From: Julien Thierry <jthierry@redhat.com> To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: catalin.marinas@arm.com, will@kernel.org, ardb@kernel.org, masahiroy@kernel.org, keescook@chromium.org, michal.lkml@markovi.net, jpoimboe@redhat.com, peterz@infradead.org, mark.rutland@arm.com, broonie@kernel.org, linux-efi@vger.kernel.org, linux-hardening@vger.kernel.org, Raphael Gault <raphael.gault@arm.com>, Julien Thierry <jthierry@redhat.com> Subject: [RFC PATCH 12/17] gcc-plugins: objtool: Add plugin to detect switch table on arm64 Date: Wed, 20 Jan 2021 18:37:55 +0100 [thread overview] Message-ID: <20210120173800.1660730-13-jthierry@redhat.com> (raw) In-Reply-To: <20210120173800.1660730-1-jthierry@redhat.com> From: Raphael Gault <raphael.gault@arm.com> This plugins comes into play before the final 2 RTL passes of GCC and detects switch-tables that are to be outputed in the ELF and writes information in an ".discard.switch_table_info" section which will be used by objtool. Signed-off-by: Raphael Gault <raphael.gault@arm.com> [J.T.: Change section name to store switch table information, Make plugin Kconfig be selected rather than opt-in by user, Add a relocation in the switch_table_info that points to the jump operation itself] Signed-off-by: Julien Thierry <jthierry@redhat.com> --- arch/arm64/Kconfig | 1 + scripts/Makefile.gcc-plugins | 2 + scripts/gcc-plugins/Kconfig | 4 + .../arm64_switch_table_detection_plugin.c | 85 +++++++++++++++++++ 4 files changed, 92 insertions(+) create mode 100644 scripts/gcc-plugins/arm64_switch_table_detection_plugin.c diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 05e17351e4f3..93a320cc8e03 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -100,6 +100,7 @@ config ARM64 select DMA_DIRECT_REMAP select EDAC_SUPPORT select FRAME_POINTER + select GCC_PLUGIN_SWITCH_TABLES if STACK_VALIDATION select GENERIC_ALLOCATOR select GENERIC_ARCH_TOPOLOGY select GENERIC_CLOCKEVENTS_BROADCAST diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins index 952e46876329..8af322311f6b 100644 --- a/scripts/Makefile.gcc-plugins +++ b/scripts/Makefile.gcc-plugins @@ -46,6 +46,8 @@ ifdef CONFIG_GCC_PLUGIN_ARM_SSP_PER_TASK endif export DISABLE_ARM_SSP_PER_TASK_PLUGIN +gcc-plugin-$(CONFIG_GCC_PLUGIN_SWITCH_TABLES) += arm64_switch_table_detection_plugin.so + # 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 ab9eb4cbe33a..76efbb97d223 100644 --- a/scripts/gcc-plugins/Kconfig +++ b/scripts/gcc-plugins/Kconfig @@ -104,4 +104,8 @@ config GCC_PLUGIN_ARM_SSP_PER_TASK bool depends on GCC_PLUGINS && ARM +config GCC_PLUGIN_SWITCH_TABLES + bool + depends on GCC_PLUGINS && ARM64 + endif diff --git a/scripts/gcc-plugins/arm64_switch_table_detection_plugin.c b/scripts/gcc-plugins/arm64_switch_table_detection_plugin.c new file mode 100644 index 000000000000..60ef00ff2c5b --- /dev/null +++ b/scripts/gcc-plugins/arm64_switch_table_detection_plugin.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <stdio.h> +#include "gcc-common.h" + +__visible int plugin_is_GPL_compatible; + +#define GEN_QUAD(rtx) assemble_integer_with_op(".quad ", rtx) + +/* + * Create an array of metadata for each jump table found in the rtl. + * The metadata contains: + * - A reference to first instruction part of the RTL expanded into an + * acutal jump + * - The number of entries in the table of offsets + * - A reference to each possible jump target + * + * Separate each entry with a null quad word. + */ +static unsigned int arm64_switchtbl_rtl_execute(void) +{ + rtx_insn *insn; + rtx_insn *labelp = NULL; + rtx_jump_table_data *tablep = NULL; + section *swt_sec; + section *curr_sec = current_function_section(); + + swt_sec = get_section(".discard.switch_table_info", + SECTION_DEBUG | SECTION_EXCLUDE, NULL); + + for (insn = get_insns(); insn; insn = NEXT_INSN(insn)) { + /* + * Find a tablejump_p