From 0b0568a19fc4c197871ceafbabc91fabf17ca152 Mon Sep 17 00:00:00 2001
From: jca <jca@openbsd.org>
Date: Sun, 21 Jul 2024 16:49:26 +0000
Subject: [PATCH] Export basic HWCAP bits to let applications detect Altivec &
 VSX on powerpc64

Input from miod@ and gkoehler@, tests & ok gkoehler@
---
 sys/arch/powerpc64/include/cpu.h   |  6 ++--
 sys/arch/powerpc64/include/elf.h   | 54 ++++++++++++++++++++++++++++--
 sys/arch/powerpc64/powerpc64/cpu.c |  9 ++++-
 3 files changed, 62 insertions(+), 7 deletions(-)

diff --git a/sys/arch/powerpc64/include/cpu.h b/sys/arch/powerpc64/include/cpu.h
index fe0394f457b..d773d0bdc95 100644
--- a/sys/arch/powerpc64/include/cpu.h
+++ b/sys/arch/powerpc64/include/cpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.h,v 1.37 2024/06/09 21:15:29 jca Exp $	*/
+/*	$OpenBSD: cpu.h,v 1.38 2024/07/21 16:49:26 jca Exp $	*/
 
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
@@ -41,6 +41,7 @@
  */
 
 #include <machine/cpufunc.h>
+#include <machine/elf.h>
 #include <machine/frame.h>
 #include <machine/intr.h>
 #include <machine/psl.h>
@@ -177,9 +178,6 @@ void signotify(struct proc *);
 extern uint32_t cpu_features;
 extern uint32_t cpu_features2;
 
-#define PPC_FEATURE2_ARCH_3_00	0x00800000
-#define PPC_FEATURE2_DARN	0x00200000
-
 void cpu_init_features(void);
 void cpu_init(void);
 
diff --git a/sys/arch/powerpc64/include/elf.h b/sys/arch/powerpc64/include/elf.h
index a3503ab099b..a7f54488f63 100644
--- a/sys/arch/powerpc64/include/elf.h
+++ b/sys/arch/powerpc64/include/elf.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: elf.h,v 1.1 2024/07/14 09:48:49 jca Exp $	*/
+/*	$OpenBSD: elf.h,v 1.2 2024/07/21 16:49:26 jca Exp $	*/
 
 /*
  * This file is in the public domain.
@@ -8,7 +8,57 @@
 #define	_MACHINE_ELF_H_
 
 /*
- * TODO FreeBSD puts PPC_FEATURE* in cpu.h
+ * CPU Feature Attributes
+ *
+ * These are defined in the PowerPC ELF ABI for the AT_HWCAP vector,
+ * and are exported to userland via the elf_aux_info(3) function.
  */
 
+#ifdef _KERNEL
+# define __HAVE_CPU_HWCAP
+# define __HAVE_CPU_HWCAP2
+extern unsigned long hwcap;
+extern unsigned long hwcap2;
+#endif /* _KERNEL */
+
+#define	PPC_FEATURE_32		0x80000000	/* Always true */
+#define	PPC_FEATURE_64		0x40000000	/* Defined on a 64-bit CPU */
+#define	PPC_FEATURE_601_INSTR	0x20000000
+#define	PPC_FEATURE_HAS_ALTIVEC	0x10000000
+#define	PPC_FEATURE_HAS_FPU	0x08000000
+#define	PPC_FEATURE_HAS_MMU	0x04000000
+#define	PPC_FEATURE_UNIFIED_CACHE 0x01000000
+#define	PPC_FEATURE_HAS_SPE	0x00800000
+#define	PPC_FEATURE_HAS_EFP_SINGLE	0x00400000
+#define	PPC_FEATURE_HAS_EFP_DOUBLE	0x00200000
+#define	PPC_FEATURE_NO_TB	0x00100000
+#define	PPC_FEATURE_POWER4	0x00080000
+#define	PPC_FEATURE_POWER5	0x00040000
+#define	PPC_FEATURE_POWER5_PLUS	0x00020000
+#define	PPC_FEATURE_CELL	0x00010000
+#define	PPC_FEATURE_BOOKE	0x00008000
+#define	PPC_FEATURE_SMT		0x00004000
+#define	PPC_FEATURE_ICACHE_SNOOP	0x00002000
+#define	PPC_FEATURE_ARCH_2_05	0x00001000
+#define	PPC_FEATURE_HAS_DFP	0x00000400
+#define	PPC_FEATURE_POWER6_EXT	0x00000200
+#define	PPC_FEATURE_ARCH_2_06	0x00000100
+#define	PPC_FEATURE_HAS_VSX	0x00000080
+#define	PPC_FEATURE_TRUE_LE	0x00000002
+#define	PPC_FEATURE_PPC_LE	0x00000001
+
+#define	PPC_FEATURE2_ARCH_2_07	0x80000000
+#define	PPC_FEATURE2_HTM	0x40000000
+#define	PPC_FEATURE2_DSCR	0x20000000
+#define	PPC_FEATURE2_EBB	0x10000000
+#define	PPC_FEATURE2_ISEL	0x08000000
+#define	PPC_FEATURE2_TAR	0x04000000
+#define	PPC_FEATURE2_HAS_VEC_CRYPTO	0x02000000
+#define	PPC_FEATURE2_HTM_NOSC	0x01000000
+#define	PPC_FEATURE2_ARCH_3_00	0x00800000
+#define	PPC_FEATURE2_HAS_IEEE128	0x00400000
+#define	PPC_FEATURE2_DARN	0x00200000
+#define	PPC_FEATURE2_SCV	0x00100000
+#define	PPC_FEATURE2_HTM_NOSUSPEND	0x00080000
+
 #endif /* !_MACHINE_ELF_H_ */
diff --git a/sys/arch/powerpc64/powerpc64/cpu.c b/sys/arch/powerpc64/powerpc64/cpu.c
index 3f0bd032eab..252356be0c6 100644
--- a/sys/arch/powerpc64/powerpc64/cpu.c
+++ b/sys/arch/powerpc64/powerpc64/cpu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.c,v 1.28 2023/10/24 13:20:10 claudio Exp $	*/
+/*	$OpenBSD: cpu.c,v 1.29 2024/07/21 16:49:26 jca Exp $	*/
 
 /*
  * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org>
@@ -226,6 +226,10 @@ cpu_init_features(void)
 {
 	uint32_t pvr = mfpvr();
 
+	cpu_features = PPC_FEATURE_32 | PPC_FEATURE_64 | PPC_FEATURE_HAS_FPU |
+	    PPC_FEATURE_HAS_MMU | PPC_FEATURE_HAS_ALTIVEC |
+	    PPC_FEATURE_HAS_VSX;
+
 	switch (CPU_VERSION(pvr)) {
 	case CPU_IBMPOWER9:
 	case CPU_IBMPOWER9P:
@@ -233,6 +237,9 @@ cpu_init_features(void)
 		cpu_features2 |= PPC_FEATURE2_DARN;
 		break;
 	}
+
+	hwcap = cpu_features;
+	hwcap2 = cpu_features2;
 }
 
 void
-- 
2.20.1