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2896b2dff4
Implement the AT_MINSIGSTKSZ AUXV entry, allowing userspace to
dynamically size stack allocations in a manner forward-compatible with
new processor state saved in the signal frame
For now these statically find the maximum signal frame size rather than
doing any runtime testing of features to minimise the size.
glibc 2.34 will take advantage of this, as will applications that use
use _SC_MINSIGSTKSZ and _SC_SIGSTKSZ.
Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
References: 94b07c1f8c ("arm64: signal: Report signal frame size to userspace via auxv")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220307182734.289289-2-npiggin@gmail.com
55 lines
1.8 KiB
C
55 lines
1.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
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#ifndef _ASM_POWERPC_AUXVEC_H
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#define _ASM_POWERPC_AUXVEC_H
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/*
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* We need to put in some extra aux table entries to tell glibc what
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* the cache block size is, so it can use the dcbz instruction safely.
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*/
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#define AT_DCACHEBSIZE 19
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#define AT_ICACHEBSIZE 20
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#define AT_UCACHEBSIZE 21
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/* A special ignored type value for PPC, for glibc compatibility. */
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#define AT_IGNOREPPC 22
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/* The vDSO location. We have to use the same value as x86 for glibc's
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* sake :-)
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*/
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#define AT_SYSINFO_EHDR 33
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/*
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* AT_*CACHEBSIZE above represent the cache *block* size which is
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* the size that is affected by the cache management instructions.
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*
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* It doesn't nececssarily matches the cache *line* size which is
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* more of a performance tuning hint. Additionally the latter can
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* be different for the different cache levels.
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*
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* The set of entries below represent more extensive information
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* about the caches, in the form of two entry per cache type,
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* one entry containing the cache size in bytes, and the other
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* containing the cache line size in bytes in the bottom 16 bits
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* and the cache associativity in the next 16 bits.
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*
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* The associativity is such that if N is the 16-bit value, the
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* cache is N way set associative. A value if 0xffff means fully
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* associative, a value of 1 means directly mapped.
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*
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* For all these fields, a value of 0 means that the information
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* is not known.
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*/
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#define AT_L1I_CACHESIZE 40
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#define AT_L1I_CACHEGEOMETRY 41
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#define AT_L1D_CACHESIZE 42
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#define AT_L1D_CACHEGEOMETRY 43
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#define AT_L2_CACHESIZE 44
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#define AT_L2_CACHEGEOMETRY 45
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#define AT_L3_CACHESIZE 46
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#define AT_L3_CACHEGEOMETRY 47
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#define AT_MINSIGSTKSZ 51 /* stack needed for signal delivery */
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#define AT_VECTOR_SIZE_ARCH 15 /* entries in ARCH_DLINFO */
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#endif
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