[PATCH] gcc-plugins: Remove ARM_SSP_PER_TASK plugin
Kees Cook
kees at kernel.org
Wed Apr 9 09:04:10 PDT 2025
As part of trying to remove GCC plugins from Linux, drop the
ARM_SSP_PER_TASK plugin. The feature is available upstream since GCC
12, so anyone needing newer kernels with per-task ssp can update their
compiler[1].
Suggested-by: Arnd Bergmann <arnd at arndb.de>
Link: https://lore.kernel.org/all/08393aa3-05a3-4e3f-8004-f374a3ec4b7e@app.fastmail.com/ [1]
Signed-off-by: Kees Cook <kees at kernel.org>
---
Cc: Ard Biesheuvel <ardb at kernel.org>
Cc: Chris Packham <chris.packham at alliedtelesis.co.nz>
Cc: Douglas Anderson <dianders at chromium.org>
Cc: Russell King <linux at armlinux.org.uk>
Cc: Masahiro Yamada <masahiroy at kernel.org>
Cc: Nathan Chancellor <nathan at kernel.org>
Cc: Nicolas Schier <nicolas at fjasle.eu>
Cc: "Russell King (Oracle)" <rmk+kernel at armlinux.org.uk>
Cc: Linus Walleij <linus.walleij at linaro.org>
Cc: Andrew Davis <afd at ti.com>
Cc: Seung-Woo Kim <sw0312.kim at samsung.com>
Cc: Xin Li <xin3.li at intel.com>
Cc: Jinjie Ruan <ruanjinjie at huawei.com>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-hardening at vger.kernel.org
Cc: linux-kbuild at vger.kernel.org
---
arch/arm/Kconfig | 3 +-
arch/arm/boot/compressed/Makefile | 2 +-
scripts/Makefile.gcc-plugins | 6 -
scripts/gcc-plugins/Kconfig | 4 -
scripts/gcc-plugins/arm_ssp_per_task_plugin.c | 107 ------------------
5 files changed, 2 insertions(+), 120 deletions(-)
delete mode 100644 scripts/gcc-plugins/arm_ssp_per_task_plugin.c
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 835b5f100e92..6f037edf0f41 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1379,8 +1379,7 @@ config CC_HAVE_STACKPROTECTOR_TLS
config STACKPROTECTOR_PER_TASK
bool "Use a unique stack canary value for each task"
depends on STACKPROTECTOR && CURRENT_POINTER_IN_TPIDRURO && !XIP_DEFLATED_DATA
- depends on GCC_PLUGINS || CC_HAVE_STACKPROTECTOR_TLS
- select GCC_PLUGIN_ARM_SSP_PER_TASK if !CC_HAVE_STACKPROTECTOR_TLS
+ depends on CC_HAVE_STACKPROTECTOR_TLS
default y
help
Due to the fact that GCC uses an ordinary symbol reference from
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 945b5975fce2..d61369b1eabe 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -96,7 +96,7 @@ KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
ccflags-y := -fpic $(call cc-option,-mno-single-pic-base,) -fno-builtin \
-I$(srctree)/scripts/dtc/libfdt -fno-stack-protector \
- -I$(obj) $(DISABLE_ARM_SSP_PER_TASK_PLUGIN)
+ -I$(obj)
ccflags-remove-$(CONFIG_FUNCTION_TRACER) += -pg
asflags-y := -DZIMAGE
diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
index 6da109d563a5..194122d969a8 100644
--- a/scripts/Makefile.gcc-plugins
+++ b/scripts/Makefile.gcc-plugins
@@ -36,12 +36,6 @@ ifdef CONFIG_GCC_PLUGIN_STACKLEAK
endif
export DISABLE_STACKLEAK_PLUGIN
-gcc-plugin-$(CONFIG_GCC_PLUGIN_ARM_SSP_PER_TASK) += arm_ssp_per_task_plugin.so
-ifdef CONFIG_GCC_PLUGIN_ARM_SSP_PER_TASK
- DISABLE_ARM_SSP_PER_TASK_PLUGIN += -fplugin-arg-arm_ssp_per_task_plugin-disable
