b49e578b93
This partly reverts commit1e688dd2a3. 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 commit93e3f45a26("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. mpe: Retain EMIT_WARN_ENTRY as a synonym for EMIT_BUG_ENTRY to reduce churn, as there are now nearly as many uses of EMIT_WARN_ENTRY as EMIT_BUG_ENTRY. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Acked-by: Naveen N Rao <naveen@kernel.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20230712134552.534955-1-mpe@ellerman.id.au
133 lines
3.2 KiB
C
133 lines
3.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_BUG_H
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#define _ASM_POWERPC_BUG_H
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#ifdef __KERNEL__
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#include <asm/asm-compat.h>
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#ifdef CONFIG_BUG
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#ifdef __ASSEMBLY__
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#include <asm/asm-offsets.h>
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#ifdef CONFIG_DEBUG_BUGVERBOSE
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.macro EMIT_BUG_ENTRY addr,file,line,flags
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.section __bug_table,"aw"
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5001: .4byte \addr - .
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.4byte 5002f - .
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.short \line, \flags
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.org 5001b+BUG_ENTRY_SIZE
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.previous
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.section .rodata,"a"
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5002: .asciz "\file"
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.previous
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.endm
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#else
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.macro EMIT_BUG_ENTRY addr,file,line,flags
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.section __bug_table,"aw"
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5001: .4byte \addr - .
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.short \flags
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.org 5001b+BUG_ENTRY_SIZE
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.previous
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.endm
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#endif /* verbose */
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#else /* !__ASSEMBLY__ */
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/* _EMIT_BUG_ENTRY expects args %0,%1,%2,%3 to be FILE, LINE, flags and
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sizeof(struct bug_entry), respectively */
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#ifdef CONFIG_DEBUG_BUGVERBOSE
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#define _EMIT_BUG_ENTRY \
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".section __bug_table,\"aw\"\n" \
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"2: .4byte 1b - .\n" \
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" .4byte %0 - .\n" \
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" .short %1, %2\n" \
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".org 2b+%3\n" \
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".previous\n"
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#else
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#define _EMIT_BUG_ENTRY \
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".section __bug_table,\"aw\"\n" \
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"2: .4byte 1b - .\n" \
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" .short %2\n" \
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".org 2b+%3\n" \
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".previous\n"
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#endif
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#define BUG_ENTRY(insn, flags, ...) \
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__asm__ __volatile__( \
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"1: " insn "\n" \
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_EMIT_BUG_ENTRY \
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: : "i" (__FILE__), "i" (__LINE__), \
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"i" (flags), \
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"i" (sizeof(struct bug_entry)), \
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##__VA_ARGS__)
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/*
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* BUG_ON() and WARN_ON() do their best to cooperate with compile-time
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* optimisations. However depending on the complexity of the condition
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* some compiler versions may not produce optimal results.
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*/
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#define BUG() do { \
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BUG_ENTRY("twi 31, 0, 0", 0); \
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unreachable(); \
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} while (0)
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#define HAVE_ARCH_BUG
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#define __WARN_FLAGS(flags) BUG_ENTRY("twi 31, 0, 0", BUGFLAG_WARNING | (flags))
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#ifdef CONFIG_PPC64
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#define BUG_ON(x) do { \
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if (__builtin_constant_p(x)) { \
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if (x) \
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BUG(); \
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} else { \
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BUG_ENTRY(PPC_TLNEI " %4, 0", 0, "r" ((__force long)(x))); \
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} \
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} while (0)
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#define WARN_ON(x) ({ \
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int __ret_warn_on = !!(x); \
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if (__builtin_constant_p(__ret_warn_on)) { \
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if (__ret_warn_on) \
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__WARN(); \
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} else { \
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BUG_ENTRY(PPC_TLNEI " %4, 0", \
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BUGFLAG_WARNING | BUGFLAG_TAINT(TAINT_WARN), \
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"r" (__ret_warn_on)); \
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} \
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unlikely(__ret_warn_on); \
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})
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#define HAVE_ARCH_BUG_ON
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#define HAVE_ARCH_WARN_ON
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#endif
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#endif /* __ASSEMBLY __ */
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#else
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#ifdef __ASSEMBLY__
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.macro EMIT_BUG_ENTRY addr,file,line,flags
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.endm
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#else /* !__ASSEMBLY__ */
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#define _EMIT_BUG_ENTRY
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#endif
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#endif /* CONFIG_BUG */
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#define EMIT_WARN_ENTRY EMIT_BUG_ENTRY
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#include <asm-generic/bug.h>
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#ifndef __ASSEMBLY__
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struct pt_regs;
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void hash__do_page_fault(struct pt_regs *);
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void bad_page_fault(struct pt_regs *, int);
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extern void _exception(int, struct pt_regs *, int, unsigned long);
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extern void _exception_pkey(struct pt_regs *, unsigned long, int);
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extern void die(const char *, struct pt_regs *, long);
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void die_mce(const char *str, struct pt_regs *regs, long err);
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extern bool die_will_crash(void);
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extern void panic_flush_kmsg_start(void);
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extern void panic_flush_kmsg_end(void);
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#endif /* !__ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_BUG_H */
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