avoiding the builtin
memcpy/memset implementations.

- Address missing prototype warnings by including the proper header

- Fix yet more fall-through issues

Thanks,

tglx

------------------>
Gustavo A. R. Silva (2):
x86/ptrace: Mark expected switch fall-through
x86: mtrr: cyrix: Mark expected switch fall-through

Nick Desaulniers (2):
x86/purgatory: Do not use __builtin_memcpy and __builtin_memset
x86/purgatory: Use CFLAGS_REMOVE rather than reset KBUILD_CFLAGS

Valdis Kletnieks (1):
x86/lib/cpu: Address missing prototypes warning


arch/x86/boot/string.c | 8 ++++++++
arch/x86/kernel/cpu/mtrr/cyrix.c | 1 +
arch/x86/kernel/ptrace.c | 1 +
arch/x86/lib/cpu.c | 1 +
arch/x86/purgatory/Makefile | 36 +++++++++++++++++++++++++++++++-----
arch/x86/purgatory/purgatory.c | 6 ++++++
arch/x86/purgatory/string.c | 23 -----------------------
7 files changed, 48 insertions(+), 28 deletions(-)
delete mode 100644 arch/x86/purgatory/string.c

diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c
index 401e30ca0a75..8272a4492844 100644
--- a/arch/x86/boot/string.c
+++ b/arch/x86/boot/string.c
@@ -37,6 +37,14 @@ int memcmp(const void *s1, const void *s2, size_t len)
return diff;
}

+/*
+ * Clang may lower `memcmp == 0` to `bcmp == 0`.
+ */
+int bcmp(const void *s1, const void *s2, size_t len)
+{
+ return memcmp(s1, s2, len);
+}
+
int strcmp(const char *str1, const char *str2)
{
const unsigned char *s1 = (const unsigned char *)str1;
diff --git a/arch/x86/kernel/cpu/mtrr/cyrix.c b/arch/x86/kernel/cpu/mtrr/cyrix.c
index 4296c702a3f7..72182809b333 100644
--- a/arch/x86/kernel/cpu/mtrr/cyrix.c
+++ b/arch/x86/kernel/cpu/mtrr/cyrix.c
@@ -98,6 +98,7 @@ cyrix_get_free_region(unsigned long base, unsigned long size, int replace_reg)
case 7:
if (size < 0x40)
break;
+ /* Else, fall through */
case 6:
case 5:
case 4:
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 0fdbe89d0754..3c5bbe8e4120 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -201,6 +201,7 @@ static int set_segment_reg(struct task_struct *task,
case offsetof(struct user_regs_struct, ss):
if (unlikely(value == 0))
return -EIO;
+ /* Else, fall through */

default:
*pt_regs_access(task_pt_regs(task), offset) = value;
diff --git a/arch/x86/lib/cpu.c b/arch/x86/lib/cpu.c
index 04967cdce5d1..7ad68917a51e 100644
--- a/arch/x86/lib/cpu.c
+++ b/arch/x86/lib/cpu.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/types.h>
#include <linux/export.h>
+#include <asm/cpu.h>

unsigned int x86_family(unsigned int sig)
{
diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 3cf302b26332..8901a1f89cf5 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -6,6 +6,9 @@ purgatory-y := purgatory.o stack.o setup-x86_$(BITS).o sha256.o entry64.o string
targets += $(purgatory-y)
PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))

+$(obj)/string.o: $(srctree)/arch/x86/boot/compressed/string.c FORCE
+ $(call if_changed_rule,cc_o_c)
+
$(obj)/sha256.o: $(srctree)/lib/sha256.c FORCE
$(call if_changed_rule,cc_o_c)

@@ -17,11 +20,34 @@ KCOV_INSTRUMENT := n

# Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That
# in turn leaves some undefined symbols like __fentry__ in purgatory and not
-# sure how to relocate those. Like kexec-tools, use custom flags.
-
-KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initialized-in-bss -fno-builtin -ffreestanding -c -Os -mcmodel=large
-KBUILD_CFLAGS += -m$(BITS)
-KBUILD_CFLAGS += $(call cc-option,-fno-PIE)
+# sure how to relocate those.
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_sha256.o += $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_purgatory.o += $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_string.o += $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_kexec-purgatory.o += $(CC_FLAGS_FTRACE)
+endif
+
+ifdef CONFIG_STACKPROTECTOR
+CFLAGS_REMOVE_sha256.o += -fstack-protector
+CFLAGS_REMOVE_purgatory.o += -fstack-protector
+CFLAGS_REMOVE_string.o += -fstack-protector
+CFLAGS_REMOVE_kexec-purgatory.o += -fstack-protector
+endif
+
+ifdef CONFIG_STACKPROTECTOR_STRONG
+CFLAGS_REMOVE_sha256.o += -fstack-protector-strong
+CFLAGS_REMOVE_purgatory.o += -fstack-protector-strong
+CFLAGS_REMOVE_string.o += -fstack-protector-strong
+CFLAGS_REMOVE_kexec-purgatory.o += -fstack-protector-strong
+endif
+
+ifdef CONFIG_RETPOLINE
+CFLAGS_REMOVE_sha256.o += $(RETPOLINE_CFLAGS)
+CFLAGS_REMOVE_purgatory.o += $(RETPOLINE_CFLAGS)
+CFLAGS_REMOVE_string.o += $(RETPOLINE_CFLAGS)
+CFLAGS_REMOVE_kexec-purgatory.o += $(RETPOLINE_CFLAGS)
+endif

$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
$(call if_changed,ld)
diff --git a/arch/x86/purgatory/purgatory.c b/arch/x86/purgatory/purgatory.c
index 6d8d5a34c377..b607bda786f6 100644
--- a/arch/x86/purgatory/purgatory.c
+++ b/arch/x86/purgatory/purgatory.c
@@ -68,3 +68,9 @@ void purgatory(void)
}
copy_backup_region();
}
+
+/*
+ * Defined in order to reuse memcpy() and memset() from
+ * arch/x86/boot/compressed/string.c
+ */
+void warn(const char *msg) {}
diff --git a/arch/x86/purgatory/string.c b/arch/x86/purgatory/string.c
deleted file mode 100644
index 01ad43873ad9..000000000000
--- a/arch/x86/purgatory/string.c
+++ /dev/null
@@ -1,23 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Simple string functions.
- *
- * Copyright (C) 2014 Red Hat Inc.
- *
- * Author:
- * Vivek Goyal <vgoyal@xxxxxxxxxx>
- */
-
-#include <linux/types.h>
-
-#include "../boot/string.c"
-
-void *memcpy(void *dst, const void *src, size_t len)
-{
- return __builtin_memcpy(dst, src, len);
-}
-
-void *memset(void *dst, int c, size_t len)
-{
- return __builtin_memset(dst, c, len);
-}