-endif
-export DISABLE_ARM_SSP_PER_TASK_PLUGIN
-
# All the plugin CFLAGS are collected here in case a build target needs to
# filter them out of the KBUILD_CFLAGS.
GCC_PLUGINS_CFLAGS := $(strip $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) $(gcc-plugin-cflags-y))
diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig
index ba868d1eef3d..6b34ba19358d 100644
--- a/scripts/gcc-plugins/Kconfig
+++ b/scripts/gcc-plugins/Kconfig
@@ -36,8 +36,4 @@ config GCC_PLUGIN_LATENT_ENTROPY
* https://grsecurity.net/
* https://pax.grsecurity.net/
-config GCC_PLUGIN_ARM_SSP_PER_TASK
- bool
- depends on GCC_PLUGINS && ARM
-
endif
diff --git a/scripts/gcc-plugins/arm_ssp_per_task_plugin.c b/scripts/gcc-plugins/arm_ssp_per_task_plugin.c
deleted file mode 100644
index 7328d037f975..000000000000
--- a/scripts/gcc-plugins/arm_ssp_per_task_plugin.c
+++ /dev/null
@@ -1,107 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-#include "gcc-common.h"
-
-__visible int plugin_is_GPL_compatible;
-
-static unsigned int canary_offset;
-
-static unsigned int arm_pertask_ssp_rtl_execute(void)
-{
- rtx_insn *insn;
-
- for (insn = get_insns(); insn; insn = NEXT_INSN(insn)) {
- const char *sym;
- rtx body;
- rtx current;
-
- /*
- * Find a SET insn involving a SYMBOL_REF to __stack_chk_guard
- */
- if (!INSN_P(insn))
- continue;
- body = PATTERN(insn);
- if (GET_CODE(body) != SET ||
- GET_CODE(SET_SRC(body)) != SYMBOL_REF)
- continue;
- sym = XSTR(SET_SRC(body), 0);
- if (strcmp(sym, "__stack_chk_guard"))
- continue;
-
- /*
- * Replace the source of the SET insn with an expression that
- * produces the address of the current task's stack canary value
- */
- current = gen_reg_rtx(Pmode);
-
- emit_insn_before(gen_load_tp_hard(current), insn);
-
- SET_SRC(body) = gen_rtx_PLUS(Pmode, current,
- GEN_INT(canary_offset));
- }
- return 0;
-}
-
-#define PASS_NAME arm_pertask_ssp_rtl
-
-#define NO_GATE
-#include "gcc-generate-rtl-pass.h"
-
-#if BUILDING_GCC_VERSION >= 9000
-static bool no(void)
-{
- return false;
-}
-
-static void arm_pertask_ssp_start_unit(void *gcc_data, void *user_data)
-{
- targetm.have_stack_protect_combined_set = no;
- targetm.have_stack_protect_combined_test = no;
-}
-#endif
-
-__visible int plugin_init(struct plugin_name_args *plugin_info,
- struct plugin_gcc_version *version)
-{
- const char * const plugin_name = plugin_info->base_name;
- const int argc = plugin_info->argc;
- const struct plugin_argument *argv = plugin_info->argv;
- int i;
-
- if (!plugin_default_version_check(version, &gcc_version)) {
- error(G_("incompatible gcc/plugin versions"));
- return 1;
- }
-
- for (i = 0; i < argc; ++i) {
- if (!strcmp(argv[i].key, "disable"))
- return 0;
-
- /* all remaining options require a value */
- if (!argv[i].value) {
- error(G_("no value supplied for option '-fplugin-arg-%s-%s'"),
- plugin_name, argv[i].key);
- return 1;
- }
-
- if (!strcmp(argv[i].key, "offset")) {
- canary_offset = atoi(argv[i].value);
- continue;
- }
- error(G_("unknown option '-fplugin-arg-%s-%s'"),
- plugin_name, argv[i].key);
- return 1;
- }
-
- PASS_INFO(arm_pertask_ssp_rtl, "expand", 1, PASS_POS_INSERT_AFTER);
-
- register_callback(plugin_info->base_name, PLUGIN_PASS_MANAGER_SETUP,
- NULL, &arm_pertask_ssp_rtl_pass_info);
-
-#if BUILDING_GCC_VERSION >= 9000
- register_callback(plugin_info->base_name, PLUGIN_START_UNIT,
- arm_pertask_ssp_start_unit, NULL);
-#endif
-
- return 0;
-}
--
2.34.1
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