INSN (using a dispatch table) + */ + if (!tablejump_p(insn, &labelp, &tablep)) + continue; + + if (labelp && tablep) { + rtx_code_label *label_to_jump; + rtvec jump_labels = tablep->get_labels(); + int nr_labels = GET_NUM_ELEM(jump_labels); + int i; + + label_to_jump = gen_label_rtx(); + SET_LABEL_KIND(label_to_jump, LABEL_NORMAL); + emit_label_before(label_to_jump, insn); + LABEL_PRESERVE_P(label_to_jump) = 1; + + switch_to_section(swt_sec); + GEN_QUAD(GEN_INT(0)); // mark separation between rela tables + GEN_QUAD(gen_rtx_LABEL_REF(Pmode, label_to_jump)); + GEN_QUAD(GEN_INT(nr_labels)); + for (i = 0; i < nr_labels; i++) + GEN_QUAD(gen_rtx_LABEL_REF(Pmode, + label_ref_label(RTVEC_ELT(jump_labels, i)))); + switch_to_section(curr_sec); + delete_insn(label_to_jump); + } + } + return 0; +} + +#define PASS_NAME arm64_switchtbl_rtl + +#define NO_GATE +#include "gcc-generate-rtl-pass.h" + +__visible int plugin_init(struct plugin_name_args *plugin_info, + struct plugin_gcc_version *version) +{ + const char * const plugin_name = plugin_info->base_name; + + if (!plugin_default_version_check(version, &gcc_version)) { + error(G_("incompatible gcc/plugin versions")); + return 1; + } + + PASS_INFO(arm64_switchtbl_rtl, "final", 1, + PASS_POS_INSERT_BEFORE); + + register_callback(plugin_info->base_name, PLUGIN_PASS_MANAGER_SETUP, + NULL, &arm64_switchtbl_rtl_pass_info); + + return 0; +} -- 2.25.4
WARNING: multiple messages have this Message-ID (diff)
From: Julien Thierry <jthierry@redhat.com> To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: mark.rutland@arm.com, linux-efi@vger.kernel.org, michal.lkml@markovi.net, keescook@chromium.org, peterz@infradead.org, catalin.marinas@arm.com, masahiroy@kernel.org, Raphael Gault <raphael.gault@arm.com>, broonie@kernel.org, linux-hardening@vger.kernel.org, jpoimboe@redhat.com, will@kernel.org, ardb@kernel.org, Julien Thierry <jthierry@redhat.com> Subject: [RFC PATCH 12/17] gcc-plugins: objtool: Add plugin to detect switch table on arm64 Date: Wed, 20 Jan 2021 18:37:55 +0100 [thread overview] Message-ID: <20210120173800.1660730-13-jthierry@redhat.com> (raw) In-Reply-To: <20210120173800.1660730-1-jthierry@redhat.com> From: Raphael Gault <raphael.gault@arm.com> This plugins comes into play before the final 2 RTL passes of GCC and detects switch-tables that are to be outputed in the ELF and writes information in an ".discard.switch_table_info" section which will be used by objtool. Signed-off-by: Raphael Gault <raphael.gault@arm.com> [J.T.: Change section name to store switch table information, Make plugin Kconfig be selected rather than opt-in by user, Add a relocation in the switch_table_info that points to the jump operation itself] Signed-off-by: Julien Thierry <jthierry@redhat.com> --- arch/arm64/Kconfig | 1 + scripts/Makefile.gcc-plugins | 2 + scripts/gcc-plugins/Kconfig | 4 + .../arm64_switch_table_detection_plugin.c | 85 +++++++++++++++++++ 4 files changed, 92 insertions(+) create mode 100644 scripts/gcc-plugins/arm64_switch_table_detection_plugin.c diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 05e17351e4f3..93a320cc8e03 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -100,6 +100,7 @@ config ARM64 select DMA_DIRECT_REMAP select EDAC_SUPPORT select FRAME_POINTER + select GCC_PLUGIN_SWITCH_TABLES if STACK_VALIDATION select GENERIC_ALLOCATOR select GENERIC_ARCH_TOPOLOGY select GENERIC_CLOCKEVENTS_BROADCAST diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins index 952e46876329..8af322311f6b 100644 --- a/scripts/Makefile.gcc-plugins +++ b/scripts/Makefile.gcc-plugins @@ -46,6 +46,8 @@ ifdef CONFIG_GCC_PLUGIN_ARM_SSP_PER_TASK endif export DISABLE_ARM_SSP_PER_TASK_PLUGIN +gcc-plugin-$(CONFIG_GCC_PLUGIN_SWITCH_TABLES) += arm64_switch_table_detection_plugin.so + # 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 ab9eb4cbe33a..76efbb97d223 100644 --- a/scripts/gcc-plugins/Kconfig +++ b/scripts/gcc-plugins/Kconfig @@ -104,4 +104,8 @@ config GCC_PLUGIN_ARM_SSP_PER_TASK bool depends on GCC_PLUGINS && ARM +config GCC_PLUGIN_SWITCH_TABLES + bool + depends on GCC_PLUGINS && ARM64 + endif diff --git a/scripts/gcc-plugins/arm64_switch_table_detection_plugin.c b/scripts/gcc-plugins/arm64_switch_table_detection_plugin.c new file mode 100644 index 000000000000..60ef00ff2c5b --- /dev/null +++ b/scripts/gcc-plugins/arm64_switch_table_detection_plugin.