Morello vDSO fixes

arch/arm64/include/asm/elf.h

@@ -165,17 +165,21 @@
 		NEW_AUX_ENT(AT_IGNORE, 0);				\
 } while (0)
 
+#define ARCH_HAS_SETUP_ADDITIONAL_PAGES
+struct linux_binprm;
+extern int aarch64_setup_additional_pages(struct linux_binprm *bprm,
+				       int uses_interp);
+
 #ifdef CONFIG_CHERI_PURECAP_UABI
+extern int purecap_setup_additional_pages(struct linux_binprm *bprm,
+				       int uses_interp);
+#define arch_setup_additional_pages	purecap_setup_additional_pages
 #define ARCH_DLINFO	SETUP_DLINFO(current->mm->context.vdso)
 #else /* !CONFIG_CHERI_PURECAP_UABI */
+#define arch_setup_additional_pages	aarch64_setup_additional_pages
 #define ARCH_DLINFO	SETUP_DLINFO((elf_addr_t)current->mm->context.vdso)
 #endif /* CONFIG_CHERI_PURECAP_UABI */
 
-#define ARCH_HAS_SETUP_ADDITIONAL_PAGES
-struct linux_binprm;
-extern int arch_setup_additional_pages(struct linux_binprm *bprm,
-				       int uses_interp);
-
 /* 1GB of VA */
 #ifdef CONFIG_COMPAT32
 #define STACK_RND_MASK			(test_thread_flag(TIF_32BIT) ? \
@@ -210,6 +214,8 @@
 
 #define COMPAT_ARCH_DLINFO	SETUP_DLINFO(current->mm->context.vdso)
 
+#define compat_arch_setup_additional_pages	aarch64_setup_additional_pages
+
 #else /* !CONFIG_COMPAT64 */
 
 /* AArch32 registers. */

arch/arm64/include/asm/vdso.h

@@ -18,6 +18,7 @@
 
 extern char vdso_start[], vdso_end[];
 extern char vdso32_start[], vdso32_end[];
+extern char vdso_purecap_start[], vdso_purecap_end[];
 
 #endif /* !__ASSEMBLER__ */
 

arch/arm64/include/asm/vdso/gettimeofday.h

@@ -102,6 +102,32 @@ const struct vdso_data *__arch_get_vdso_data(void)
 	return vd;
 }
 
+static __always_inline
+const struct vdso_time_data *__arch_get_vdso_u_time_data(void)
+{
+	const struct vdso_time_data *ret;
+
+	asm(".hidden vdso_u_time_data\n\t"
+	    "adrp %0, vdso_u_time_data\n\t"
+	    "add %0, %0, #:lo12:vdso_u_time_data"
+	    : "=C"(ret));
+	return ret;
+}
+
+static __always_inline
+const struct vdso_rng_data *__arch_get_vdso_u_rng_data(void)
+{
+	const struct vdso_rng_data *ret;
+
+	asm(".hidden vdso_u_rng_data\n\t"
+	    "adrp %0, vdso_u_rng_data\n\t"
+	    "add %0, %0, #:lo12:vdso_u_rng_data"
+	    : "=C"(ret));
+	return ret;
+}
+
+#define __arch_get_vdso_u_time_data __arch_get_vdso_u_time_data
+#define __arch_get_vdso_u_rng_data __arch_get_vdso_u_rng_data
 #else /* !__CHERI_PURE_CAPABILITY__ */
 #if IS_ENABLED(CONFIG_CC_IS_GCC) && IS_ENABLED(CONFIG_PAGE_SIZE_64KB)
 static __always_inline const struct vdso_time_data *__arch_get_vdso_u_time_data(void)

arch/arm64/kernel/Makefile

@@ -71,10 +71,12 @@ obj-$(CONFIG_ARM64_MTE)			+= mte.o
 obj-$(CONFIG_ARM64_MORELLO)		+= morello.o
 obj-y					+= vdso-wrap.o
 obj-$(CONFIG_COMPAT_VDSO)		+= vdso32-wrap.o
+obj-$(CONFIG_CHERI_PURECAP_UABI)	+= vdso-purecap-wrap.o
 
