[PATCH] ppc64: Add VMX registers to sigcontext, from Steve Munroe

From: Anton Blanchard <anton@samba.org>

Add VMX registers to sigcontext, from Steve Munroe

arch/ppc64/boot/ppc32-types.h

@@ -25,6 +25,10 @@ typedef unsigned int u32;
 typedef signed long long s64;
 typedef unsigned long long u64;
 
+typedef struct {
+	__u32 u[4];
+} __attribute((aligned(16))) __vector128;
+
 #define BITS_PER_LONG 32
 
 #endif /* _PPC64_TYPES_H */

include/asm-ppc64/elf.h

@@ -54,7 +54,7 @@
 
 #define ELF_NGREG	48	/* includes nip, msr, lr, etc. */
 #define ELF_NFPREG	33	/* includes fpscr */
-#define ELF_NVRREG	33	/* includes vscr */
+#define ELF_NVRREG	34	/* includes vscr */
 
 typedef unsigned long elf_greg_t64;
 typedef elf_greg_t64 elf_gregset_t64[ELF_NGREG];
@@ -82,6 +82,23 @@ typedef elf_greg_t32 elf_gregset_t32[ELF_NGREG];
 typedef double elf_fpreg_t;
 typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
 
+/* Altivec registers */
+/*
+ * The entries with indexes 0-31 contain the corresponding vector registers. 
+ * The entry with index 32 contains the vscr as the last word (offset 12) 
+ * within the quadword.  This allows the vscr to be stored as either a 
+ * quadword (since it must be copied via a vector register to/from storage) 
+ * or as a word.  The entry with index 33 contains the vrsave as the first 
+ * word (offset 0) within the quadword.
+ *
+ * This definition of the VMX state is compatible with the current PPC32 
+ * ptrace interface.  This allows signal handling and ptrace to use the same 
+ * structures.  This also simplifies the implementation of a bi-arch 
+ * (combined (32- and 64-bit) gdb.
+ */
+typedef __vector128 elf_vrreg_t;
+typedef elf_vrreg_t elf_vrregset_t[ELF_NVRREG];
+
 /*
  * This is used to ensure we don't load something for the wrong architecture.
  */

include/asm-ppc64/ptrace.h

@@ -130,6 +130,31 @@ struct pt_regs32 {
 #define PT_FPSCR32 (PT_FPR0 + 2*32 + 1)	  /* each FP reg occupies 2 32-bit userspace slots */
 #endif
 
+#define PT_VR0 82	/* each Vector reg occupies 2 slots in 64-bit */
+#define PT_VSCR (PT_VR0 + 32*2 + 1)
+#define PT_VRSAVE (PT_VR0 + 33*2)
+
+#ifdef __KERNEL__
+#define PT_VR0_32 164	/* each Vector reg occupies 4 slots in 32-bit */
+#define PT_VSCR_32 (PT_VR0 + 32*4 + 3)
+#define PT_VRSAVE_32 (PT_VR0 + 33*4)
+#endif
+
+/*
+ * Get/set all the altivec registers vr0..vr31, vscr, vrsave, in one go. 
+ * The transfer totals 34 quadword.  Quadwords 0-31 contain the 
+ * corresponding vector registers.  Quadword 32 contains the vscr as the 
+ * last word (offset 12) within that quadword.  Quadword 33 contains the 
+ * vrsave as the first word (offset 0) within the quadword.
+ *
+ * This definition of the VMX state is compatible with the current PPC32 
+ * ptrace interface.  This allows signal handling and ptrace to use the same 
+ * structures.  This also simplifies the implementation of a bi-arch 
+ * (combined (32- and 64-bit) gdb.
+ */
+#define PTRACE_GETVRREGS	18
+#define PTRACE_SETVRREGS	19
+
 /* Additional PTRACE requests implemented on PowerPC. */
 #define PPC_PTRACE_GETREGS	      0x99  /* Get GPRs 0 - 31 */
 #define PPC_PTRACE_SETREGS	      0x98  /* Set GPRs 0 - 31 */

include/asm-ppc64/sigcontext.h

@@ -21,6 +21,27 @@ struct sigcontext {
 	struct pt_regs	*regs;
 	elf_gregset_t	gp_regs;
 	elf_fpregset_t	fp_regs;
+/*
+ * To maintain compatibility with current implementations the sigcontext is 
+ * extended by appending a pointer (v_regs) to a quadword type (elf_vrreg_t) 
+ * followed by an unstructured (vmx_reserve) field of 69 doublewords.  This 
+ * allows the array of vector registers to be quadword aligned independent of 
+ * the alignment of the containing sigcontext or ucontext. It is the 
+ * responsibility of the code setting the sigcontext to set this pointer to 
+ * either NULL (if this processor does not support the VMX feature) or the 
+ * address of the first quadword within the allocated (vmx_reserve) area.
+ *
+ * The pointer (v_regs) of vector type (elf_vrreg_t) is type compatible with 
+ * an array of 34 quadword entries (elf_vrregset_t).  The entries with 
+ * indexes 0-31 contain the corresponding vector registers.  The entry with 
+ * index 32 contains the vscr as the last word (offset 12) within the 
+ * quadword.  This allows the vscr to be stored as either a quadword (since 
+ * it must be copied via a vector register to/from storage) or as a word.  
+ * The entry with index 33 contains the vrsave as the first word (offset 0) 
+ * within the quadword.
+ */
+	elf_vrreg_t	*v_regs;
+	long		vmx_reserve[ELF_NVRREG+ELF_NVRREG+1];
 };
 
 #endif /* _ASM_PPC64_SIGCONTEXT_H */