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <stdio.h> +#include "gcc-common.h" + +__visible int plugin_is_GPL_compatible; + +#define GEN_QUAD(rtx) assemble_integer_with_op(".quad ", rtx) + +/* + * Create an array of metadata for each jump table found in the rtl. + * The metadata contains: + * - A reference to first instruction part of the RTL expanded into an + * acutal jump + * - The number of entries in the table of offsets + * - A reference to each possible jump target + * + * Separate each entry with a null quad word. + */ +static unsigned int arm64_switchtbl_rtl_execute(void) +{ + rtx_insn *insn; + rtx_insn *labelp = NULL; + rtx_jump_table_data *tablep = NULL; + section *swt_sec; + section *curr_sec = current_function_section(); + + swt_sec = get_section(".discard.switch_table_info", + SECTION_DEBUG | SECTION_EXCLUDE, NULL); + + for (insn = get_insns(); insn; insn = NEXT_INSN(insn)) { + /* + * Find a tablejump_p INSN (using a dispatch table) + */ + if (!tablejump_p(insn, &labelp, &tablep)) + continue; + + if (labelp && tablep) { + rtx_code_label *label_to_jump; + rtvec jump_labels = tablep->get_labels(); + int nr_labels = GET_NUM_ELEM(jump_labels); + int i; + + label_to_jump = gen_label_rtx(); + SET_LABEL_KIND(label_to_jump, LABEL_NORMAL); + emit_label_before(label_to_jump, insn); + LABEL_PRESERVE_P(label_to_jump) = 1; + + switch_to_section(swt_sec); + GEN_QUAD(GEN_INT(0)); // mark separation between rela tables + GEN_QUAD(gen_rtx_LABEL_REF(Pmode, label_to_jump)); + GEN_QUAD(GEN_INT(nr_labels)); + for (i = 0; i < nr_labels; i++) + GEN_QUAD(gen_rtx_LABEL_REF(Pmode, + label_ref_label(RTVEC_ELT(jump_labels, i)))); + switch_to_section(curr_sec); + delete_insn(label_to_jump); + } + } + return 0; +} + +#define PASS_NAME arm64_switchtbl_rtl + +#define NO_GATE +#include "gcc-generate-rtl-pass.h" + +__visible int plugin_init(struct plugin_name_args *plugin_info, + struct plugin_gcc_version *version) +{ + const char * const plugin_name = plugin_info->base_name; + + if (!plugin_default_version_check(version, &gcc_version)) { + error(G_("incompatible gcc/plugin versions")); + return 1; + } + + PASS_INFO(arm64_switchtbl_rtl, "final", 1, + PASS_POS_INSERT_BEFORE); + + register_callback(plugin_info->base_name, PLUGIN_PASS_MANAGER_SETUP, + NULL, &arm64_switchtbl_rtl_pass_info); + + return 0; +} -- 2.25.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-01-20 19:15 UTC|newest] Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-01-20 17:37 [RFC PATCH 00/17] objtool: add base support for arm64 Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 01/17] tools: Add some generic functions and headers Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 02/17] tools: arm64: Make aarch64 instruction decoder available to tools Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 03/17] tools: bug: Remove duplicate definition Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 04/17] objtool: arm64: Add base definition for arm64 backend Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 05/17] objtool: arm64: Decode add/sub instructions Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 06/17] objtool: arm64: Decode jump and call related instructions Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 07/17] objtool: arm64: Decode other system