X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=Makefile;h=79ad2bfa24b68f279af011f82e87f16d64d1440d;hb=6afad54d2f0ddebacfcf3b829147d7fed8dab298;hp=0d49ff4022fb532ab8db9da7bb03dbfa672e88fb;hpb=0e410e158e5baa1300bdf678cea4f4e0cf9d8b94;p=linux.git

diff --git a/Makefile b/Makefile
index 0d49ff4022fb..79ad2bfa24b6 100644
--- a/Makefile
+++ b/Makefile
@@ -1,8 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 VERSION = 4
-PATCHLEVEL = 15
+PATCHLEVEL = 16
 SUBLEVEL = 0
-EXTRAVERSION =
+EXTRAVERSION = -rc1
 NAME = Fearless Coyote
 
 # *DOCUMENTATION*
@@ -680,6 +680,10 @@ endif
 # This selects the stack protector compiler flag. Testing it is delayed
 # until after .config has been reprocessed, in the prepare-compiler-check
 # target.
+ifdef CONFIG_CC_STACKPROTECTOR_AUTO
+  stackp-flag := $(call cc-option,-fstack-protector-strong,$(call cc-option,-fstack-protector))
+  stackp-name := AUTO
+else
 ifdef CONFIG_CC_STACKPROTECTOR_REGULAR
   stackp-flag := -fstack-protector
   stackp-name := REGULAR
@@ -688,20 +692,43 @@ ifdef CONFIG_CC_STACKPROTECTOR_STRONG
   stackp-flag := -fstack-protector-strong
   stackp-name := STRONG
 else
+  # If either there is no stack protector for this architecture or
+  # CONFIG_CC_STACKPROTECTOR_NONE is selected, we're done, and $(stackp-name)
+  # is empty, skipping all remaining stack protector tests.
+  #
   # Force off for distro compilers that enable stack protector by default.
-  stackp-flag := $(call cc-option, -fno-stack-protector)
+  KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)
+endif
 endif
 endif
 # Find arch-specific stack protector compiler sanity-checking script.
-ifdef CONFIG_CC_STACKPROTECTOR
+ifdef stackp-name
+ifneq ($(stackp-flag),)
   stackp-path := $(srctree)/scripts/gcc-$(SRCARCH)_$(BITS)-has-stack-protector.sh
   stackp-check := $(wildcard $(stackp-path))
+  # If the wildcard test matches a test script, run it to check functionality.
+  ifdef stackp-check
+    ifneq ($(shell $(CONFIG_SHELL) $(stackp-check) $(CC) $(KBUILD_CPPFLAGS) $(biarch)),y)
+      stackp-broken := y
+    endif
+  endif
+  ifndef stackp-broken
+    # If the stack protector is functional, enable code that depends on it.
+    KBUILD_CPPFLAGS += -DCONFIG_CC_STACKPROTECTOR
+    # Either we've already detected the flag (for AUTO) or we'll fail the
+    # build in the prepare-compiler-check rule (for specific flag).
+    KBUILD_CFLAGS += $(stackp-flag)
+  else
+    # We have to make sure stack protector is unconditionally disabled if
+    # the compiler is broken (in case we're going to continue the build in
+    # AUTO mode).
+    KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)
+  endif
+endif
 endif
-KBUILD_CFLAGS += $(stackp-flag)
 
 ifeq ($(cc-name),clang)
 KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)
-KBUILD_CFLAGS += $(call cc-disable-warning, unused-variable)
 KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier)
 KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
 KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)
@@ -719,9 +746,9 @@ else
 # These warnings generated too much noise in a regular build.
 # Use make W=1 to enable them (see scripts/Makefile.extrawarn)
 KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)
-KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)
 endif
 
+KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)
 ifdef CONFIG_FRAME_POINTER
 KBUILD_CFLAGS	+= -fno-omit-frame-pointer -fno-optimize-sibling-calls
 else
@@ -1092,14 +1119,25 @@ PHONY += prepare-compiler-check
 prepare-compiler-check: FORCE
 # Make sure compiler supports requested stack protector flag.
 ifdef stackp-name
+  # Warn about CONFIG_CC_STACKPROTECTOR_AUTO having found no option.
+  ifeq ($(stackp-flag),)
+	@echo CONFIG_CC_STACKPROTECTOR_$(stackp-name): \
+		  Compiler does not support any known stack-protector >&2
+  else
+  # Fail if specifically requested stack protector is missing.
   ifeq ($(call cc-option, $(stackp-flag)),)
 	@echo Cannot use CONFIG_CC_STACKPROTECTOR_$(stackp-name): \
 		  $(stackp-flag) not supported by compiler >&2 && exit 1
   endif
+  endif
 endif
-# Make sure compiler does not have buggy stack-protector support.
-ifdef stackp-check
-  ifneq ($(shell $(CONFIG_SHELL) $(stackp-check) $(CC) $(KBUILD_CPPFLAGS) $(biarch)),y)
+# Make sure compiler does not have buggy stack-protector support. If a
+# specific stack-protector was requested, fail the build, otherwise warn.
+ifdef stackp-broken
+  ifeq ($(stackp-name),AUTO)
+	@echo CONFIG_CC_STACKPROTECTOR_$(stackp-name): \
+                  $(stackp-flag) available but compiler is broken: disabling >&2
+  else
 	@echo Cannot use CONFIG_CC_STACKPROTECTOR_$(stackp-name): \
                   $(stackp-flag) available but compiler is broken >&2 && exit 1
   endif