From 93e3f45a26310e3f3f8558be40df411e23ab742c Mon Sep 17 00:00:00 2001 From: Sathvika Vasireddy Date: Mon, 14 Nov 2022 23:27:39 +0530 Subject: powerpc: Fix __WARN_FLAGS() for use with Objtool Commit 1e688dd2a3d675 ("powerpc/bug: Provide better flexibility to WARN_ON/__WARN_FLAGS() with asm goto") updated __WARN_FLAGS() to use asm goto, and added a call to 'unreachable()' after the asm goto for optimal code generation. With CONFIG_OBJTOOL enabled, 'annotate_unreachable()' statement in 'unreachable()' tries to note down the location of the subsequent instruction in a separate elf section to aid code flow analysis. However, on powerpc, this results in gcc emitting a call to a symbol of size 0. This results in objtool complaining of "unannotated intra-function call" since the target symbol is not a valid function call destination. Objtool wants this annotation for code flow analysis, which we are not yet enabling on powerpc. As such, expand the call to 'unreachable()' in __WARN_FLAGS() without annotate_unreachable(): barrier_before_unreachable(); __builtin_unreachable(); This still results in optimal code generation for __WARN_FLAGS(), while getting rid of the objtool warning. We still need barrier_before_unreachable() to work around gcc bugs 82365 and 106751: - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365 - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106751 Tested-by: Naveen N. Rao Reviewed-by: Naveen N. Rao Reviewed-by: Christophe Leroy Acked-by: Josh Poimboeuf Signed-off-by: Sathvika Vasireddy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221114175754.1131267-2-sv@linux.ibm.com --- arch/powerpc/include/asm/bug.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/include/asm') diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h index 61a4736355c2..ef42adb44aa3 100644 --- a/arch/powerpc/include/asm/bug.h +++ b/arch/powerpc/include/asm/bug.h @@ -99,7 +99,8 @@ __label__ __label_warn_on; \ \ WARN_ENTRY("twi 31, 0, 0", BUGFLAG_WARNING | (flags), __label_warn_on); \ - unreachable(); \ + barrier_before_unreachable(); \ + __builtin_unreachable(); \ \ __label_warn_on: \ break; \ -- cgit v1.2.3 From 01f2cf0b990e58ae89142f57c7e02d33621311d2 Mon Sep 17 00:00:00 2001 From: Sathvika Vasireddy Date: Mon, 14 Nov 2022 23:27:40 +0530 Subject: powerpc: Override __ALIGN and __ALIGN_STR macros In a subsequent patch, we would want to annotate powerpc assembly functions with SYM_FUNC_START_LOCAL macro. This macro depends on __ALIGN macro. The default expansion of __ALIGN macro is: #define __ALIGN .align 4,0x90 So, override __ALIGN and __ALIGN_STR macros to use the same alignment as that of the existing _GLOBAL macro. Also, do not pad with 0x90, because repeated 0x90s are not a nop or trap on powerpc. Tested-by: Naveen N. Rao Reviewed-by: Naveen N. Rao Reviewed-by: Christophe Leroy Acked-by: Josh Poimboeuf Signed-off-by: Sathvika Vasireddy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221114175754.1131267-3-sv@linux.ibm.com --- arch/powerpc/include/asm/linkage.