From patchwork Tue Jul 11 16:08:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 1806432 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=112.213.38.117; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4R0m5y2Sn5z20Ph for ; Wed, 12 Jul 2023 02:09:26 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4R0m5y0Knmz3ckD for ; Wed, 12 Jul 2023 02:09:26 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=csgroup.eu (client-ip=93.17.236.30; helo=pegase1.c-s.fr; envelope-from=christophe.leroy@csgroup.eu; receiver=lists.ozlabs.org) Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4R0m5F3qBVz3bcP for ; Wed, 12 Jul 2023 02:08:49 +1000 (AEST) Received: from localhost (mailhub3.si.c-s.fr [192.168.12.233]) by localhost (Postfix) with ESMTP id 4R0m581X4jz9sF7; Tue, 11 Jul 2023 18:08:44 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id DWiUEgpdKcU7; Tue, 11 Jul 2023 18:08:44 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4R0m544gJCz9sFF; Tue, 11 Jul 2023 18:08:40 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 9A15F8B77B; Tue, 11 Jul 2023 18:08:40 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id HFMQqSkXBf4Y; Tue, 11 Jul 2023 18:08:40 +0200 (CEST) Received: from PO20335.IDSI0.si.c-s.fr (unknown [192.168.233.184]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 4FCDA8B779; Tue, 11 Jul 2023 18:08:40 +0200 (CEST) Received: from PO20335.IDSI0.si.c-s.fr (localhost [127.0.0.1]) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.16.1) with ESMTPS id 36BG8ahG3696795 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 11 Jul 2023 18:08:36 +0200 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.17.1/Submit) id 36BG8awH3696794; Tue, 11 Jul 2023 18:08:36 +0200 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Michael Ellerman , Nicholas Piggin , Josh Poimboeuf , Peter Zijlstra , Sathvika Vasireddy , Naveen N Rao Subject: [PATCH v4 01/15] Revert "powerpc/bug: Provide better flexibility to WARN_ON/__WARN_FLAGS() with asm goto" Date: Tue, 11 Jul 2023 18:08:27 +0200 Message-ID: X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1689091705; l=7365; i=christophe.leroy@csgroup.eu; s=20211009; h=from:subject:message-id; bh=6M3Y85/oZXODmOfDrgl72xn8raECr/pB55XPXeReufA=; b=peb5nyasE621DG7NrrpDW1vT0A5Mz52jk6dyMj8JuV8UdPW0EeyjRG8wZXpIKV9jdhLZRENUQ Gr2VWWairTmABuPIcp8DAwRVoKz7M5sShVLLlO32LUixbLrGeuTDzl3 X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" This reverts commit 1e688dd2a3d6759d416616ff07afc4bb836c4213. That commit aimed at optimising the code around generation of WARN_ON/BUG_ON but this leads to a lot of dead code erroneously generated by GCC. That dead code becomes a problem when we start using objtool validation because objtool will abort validation with a warning as soon as it detects unreachable code. This is because unreachable code might be the indication that objtool doesn't properly decode object text. text data bss dec hex filename 9551585 3627834 224376 13403795 cc8693 vmlinux.before 9535281 3628358 224376 13388015 cc48ef vmlinux.after Once this change is reverted, in a standard configuration (pmac32 + function tracer) the text is reduced by 16k which is around 1.7% We already had problem with it when starting to use objtool on powerpc as a replacement for recordmcount, see commit 93e3f45a2631 ("powerpc: Fix __WARN_FLAGS() for use with Objtool") There is also a problem with at least GCC 12, on ppc64_defconfig + CONFIG_CC_OPTIMIZE_FOR_SIZE=y + CONFIG_DEBUG_SECTION_MISMATCH=y : LD .tmp_vmlinux.kallsyms1 powerpc64-linux-ld: net/ipv4/tcp_input.o:(__ex_table+0xc4): undefined reference to `.L2136' make[2]: *** [scripts/Makefile.vmlinux:36: vmlinux] Error 1 make[1]: *** [/home/chleroy/linux-powerpc/Makefile:1238: vmlinux] Error 2 Taking into account that other problems are encountered with that 'asm goto' in WARN_ON(), including build failures, keeping that change is not worth it allthough it is primarily a compiler bug. Revert it for now. Signed-off-by: Christophe Leroy Acked-by: Naveen N Rao --- arch/powerpc/include/asm/book3s/64/kup.h | 2 +- arch/powerpc/include/asm/bug.h | 67 ++++-------------------- arch/powerpc/kernel/misc_32.S | 2 +- arch/powerpc/kernel/traps.c | 9 +--- 4 files changed, 15 insertions(+), 65 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h index 497a7bd31ecc..e875cb7e68dc 100644 --- a/arch/powerpc/include/asm/book3s/64/kup.h +++ b/arch/powerpc/include/asm/book3s/64/kup.h @@ -90,7 +90,7 @@ /* Prevent access to userspace using any key values */ LOAD_REG_IMMEDIATE(\gpr2, AMR_KUAP_BLOCKED) 999: tdne \gpr1, \gpr2 - EMIT_WARN_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE) + EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | BUGFLAG_ONCE) END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_KUAP, 67) #endif .endm diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h index 492530adecc2..abb608dff15a 100644 --- a/arch/powerpc/include/asm/bug.h +++ b/arch/powerpc/include/asm/bug.h @@ -4,14 +4,13 @@ #ifdef __KERNEL__ #include -#include #ifdef CONFIG_BUG #ifdef __ASSEMBLY__ #include #ifdef CONFIG_DEBUG_BUGVERBOSE -.macro __EMIT_BUG_ENTRY addr,file,line,flags +.macro EMIT_BUG_ENTRY addr,file,line,flags .section __bug_table,"aw" 5001: .4byte \addr - . .4byte 5002f - . @@ -23,7 +22,7 @@ .previous .endm #else -.macro __EMIT_BUG_ENTRY addr,file,line,flags +.macro EMIT_BUG_ENTRY addr,file,line,flags .section __bug_table,"aw" 5001: .4byte \addr - . .short \flags @@ -32,18 +31,6 @@ .endm #endif /* verbose */ -.macro EMIT_WARN_ENTRY addr,file,line,flags - EX_TABLE(\addr,\addr+4) - __EMIT_BUG_ENTRY \addr,\file,\line,\flags -.endm - -.macro EMIT_BUG_ENTRY addr,file,line,flags - .if \flags & 1 /* BUGFLAG_WARNING */ - .err /* Use EMIT_WARN_ENTRY for warnings */ - .endif - __EMIT_BUG_ENTRY \addr,\file,\line,\flags -.endm - #else /* !__ASSEMBLY__ */ /* _EMIT_BUG_ENTRY expects args %0,%1,%2,%3 to be FILE, LINE, flags and sizeof(struct bug_entry), respectively */ @@ -73,16 +60,6 @@ "i" (sizeof(struct bug_entry)), \ ##__VA_ARGS__) -#define WARN_ENTRY(insn, flags, label, ...) \ - asm_volatile_goto( \ - "1: " insn "\n" \ - EX_TABLE(1b, %l[label]) \ - _EMIT_BUG_ENTRY \ - : : "i" (__FILE__), "i" (__LINE__), \ - "i" (flags), \ - "i" (sizeof(struct bug_entry)), \ - ##__VA_ARGS__ : : label) - /* * BUG_ON() and WARN_ON() do their best to cooperate with compile-time * optimisations. However depending on the complexity of the condition @@ -95,16 +72,7 @@ } while (0) #define HAVE_ARCH_BUG -#define __WARN_FLAGS(flags) do { \ - __label__ __label_warn_on; \ - \ - WARN_ENTRY("twi 31, 0, 0", BUGFLAG_WARNING | (flags), __label_warn_on); \ - barrier_before_unreachable(); \ - __builtin_unreachable(); \ - \ -__label_warn_on: \ - break; \ -} while (0) +#define __WARN_FLAGS(flags) BUG_ENTRY("twi 31, 0, 0", BUGFLAG_WARNING | (flags)) #ifdef CONFIG_PPC64 #define BUG_ON(x) do { \ @@ -117,25 +85,15 @@ __label_warn_on: \ } while (0) #define WARN_ON(x) ({ \ - bool __ret_warn_on = false; \ - do { \ - if (__builtin_constant_p((x))) { \ - if (!(x)) \ - break; \ + int __ret_warn_on = !!(x); \ + if (__builtin_constant_p(__ret_warn_on)) { \ + if (__ret_warn_on) \ __WARN(); \ - __ret_warn_on = true; \ - } else { \ - __label__ __label_warn_on; \ - \ - WARN_ENTRY(PPC_TLNEI " %4, 0", \ - BUGFLAG_WARNING | BUGFLAG_TAINT(TAINT_WARN), \ - __label_warn_on, \ - "r" ((__force long)(x))); \ - break; \ -__label_warn_on: \ - __ret_warn_on = true; \ - } \ - } while (0); \ + } else { \ + BUG_ENTRY(PPC_TLNEI " %4, 0", \ + BUGFLAG_WARNING | BUGFLAG_TAINT(TAINT_WARN), \ + "r" (__ret_warn_on)); \ + } \ unlikely(__ret_warn_on); \ }) @@ -148,11 +106,8 @@ __label_warn_on: \ #ifdef __ASSEMBLY__ .macro EMIT_BUG_ENTRY addr,file,line,flags .endm -.macro EMIT_WARN_ENTRY addr,file,line,flags -.endm #else /* !__ASSEMBLY__ */ #define _EMIT_BUG_ENTRY -#define _EMIT_WARN_ENTRY #endif #endif /* CONFIG_BUG */ diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S index daf8f87d2372..fd11ec42df89 100644 --- a/arch/powerpc/kernel/misc_32.S +++ b/arch/powerpc/kernel/misc_32.S @@ -237,7 +237,7 @@ _GLOBAL(copy_page) addi r3,r3,-4 0: twnei r5, 0 /* WARN if r3 is not cache aligned */ - EMIT_WARN_ENTRY 0b,__FILE__,__LINE__, BUGFLAG_WARNING + EMIT_BUG_ENTRY 0b,__FILE__,__LINE__, BUGFLAG_WARNING addi r4,r4,-4 diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index ab95105c69ca..f5ce282dc4b8 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -1508,13 +1508,8 @@ static void do_program_check(struct pt_regs *regs) if (!(regs->msr & MSR_PR) && /* not user-mode */ report_bug(bugaddr, regs) == BUG_TRAP_TYPE_WARN) { - const struct exception_table_entry *entry; - - entry = search_exception_tables(bugaddr); - if (entry) { - regs_set_return_ip(regs, extable_fixup(entry) + regs->nip - bugaddr); - return; - } + regs_add_return_ip(regs, 4); + return; } if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE) && user_mode(regs)) {