mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-27 13:55:23 +07:00
32ee8230b2
This helps preventing a BUG* or WARN* in some static inline from
preventing that (or one of its callers) being inlined, so should allow
gcc to make better informed inlining decisions.
For example, with gcc 9.2, tcp_fastopen_no_cookie() vanishes from
net/ipv4/tcp_fastopen.o. It does not itself have any BUG or WARN, but
it calls dst_metric() which has a WARN_ON_ONCE - and despite that
WARN_ON_ONCE vanishing since the condition is compile-time false,
dst_metric() is apparently sufficiently "large" that when it gets
inlined into tcp_fastopen_no_cookie(), the latter becomes too large
for inlining.
Overall, if one asks size(1), .text decreases a little and .data
increases by about the same amount (x86-64 defconfig)
$ size vmlinux.{before,after}
text data bss dec hex filename
19709726 5202600 1630280 26542606 195020e vmlinux.before
19709330 5203068 1630280 26542678 1950256 vmlinux.after
while bloat-o-meter says
add/remove: 10/28 grow/shrink: 103/51 up/down: 3669/-2854 (815)
...
Total: Before=14783683, After=14784498, chg +0.01%
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
86 lines
2.1 KiB
C
86 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_BUG_H
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#define _ASM_X86_BUG_H
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#include <linux/stringify.h>
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/*
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* Despite that some emulators terminate on UD2, we use it for WARN().
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*
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* Since various instruction decoders/specs disagree on the encoding of
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* UD0/UD1.
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*/
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#define ASM_UD0 ".byte 0x0f, 0xff" /* + ModRM (for Intel) */
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#define ASM_UD1 ".byte 0x0f, 0xb9" /* + ModRM */
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#define ASM_UD2 ".byte 0x0f, 0x0b"
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#define INSN_UD0 0xff0f
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#define INSN_UD2 0x0b0f
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#define LEN_UD2 2
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#ifdef CONFIG_GENERIC_BUG
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#ifdef CONFIG_X86_32
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# define __BUG_REL(val) ".long " __stringify(val)
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#else
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# define __BUG_REL(val) ".long " __stringify(val) " - 2b"
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#endif
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#ifdef CONFIG_DEBUG_BUGVERBOSE
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#define _BUG_FLAGS(ins, flags) \
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do { \
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asm_inline volatile("1:\t" ins "\n" \
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".pushsection __bug_table,\"aw\"\n" \
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"2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \
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"\t" __BUG_REL(%c0) "\t# bug_entry::file\n" \
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"\t.word %c1" "\t# bug_entry::line\n" \
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"\t.word %c2" "\t# bug_entry::flags\n" \
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"\t.org 2b+%c3\n" \
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".popsection" \
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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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} while (0)
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#else /* !CONFIG_DEBUG_BUGVERBOSE */
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#define _BUG_FLAGS(ins, flags) \
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do { \
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asm_inline volatile("1:\t" ins "\n" \
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".pushsection __bug_table,\"aw\"\n" \
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"2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \
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"\t.word %c0" "\t# bug_entry::flags\n" \
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"\t.org 2b+%c1\n" \
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".popsection" \
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: : "i" (flags), \
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"i" (sizeof(struct bug_entry))); \
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} while (0)
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#endif /* CONFIG_DEBUG_BUGVERBOSE */
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#else
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#define _BUG_FLAGS(ins, flags) asm volatile(ins)
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#endif /* CONFIG_GENERIC_BUG */
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#define HAVE_ARCH_BUG
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#define BUG() \
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do { \
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_BUG_FLAGS(ASM_UD2, 0); \
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unreachable(); \
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} while (0)
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#define __WARN_FLAGS(flags) \
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do { \
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_BUG_FLAGS(ASM_UD2, BUGFLAG_WARNING|(flags)); \
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annotate_reachable(); \
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} while (0)
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#include <asm-generic/bug.h>
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#endif /* _ASM_X86_BUG_H */
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