instructions Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 08/17] objtool: arm64: Decode load/store instructions Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 09/17] objtool: arm64: Decode LDR instructions Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 10/17] objtool: arm64: Accept padding in code sections Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 11/17] efi: libstub: Ignore relocations for .discard sections Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` Julien Thierry [this message] 2021-01-20 17:37 ` [RFC PATCH 12/17] gcc-plugins: objtool: Add plugin to detect switch table on arm64 Julien Thierry 2021-01-27 22:15 ` Nick Desaulniers 2021-01-27 22:15 ` Nick Desaulniers 2021-01-27 23:26 ` Josh Poimboeuf 2021-01-27 23:26 ` Josh Poimboeuf 2021-01-29 18:10 ` Nick Desaulniers 2021-01-29 18:10 ` Nick Desaulniers 2021-02-01 21:44 ` Josh Poimboeuf 2021-02-01 21:44 ` Josh Poimboeuf 2021-02-01 23:17 ` Nick Desaulniers 2021-02-01 23:17 ` Nick Desaulniers 2021-02-02 0:02 ` Josh Poimboeuf 2021-02-02 0:02 ` Josh Poimboeuf 2021-02-02 14:24 ` David Laight 2021-02-02 14:24 ` David Laight 2021-02-02 22:33 ` Nick Desaulniers 2021-02-02 22:33 ` Nick Desaulniers 2021-02-02 23:36 ` Josh Poimboeuf 2021-02-02 23:36 ` Josh Poimboeuf 2021-02-02 23:52 ` Nick Desaulniers 2021-02-02 23:52 ` Nick Desaulniers 2021-02-02 8:57 ` Julien Thierry 2021-02-02 8:57 ` Julien Thierry 2021-02-02 23:01 ` Nick Desaulniers 2021-02-02 23:01 ` Nick Desaulniers 2021-02-03 0:14 ` Josh Poimboeuf 2021-02-03 0:14 ` Josh Poimboeuf 2021-02-03 11:57 ` Peter Zijlstra 2021-02-03 11:57 ` Peter Zijlstra 2021-02-03 13:04 ` Mark Brown 2021-02-03 13:04 ` Mark Brown 2021-02-03 13:58 ` Mark Rutland 2021-02-03 13:58 ` Mark Rutland 2021-02-03 8:11 ` Julien Thierry 2021-02-03 8:11 ` Julien Thierry 2021-02-09 16:30 ` Daniel Kiss 2021-02-09 16:30 ` Daniel Kiss 2021-01-20 17:37 ` [RFC PATCH 13/17] objtool: arm64: Implement functions to add switch tables alternatives Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 14/17] objtool: arm64: Cache section with switch table information Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 15/17] objtool: arm64: Handle supported relocations in alternatives Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:37 ` [RFC PATCH 16/17] objtool: arm64: Ignore replacement section for alternative callback Julien Thierry 2021-01-20 17:37 ` Julien Thierry 2021-01-20 17:38 ` [RFC PATCH 17/17] objtool: arm64: Enable stack validation for arm64 Julien Thierry 2021-01-20 17:38 ` Julien Thierry 2021-01-21 5:39 ` kernel test robot 2021-01-21 9:03 ` [RFC PATCH 00/17] objtool: add base support " Ard Biesheuvel 2021-01-21 9:03 ` Ard Biesheuvel 2021-01-21 10:26 ` Julien Thierry 2021-01-21 10:26 ` Julien Thierry 2021-01-21 11:08 ` Ard Biesheuvel 2021-01-21 11:08 ` Ard Biesheuvel 2021-01-21 11:23 ` Peter Zijlstra 2021-01-21 11:23 ` Peter Zijlstra 2021-01-21 11:48 ` Ard Biesheuvel 2021-01-21 11:48 ` Ard Biesheuvel 2021-01-21 18:54 ` Josh Poimboeuf 2021-01-21 18:54 ` Josh Poimboeuf 2021-01-22 17:43 ` Mark Brown 2021-01-22 17:43 ` Mark Brown 2021-01-22 17:54 ` Ard Biesheuvel 2021-01-22 17:54 ` Ard Biesheuvel 2021-01-28 22:10 ` Madhavan T. Venkataraman 2021-01-28 22:10 ` Madhavan T. Venkataraman 2021-01-29 15:47 ` Mark Brown 2021-01-22 21:15 ` Madhavan T. Venkataraman 2021-01-22 21:15 ` Madhavan T. Venkataraman 2021-01-22 21:43 ` Ard Biesheuvel 2021-01-22 21:43 ` Ard Biesheuvel 2021-01-22 21:44 ` Madhavan T. Venkataraman 2021-01-22 21:44 ` Madhavan T. Venkataraman 2021-01-25 21:19 ` Josh Poimboeuf 2021-01-25 21:19 ` Josh Poimboeuf 2021-01-22 21:16 ` Madhavan T. Venkataraman 2021-01-22 21:16 ` Madhavan T. Venkataraman 2021-01-21 13:23 ` Julien Thierry 2021-01-21 13:23 ` Julien Thierry 2021-01-21 14:23 ` Mark Brown 2021-01-21 14:23 ` Mark Brown
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