 # Force dependency (vdso*-wrap.S includes vdso.so through incbin)
 $(obj)/vdso-wrap.o: $(obj)/vdso/vdso.so
 $(obj)/vdso32-wrap.o: $(obj)/vdso32/vdso.so
+$(obj)/vdso-purecap-wrap.o: $(obj)/vdso-purecap/vdso.so
 
 obj-y					+= probes/
 obj-y					+= head.o

arch/arm64/kernel/signal.c

@@ -41,6 +41,11 @@
 #endif
 #include <asm/traps.h>
 #include <asm/vdso.h>
+#if defined(CONFIG_CHERI_PURECAP_UABI) && !defined(SIGNAL_COMPAT64)
+#include <generated/vdso-purecap-offsets.h>
+#else
+#include <generated/vdso-offsets.h>
+#endif
 
 #define GCS_SIGNAL_CAP(addr) (((unsigned long)addr) & GCS_CAP_ADDR_MASK)
 

arch/arm64/kernel/vdso-purecap-wrap.S

@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 ARM Limited
+ */
+
+#include <linux/init.h>
+#include <linux/linkage.h>
+#include <linux/const.h>
+#include <asm/assembler.h>
+#include <asm/page.h>
+
+	.globl vdso_purecap_start, vdso_purecap_end
+	.section .rodata
+	.balign PAGE_SIZE
+vdso_purecap_start:
+	.incbin "arch/arm64/kernel/vdso-purecap/vdso.so"
+	.balign PAGE_SIZE
+vdso_purecap_end:
+
+	.previous
+
+emit_aarch64_feature_1_and

arch/arm64/kernel/vdso.c

@@ -32,6 +32,7 @@
 enum vdso_abi {
 	VDSO_ABI_AA64,
 	VDSO_ABI_AA32,
+	VDSO_ABI_PURECAP,
 };
 
 struct vdso_abi_info {
@@ -56,6 +57,13 @@ static struct vdso_abi_info vdso_info[] __ro_after_init = {
 		.vdso_code_end = vdso32_end,
 	},
 #endif /* CONFIG_COMPAT_VDSO */
+#ifdef CONFIG_CHERI_PURECAP_UABI
+	[VDSO_ABI_PURECAP] = {
+		.name = "vdso_purecap",
+		.vdso_code_start = vdso_purecap_start,
+		.vdso_code_end = vdso_purecap_end,
+	},
+#endif /* CONFIG_CHERI_PURECAP_UABI */
 };
 
 static user_uintptr_t make_vdso_ptr(struct vm_area_struct *vdso_text_vma)
@@ -340,6 +348,41 @@ int aarch32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 }
 #endif /* CONFIG_COMPAT32 */
 
+#ifdef CONFIG_CHERI_PURECAP_UABI
+enum purecap_map {
+	PURECAP_MAP_VDSO,
+};
+
+static struct vm_special_mapping purecap_vdso_maps[] __ro_after_init = {
+	[PURECAP_MAP_VDSO] = {
+		.name	= "[vdso]",
+		.mremap = vdso_mremap,
+	},
+};
+
+static int __init purecap_vdso_init(void)
+{
+	vdso_info[VDSO_ABI_PURECAP].cm = &purecap_vdso_maps[PURECAP_MAP_VDSO];
+
+	return __vdso_init(VDSO_ABI_PURECAP);
+}
+arch_initcall(purecap_vdso_init);
+
+int purecap_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+{
+	struct mm_struct *mm = current->mm;
+	int ret;
+
+	if (mmap_write_lock_killable(mm))
+		return -EINTR;
+
+	ret = __setup_additional_pages(VDSO_ABI_PURECAP, mm, bprm, uses_interp);
+	mmap_write_unlock(mm);
+
+	return ret;
+}
+#endif /* CONFIG_CHERI_PURECAP_UABI */
+
 static struct vm_special_mapping aarch64_vdso_map __ro_after_init = {
 	.name	= "[vdso]",
 	.mremap = vdso_mremap,
@@ -353,7 +396,7 @@ static int __init vdso_init(void)
 }
 arch_initcall(vdso_init);
 
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
+int aarch64_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 {
 	struct mm_struct *mm = current->mm;
 	int ret;

tools/testing/selftests/arm64/morello/bootstrap.c

@@ -85,6 +85,7 @@ int verify_auxval(struct morello_auxv *auxv)
 	case AT_PLATFORM:
 	case AT_RANDOM:
 	case AT_PHDR:
+	case AT_SYSINFO_EHDR:
 	case AT_CHERI_EXEC_RX_CAP:
 	case AT_CHERI_STACK_CAP:
 	case AT_CHERI_SEAL_CAP: