From: "Thomas Weißschuh" <linux@weissschuh.net>
To: Richard Weinberger <richard@nod.at>,
Anton Ivanov <anton.ivanov@cambridgegreys.com>,
Johannes Berg <johannes@sipsolutions.net>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Kees Cook <kees@kernel.org>
Cc: linux-um@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, "Thomas Weißschuh" <linux@weissschuh.net>
Subject: [PATCH 10/10] um: Always set up AT_HWCAP and AT_PLATFORM
Date: Tue, 28 Oct 2025 10:15:45 +0100 [thread overview]
Message-ID: <20251028-uml-remove-32bit-pseudo-vdso-v1-10-e930063eff5f@weissschuh.net> (raw)
In-Reply-To: <20251028-uml-remove-32bit-pseudo-vdso-v1-0-e930063eff5f@weissschuh.net>
Historically the code to set up AT_HWCAP and AT_PLATFORM was only built
for 32bit x86 as it was intermingled with the vDSO passthrough code.
Now that vDSO passthrough has been removed, always pass through AT_HWCAP
and AT_PLATFORM.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
arch/um/os-Linux/Makefile | 4 +---
arch/um/os-Linux/elf_aux.c | 7 ++++++-
arch/um/os-Linux/main.c | 4 ----
arch/x86/um/Kconfig | 3 ---
arch/x86/um/asm/elf.h | 7 ++++---
5 files changed, 11 insertions(+), 14 deletions(-)
diff --git a/arch/um/os-Linux/Makefile b/arch/um/os-Linux/Makefile
index 70c73c22f715..f8d672d570d9 100644
--- a/arch/um/os-Linux/Makefile
+++ b/arch/um/os-Linux/Makefile
@@ -6,7 +6,7 @@
# Don't instrument UML-specific code
KCOV_INSTRUMENT := n
-obj-y = execvp.o file.o helper.o irq.o main.o mem.o process.o \
+obj-y = elf_aux.o execvp.o file.o helper.o irq.o main.o mem.o process.o \
registers.o sigio.o signal.o start_up.o time.o tty.o \
umid.o user_syms.o util.o skas/
@@ -14,8 +14,6 @@ CFLAGS_signal.o += -Wframe-larger-than=4096
CFLAGS_main.o += -Wno-frame-larger-than
-obj-$(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA) += elf_aux.o
-
obj-$(CONFIG_SMP) += smp.o
USER_OBJS := $(user-objs-y) elf_aux.o execvp.o file.o helper.o irq.o \
diff --git a/arch/um/os-Linux/elf_aux.c b/arch/um/os-Linux/elf_aux.c
index f8927a5959d8..72f416edf252 100644
--- a/arch/um/os-Linux/elf_aux.c
+++ b/arch/um/os-Linux/elf_aux.c
@@ -14,12 +14,17 @@
#include <elf_user.h>
#include <mem_user.h>
#include "internal.h"
+#include <linux/swab.h>
+#if __BITS_PER_LONG == 64
+typedef Elf64_auxv_t elf_auxv_t;
+#else
typedef Elf32_auxv_t elf_auxv_t;
+#endif
/* These are initialized very early in boot and never changed */
char * elf_aux_platform;
-extern long elf_aux_hwcap;
+long elf_aux_hwcap;
__init void scan_elf_aux( char **envp)
{
diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c
index 730723106228..7e114862a723 100644
--- a/arch/um/os-Linux/main.c
+++ b/arch/um/os-Linux/main.c
@@ -21,8 +21,6 @@
#define STACKSIZE (8 * 1024 * 1024)
-long elf_aux_hwcap;
-
static void __init set_stklim(void)
{
struct rlimit lim;
@@ -149,9 +147,7 @@ int __init main(int argc, char **argv, char **envp)
install_fatal_handler(SIGINT);
install_fatal_handler(SIGTERM);
-#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
scan_elf_aux(envp);
-#endif
change_sig(SIGPIPE, 0);
ret = linux_main(argc, argv, envp);
diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig
index 798c6cc53e82..bdd7c8e39b01 100644
--- a/arch/x86/um/Kconfig
+++ b/arch/x86/um/Kconfig
@@ -34,8 +34,5 @@ config X86_64
config ARCH_HAS_SC_SIGNALS
def_bool !64BIT
-config ARCH_REUSE_HOST_VSYSCALL_AREA
- def_bool !64BIT
-
config GENERIC_HWEIGHT
def_bool y
diff --git a/arch/x86/um/asm/elf.h b/arch/x86/um/asm/elf.h
index fdd5a612f678..22d0111b543b 100644
--- a/arch/x86/um/asm/elf.h
+++ b/arch/x86/um/asm/elf.h
@@ -68,9 +68,7 @@
pr_reg[16] = PT_REGS_SS(regs); \
} while (0);
-extern char * elf_aux_platform;
#define ELF_PLATFORM_FALLBACK "i586"
-#define ELF_PLATFORM (elf_aux_platform ?: ELF_PLATFORM_FALLBACK)
#else
@@ -151,7 +149,7 @@ extern char * elf_aux_platform;
(pr_reg)[25] = 0; \
(pr_reg)[26] = 0;
-#define ELF_PLATFORM "x86_64"
+#define ELF_PLATFORM_FALLBACK "x86_64"
#define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
struct linux_binprm;
@@ -180,6 +178,9 @@ struct task_struct;
extern long elf_aux_hwcap;
#define ELF_HWCAP (elf_aux_hwcap)
+extern char *elf_aux_platform;
+#define ELF_PLATFORM (elf_aux_platform ?: ELF_PLATFORM_FALLBACK)
+
#define SET_PERSONALITY(ex) do {} while(0)
#endif
--
2.51.1.dirty
prev parent reply other threads:[~2025-10-28 9:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-28 9:15 [PATCH 00/10] um: remove vDSO passthrough on 32bit x86 Thomas Weißschuh
2025-10-28 9:15 ` [PATCH 01/10] um: Split out default elf_aux_platform Thomas Weißschuh
2025-10-28 9:15 ` [PATCH 02/10] x86/um: Move ELF_PLATFORM fallback to x86-specific code Thomas Weißschuh
2025-10-28 9:15 ` [PATCH 03/10] um: Split out default elf_aux_hwcap Thomas Weißschuh
2025-10-28 9:15 ` [PATCH 04/10] x86/um: Do not inherit vDSO from host Thomas Weißschuh
2025-10-28 9:15 ` [PATCH 05/10] x86/um: Drop gate area handling Thomas Weißschuh
2025-10-28 9:15 ` [PATCH 06/10] um: Remove fixaddr_user_init() Thomas Weißschuh
2025-10-28 9:15 ` [PATCH 07/10] um: Remove redundant range check from __access_ok_vsyscall() Thomas Weißschuh
2025-10-28 9:15 ` [PATCH 08/10] um: Remove __access_ok_vsyscall() Thomas Weißschuh
2025-10-28 9:15 ` [PATCH 09/10] x86/um: Remove FIXADDR_USER_START and FIXADDR_USE_END Thomas Weißschuh
2025-10-28 9:15 ` Thomas Weißschuh [this message]
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