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![Christophe Leroy](/assets/img/avatar_default.png)
The code relies on constant folding of cpu_has_feature() based
on possible and always true values as defined per
CPU_FTRS_ALWAYS and CPU_FTRS_POSSIBLE.
Build failure is encountered with for instance
book3e_all_defconfig on kisskb in the AMDGPU driver which uses
cpu_has_feature(CPU_FTR_VSX_COMP) to decide whether calling
kernel_enable_vsx() or not.
The failure is due to cpu_has_feature() not being inlined with
that configuration with gcc 4.9.
In the same way as commit acdad8fb4a
("powerpc: Force inlining of
mmu_has_feature to fix build failure"), for inlining of
cpu_has_feature().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b231dfa040ce4cc37f702f5c3a595fdeabfe0462.1615378209.git.christophe.leroy@csgroup.eu
56 lines
1.3 KiB
C
56 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_POWERPC_CPU_HAS_FEATURE_H
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#define __ASM_POWERPC_CPU_HAS_FEATURE_H
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#ifndef __ASSEMBLY__
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#include <linux/bug.h>
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#include <asm/cputable.h>
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static __always_inline bool early_cpu_has_feature(unsigned long feature)
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{
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return !!((CPU_FTRS_ALWAYS & feature) ||
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(CPU_FTRS_POSSIBLE & cur_cpu_spec->cpu_features & feature));
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}
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#ifdef CONFIG_JUMP_LABEL_FEATURE_CHECKS
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#include <linux/jump_label.h>
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#define NUM_CPU_FTR_KEYS BITS_PER_LONG
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extern struct static_key_true cpu_feature_keys[NUM_CPU_FTR_KEYS];
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static __always_inline bool cpu_has_feature(unsigned long feature)
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{
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int i;
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#ifndef __clang__ /* clang can't cope with this */
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BUILD_BUG_ON(!__builtin_constant_p(feature));
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#endif
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#ifdef CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG
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if (!static_key_initialized) {
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printk("Warning! cpu_has_feature() used prior to jump label init!\n");
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dump_stack();
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return early_cpu_has_feature(feature);
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}
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#endif
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if (CPU_FTRS_ALWAYS & feature)
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return true;
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if (!(CPU_FTRS_POSSIBLE & feature))
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return false;
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i = __builtin_ctzl(feature);
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return static_branch_likely(&cpu_feature_keys[i]);
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}
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#else
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static __always_inline bool cpu_has_feature(unsigned long feature)
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{
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return early_cpu_has_feature(feature);
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}
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#endif
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_POWERPC_CPU_HAS_FEATURE_H */
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