![Anshuman Khandual](/assets/img/avatar_default.png)
Commit ce48b21007
"powerpc: Add VSX context save/restore, ptrace and
signal support" expanded the 'vmx_reserve' array element to contain 101
double words, but the comment block above was not updated.
Also reorder the constants in the array size declaration to reflect the
logic mentioned in the comment block above. This change helps in
explaining how the HW registers are represented in the array. But no
functional change.
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
[mpe: Reworded change log and added whitespace around +'s]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
88 lines
4.2 KiB
C
88 lines
4.2 KiB
C
#ifndef _ASM_POWERPC_SIGCONTEXT_H
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#define _ASM_POWERPC_SIGCONTEXT_H
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/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/compiler.h>
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#include <asm/ptrace.h>
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#ifdef __powerpc64__
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#include <asm/elf.h>
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#endif
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struct sigcontext {
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unsigned long _unused[4];
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int signal;
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#ifdef __powerpc64__
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int _pad0;
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#endif
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unsigned long handler;
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unsigned long oldmask;
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struct pt_regs __user *regs;
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#ifdef __powerpc64__
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elf_gregset_t gp_regs;
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elf_fpregset_t fp_regs;
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/*
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* To maintain compatibility with current implementations the sigcontext is
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* extended by appending a pointer (v_regs) to a quadword type (elf_vrreg_t)
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* followed by an unstructured (vmx_reserve) field of 101 doublewords. This
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* allows the array of vector registers to be quadword aligned independent of
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* the alignment of the containing sigcontext or ucontext. It is the
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* responsibility of the code setting the sigcontext to set this pointer to
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* either NULL (if this processor does not support the VMX feature) or the
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* address of the first quadword within the allocated (vmx_reserve) area.
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*
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* The pointer (v_regs) of vector type (elf_vrreg_t) is type compatible with
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* an array of 34 quadword entries (elf_vrregset_t). The entries with
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* indexes 0-31 contain the corresponding vector registers. The entry with
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* index 32 contains the vscr as the last word (offset 12) within the
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* quadword. This allows the vscr to be stored as either a quadword (since
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* it must be copied via a vector register to/from storage) or as a word.
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* The entry with index 33 contains the vrsave as the first word (offset 0)
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* within the quadword.
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*
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* Part of the VSX data is stored here also by extending vmx_restore
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* by an additional 32 double words. Architecturally the layout of
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* the VSR registers and how they overlap on top of the legacy FPR and
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* VR registers is shown below:
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*
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* VSR doubleword 0 VSR doubleword 1
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* ----------------------------------------------------------------
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* VSR[0] | FPR[0] | |
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* ----------------------------------------------------------------
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* VSR[1] | FPR[1] | |
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* ----------------------------------------------------------------
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* | ... | |
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* | ... | |
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* ----------------------------------------------------------------
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* VSR[30] | FPR[30] | |
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* ----------------------------------------------------------------
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* VSR[31] | FPR[31] | |
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* ----------------------------------------------------------------
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* VSR[32] | VR[0] |
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* ----------------------------------------------------------------
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* VSR[33] | VR[1] |
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* ----------------------------------------------------------------
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* | ... |
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* | ... |
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* ----------------------------------------------------------------
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* VSR[62] | VR[30] |
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* ----------------------------------------------------------------
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* VSR[63] | VR[31] |
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* ----------------------------------------------------------------
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*
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* FPR/VSR 0-31 doubleword 0 is stored in fp_regs, and VMX/VSR 32-63
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* is stored at the start of vmx_reserve. vmx_reserve is extended for
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* backwards compatility to store VSR 0-31 doubleword 1 after the VMX
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* registers and vscr/vrsave.
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*/
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elf_vrreg_t __user *v_regs;
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long vmx_reserve[ELF_NVRREG + ELF_NVRREG + 1 + 32];
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#endif
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};
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#endif /* _ASM_POWERPC_SIGCONTEXT_H */
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