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/powerpc/include/asm') diff --git a/arch/powerpc/include/asm/linkage.h b/arch/powerpc/include/asm/linkage.h index b71b9582e754..b88d1d2cf304 100644 --- a/arch/powerpc/include/asm/linkage.h +++ b/arch/powerpc/include/asm/linkage.h @@ -4,6 +4,9 @@ #include +#define __ALIGN .align 2 +#define __ALIGN_STR ".align 2" + #ifdef CONFIG_PPC64_ELF_ABI_V1 #define cond_syscall(x) \ asm ("\t.weak " #x "\n\t.set " #x ", sys_ni_syscall\n" \ -- cgit v1.2.3 From e52ec98c5ab18c0710ea22bf52f45e60a725adaf Mon Sep 17 00:00:00 2001 From: Sathvika Vasireddy Date: Mon, 14 Nov 2022 23:27:53 +0530 Subject: objtool/powerpc: Enable objtool to be built on ppc This patch adds [stub] implementations for required functions, inorder to enable objtool build on powerpc. [Christophe Leroy: powerpc: Add missing asm/asm.h for objtool, Use local variables for type and imm in arch_decode_instruction(), Adapt len for prefixed instructions.] Tested-by: Naveen N. Rao Reviewed-by: Naveen N. Rao Acked-by: Josh Poimboeuf Signed-off-by: Sathvika Vasireddy Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221114175754.1131267-16-sv@linux.ibm.com --- arch/powerpc/Kconfig | 1 + arch/powerpc/include/asm/asm.h | 7 ++ tools/objtool/arch/powerpc/Build | 2 + tools/objtool/arch/powerpc/decode.c | 85 ++++++++++++++++++++++ tools/objtool/arch/powerpc/include/arch/cfi_regs.h | 11 +++ tools/objtool/arch/powerpc/include/arch/elf.h | 8 ++ tools/objtool/arch/powerpc/include/arch/special.h | 21 ++++++ tools/objtool/arch/powerpc/special.c | 19 +++++ 8 files changed, 154 insertions(+) create mode 100644 arch/powerpc/include/asm/asm.h create mode 100644 tools/objtool/arch/powerpc/Build create mode 100644 tools/objtool/arch/powerpc/decode.c create mode 100644 tools/objtool/arch/powerpc/include/arch/cfi_regs.h create mode 100644 tools/objtool/arch/powerpc/include/arch/elf.h create mode 100644 tools/objtool/arch/powerpc/include/arch/special.h create mode 100644 tools/objtool/arch/powerpc/special.c (limited to 'arch/powerpc/include/asm') diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 699df27b0e2f..12e6c16be54e 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -238,6 +238,7 @@ config PPC select HAVE_MOD_ARCH_SPECIFIC select HAVE_NMI if PERF_EVENTS || (PPC64 && PPC_BOOK3S) select HAVE_OPTPROBES + select HAVE_OBJTOOL if PPC32 || MPROFILE_KERNEL select HAVE_PERF_EVENTS select HAVE_PERF_EVENTS_NMI if PPC64 select HAVE_PERF_REGS diff --git a/arch/powerpc/include/asm/asm.h b/arch/powerpc/include/asm/asm.h new file mode 100644 index 000000000000..86f46b604e9a --- /dev/null +++ b/arch/powerpc/include/asm/asm.h @@ -0,0 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_POWERPC_ASM_H +#define _ASM_POWERPC_ASM_H + +#define _ASM_PTR " .long " + +#endif /* _ASM_POWERPC_ASM_H */ diff --git a/tools/objtool/arch/powerpc/Build b/tools/objtool/arch/powerpc/Build new file mode 100644 index 000000000000..d24d5636a5b8 --- /dev/null +++ b/tools/objtool/arch/powerpc/Build @@ -0,0 +1,2 @@ +objtool-y += decode.o +objtool-y += special.o diff --git a/tools/objtool/arch/powerpc/decode.c b/tools/objtool/arch/powerpc/decode.c new file mode 100644 index 000000000000..dcd0975cad6b --- /dev/null +++ b/tools/objtool/arch/powerpc/decode.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include +#include +#include +#include +#include +#include +#include +#include + +unsigned long arch_dest_reloc_offset(int addend) +{ + return addend; +} + +bool arch_callee_saved_reg(unsigned char reg) +{ + return false; +} + +int arch_decode_hint_reg(u8 sp_reg, int *base) +{ + exit(-1); +} + +const char *arch_nop_insn(int len) +{ + exit(-1); +} + +const char *arch_ret_insn(int len) +{ + exit(-1); +} + +int arch_decode_instruction(struct objtool_file *file, const struct section *sec, + unsigned long offset, unsigned int maxlen, + unsigned int *len, enum insn_type *type, + unsigned long *immediate, + struct list_head *ops_list) +{ + unsigned int opcode; + enum insn_type typ; + unsigned long imm; + u32 insn; + + insn = bswap_if_needed(file->elf, *(u32 *)(sec->data->d_buf + offset)); + opcode = insn >> 26; + typ = INSN_OTHER; + imm = 0; + + if (opcode == 1) + *len = 8; + else + *len = 4; + + *type = typ; + *immediate = imm; + + return 0; +} + +unsigned long arch_jump_destination(struct instruction *insn) +{ + return insn->offset + insn->immediate; +} + +void arch_initial_func_cfi_state(struct cfi_init_state *state) +{ + int i; + + for (i = 0; i < CFI_NUM_REGS; i++) { + state->regs[i].base = CFI_UNDEFINED; + state->regs[i].offset = 0; + } + + /* initial CFA (call frame address) */ + state->cfa.base = CFI_SP; + state->cfa.offset = 0; + + /* initial LR (return address) */ + state->regs[CFI_RA].base = CFI_CFA; + state->regs[CFI_RA].offset = 0; +} diff --git a/tools/objtool/arch/powerpc/include/arch/cfi_regs.h b/tools/objtool/arch/powerpc/include/arch/cfi_regs.h new file mode 100644 index 000000000000..59638ebeafc8 --- /dev/null +++ b/tools/objtool/arch/powerpc/include/arch/cfi_regs.h @@ -0,0 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#ifndef _OBJTOOL_CFI_REGS_H +#define _OBJTOOL_CFI_REGS_H + +#define CFI_BP 1 +#define CFI_SP CFI_BP +#define CFI_RA 32 +#define CFI_NUM_REGS 33 + +#endif diff --git a/tools/objtool/arch/powerpc/include/arch/elf.h b/tools/objtool/arch/powerpc/include/arch/elf.h new file mode 100644 index 000000000000..3c8ebb7d2a6b --- /dev/null +++ b/tools/objtool/arch/powerpc/include/arch/elf.h @@ -0,0 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#ifndef _OBJTOOL_ARCH_ELF +#define _OBJTOOL_ARCH_ELF + +#define R_NONE R_PPC_NONE + +#endif /* _OBJTOOL_ARCH_ELF */ diff --git a/tools/objtool/arch/powerpc/include/arch/special.h b/tools/objtool/arch/powerpc/include/arch/special.h new file mode 100644 index 000000000000..ffef9ada7133 --- /dev/null +++ b/tools/objtool/arch/powerpc/include/arch/special.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _PPC_ARCH_SPECIAL_H +#define _PPC_ARCH_SPECIAL_H + +#define EX_ENTRY_SIZE 8 +#define EX_ORIG_OFFSET 0 +#define EX_NEW_OFFSET 4 + +#define JUMP_ENTRY_SIZE 16 +#define JUMP_ORIG_OFFSET 0 +#define JUMP_NEW_OFFSET 4 +#define JUMP_KEY_OFFSET 8 + +#define ALT_ENTRY_SIZE 12 +#define ALT_ORIG_OFFSET 0 +#define ALT_NEW_OFFSET 4 +#define ALT_FEATURE_OFFSET 8 +#define ALT_ORIG_LEN_OFFSET 10 +#define ALT_NEW_LEN_OFFSET 11 + +#endif /* _PPC_ARCH_SPECIAL_H */ diff --git a/tools/objtool/arch/powerpc/special.c b/tools/objtool/arch/powerpc/special.c new file mode 100644 index 000000000000..d33868147196 --- /dev/null +++ b/tools/objtool/arch/powerpc/special.c @@ -0,0 +1,19 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +#include +#include +#include +#include + + +bool arch_support_alt_relocation(struct special_alt *special_alt, + struct instruction *insn, + struct reloc *reloc) +{ + exit(-1); +} + +struct reloc *arch_find_switch_table(struct objtool_file *file, + struct instruction *insn) +{ + exit(-1); +} -- cgit v1.2.3